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Sample records for rapid colorimetric quantification

  1. Rapid quantification of microalgal lipids in aqueous medium by a simple colorimetric method.

    PubMed

    Mishra, Sanjiv K; Suh, William I; Farooq, Wasif; Moon, Myounghoon; Shrivastav, Anupama; Park, Min S; Yang, Ji-Won

    2014-03-01

    Identification of novel microalgal strains with high lipid productivity is one of the most important research topics in renewable biofuel research. However, the major bottleneck in the strain screening process is that currently known methods for the estimation of microalgal lipid are laborious and time-consuming. The present study successfully employed sulpho-phospho-vanillin (SPV) colorimetric method for direct quantitative measurement of lipids within liquid microalgal culture. The SPV reacts with lipids to produce a distinct pink color, and its intensity can be quantified using spectrophotometric methods by measuring absorbance at 530nm. This method was employed for a rapid quantification of intracellular lipid contents within Chlorella sp., Monoraphidium sp., Ettlia sp. and Nannochloropsis sp., all of which were found to have lipid contents ranging in between 10% and 30%. Subsequent analysis of the biomass using gas chromatography confirmed that our protocol is highly accurate (R(2)=0.99). PMID:24463407

  2. A quick colorimetric method for total lipid quantification in microalgae.

    PubMed

    Byreddy, Avinesh R; Gupta, Adarsha; Barrow, Colin J; Puri, Munish

    2016-06-01

    Discovering microalgae with high lipid productivity are among the key milestones for achieving sustainable biodiesel production. Current methods of lipid quantification are time intensive and costly. A rapid colorimetric method based on sulfo-phospho-vanillin (SPV) reaction was developed for the quantification of microbial lipids to facilitate screening for lipid producing microalgae. This method was successfully tested on marine thraustochytrid strains and vegetable oils. The colorimetric method results correlated well with gravimetric method estimates. The new method was less time consuming than gravimetric analysis and is quantitative for lipid determination, even in the presence of carbohydrates, proteins and glycerol. PMID:27050419

  3. Rapid identification of bacteria with a disposable colorimetric sensing array.

    PubMed

    Carey, James R; Suslick, Kenneth S; Hulkower, Keren I; Imlay, James A; Imlay, Karin R C; Ingison, Crystal K; Ponder, Jennifer B; Sen, Avijit; Wittrig, Aaron E

    2011-05-18

    Rapid identification of both species and even specific strains of human pathogenic bacteria grown on standard agar has been achieved from the volatiles they produce using a disposable colorimetric sensor array in a Petri dish imaged with an inexpensive scanner. All 10 strains of bacteria tested, including Enterococcus faecalis and Staphylococcus aureus and their antibiotic-resistant forms, were identified with 98.8% accuracy within 10 h, a clinically important time frame. Furthermore, the colorimetric sensor arrays also proved useful as a simple research tool for the study of bacterial metabolism and as an easy method for the optimization of bacterial production of fine chemicals or other fermentation processes. PMID:21524080

  4. Rapid Quantification of Trimethylamine.

    PubMed

    Li, Zheng; Li, Hao; LaGasse, Maria K; Suslick, Kenneth S

    2016-06-01

    Sensitive detection of trimethylamine both in aqueous and gaseous phases has been accomplished using an inexpensive colorimetric sensor array. Distinctive color change patterns provide facile discrimination over a wide range of concentrations for trimethylamine with >99% accuracy of classification. Calculated limits of detection are well below the diagnostically significant concentration for trimethylaminuria (fish malodor syndrome). The sensor array shows good reversibility after multiple uses and is able to cleanly discriminate trimethylamine from similar amine odorants. Portable sensing of trimethylamine vapors at ppb concentrations is described using a cell phone camera or a hand-held optoelectronic nose. Application of the sensor array in detecting mouth and skin odor as a potential tool for portable diagnosis of trimethylaminuria is also illustrated. PMID:27220015

  5. Quantification of Wheat Grain Arabinoxylans Using a Phloroglucinol Colorimetric Assay

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Arabinoxylans (AX) play a critical role in end-use quality and nutrition of wheat (Triticum aestivum L.). An efficient, accurate method of AX quantification is desirable as AX plays an important role in processing, end use quality and human health. The objective of this work was to evaluate a stand...

  6. Colorimetric Quantification and in Situ Detection of Collagen

    ERIC Educational Resources Information Center

    Esteban, Francisco J.; del Moral, Maria L.; Sanchez-Lopez, Ana M.; Blanco, Santos; Jimenez, Ana; Hernandez, Raquel; Pedrosa, Juan A.; Peinado, Maria A.

    2005-01-01

    A simple multidisciplinary and inexpensive laboratory exercise is proposed, in which the undergraduate student may correlate biochemical and anatomical findings. The entire practical session can be completed in one 2.5-3 hour laboratory period, and consists of the quantification of collagen and total protein content from tissue sections--without…

  7. Direct Quantification of Carotenoids in Low Fat Baby Foods Via Laser Photoacoustics and Colorimetric Index *

    NASA Astrophysics Data System (ADS)

    Dóka, O.; Ajtony, Zs.; Bicanic, D.; Valinger, D.; Végvári, Gy.

    2014-12-01

    Carotenoids are important antioxidants found in various foods including those for nutrition of infants. In this investigation, the total carotenoid content (TCC) of nine different commercially available baby foods was quantified using colorimetric index * obtained via reflectance colorimetry (RC) and by laser photoacoustic spectroscopy (LPAS) at 473 nm. The latter requires a minimum of sample preparation and only a one time calibration step which enables practically direct quantification of TCC. Results were verified versus UV-Vis spectrophotometry (SP) as the reference technique. It was shown that RC and LPAS (at 473 nm) provide satisfactory results for *, = 0.9925 and = 0.9972, respectively. Other color indices do not show a correlation with TCC. When determining the TCC in baby foods containing tomatoes, it is necessary to select a different analytical wavelength to compensate for the effect of lycopene's presence in the test samples.

  8. Rapid colorimetric sensing of tetracycline antibiotics with in situ growth of gold nanoparticles.

    PubMed

    Shen, Li; Chen, Jing; Li, Na; He, Pingli; Li, Zhen

    2014-08-11

    A colorimetric assay utilizing the formation of gold nanoparticles was developed to detect tetracycline antibiotics in fluidic samples. Tetracycline antibiotics showed the capability of directly reducing aurate salts into atomic gold which form gold nanoparticles spontaneously under proper conditions. The resulted gold nanoparticles showed characteristic plasmon absorbance at 526 nm, which can be visualized by naked eyes or with a spectrophotometer. UV-vis absorbance of the resulted gold nanoparticles is correlated directly with the concentrations of tetracycline antibiotics in the solution, allowing for quantitative colorimetric detection of tetracycline antibiotics. Reaction conditions, such as pH, temperature, reaction time, and ionic strength were optimized. Sensitivity of the colorimetric assay can be enhanced by the addition of gold nanoparticle seeds, a LOD as low as 20 ng mL(-1) can be achieved with the help of seed particles. The colorimetric assay showed minimum interference from ethanol, methanol, urea, glucose, and other antibiotics such as sulfonamides, amino glycosides etc. Validity of the method was also evaluated on urine samples spiked with tetracycline antibiotics. The method provides a broad spectrum detection method for rapid and sensitive detection of reductive substances such as tetracycline antibiotics in liquid and biological samples. PMID:25066722

  9. A Rapid Colorimetric Sensor of Clenbuterol Based on Cysteamine-Modified Gold Nanoparticles.

    PubMed

    Kang, Jingyan; Zhang, Yujie; Li, Xing; Miao, Lijing; Wu, Aiguo

    2016-01-13

    Demonstrated was a simple visual and rapid colorimetric sensor for detection of clenbuterol (CLB) based on gold nanoparticles (AuNPs) modified with cysteamine (CA) and characterized by transmission electron microscopy (TEM), dynamic light scattering (DLS), UV-vis. The solution color from red to blue gray with increasing clenbuterol concentration resulted from the aggregation of AuNPs. The detection limit of clenbuterol is 50 nM by naked eyes. The selectivity of CA-AuNPs detection system for clenbuterol is excellent compared with other interferents in food. This sensor has been successfully applied to detect clenbuterol in real blood sample. PMID:26673452

  10. A Simple Paper-Based Colorimetric Device for Rapid Mercury(II) Assay.

    PubMed

    Chen, Weiwei; Fang, Xueen; Li, Hua; Cao, Hongmei; Kong, Jilie

    2016-01-01

    Contamination of the environment by mercury(II) ions (Hg(2+)) poses a serious threat to human health and ecosystems. Up to now, many reported Hg(2+) sensors require complex procedures, long measurement times and sophisticated instrumentation. We have developed a simple, rapid, low cost and naked-eye quantitative method for Hg(2+) environmental analysis using a paper-based colorimetric device (PCD). The sample solution to which platinum nanoparticles (PtNPs) have been added is dispensed to the detection zone on the PCD, where the 3,3,5,5-tetramethylbenzidine (TMB) substrate has been pre-loaded. The PtNPs effect a rapid oxidization of TMB, inducing blue colorization on the PCD. However, Hg(2+) in the solution rapidly interact with the PtNPs, suppressing the oxidation capacity and hence causing a decrease in blue intensity, which can be observed directly by the naked eye. Moreover, Hg(2+) at concentrations as low as 0.01 uM, can be successfully monitored using a fiber optic device, which gives a digital readout proportional to the intensity of the blue color change. This paper-based colorimetric device (PCD) shows great potential for field measurement of Hg(2+). PMID:27554633

  11. A Simple Paper-Based Colorimetric Device for Rapid Mercury(II) Assay

    PubMed Central

    Chen, Weiwei; Fang, Xueen; Li, Hua; Cao, Hongmei; Kong, Jilie

    2016-01-01

    Contamination of the environment by mercury(II) ions (Hg2+) poses a serious threat to human health and ecosystems. Up to now, many reported Hg2+ sensors require complex procedures, long measurement times and sophisticated instrumentation. We have developed a simple, rapid, low cost and naked-eye quantitative method for Hg2+ environmental analysis using a paper-based colorimetric device (PCD). The sample solution to which platinum nanoparticles (PtNPs) have been added is dispensed to the detection zone on the PCD, where the 3,3,5,5-tetramethylbenzidine (TMB) substrate has been pre-loaded. The PtNPs effect a rapid oxidization of TMB, inducing blue colorization on the PCD. However, Hg2+ in the solution rapidly interact with the PtNPs, suppressing the oxidation capacity and hence causing a decrease in blue intensity, which can be observed directly by the naked eye. Moreover, Hg2+ at concentrations as low as 0.01 uM, can be successfully monitored using a fiber optic device, which gives a digital readout proportional to the intensity of the blue color change. This paper-based colorimetric device (PCD) shows great potential for field measurement of Hg2+. PMID:27554633

  12. A Rapid In Situ Colorimetric Assay for Cobalt Detection by the Naked Eye.

    PubMed

    Kang, Sung-Min; Jang, Sung-Chan; Kim, Gi Yong; Lee, Chang-Soo; Huh, Yun Suk; Roh, Changhyun

    2016-01-01

    A simple, rapid, and convenient colorimetric chemosensor of a specific target toward the end user is still required for on-site detection and real-time monitoring applications. In this study, we developed a rapid in situ colorimetric assay for cobalt detection using the naked eye. Interestingly, a yellow to light orange visual color transition was observed within 3 s when a Chrysoidine G (CG) chemosensor was exposed to cobalt. Surprisingly, the CG chemosensor had great selectivity toward cobalt without any interference of other metal ions. Under optimized conditions, a lower detection limit of 0.1 ppm via a spectrophotometer and a visual detection limit of 2 ppm with a linear range from 0.4 to 1 ppm (R² = 0.97) were determined. Moreover, the CG chemosensor is reversible and maintains its functionality after treatment with chelating agents. In conclusion, we show the superior capabilities of the CG chemosensor, which has the potential to provide extremely facile handling, high sensitivity, and a fast response time for applications of on-site detection to real-time cobalt monitoring for the general public. PMID:27144568

  13. A Rapid In Situ Colorimetric Assay for Cobalt Detection by the Naked Eye

    PubMed Central

    Kang, Sung-Min; Jang, Sung-Chan; Kim, Gi Yong; Lee, Chang-Soo; Huh, Yun Suk; Roh, Changhyun

    2016-01-01

    A simple, rapid, and convenient colorimetric chemosensor of a specific target toward the end user is still required for on-site detection and real-time monitoring applications. In this study, we developed a rapid in situ colorimetric assay for cobalt detection using the naked eye. Interestingly, a yellow to light orange visual color transition was observed within 3 s when a Chrysoidine G (CG) chemosensor was exposed to cobalt. Surprisingly, the CG chemosensor had great selectivity toward cobalt without any interference of other metal ions. Under optimized conditions, a lower detection limit of 0.1 ppm via a spectrophotometer and a visual detection limit of 2 ppm with a linear range from 0.4 to 1 ppm (R2 = 0.97) were determined. Moreover, the CG chemosensor is reversible and maintains its functionality after treatment with chelating agents. In conclusion, we show the superior capabilities of the CG chemosensor, which has the potential to provide extremely facile handling, high sensitivity, and a fast response time for applications of on-site detection to real-time cobalt monitoring for the general public. PMID:27144568

  14. Colorimetric Quantification of Glucose and Cholesterol in Human Blood Using a Nanocomposite Entrapping Magnetic Nanoparticles and Oxidases.

    PubMed

    Kim, Moon Il; Cho, Daeyeon; Park, Hyun Gyu

    2015-10-01

    In this study, a microscale well-plate colorimetric assay for the multiplexed detection of glucose and cholesterol in clinical human blood samples has been developed. This system utilized one-pot nanocomposite entrapping Fe3O4 magnetic nanoparticles (MNPs) as peroxidase mimetics and glucose oxidase (GOx)/cholesterol oxidase (ChOx) in mesoporous silica to detect glucose and cholesterol in blood samples. The sensing mechanism involves the generation of H2O2 by the catalytic action of an immobilized oxidase on the target molecules in the sample. This subsequently activates the MNPs in the mesopores, thereby leading to the conversion of the substrate into a colored end product. This strategy is used to detect the target glucose or cholesterol molecules in the concentration range of 15-250 mg/dL. The response is highly linear and the lower detection limit is 7.5 mg/dL. The aforementioned colorimetric assay is extremely convenient, and it exhibits a high degree of linearity, precision, and reproducibility when employing real human blood samples. Therefore, this assay can be used in clinical practice for the multiplexed and reliable quantification of glucose and cholesterol. PMID:26726446

  15. Comparison of colorimetric methods for the quantification of model proteins in aqueous two-phase systems.

    PubMed

    Glyk, Anna; Heinisch, Sandra L; Scheper, Thomas; Beutel, Sascha

    2015-05-15

    In the current study, the quantification of different model proteins in the presence of typical aqueous two-phase system components was investigated by using the Bradford and bicinchoninic acid (BCA) assays. Each phase-forming component above 1 and 5 wt% had considerable effects on the protein quantification in both assays, respectively, resulting in diminished protein recoveries/absorption values by increasing poly(ethylene glycol) (PEG)/salt concentration and PEG molecular weight. Therefore, a convenient dilution of both components (up to 1 and 5 wt%) before protein quantification is recommended in both assays, respectively, where the BCA assay is favored in comparison with the Bradford assay. PMID:25684109

  16. Gold nanoparticle-based colorimetric aptasensor for rapid detection of six organophosphorous pesticides.

    PubMed

    Bai, Wenhui; Zhu, Chao; Liu, Jinchuan; Yan, Mengmeng; Yang, Shuming; Chen, Ailiang

    2015-10-01

    Fast immunoassay-based screening methods are unavailable for most small-molecule pesticides because of a lack of immunogenicity and the difficulty in obtaining antibodies by animal immunization. Aptamers are single-stranded DNA molecules selected through an in vitro process, which can bind to any target including nonimmunogenic small molecules with high affinity and specificity. Although various aptamer-based sensing methods have been developed for antibiotics, microorganisms, heavy metal ions, and biotoxins, there are few reports on aptamer-based methods for quick detection of organophosphorous pesticides. The gold (Au) nanoparticle (AuNP) colorimetric assay is a widely utilized rapid detection method because of properties such as easy operation and visualized results. In the present study, organophosphorous pesticide aptamers were adsorbed on the surface of AuNPs to stabilize the AuNP solution against high concentrations of salt to prevent AuNP aggregation. After the addition of targets, the aptamers binding to the targets are detached from the AuNPs, resulting in aggregation of AuNPs and a color change from red to purple-blue. The proposed method can detect 6 organophosphorous pesticides with good recoveries from 72% to 135% in environmental river water samples. The present study provides a new way for simple, rapid, and multiplex detection of organophosphorous pesticides. PMID:26031388

  17. Ultrasensitive electrospun fluorescent nanofibrous membrane for rapid visual colorimetric detection of H2O2.

    PubMed

    Senthamizhan, Anitha; Balusamy, Brabu; Aytac, Zeynep; Uyar, Tamer

    2016-02-01

    We report herein a flexible fluorescent nanofibrous membrane (FNFM) prepared by decorating the gold nanocluster (AuNC) on electrospun polysulfone nanofibrous membrane for rapid visual colorimetric detection of H2O2. The provision of AuNC coupled to NFM has proven to be advantageous for facile and quick visualization of the obtained results, permitting instant, selective, and on-site detection. We strongly suggest that the fast response time is ascribed to the enhanced probabilities of interaction with AuNC located at the surface of NF. It has been observed that the color change from red to blue is dependent on the concentration, which is exclusively selective for hydrogen peroxide. The detection limit has been found to be 500 nM using confocal laser scanning microscope (CLSM), visually recognizable with good accuracy and stability. A systematic comparison was performed between the sensing performance of FNFM and AuNC solution. The underlying sensing mechanism is demonstrated using UV spectra, transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). The corresponding disappearance of the characteristic emissions of gold nanoclusters and the emergence of a localized surface plasmon resonance (LSPR) band, stressing this unique characteristic of gold nanoparticles. Hence, it is evident that the conversion of nanoparticles from nanoclusters has taken place in the presence of H2O2. Our work here has paved a new path for the detection of bioanalytes, highlighting the merits of rapid readout, sensitivity, and user-friendliness. PMID:26637215

  18. Field-deployable colorimetric biosensor system for the rapid detection of pathogenic organisms

    NASA Astrophysics Data System (ADS)

    Duy, Janice

    The rapid identification of pathogenic organisms is necessary for recognizing and managing human and environmental health risks. Numerous detection schemes are available, but most are difficult to employ in non-laboratory settings due to their need for bulky, specialized equipment, multiple reagents, or highly trained personnel. To address this problem, a rapid, field-compatible biosensor system based on the colorimetric detection of nucleic acid hybrids was developed. Peptide nucleic acid (PNA) probes were used to capture ribosomal RNA sequences from environmental samples. Non-target nucleic acids, including single-base mismatches flanked by adenines and uracils, were removed with a micrococcal nuclease digestion step. Matched PNA-RNA hybrids remained intact and were indicated by the cyanine dye DiSC2(5). PNA-containing duplexes function as templates for the aggregation of DiSC2(5), visualized as a change in solution color from blue to purple. This transition can be measured as an increase in the solution absorbance at 540 nm (dye aggregate) at the expense of the dye monomer peak at 650 nm. These concomitant spectral changes were used to calculate a "hybridization signal" using the ratio A aggregate/Amonomer ≈ A540/A650. Testing with pathogenic environmental samples was accomplished using two model organisms: the harmful algal bloom-causing dinoflagellate Alexandrium species, and the potato wart disease-causing fungus Synchytrium endobioticum. In both cases, the colorimetric approach was able to distinguish the targets with sensitivities rivaling those of established techniques, but with the advantages of decreased hands-on time and cost. Assay fieldability was tested with a portable colorimeter designed to quantify the dye-indicated hybridization signal and assembled from commercially available components. Side-by-side testing revealed no difference in the sensing performance of the colorimeter compared to a laboratory spectrophotometer (Pearson's r=0

  19. A colorimetric and ratiometric fluorescent probe for quantification of bovine serum albumin.

    PubMed

    Zeng, Xiaodan; Zhang, Xiaoling; Zhu, Baocun; Jia, Hongying; Li, Yamin; Xue, Juan

    2011-10-01

    A 4-aminonaphthalimide-based ratiometric fluorescent probe 1 employing the internal charge transfer (ICT) mechanism was designed and synthesized to detect bovine serum albumin (BSA). The interaction of 1 and BSA was investigated by fluorescence and UV-vis absorption spectroscopy. Upon treatment with BSA, the probe successfully exhibited a ratiometric fluorescent response at 540 nm and 480 nm. The fluorescent intensity ratio at 540 nm and 480 nm (F(540)/F(480)) increases linearly with BSA concentration in the range of 0-75.0 μg mL(-1) and the detection limit was about 2.4 ng mL(-1). Our strategy is expected to provide a methodology to quantify BSA either by a normal or by a ratiometric and colorimetric way with high sensitivity. PMID:21858298

  20. Screening the toxicity and biodegradability of petroleum hydrocarbons by a rapid colorimetric method.

    PubMed

    Montagnolli, Renato Nallin; Lopes, Paulo Renato Matos; Bidoia, Ederio Dino

    2015-02-01

    Crude oil and petroleum products have a wide variety of hazardous components with high toxicity and low biodegradability. Certain dyes change their colors by intercepting electron transfer reactions during the transformation processes. This study applied resazurin and 2,6-dichlorophenol-indophenol indicators for a rapid screening biodegradation capability and toxicity response to various petroleum products such as motor oil, diesel, gasoline, and phenol. Colorimetry tests were performed in test tubes, and the absorbance values were measured over time. We observed different discoloration profiles after degradation tests using Bacillus subtilis inoculum. Phytotoxicity assays were also performed to compare colorimetric screening assays with a conventional toxicity testing with plants (seed germination). The results indicated that biotransformation of oils can increase its overall toxicity. Intermediate byproducts can be formed through biodegradation and thereby increase the toxicity of oils. The assessment of acute toxicity has shown that phenol is extremely toxic to petroleum-biodegrading microbial communities. Low molecular-weight gasoline was considered biodegradable, but it also exhibited a high acute toxic effect, mainly due to its high solubility and the presence of more volatile compounds that can penetrate cells and potentially damage cellular structures. PMID:25537922

  1. Simple colorimetric method for quantification of surface carboxy groups on polymer particles.

    PubMed

    Hennig, Andreas; Hoffmann, Angelika; Borcherding, Heike; Thiele, Thomas; Schedler, Uwe; Resch-Genger, Ute

    2011-06-15

    We present a novel, simple, and fast colorimetric method to quantify the total number of carboxy groups on polymer microparticle and nanoparticle surfaces. This method exploits that small divalent transition metal cations (M(2+) = Ni(2+), Co(2+), Cd(2+)) are efficiently bound to these surface functional groups, which allows their extraction by a single centrifugation step. Remaining M(2+) in the supernatant is subsequently quantified spectrophotometrically after addition of the metal ion indicator pyrocatechol violet, for which Ni(2+) was identified to be the most suitable transition metal cation. We demonstrate that the difference between added and detected M(2+) is nicely correlated to the number of surface carboxy groups as determined by conductometry, thereby affording a validated measure for the trueness of this procedure. The variation coefficient of ~5% found in reproducibility studies underlines the potential of this novel method that can find conceivable applications for the characterization of different types of poly(carboxylic acid)-functionalized materials, e.g., for quality control by manufacturers of such materials. PMID:21561064

  2. Antimicrobial susceptibility of rapidly growing mycobacteria using the rapid colorimetric method.

    PubMed

    Ramis, I B; Cnockaert, M; von Groll, A; Nogueira, C L; Leão, S C; Andre, E; Simon, A; Palomino, J C; da Silva, P E A; Vandamme, P; Martin, A

    2015-07-01

    Drug susceptibility testing (DST) of rapidly growing mycobacteria (RGM) are recommended for guiding the antimicrobial therapy. We have evaluated the use of resazurin in Mueller-Hinton medium (MHR) for MIC determination of RGM and compared the results with those obtained with the reference standard broth microdilution in Mueller-Hinton (MH) and with the resazurin microtiter assay (REMA) in 7H9 broth. The MIC of eight drugs: amikacin (AMI), cefoxitin (FOX), ciprofloxacin (CIP), clarithromycin (CLA), doxycycline (DOX), linezolid (LZD), moxifloxacin (MXF) and trimethoprim-sulfamethoxazole (TMP-SMX) were evaluated against 76 RGM (18 species) using three methods (MH, MHR, and REMA) in a 96-well plate format incubated at 37 °C over 3-5 days. Results obtained in the MH plates were interpreted by the appearance of turbidity at the bottom of the well before adding the resazurin. MHR and 7H9-REMA plates were read by visual observation for a change in color from blue to pink. The majority of results were obtained at day 5 for MH and 1 day after for MHR and 7H9-REMA. However, the preliminary experiment on time to positivity results using the reference strain showed that the resazurin can be added to the MH at day 2 to produce the results at day 3, but future studies with large sets of strains are required to confirm this suggestion. A high level of agreement (kappa 1.000-0.884) was obtained between the MH and the MHR. Comparison of results obtained with 7H9-REMA, on the other hand, revealed several discrepancies and a lower level of agreement (kappa 1.000-0.111). The majority of the strains were resistant to DOX and TMP-SMX, and the most active antimicrobials for RGM were AMI and FOX. In the present study, MHR represented an excellent alternative for MIC determination of RGM. The results could be read reliably, more easily, and more quickly than with the classical MH method. PMID:25820290

  3. Rapid digital quantification of microfracture populations

    NASA Astrophysics Data System (ADS)

    Gomez, Leonel A.; Laubach, Stephen E.

    2006-03-01

    Populations of microfractures are a structural fabric in many rocks deformed at upper crustal conditions. In some cases these fractures are visible in transmitted-light microscopy as fluid-inclusion planes or cement filled microfractures, but because SEM-based cathodoluminescence (CL) reveals more fractures and delineates their shapes, sizes, and crosscutting relations, it is a more effective structural tool. Yet at magnifications of 150-300×, at which many microfractures are visible, SEM-CL detectors image only small sample areas (0.5-0.1 mm 2) relative to fracture population patterns. The substantial effort required to image and measure centimeter-size areas at high-magnification has impeded quantitative study of microfractures. We present a method for efficient collection of mosaics of high-resolution CL imagery, a preparation method that allows samples to be any size while retaining continuous imagery of rock (no gaps), and software that facilitates fracture mapping and data reduction. Although the method introduced here was developed for CL imagery, it can be used with any other kind of images, including mosaics from petrographic microscopes. Compared with manual measurements, the new method increases several fold the number of microfractures imaged without a proportional increase in level of effort, increases the accuracy and repeatability of fracture measurements, and speeds quantification and display of fracture population attributes. We illustrate the method on microfracture arrays in dolostone from NE Mexico and sandstone from NW Scotland. We show that key aspects of microfracture population attributes are only fully manifest at scales larger than a single thin section.

  4. Straightforward rapid spectrophotometric quantification of total cyanogenic glycosides in fresh and processed cassava products.

    PubMed

    Tivana, Lucas Daniel; Da Cruz Francisco, Jose; Zelder, Felix; Bergenståhl, Bjorn; Dejmek, Petr

    2014-09-01

    In this study, we extend pioneering studies and demonstrate straightforward applicability of the corrin-based chemosensor, aquacyanocobyrinic acid (ACCA), for the instantaneous detection and rapid quantification of endogenous cyanide in fresh and processed cassava roots. Hydrolytically liberated endogenous cyanide from cyanogenic glycosides (CNp) reacts with ACCA to form dicyanocobyrinic acid (DCCA), accompanied by a change of colour from orange to violet. The method was successfully tested on various cassava samples containing between 6 and 200 mg equiv. HCN/kg as verified with isonicotinate/1,3-dimethylbarbiturate as an independent method. The affinity of ACCA sensor to cyanide is high, coordination occurs fast and the colorimetric response can therefore be instantaneously monitored with spectrophotometric methods. Direct applications of the sensor without need of extensive and laborious extraction processes are demonstrated in water-extracted samples, in acid-extracted samples, and directly on juice drops. ACCA showed high precision with a standard deviation (STDV) between 0.03 and 0.06 and high accuracy (93-96%). Overall, the ACCA procedure is straightforward, safe and easily performed. In a proof-of-concept study, rapid screening of ten samples within 20 min has been tested. PMID:24731309

  5. A smartphone-based colorimetric reader coupled with a remote server for rapid on-site catechols analysis.

    PubMed

    Wang, Yun; Li, Yuanyuan; Bao, Xu; Han, Juan; Xia, Jinchen; Tian, Xiaoyu; Ni, Liang

    2016-11-01

    The search of a practical method to analyze cis-diol-containing compounds outside laboratory settings remains a substantial scientific challenge. Herein, a smartphone-based colorimetric reader was coupled with a remote server for rapid on-site analysis of catechols. A smallest-scale 2×2 colorimetric sensor array composed of pH indicators and phenylboronic acid was configured. The array was able to distinguish 13 catechols at 6 serial concentrations, through simultaneous treatment via principal component analysis, hierarchical cluster analysis, and linear discriminant analysis. After both the discriminatory power of the array and the prediction ability of the partial least squares quantitative models were proved to be predominant, the smartphone was coupled to the remote server. All the ΔRGB data were uploaded to the remote server wherein linear discriminant analysis and partial least squares processing modules were established to provide qualitative discrimination and quantitative calculation, respectively, of the analytes in real time. The applicability of this novel method to a real-life scenario was confirmed by the on-site analysis of various catechols from a water sample of the Yangtze River; the feedback result in the smartphone showed the method was able to identify the catechols with 100% accuracy and predict the concentrations to within 0.706-2.240 standard deviation. PMID:27591604

  6. The Rapid and Sensitive Quantitative Determination of Galactose by Combined Enzymatic and Colorimetric Method: Application in Neonatal Screening.

    PubMed

    Kianmehr, Anvarsadat; Mahrooz, Abdolkarim; Ansari, Javad; Oladnabi, Morteza; Shahbazmohammadi, Hamid

    2016-05-01

    The quantitative measurement of galactose in blood is essential for the early diagnosis, treatment, and dietary monitoring of galactosemia patients. In this communication, we aimed to develop a rapid, sensitive, and cost-effective combined method for galactose determination in dry blood spots. This procedure was based on the combination of enzymatic reactions of galactose dehydrogenase (GalDH), dihydrolipoyl dehydrogenase (DLD), and alkaline phosphates with a colorimetric system. The incubation time and the concentration of enzymes used in new method were also optimized. The analytical performance was studied by the precision, recovery, linearity, and sensitivity parameters. Statistical analysis was applied to method comparison experiment. The regression equation and correlation coefficient (R (2)) were Y = 0.0085x + 0.032 and R (2) = 0.998, respectively. This assay exhibited a recovery in the range of 91.7-114.3 % and had the limit detection of 0.5 mg/dl for galactose. The between-run coefficient of variation (CV) was between 2.6 and 11.1 %. The within-run CV was between 4.9 and 9.2 %. Our results indicated that the new and reference methods were in agreement because no significant biases exist between them. Briefly, a quick and reliable combined enzymatic and colorimetric assay was presented for application in newborn mass screening and monitoring of galactosemia patients. PMID:26821257

  7. Centrifugal loop-mediated isothermal amplification microdevice for rapid, multiplex and colorimetric foodborne pathogen detection.

    PubMed

    Oh, Seung Jun; Park, Byung Hyun; Jung, Jae Hwan; Choi, Goro; Lee, Doh C; Kim, Do Hyun; Seo, Tae Seok

    2016-01-15

    We present a centrifugal microfluidic device which enables multiplex foodborne pathogen identification by loop-mediated isothermal amplification (LAMP) and colorimetric detection using Eriochrome Black T (EBT). Five identical structures were designed in the centrifugal microfluidic system to perform the genetic analysis of 25 pathogen samples in a high-throughput manner. The sequential loading and aliquoting of the LAMP cocktail, the primer mixtures, and the DNA sample solutions were accomplished by the optimized zigzag-shaped microchannels and RPM control. We targeted three kinds of pathogenic bacteria (Escherichia coli O157:H7, Salmonella typhimurium and Vibrio parahaemolyticus) and detected the amplicons of the LAMP reaction by the EBT-mediated colorimetric method. For the limit-of-detection (LOD) test, we carried out the LAMP reaction on a chip with serially diluted DNA templates of E. coli O157:H7, and could observe the color change with 380 copies. The used primer sets in the LAMP reaction were specific only to the genomic DNA of E. coli O157:H7, enabling the on-chip selective, sensitive, and high-throughput pathogen identification with the naked eyes. The entire process was completed in 60min. Since the proposed microsystem does not require any bulky and expensive instrumentation for end-point detection, our microdevice would be adequate for point-of-care (POC) testing with high simplicity and high speed, providing an advanced genetic analysis microsystem for foodborne pathogen detection. PMID:26322592

  8. Rapid fluorometric quantification of bacterial cells using Redsafe nucleic acid stain

    PubMed Central

    Khalili, Ehsan; Hosseini, Vahid; Solhi, Roya; Aminian, Mahdi

    2015-01-01

    Background and Objectives: Numerous procedures in biology and medicine require the counting of cells. Direct enumeration of Colony Forming Units (CFUs) is time-consuming and dreary accurate cell counting on plates with high numbers of CFUs is error prone. In this study we report a new indirect cell counting method that was developed based on the use of Redsafe fluorometric assay. The usefulness of Redsafe, a nucleic acid stain, in liquid medium is based on the binding of the fluorescent dye to DNA. Materials and Methods: Redsafe fluorometric assay was evaluated in comparison with MTT colorimetric assay as a colourimetric assay for enumeration of bacterial cells. Results: Obtained results showed that fluorometric assay threshold for LB grown E. coli is 6×104 CFU/ml. Redsafe fluorescent assay can be used as a rapid and inexpensive method for bacterial enumeration and quantification with increased sensitivity. Conclusion: The sensitivity of the Redsafe fluorometric assay for detection and enumeration of bacterial cells was 2-log-unit more than that was observed for the MTT assay. PMID:26885332

  9. O-antigen and virulence profiling of Shiga toxin-producing Escherichia coli by a rapid and cost-effective DNA microarray colorimetric method

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Shiga toxin-producing Escherichia coli (STEC) is a leading cause of foodborne illness worldwide. To evaluate better methods to rapidly detect and genotype Shiga toxin-producing Escherichia coli strains, the present study evaluated the use of the ampliPHOX colorimetric detection technology, based on ...

  10. Rapid quantification method for Legionella pneumophila in surface water.

    PubMed

    Wunderlich, Anika; Torggler, Carmen; Elsässer, Dennis; Lück, Christian; Niessner, Reinhard; Seidel, Michael

    2016-03-01

    World-wide legionellosis outbreaks caused by evaporative cooling systems have shown that there is a need for rapid screening methods for Legionella pneumophila in water. Antibody-based methods for the quantification of L. pneumophila are rapid, non-laborious, and relatively cheap but not sensitive enough for establishment as a screening method for surface and drinking water. Therefore, preconcentration methods have to be applied in advance to reach the needed sensitivity. In a basic test, monolithic adsorption filtration (MAF) was used as primary preconcentration method that adsorbs L. pneumophila with high efficiency. Ten-liter water samples were concentrated in 10 min and further reduced to 1 mL by centrifugal ultrafiltration (CeUF). The quantification of L. pneumophila strains belonging to the monoclonal subtype Bellingham was performed via flow-based chemiluminescence sandwich microarray immunoassays (CL-SMIA) in 36 min. The whole analysis process takes 90 min. A polyclonal antibody (pAb) against L. pneumophila serogroup 1-12 and a monoclonal antibody (mAb) against L. pneumophila SG 1 strain Bellingham were immobilized on a microarray chip. Without preconcentration, the detection limit was 4.0 × 10(3) and 2.8 × 10(3) CFU/mL determined by pAb and mAb 10/6, respectively. For samples processed by MAF-CeUF prior to SMIA detection, the limit of detection (LOD) could be decreased to 8.7 CFU/mL and 0.39 CFU/mL, respectively. A recovery of 99.8 ± 15.9% was achieved for concentrations between 1-1000 CFU/mL. The established combined analytical method is sensitive for rapid screening of surface and drinking water to allow fast hygiene control of L. pneumophila. PMID:26873217

  11. Colorimetric method for rapid detection of Oxacillin resistance in Staphylococcus aureus and its comparison with PCR for mec A gene

    PubMed Central

    Ghanwate, Niraj; Thakare, Prashant; Bhise, P. R.; Gawande, Sonali

    2016-01-01

    Rapid and accurate detection of Methicillin Resistant Staphylococcus aureus (MRSA) is an important role of clinical microbiology laboratories to avoid treatment failure. The detection of MRSA is based on phenotypic assays which require at least 24 h to perform. Detection of the mecA gene or of PBP 2a is the “gold standard”, but not always available. The aim of this study was to evaluate a rapid method for detection of MRSA by using 3 (4, 5 dimethyl thiazole -2-yl) -2, 5 diphenyl tetrazolium bromide (MTT). Total 126 isolates of MRSA were collected from tertiary healthcare center and were confirmed by oxacillin screening agar test as per CLSI guidelines. Amplification of mecA gene was performed by using PCR. MTT assay was carried out for all the isolates in 96 well Microtitre plate and compared with standard methods of CLSI. Out of 126 isolates, 98 were found to be mecA positive. MTT method was found to be 98.98% sensitive and 96.43% specific. The MTT based colorimetric method is rapid and simple test for screening of oxacillin resistance in Staphylococcus aureus. It significantly shortens the time to just 7 h required to obtained a drug susceptibility test and could be useful to screen MRSA. PMID:26960268

  12. Colorimetric method for rapid detection of Oxacillin resistance in Staphylococcus aureus and its comparison with PCR for mec A gene.

    PubMed

    Ghanwate, Niraj; Thakare, Prashant; Bhise, P R; Gawande, Sonali

    2016-01-01

    Rapid and accurate detection of Methicillin Resistant Staphylococcus aureus (MRSA) is an important role of clinical microbiology laboratories to avoid treatment failure. The detection of MRSA is based on phenotypic assays which require at least 24 h to perform. Detection of the mecA gene or of PBP 2a is the "gold standard", but not always available. The aim of this study was to evaluate a rapid method for detection of MRSA by using 3 (4, 5 dimethyl thiazole -2-yl) -2, 5 diphenyl tetrazolium bromide (MTT). Total 126 isolates of MRSA were collected from tertiary healthcare center and were confirmed by oxacillin screening agar test as per CLSI guidelines. Amplification of mecA gene was performed by using PCR. MTT assay was carried out for all the isolates in 96 well Microtitre plate and compared with standard methods of CLSI. Out of 126 isolates, 98 were found to be mecA positive. MTT method was found to be 98.98% sensitive and 96.43% specific. The MTT based colorimetric method is rapid and simple test for screening of oxacillin resistance in Staphylococcus aureus. It significantly shortens the time to just 7 h required to obtained a drug susceptibility test and could be useful to screen MRSA. PMID:26960268

  13. Genetically engineered colorimetric single-chain antibody fusion protein for rapid diagnosis of rabies virus.

    PubMed

    Mousli, M; Turki, I; Kharmachi, H; Dellagi, K

    2008-01-01

    The most widely used test for rabies diagnostics is the fluorescent antibody test, which is recommended by both the World Health Organization and the World Organisation for Animal Health (OIE). This test may be used directly on a smear, and can also be used to confirm the presence of rabies antigen in cell culture or in brain tissue for diagnosis. The colorimetric enzymes are usually coupled to an antibody by chemical means using cross-linking reagents. However, such non-specific procedures lead to heterogeneous conjugates, sometimes with reduced activity and specificity. To bypass these problems, genetic engineering has provided a way to create chimeric bifunctional molecules in which the variable domains of an antibody are genetically linked to unrelated protein tracers. In this study, we describe the successful production of a bifunctional chimeric protein based on alkaline phosphatase-fused anti-rabies virus glycoprotein scFv antibody fragment. We also report the antigen binding properties and the alkaline phosphatase activity of the recombinant conjugate protein. We established its value as a novel in vitro tool for detecting the rabies virus in brain smear in a one-step procedure; it presents a similar sensitivity and specificity to that obtained using standard reagents. PMID:18634511

  14. Rapid enumeration of Fecal Coliforms in water by a colorimetric beta-galactosidase assay.

    PubMed Central

    Warren, L S; Benoit, R E; Jessee, J A

    1978-01-01

    The colorimetric beta-galactosidase assay is based upon the enzymatic hydrolysis of the substrate o-nitrophenyl-beta-D-galactoside (ONPG) by fecal coliforms. This technique provides an estimate of the fecal coliform concentration within 8 to 20 h. A 100-ml portion of test sample was passed through a 0.45 micrometer membrane filter. This filter was then incubated at 37 degrees C for 1 h in EC medium followed by the addition of filter-sterilized ONPG. The incubation was continued at 44.5 degrees C until a half-maximum absorbance (at 420 nm) was reached. The time between the start of incubation and the half-maximum absorbance was proportional to the concentration of fecal coliforms present. Escherichia coli (K-12) was used to measure the kinetics of substrate hydrolysis and the response time of different cell concentrations. High cell densities produced an immediate response, whereas 1 cell/ml will produce a response in less than 20 h. In field studies in which samples were taken from a range of grossly polluted streams to relatively clean lake water, a linear correlation between ONPG hydrolysis times and fecal coliform most-probable-number values was established. A total of 302 isolates randomly selected from positive ONPG-EC media, which were derived from 11 different habitats, were identified as E. coli (96.69 percent), Enterobacter cloacae (2.32 percent), Klebsiella pneumoniae (0.66 percent), and Citrobacter freundii (0.33 percent). PMID:414659

  15. Rapid quantitative analysis of lipids using a colorimetric method in a microplate format.

    PubMed

    Cheng, Yu-Shen; Zheng, Yi; VanderGheynst, Jean S

    2011-01-01

    A colorimetric sulfo-phospho-vanillin (SPV) method was developed for high throughput analysis of total lipids. The developed method uses a reaction mixture that is maintained in a 96-well microplate throughout the entire assay. The new assay provides the following advantages over other methods of lipid measurement: (1) background absorbance can be easily corrected for each well, (2) there is less risk of handling and transferring sulfuric acid contained in reaction mixtures, (3) color develops more consistently providing more accurate measurement of absorbance, and (4) the assay can be used for quantitative measurement of lipids extracted from a wide variety of sources. Unlike other spectrophotometric approaches that use fluorescent dyes, the optimal spectra and reaction conditions for the developed assay do not vary with the sample source. The developed method was used to measure lipids in extracts from four strains of microalgae. No significant difference was found in lipid determination when lipid content was measured using the new method and compared to results obtained using a macro-gravimetric method. PMID:21069472

  16. Integration of Novel Low-Cost Colorimetric, Laser Photometric, and Visual Fluorescent Techniques for Rapid Identification of Falsified Medicines in Resource-Poor Areas: Application to Artemether–Lumefantrine

    PubMed Central

    Green, Michael D.; Hostetler, Dana M.; Nettey, Henry; Swamidoss, Isabel; Ranieri, Nicola; Newton, Paul N.

    2015-01-01

    The availability of falsified antimalarial drugs can be reduced with effective drug regulatory agencies and proper enforcement. Fundamental to these agencies taking action, rapid identification must be made as soon as they appear in the market place. Since falsified antimalarials occur mostly in developing countries, performing drug analysis presents itself with unique challenges. A fundamental factor in choosing a useful technique is affordability and simplicity. Therefore, we suggest a three-tiered drug evaluation strategy for identifying a falsified drug in resource-poor areas. Tier I is a simple comparison of a tablet's weight and dimensions with official specifications. Tier II uses inexpensive photometric devices (laser and fluorescence) to evaluate a tablet. Suspicious samples from Tier I and II assessments are then subjected to a colorimetric assay for active ingredients identification and quantification. In this article, we evaluate a novel colorimetric assay for the simultaneous assessment of both lumefantrine and artemether in co-formulated Coartem™ tablets, and integrate the method with two novel, low-cost, fluorescence and laser photometric devices. Image analysis software is used for the assessments. Although artemether–lumefantrine is used as an example, the strategy may be adapted to other medicines. PMID:25897066

  17. Rapid susceptibility testing for slowly growing nontuberculous mycobacteria using a colorimetric microbial viability assay based on the reduction of water-soluble tetrazolium WST-1.

    PubMed

    Tsukatani, T; Suenaga, H; Shiga, M; Ikegami, T; Ishiyama, M; Ezoe, T; Matsumoto, K

    2015-10-01

    Rapid susceptibility testing for slowly growing nontuberculous mycobacteria (NTM) using a colorimetric microbial viability assay based on the reduction of the water-soluble tetrazolium salt {2-(4-iodophenyl)-3-(4-nitrophenyl)-5-(2,4-disulfophenyl)-2H-tetrazolium, monosodium salt (WST-1)} using 2,3,5,6-tetramethyl-1,4-benzoquinone as an electron mediator was developed. Using the Clinical and Laboratory Standards Institute (CLSI) method, a long-term incubation time (7-14 days) was required to determine the minimum inhibitory concentrations (MICs) of the slowly growing NTM. The MICs for a variety of different antibiotics against the slowly growing NTM were determined by the WST-1 colorimetric method and compared with those obtained using the broth microdilution methods approved by the CLSI. Good agreement was found between the MICs determined after 3-4 days using the WST-1 colorimetric method and those obtained after 10-14 days using the broth microdilution method. The results suggest that the WST-1 colorimetric assay is a useful method for the rapid determination of the MICs for the slowly growing NTM. PMID:26173690

  18. Rapid method for the quantification of hydroquinone concentration: chemiluminescent analysis.

    PubMed

    Chen, Tung-Sheng; Liou, Show-Yih; Kuo, Wei-Wen; Wu, Hsi-Chin; Jong, Gwo-Ping; Wang, Hsueh-Fang; Shen, Chia-Yao; Padma, V Vijaya; Huang, Chih-Yang; Chang, Yen-Lin

    2015-11-01

    Topical hydroquinone serves as a skin whitener and is usually available in cosmetics or on prescription based on the hydroquinone concentration. Quantification of hydroquinone content therefore becomes an important issue in topical agents. High-performance liquid chromatography (HPLC) is the commonest method for determining hydroquinone content in topical agents, but this method is time-consuming and uses many solvents that can become an environmental issue. We report a rapid method for quantifying hydroquinone content by chemiluminescent analysis. Hydroquinone induces the production of hydrogen peroxide in the presence of basic compounds. Hydrogen peroxide induced by hydroquinone oxidized light-emitting materials such as lucigenin, resulted in the production of ultra-weak chemiluminescence that was detected by a chemiluminescence analyzer. The intensity of the chemiluminescence was found to be proportional to the hydroquinone concentration. We suggest that the rapid (measurement time, 60 s) and virtually solvent-free (solvent volume, <2 mL) chemiluminescent method described here for quantifying hydroquinone content may be an alternative to HPLC analysis. PMID:25693839

  19. Colorimetric quantification of mRNA expression in rare tumour cells amplified by multiple ligation-dependent probe amplification.

    PubMed

    Acero Sanchez, Josep L; Henry, Olivier Y F; Mairal, Teresa; Laddach, Nadja; Nygren, Anders; Hauch, Siegfried; Fetisch, Jasmin; O'Sullivan, Ciara K

    2010-07-01

    An enzyme-linked oligonucleotide assay (ELONA) for quantification of mRNA expression of five genes involved in breast cancer, extracted from isolated rare tumour cells and amplified by multiplex ligation-dependent probe amplification (MLPA) is presented. In MLPA, a multiplex oligonucleotide ligation assay is combined with a PCR reaction in which all ligation products are amplified by use of a single primer pair. Biotinylated probes complementary to each of the target sequences were immobilised on the surface of a streptavidin-coated microtitre plate and exposed to single-stranded MLPA products. A universal reporting probe sequence modified with horseradish peroxidase (URP-HRP) and complementary to a universal primer used during the MLPA step was further added to the surface-bound duplex as a reporter probe. Simultaneous addition of anchoring probe and target, followed by addition of reporter probe, rather than sequential addition, was achieved with no significant effect on sensitivity and limits of detection, but considerably reduced the required assay time. Detection limits as low as 20 pmol L(-1), with an overall assay time of 95 min could be achieved with negligible cross-reactivity between probes and non-specific targets present in the MLPA-PCR product. The same MLPA-PCR product was analysed using capillary electrophoresis, the technique typically used for analysis of MLPA products, and good correlation was observed. The assay presented is easy to carry out, relatively inexpensive, rapid, does not require sophisticated instrumentation, and enables quantitative analysis, making it very promising for the analysis of MLPA products. PMID:20526769

  20. Fe3O4 magnetic nanoparticle peroxidase mimetic-based colorimetric assay for the rapid detection of organophosphorus pesticide and nerve agent.

    PubMed

    Liang, Minmin; Fan, Kelong; Pan, Yong; Jiang, Hui; Wang, Fei; Yang, Dongling; Lu, Di; Feng, Jing; Zhao, Jianjun; Yang, Liu; Yan, Xiyun

    2013-01-01

    Rapid and sensitive detection methods are in urgent demand for the screening of extensively used organophosphorus pesticides and highly toxic nerve agents for their neurotoxicity. In this study, we developed a novel Fe(3)O(4) magnetic nanoparticle (MNP) peroxidase mimetic-based colorimetric method for the rapid detection of organophosphorus pesticides and nerve agents. The detection assay is composed of MNPs, acetylcholinesterase (AChE), and choline oxidase (CHO). The enzymes AChE and CHO catalyze the formation of H(2)O(2) in the presence of acetylcholine, which then activates MNPs to catalyze the oxidation of colorimetric substrates to produce a color reaction. After incubation with the organophosphorus neurotoxins, the enzymatic activity of AChE was inhibited and produced less H(2)O(2), resulting in a decreased catalytic oxidation of colorimetric substrates over MNP peroxidase mimetics, accompanied by a drop in color intensity. Three organophosphorus compounds were tested on the assay: acephate and methyl-paraoxon as representative organophosphorus pesticides and the nerve agent Sarin. The novel assay displayed substantial color change after incubation in organophosphorus neurotoxins in a concentration-dependent manner. As low as 1 nM Sarin, 10 nM methyl-paraoxon, and 5 μM acephate are easily detected by the novel assay. In conclusion, by employing the peroxidase-mimicking activity of MNPs, the developed colorimetric assay has the potential of becoming a screening tool for the rapid and sensitive assessment of the neurotoxicity of an overwhelming number of organophosphate compounds. PMID:23153113

  1. Colorimetric quantification of sucrose in presence of thermo-sensitive polymers present in aqueous two-phase systems.

    PubMed

    Ramalakshmi, Subbarayalu; Ooi, Chien Wei; Ariff, Arbakariya B; Ramanan, Ramakrishnan Nagasundara

    2014-01-01

    The use of biodegradable material such as simple carbohydrates and recyclable material such as thermo-sensitive polymers is in need to develop a sustainable aqueous two-phase system (ATPS) for the purification of biomolecules. Accurate determination of sucrose concentration is important in liquid-liquid equilibrium (LLE) study of carbohydrate-based ATPS. The well-established phenol-sulfuric acid method has been widely employed in the measurement of carbohydrate concentration. However, the presence of thermo-sensitive polymers, which has a lower critical solution temperature (LCST) below room temperature, in carbohydrate samples could hamper the precision of spectrophotometric analysis due to the formation of two phases or cloudiness in the sample. Thus, the following modifications were made in an attempt to eliminate the interference occurred during conventional phenol-sulfuric acid assay.•The modified assay for sucrose quantification was performed at an ice-cold temperature throughout the reaction in order to avoid the interference from thermo-sensitive polymers.•This method required a sample volume of 3 μL and hence the volume of other reagents employed was also considerably reduced.•The absorbance was measured at 520 nm which allowed a longer linearity range (0.05-7.5%, w/v). PMID:26150957

  2. Rapid detection and quantification of impact damage in composite structures

    NASA Technical Reports Server (NTRS)

    Smith, Barry T.

    1992-01-01

    It is shown that a multidisciplinary nondestructive evaluation approach for impact damage detection in composite structures can be used to produce a more efficient inspection. The multidisciplinary NDE approach relies on fast large area thermographic inspections along with detailed ultrasonic volumetric imaging. The thermal inspection technique rapidly identifies the impact damage. The ultrasonic volumetric imaging quantifies the impact generated delaminations through the volume of the structure.

  3. Rapid colorimetric assay of urinary beta-galactosidase and N-acetyl-beta-D-glucosaminidase with Cobas Mire Auto-analyzer.

    PubMed

    Xu, G; Zhu, L; Hong, J; Cao, Y; Xia, T

    1999-01-01

    A rapid and simple colorimetric method for the assay of urinary beta-galactosidase (GAL) and N-acetyl-beta-D-glucosaminidase (NAG) using 4-nitrophenyl-glycosides as the substrates and a Cobas Mire Auto-analyzer is described. Optimal conditions for this method including substrate concentration, ionic strength, pH and incubation time were characterized. Endogenous substances in urine did not interfere with the assays. Incubation time could be shortened to 10 minutes. A small volume of an alkaline buffer to terminate the enzyme reaction achieved better sensitivity and accuracy. Buffer-substrate solutions were stable for at least one week at 4 degrees C. Normal values of the two urinary enzymes are also reported. PMID:10323472

  4. Rapid quantification of soilborne pathogen communities in wheat-based long-term field experiments

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Traditional isolation and quantification of inoculum density is difficult for most soilborne pathogens. Quantitative PCR methods have been developed to rapidly identify and quantify many of these pathogens using a single DNA extract from soil. Rainfed experiments operated continuously for up to 84 y...

  5. Simple and rapid quantification of thrombocytes in zebrafish larvae.

    PubMed

    Huarng, Michael C; Shavit, Jordan A

    2015-06-01

    Platelets are a critical component of hemostasis, with disorders of number or function resulting in coagulation disturbances. Insights into these processes have primarily been realized through studies using mammalian models or tissues. Increasingly, zebrafish embryos and larvae have been used to study the protein and cellular components of hemostasis and thrombosis, including the thrombocyte, a nucleated platelet analog. However, investigations of thrombocytes have been somewhat limited due to lack of a robust and simple methodology for quantitation, an important component of platelet studies in mammals. Using video capture, we have devised an assay that produces a rapid, reproducible, and precise measurement of thrombocyte number in zebrafish larvae by counting fluorescently tagged cells. Averaging 1000 frames, we were able to subtract background fluorescence, thus limiting assessment to circulating thrombocytes. This method facilitated rapid assessment of relative thrombocyte counts in a population of 372 zebrafish larvae by a single operator in less than 3 days. This technique requires basic microscopy equipment and rudimentary programming, lends itself to high throughput analysis, and will enhance future studies of thrombopoiesis in the zebrafish. PMID:25790244

  6. Graphene-based rapid and highly-sensitive immunoassay for C-reactive protein using a smartphone-based colorimetric reader.

    PubMed

    Vashist, Sandeep Kumar; Marion Schneider, E; Zengerle, Roland; von Stetten, Felix; Luong, John H T

    2015-04-15

    A novel immunoassay (IA) has been developed for human C-reactive protein (CRP), an important biomarker and tissue preserving factor for infection and inflammation. Graphene nanoplatelets (GNP) and 3-aminopropyltriethoxysilane (APTES) were admixed and covalently attached to a polystyrene based-microtiter plate (MTP), pretreated with KOH. The resulting surface served as a stable layer for the covalent attachment of the anti-human CRP antibody. The IA procedure was based on the one-step kinetics-based sandwich IA employing a minimum number of process steps, whereas the enzymatic reaction solution was monitored by a smartphone-based colorimetric reader. With a limit of detection and a limit of quantification of 0.07ngmL(-1) and 0.9ngmL(-1), it precisely detected CRP spiked in diluted human whole blood and plasma as well as the CRP levels in clinical plasma samples. The results obtained for "real-world" patient samples agreed well with those of the conventional immunosorbent assay and the clinically-accredited analyzer-based IA. The antibody-bound GNP-functionalized MTPs retained its original activity after 6 weeks of storage in 0.1M PBS, pH 7.4 at 4°C. PMID:25460898

  7. A rapid molecular diagnosis of cutaneous leishmaniasis by colorimetric malachite green-loop-mediated isothermal amplification (LAMP) combined with an FTA card as a direct sampling tool.

    PubMed

    Nzelu, Chukwunonso O; Cáceres, Abraham G; Guerrero-Quincho, Silvia; Tineo-Villafuerte, Edwin; Rodriquez-Delfin, Luis; Mimori, Tatsuyuki; Uezato, Hiroshi; Katakura, Ken; Gomez, Eduardo A; Guevara, Angel G; Hashiguchi, Yoshihisa; Kato, Hirotomo

    2016-01-01

    Leishmaniasis remains one of the world's most neglected diseases, and early detection of the infectious agent, especially in developing countries, will require a simple and rapid test. In this study, we established a quick, one-step, single-tube, highly sensitive loop-mediated isothermal amplification (LAMP) assay for rapid detection of Leishmania DNA from tissue materials spotted on an FTA card. An FTA-LAMP with pre-added malachite green was performed at 64°C for 60min using a heating block and/or water bath and DNA amplification was detected immediately after incubation. The LAMP assay had high detection sensitivity down to a level of 0.01 parasites per μl. The field- and clinic-applicability of the colorimetric FTA-LAMP assay was demonstrated with 122 clinical samples collected from patients suspected of having cutaneous leishmaniasis in Peru, from which 71 positives were detected. The LAMP assay in combination with an FTA card described here is rapid and sensitive, as well as simple to perform, and has great potential usefulness for diagnosis and surveillance of leishmaniasis in endemic areas. PMID:26516109

  8. Gold nanoprobe functionalized with specific fusion protein selection from phage display and its application in rapid, selective and sensitive colorimetric biosensing of Staphylococcus aureus.

    PubMed

    Liu, Pei; Han, Lei; Wang, Fei; Petrenko, Valery A; Liu, Aihua

    2016-08-15

    Staphylococcus aureus (S. aureus) is one of the most ubiquitous pathogens in public healthcare worldwide. It holds great insterest in establishing robust analytical method for S. aureus. Herein, we report a S. aureus-specific recognition element, isolated from phage monoclone GQTTLTTS, which was selected from f8/8 landscape phage library against S. aureus in a high-throughput way. By functionalizing cysteamine (CS)-stabilized gold nanoparticles (CS-AuNPs) with S. aureus-specific pVIII fusion protein (fusion-pVIII), a bifunctional nanoprobe (CS-AuNPs@fusion-pVIII) for S. aureus was developed. In this strategy, the CS-AuNPs@fusion-pVIII could be induced to aggregate quickly in the presence of target S. aureus, resulting in a rapid colorimetric response of gold nanoparticles. More importantly, the as-designed probe exhibited excellent selectivity over other bacteria. Thus, the CS-AuNPs@fusion-pVIII could be used as the indicator of target S. aureus. This assay can detect as low as 19CFUmL(-1)S. aureus within 30min. Further, this approach can be applicable to detect S. aureus in real water samples. Due to its sensitivity, specificity and rapidness, this proposed method is promising for on-site testing of S. aureus without using any costly instruments. PMID:27085951

  9. Rapid Identification and Drug Susceptibility Testing of Mycobacterium tuberculosis: Standard Operating Procedure for Non-Commercial Assays: Part 3: Colorimetric Redox Indicator Assay v1.3.12

    PubMed Central

    Singh, Sarman; Kumar, Parveen; Sharma, Shreya; Mumbowa, Francis; Martin, Anandi; Durier, Nicolas

    2012-01-01

    The previous two standard operating procedures (SOPs) related to the culture and drug susceptibility testing (DST) of Mycobacterium tuberculosis with the microscopic observation drug susceptibility assay (Part 1) and nitrate reductase assay (Part 2). The present SOP is devoted to a third non-commercial culture and DST method known as colorimetric redox indicator assay (CRI). As its name indicates, the CRI detects the ability of the M. tuberculosis to reduce the colored oxidation-reduction indicator when added to a liquid culture of M. tuberculosis, after exposing the growth to different anti-mycobacterial drugs. The change in the color of the indicator denotes the proportionate number of viable Mycobacteria in the medium. The identification and DST results can be obtained in 7-8 days. This SOP document has been developed through the culture and DST subgroup of the STOP tuberculosis (TB) Partnership New Diagnostic Working Group. It is intended for laboratories that would want to use or already use this rapid non-commercial method for culture identification and DST of M. tuberculosis, notably in resource-constraint settings in Asia and Africa. PMID:23440615

  10. A facile strategy for the preparation of ZnS nanoparticles deposited on montmorillonite and their higher catalytic activity for rapidly colorimetric detection of H2O2.

    PubMed

    Ding, Yanyuan; Sun, Lifang; Jiang, Yanling; Liu, Shunxiang; Chen, Mingxing; Chen, Miaomiao; Ding, Yanan; Liu, Qingyun

    2016-10-01

    In this paper, ZnS nanoparticles deposited on montmorillonite (ZnS-MMT) were prepared by a facile method at room temperature and characterized by powder X-ray diffraction (XRD), Energy-dispersive X-ray Detector (EDX) and transmission electron microscope (TEM), respectively. Significantly, the as-prepared ZnS-MMT nanocomposites have been proven to possess intrinsic peroxidase-like activity that can rapidly catalyze the reaction of peroxidase substrate 3,3',5,5'-tetramethylbenzidine (TMB) in the presence of H2O2 and produce a blue color product in less than 30 seconds, which provides a sensitive colorimetric sensor to detect H2O2. Due to the synergistic effects between montmorillonite and ZnS nanoparticles, the obtained ZnS-MMT nanocomposites exhibit higher catalytic activity than that of MMT or ZnS alone. The catalytic behaviors of the ZnS-MMT nanocomposites showed a typical Michaelis-Menten kinetics. The catalytic activity and the catalytic mechanism were investigated using the procedures of steady-state kinetics and hydroxyl radical detection. ESR data revealed that the peroxidase-like activity of ZnS-MMT originated from the generation of OH radicals. PMID:27287113

  11. Integration of Nanoparticle-Based Paper Sensors into the Classroom: An Example of Application for Rapid Colorimetric Analysis of Antioxidants

    ERIC Educational Resources Information Center

    Sharpe, Erica; Andreescu, Silvana

    2015-01-01

    We describe a laboratory experiment that employs the Nanoceria Reducing Antioxidant Capacity (or NanoCerac) Assay to introduce students to portable nanoparticle-based paper sensors for rapid analysis and field detection of polyphenol antioxidants. The experiment gives students a hands-on opportunity to utilize nanoparticle chemistry to develop…

  12. Rapid Non-Crosslinking Aggregation of DNA-Functionalized Gold Nanorods and Nanotriangles for Colorimetric Single-Nucleotide Discrimination.

    PubMed

    Wang, Guoqing; Akiyama, Yoshitsugu; Takarada, Tohru; Maeda, Mizuo

    2016-01-01

    Gold nanoparticles modified with DNA duplexes are rapidly and spontaneously aggregated at high ionic strength. In contrast, this aggregation is greatly suppressed when the DNA duplex has a single-base mismatch or a single-nucleotide overhang located at the outermost surface of the particle. These colloidal features emerge irrespective of the size and composition of the particle core; however, the effects of the shape remain unexplored. Using gold nanorods and nanotriangles (nanoplatelets), we show herein that both remarkable rapidity in colloidal aggregation and extreme susceptibility to DNA structural perturbations are preserved, regardless of the shape and aspect ratio of the core. It is also demonstrated that the DNA-modified gold nanorods and nanotriangles are applicable to naked-eye detection of a single-base difference in a gene model. The current study corroborates the generality of the unique colloidal properties of DNA-functionalized nanoparticles, and thus enhances the feasibility of their practical use. PMID:26767586

  13. Simple and rapid quantification of brominated vegetable oil in commercial soft drinks by LC-MS.

    PubMed

    Chitranshi, Priyanka; Gamboa da Costa, Gonçalo

    2016-12-15

    We report here a simple and rapid method for the quantification of brominated vegetable oil (BVO) in soft drinks based upon liquid chromatography-electrospray ionization mass spectrometry. Unlike previously reported methods, this novel method does not require hydrolysis, extraction or derivatization steps, but rather a simple "dilute and shoot" sample preparation. The quantification is conducted by mass spectrometry in selected ion recording mode and a single point standard addition procedure. The method was validated in the range of 5-25μg/mL BVO, encompassing the legal limit of 15μg/mL established by the US FDA for fruit-flavored beverages in the US market. The method was characterized by excellent intra- and inter-assay accuracy (97.3-103.4%) and very low imprecision [0.5-3.6% (RSD)]. The direct nature of the quantification, simplicity, and excellent statistical performance of this methodology constitute clear advantages in relation to previously published methods for the analysis of BVO in soft drinks. PMID:27451219

  14. Colorimetric Method for the Estimation of Total Limonoid Aglycones and Glucoside Contents in Citrus Juices

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A method for estimating the total limonoid aglycone and glucoside concentrations in Citrus samples in terms of limonin and limonin glucoside equivalents is presented. The method consists of extraction followed by colorimetric quantification. The colorimetric quantification was based on the formatio...

  15. Ni(II)NTA AuNPs as a low-resource malarial diagnostic platform for the rapid colorimetric detection of Plasmodium falciparum Histidine-Rich Protein-2.

    PubMed

    Gulka, Christopher P; Swartz, Joshua D; Wright, David W

    2015-04-01

    Diagnosing infectious diseases remains a challenge in the developing world where there is a lack of dependable electricity, running water, and skilled technicians. Although rapid immunochromatographic tests (RDTs) have been deployed to diagnose diseases such as malaria, the extreme climate conditions encountered in these regions compounded with the discrepancies in test manufacturing have yielded varying results, so that more innovative and robust technologies are sought. Devoid of antibodies and thermally sensitive materials, we present a robust, colorimetric diagnostic platform for the detection of a malarial biomarker, Plasmodium falciparum Histidine-Rich Protein 2 (PfHRP-II). The assay exploits the optical properties of gold nanoparticles, covalently coupling them to a Ni(II)NTA recognition element specific for PfHRP-II. In the presence of the recombinant malarial biomarker (rcHRP-II), the Ni(II)NTA AuNPs begin to crosslink and aggregate in as little as one minute, triggering a red-to-purple color change in solution. To increase assay sensitivity and platform stability suitable for low-resource regions, the Ni(II)NTA AuNPs were assembled with varying spacer ligands in a mixed monolayer presentation. When assembled with a negatively charged Peg4-thiol ligand, the Ni(II)NTA AuNPs demonstrate low nanomolar limits of rcHRP-II detection in physiological concentrations of human serum albumin and maintain excellent stability at 37°C when stored for four weeks. Detection of the malaria biomarker is also measured by capturing and processing images of aggregated gold nanoparticles with a smartphone camera. By utilizing a smartphone camera and image processing application, there is no significant difference in assay sensitivity and rcHRP-II limit of detection in comparison to a spectrophotometer, further making this diagnostic platform applicable for use in low-resource regions. PMID:25640131

  16. Simple and Portable Magnetic Immunoassay for Rapid Detection and Sensitive Quantification of Plant Viruses

    PubMed Central

    Rettcher, Stefanie; Jungk, Felicitas; Kühn, Christoph; Krause, Hans-Joachim; Nölke, Greta; Commandeur, Ulrich; Fischer, Rainer; Schillberg, Stefan

    2015-01-01

    Plant pathogens cause major economic losses in the agricultural industry because late detection delays the implementation of measures that can prevent their dissemination. Sensitive and robust procedures for the rapid detection of plant pathogens are therefore required to reduce yield losses and the use of expensive, environmentally damaging chemicals. Here we describe a simple and portable system for the rapid detection of viral pathogens in infected plants based on immunofiltration, subsequent magnetic detection, and the quantification of magnetically labeled virus particles. Grapevine fanleaf virus (GFLV) was chosen as a model pathogen. Monoclonal antibodies recognizing the GFLV capsid protein were immobilized onto immunofiltration columns, and the same antibodies were linked to magnetic nanoparticles. GFLV was quantified by immunofiltration with magnetic labeling in a double-antibody sandwich configuration. A magnetic frequency mixing technique, in which a two-frequency magnetic excitation field was used to induce a sum frequency signal in the resonant detection coil, corresponding to the virus concentration within the immunofiltration column, was used for high-sensitivity quantification. We were able to measure GFLV concentrations in the range of 6 ng/ml to 20 μg/ml in less than 30 min. The magnetic immunoassay could also be adapted to detect other plant viruses, including Potato virus X and Tobacco mosaic virus, with detection limits of 2 to 60 ng/ml. PMID:25710366

  17. Selective colorimetric sensors based on the monitoring of an unmodified silver nanoparticles (AgNPs) reduction for a simple and rapid determination of mercury

    NASA Astrophysics Data System (ADS)

    Jarujamrus, Purim; Amatatongchai, Maliwan; Thima, Araya; Khongrangdee, Thatsanee; Mongkontong, Chakrit

    2015-05-01

    In this work, selective colorimetric sensors for simple and rapid detection of Hg(II) ions based on the monitoring of an unmodified silver nanoparticles (AgNPs) reduction were developed. The average diameter of synthesized AgNPs was 8.3 ± 1.4 nm which was characterized by transmission electron microscopy (TEM). The abrupt change in absorbance of the unmodified AgNPs was observed which progressively decreased and slightly shifted to the blue wavelength as the concentration of Hg(II) increased, indicating the oxidation of Ag(0) to Ag(I) occurred. It appears that the AgNPs were oxidized by Hg(II), resulting in disintegration of the AgNPs into smaller particles as well as mediating the reduction of Hg(II) to Hg(0) adsorbed onto the surface of AgNPs. The adsorption of Hg(0) resulted in the lack of sufficient charges on AgNPs surfaces due to the decrease in the surface coverage of negatively charged citrate molecules, which then leaded to enlargement of AgNPs. The calibration curve of this technique was demonstrated from 0.5 to 7 ppm (r2 = 0.995), the limit of detection (LOD) was 0.06 ppm (SDblank/slope of calibration curve) with the precision (RSD, n = 4) of 3.24-4.53. Interestingly, the results show a significant enhance in the Hg(II) analytical sensitivity when Cu(II) is doped onto the unmodified AgNPs, which improves the quantitative detection limit to 0.008 ppm. In addition, greater selectivity toward Hg(II) compared with the other metal ions tested was observed. Furthermore, the percentage recoveries of spiked drinking water, tap water and SRM1641d (mercury in water) were in acceptable range with a good precision (RSD) which were in agreement with the values obtained from graphite furnace atomic absorption spectrometer (GFAAS). The technique proposed in this study provides a rapid, simple, sensitive and selective detection method for Hg(II) in water samples.

  18. Atomic absorption spectroscopic, conductometric and colorimetric methods for determination of some fluoroquinolone antibacterials using ammonium reineckate

    NASA Astrophysics Data System (ADS)

    Al-Ghannam, Sheikha M.

    2008-04-01

    Three accurate, rapid and simple atomic absorption spectrometric (AAS), conductometric and colorimetric methods were developed for the determination of gatifloxacin (GTF), moxifloxacin (MXF) and sparfloxacin (SPF). The proposed methods depend upon the reaction of ammonium reineckate with the studied drugs to form stable precipitate of ion-pair complexes, which was dissolved in acetone. The pink coloured complexes were determined either by AAS or colorimetrically at λmax 525 nm directly using the dissolved complex. Using conductometric titration, the studied drugs could be evaluated in 50% (v/v) acetone. The optimizations of various experimental conditions were described. Optimum concentration ranges for the determination of GTF, MXF and SPF were 5.0-150, 40-440 μg mL -1 and 0.10-1.5 mg mL -1 using atomic absorption (AAS), conductometric and colorimetric methods, respectively. Detection and quantification limits are ranges from 1.5 to 2.3 μg mL -1 using AAS method or 30-45 μg mL -1 using colorimetric method. The proposed procedures have been applied successfully to the analysis of these drugs in pharmaceutical formulations and the results are favourably comparable to the reference methods.

  19. Novel antibody/gold nanoparticle/magnetic nanoparticle nanocomposites for immunomagnetic separation and rapid colorimetric detection of Staphylococcus aureus in milk.

    PubMed

    Sung, Yun Ju; Suk, Ho-Jun; Sung, Hwa Young; Li, Taihua; Poo, Haryoung; Kim, Min-Gon

    2013-05-15

    We demonstrated the new antibody/gold nanoparticle/magnetic nanoparticle nanocomposites (antibody/AuNP/MNPs) and their application in the detection of the foodborne pathogen, Staphylococcus aureus (S. aureus), in milk. The nanocomposites were synthesized by coating the MNPs with bovine serum albumin (BSA) then adsorbing the AuNPs and anti-S. aureus antibodies on their surface. Using the completed immunomagnetic nanostructures, S. aureus inoculated in the milk sample was captured and isolated from the medium using the permanent magnet. The nanoparticle-bound cells as well as the unbound cells in the supernatant were enumerated via surface plating to evaluate the target binding capacity of the nanocomposites. The capture efficiencies of the antibody/AuNP/MNPs were 96% and 78% for S. aureus in PBS and the milk sample respectively, which were significantly higher than those of the antibody-coupled MNPs without any AuNP. The captured cells were also applied to the selective filtration system to produce color signals that were used for the detection of the target pathogen. During the filtration, the cells bound to the antibody/AuNP/MNPs remained on the surface of the membrane filter while unbound nanoparticles passed through the uniform pores of the membrane. After the gold enhancement, the cells-particles complex resting on the membrane surface rendered a visible color, and the signal intensity became higher as the target cell concentration increased. The detection limits of this colorimetric sensor were 1.5×10(3) and 1.5×10(5)CFU for S. aureus in PBS and the milk sample respectively. This sensing mechanism also had the high specificity for S. aureus over the other pathogens such as Escherichia coli, Listeria monocytogenes, and Salmonella enterica. The assay required only 40min to obtain the results. With the use of the appropriate antibodies, our immunomagnetic nanocomposites-based detection strategy can provide an easy, convenient, and rapid sensing method for a

  20. Toward rapid, high-sensitivity, volume-constrained biomarker quantification and validation using backscattering interferometry.

    PubMed

    Olmsted, Ian R; Hassanein, Mohamed; Kussrow, Amanda; Hoeksema, Megan; Li, Ming; Massion, Pierre P; Bornhop, Darryl J

    2014-08-01

    Realizing personalized medicine, which promises to enable early disease detection, efficient diagnostic staging, and therapeutic efficacy monitoring, hinges on biomarker quantification in patient samples. Yet, the lack of a sensitive technology and assay methodology to rapidly validate biomarker candidates continues to be a bottleneck for clinical translation. In our first direct and quantitative comparison of backscattering interferometry (BSI) to fluorescence sensing by ELISA, we show that BSI could aid in overcoming this limitation. The analytical validation study was performed against ELISA for two biomarkers for lung cancer detection: Cyfra 21-1 and Galectin-7. Spiked serum was used for calibration and comparison of analytical figures of merit, followed by analysis of blinded patient samples. Using the ELISA antibody as the probe chemistry in a mix-and-read assay, BSI provided significantly lower detection limits for spiked serum samples with each of the biomarkers. The limit of quantification (LOQ) for Cyrfa-21-1 was measured to be 230 pg/mL for BSI versus 4000 pg/mL for ELISA, and for Galectin-7, it was 13 pg/mL versus 500 pg/mL. The coefficient of variation for 5 day, triplicate determinations was <15% for BSI and <10% for ELISA. The two techniques correlated well, ranging from 3-29% difference for Cyfra 21-1 in a blinded patient sample analysis. The label-free and free-solution operation of BSI allowed for a significant improvement in analysis speed, with greater ease, improved LOQ values, and excellent day-to-day reproducibility. In this unoptimized format, BSI required 5.5-fold less sample quantity needed for ELISA (a 10 point calibration curve measured in triplicate required 36 μL of serum for BSI vs 200 μL for ELISA). The results indicate that the BSI platform can enable rapid, sensitive analytical validation of serum biomarkers and should significantly impact the validation bottleneck of biomarkers. PMID:24954171

  1. Paper-Based Device for Colorimetric and Photoelectrochemical Quantification of the Flux of H2O2 Releasing from MCF-7 Cancer Cells.

    PubMed

    Li, Li; Zhang, Yan; Zhang, Lina; Ge, Shenguang; Liu, Haiyun; Ren, Na; Yan, Mei; Yu, Jinghua

    2016-05-17

    In this work, a novel dual photoelectrochemical/colorimetric cyto-analysis format was first introduced into a microfluidic paper-based analytical device (μ-PAD) for synchronous sensitive and visual detection of H2O2 released from tumor cells based on an in situ hydroxyl radicals ((•)OH) cleaving DNA approach. The resulted μ-PAD offered an excellent platform for high-performance biosensing applications, which was constructed by a layer-by-layer modification of concanavalin A, graphene quantum dots (GQDs) labeled flower-like Au@Pd alloy nanoparticles (NPs) probe, and tumor cells on the surface of the vertically aligned bamboo like ZnO, which grows on a pyknotic Pt NPs modified paper working electrode (ZnO/Pt-PWE). It was the effective matching of energy levels between GQDs and ZnO levels that lead to the enhancement of the photocurrent response compared with the bare ZnO/Pt-PWE. After releasing H2O2, the DNA strand was cleaved by (•)OH generated under the synergistic catalysis of GQDs and Au@Pd alloy NPs and thus, reduced the photocurrent, resulting in a high sensitivity to H2O2 in aqueous solutions with a detection limit of 0.05 nmol observed, much lower than that in the previously reported method. The disengaged probe can result in catalytic chromogenic reaction of substrates, resulting in real-time imaging of H2O2 biological processes. Therefore, this work provided a truly low-cost, simple, and disposable μ-PAD for precise and visual detection of cellular H2O2, which had potential utility to cellular biology and pathophysiology. PMID:27065042

  2. Rapid quantification of Salmonella in seafood by real-time PCR assay.

    PubMed

    Kumar, Rakesh; Surendran, P K; Thampuran, Nirmala

    2010-03-01

    A quantitative detection method for Salmonella in seafood was developed using a SYBR Green-based real-time PCR assay. The assay was developed using pure Salmonella DNA at different dilution levels [i.e., 1,000 to 2 genome equivalents (GE)]. The sensitivity of the real-time assay for Salmonella in seeded seafood samples was determined, and the minimum detection level was 20 CFU/g, whereas a detection level of 2 CFU/ml was obtained for pure culture in water with an efficiency of > or =85%. The real-time assay was evaluated in repeated experiments with seeded seafood samples and the regression coefficient (R(2)) values were calculated. The performance of the real-time assay was further assessed with naturally contaminated seafood samples, where 4 out of 9 seafood samples tested positive for Salmonella and harbored cells <100 GE/g, which were not detected by direct plating on Salmonella Chromagar media. Thus, the method developed here will be useful for the rapid quantification of Salmonella in seafood, as the assay can be completed within 2-3 h. In addition, with the ability to detect a low number of Salmonella cells in seafood, this proposed method can be used to generate quantitative data on Salmonella in seafood, facilitating the implementation of control measures for Salmonella contamination in seafood at harvest and post-harvest levels. PMID:20372029

  3. Rapid quantification of live cell receptors using bioluminescence in a flow-based microfluidic device.

    PubMed

    Ramji, Ramesh; Cheong, Cheong Fook; Hirata, Hiroaki; Rahman, Abdur Rub Abdur; Lim, Chwee Teck

    2015-02-25

    The number of receptors expressed by cells plays an important role in controlling cell signaling events, thus determining its behaviour, state and fate. Current methods of quantifying receptors on cells are either laborious or do not maintain the cells in their native form. Here, a method integrating highly sensitive bioluminescence, high precision microfluidics and small footprint of lensfree optics is developed to quantify cell surface receptors. This method is safe to use, less laborious, and faster than the conventional radiolabelling and near field scanning methods. It is also more sensitive than fluorescence based assays and is ideal for high throughput screening. In quantifying β(1) adrenergic receptors expressed on the surface of H9c2 cardiomyocytes, this method yields receptor numbers from 3.12 × 10(5) to 9.36 × 10(5) receptors/cell which are comparable with current methods. This can serve as a very good platform for rapid quantification of receptor numbers in ligand/drug binding and receptor characterization studies, which is an important part of pharmaceutical and biological research. PMID:25336403

  4. Quantification of microsegregation during rapid solidification of Al-Cu powders

    NASA Astrophysics Data System (ADS)

    Prasad, Arvind; Nenein, Hani; Conlon, Kelly

    2006-05-01

    A new technique is introduced to quantify microsegregation during rapid solidification. The quantification involves calculation of the average solute solubility in the primary phase during solidification of an Al-Cu binary alloy. The calculation is based on using volume percent eutectic and weight percent of second phase (in the eutectic), which were obtained experimentally. Neutron diffraction experiments and stereology calculation on scanning electron microscope images were done on impulse atomized Al-Cu alloys of three compositions (nominal), 5 wt pct Cu, 10 wt pct Cu, and 17 wt pct Cu, atomized under N2 and He gas. Neutron diffraction experiments yielded weight percent CuAl2 data and stereology yielded volume percent eutectic data. These two data were first used to determine the weight percent eutectic. Using the weight percent eutectic and weight percent CuAl2 in mass and volume balance equations, the average solute solubility in the primary phase could be calculated. The experimental results of the amount of eutectic, tomography results from previous work, and results from the calculations suggest that the atomized droplets are in metastable state during the nucleation undercooling of the primary phase, and the effect of metastability propagates through to the eutectic formation stage. The metastable effect is more pronounced in alloys with higher solute composition.

  5. Rapid detection and quantification of milk adulteration using infrared microspectroscopy and chemometrics analysis.

    PubMed

    Santos, P M; Pereira-Filho, E R; Rodriguez-Saona, L E

    2013-05-01

    The application of attenuated total reflectance mid-infrared microspectroscopy (MIR-microspectroscopy) was evaluated as a rapid method for detection and quantification of milk adulteration. Milk samples were purchased from local grocery stores (Columbus, OH, USA) and spiked at different concentrations of whey, hydrogen peroxide, synthetic urine, urea and synthetic milk. Samples were place on a 192-well microarray slide, air-dried and spectra were collected by using MIR-microspectroscopy. Pattern recognition analysis by Soft Independent Modeling of Class Analogy (SIMCA) showed tight and well-separated clusters allowing discrimination of control samples from adulterated milk. Partial Least Squares Regression (PLSR) showed standard error of prediction (SEP) ~2.33, 0.06, 0.41, 0.30 and 0.014 g/L for estimation of levels of adulteration with whey, synthetic milk, synthetic urine, urea and hydrogen peroxide, respectively. Results showed that MIR-microspectroscopy can provide an alternative methodology to the dairy industry for screening potential fraudulent practice for economic adulteration of cow's milk. PMID:23265450

  6. Rapid quantification of inflammation in tissue samples using perfluorocarbon emulsion and fluorine-19 nuclear magnetic resonance

    PubMed Central

    Ahrens, Eric T.; Young, Won-Bin; Xu, Hongyan; Pusateri, Lisa K.

    2016-01-01

    Quantification of inflammation in tissue samples can be a time-intensive bottleneck in therapeutic discovery and preclinical endeavors. We describe a versatile and rapid approach to quantitatively assay macrophage burden in intact tissue samples. Perfluorocarbon (PFC) emulsion is injected intravenously, and the emulsion droplets are effectively taken up by monocytes and macrophages. These ‘in situ’ labeled cells participate in inflammatory events in vivo resulting in PFC accumulation at inflammatory loci. Necropsied tissues or intact organs are subjected to conventional fluorine-19 (19F) NMR spectroscopy to quantify the total fluorine content per sample, proportional to the macrophage burden. We applied these methods to a rat model of experimental allergic encephalomyelitis (EAE) exhibiting extensive inflammation and demyelination in the central nervous system (CNS), particularly in the spinal cord. In a cohort of EAE rats, we used 19F NMR to derive an inflammation index (IFI) in intact CNS tissues. Immunohistochemistry was used to confirm intracellular colocalization of the PFC droplets within CNS CD68+ cells having macrophage morphology. The IFI linearly correlated to mRNA levels of CD68 via real-time PCR analysis. This 19F NMR approach can accelerate tissue analysis by at least an order of magnitude compared with histological approaches. PMID:21548906

  7. Rapid quantification of microRNAs in plasma using a fast real-time PCR system.

    PubMed

    Andrews, William John; Brown, Eoin Daniel; Dellett, Margaret; Hogg, Ruth Esther; Simpson, David Arthur

    2015-05-01

    The ability to rapidly detect circulating small RNAs, in particular microRNAs (miRNAs), would further increase their already established potential as biomarkers for a range of conditions. One rate-limiting factor in miRNA detection is the time taken to perform quantitative real-time PCR (qPCR) amplification. We therefore evaluated the ability of a novel thermal cycler to perform this step in less than 10 minutes. Quantitative PCR was performed on an xxpress thermal cycler (BJS Biotechnologies), which employs a resistive heating system and forced air cooling to achieve thermal ramp rates of 10°C/s, and a conventional Peltier-controlled LightCycler 480 system (Roche) ramping at 4.8°C/s. The quantification cycle (Cq) for detection of 18S rDNA from a standard genomic DNA sample was significantly more variable across the block (F-test, P = 2.4 × 10(-25)) for the xxpress (20.01 ± 0.47 sd) than for the LightCycler (19.87 ± 0.04 sd). RNA was extracted from human plasma, reverse transcribed, and a panel of miRNAs was amplified and detected using SYBR Green. The sensitivities of the two systems were broadly comparable-both detected a panel of miRNAs reliably, and both indicated similar relative abundances. The xxpress thermal cycler facilitates rapid qPCR detection of small RNAs and brings point-of-care diagnostics based upon detection of circulating miRNAs a step closer to reality. PMID:25967903

  8. Microfluidic Integration of a Cloth-Based Hybridization Array System (CHAS) for Rapid, Colorimetric Detection of Enterohemorrhagic Escherichia coli (EHEC) Using an Articulated, Centrifugal Platform.

    PubMed

    Geissler, Matthias; Clime, Liviu; Hoa, Xuyen D; Morton, Keith J; Hébert, Harold; Poncelet, Lucas; Mounier, Maxence; Deschênes, Mylène; Gauthier, Martine E; Huszczynski, George; Corneau, Nathalie; Blais, Burton W; Veres, Teodor

    2015-10-20

    We describe the translation of a cloth-based hybridization array system (CHAS), a colorimetric DNA detection method that is used by food inspection laboratories for colony screening of pathogenic agents, onto a microfluidic chip format. We also introduce an articulated centrifugal platform with a novel fluid manipulation concept based on changes in the orientation of the chip with respect to the centrifugal force field to time the passage of multiple components required for the process. The platform features two movable and motorized carriers that can be reoriented on demand between 0 and 360° during stage rotation. Articulation of the chip can be used to trigger on-the-fly fluid dispensing through independently addressable siphon structures or to relocate solutions against the centrifugal force field, making them newly accessible for downstream transfer. With the microfluidic CHAS, we achieved significant reduction in the size of the cloth substrate as well as the volume of reagents and wash solutions. Both the chip design and the operational protocol were optimized to perform the entire process in a reliable, fully automated fashion. A demonstration with PCR-amplified genomic DNA confirms on-chip detection and identification of Escherichia coli O157:H7 from colony isolates in a colorimetric multiplex assay using rfbO157, fliCH7, vt1, and vt2 genes. PMID:26416260

  9. Rapid separation and quantification of major caseins and whey proteins of bovine milk by capillary electrophoresis.

    PubMed

    Vallejo-Cordoba, B

    1997-01-01

    A rapid capillary zone electrophoresis (CZE) method was established for separating and quantifying major casein and whey proteins in milk. Optimum sample preparation and electrophoretic conditions in a coated capillary maintained at 40 degrees C allowed accurate and reproducible quantification of milk proteins in a single analysis. Sample and run buffer allowed caseins to be maintained in solution by using a combination of urea and a nonionic detergent in phosphate buffer at pH 2.5. Quantitative CZE protein data were derived by calculating percentages and concentrations (mg/mL) of alpha-casein, beta-casein, alpha-lactalbumin, and beta-lactoglobulin. Calibration curves followed linear relationships with highly significant (p < 0.1) correlation coefficients. Relative standard deviations of less than 0.82 (%) for migration times and 2.18 (%) for percent protein indicated that the technique was reproducible. Electrophoretic protein profiles of fresh bovine milk and rehydrated dry milk showed marked quantitative differences in whey protein concentrations. Whey protein represented 12.37 +/- 0.07% beta-lactoglobulin and 3.05 +/- 0.08% alpha-lactalbumin of total protein in typical fresh milk, while only 1.90 +/- 0.16% beta-lactoglobulin and 0.86 +/- 0.04% alpha-lactalbumin of total protein were detected in a commercial rehydrated milk powder. By quantifying these differences, the established technique may allow the detection of substitution of fresh milk with rehydrated milk powder. The accuracy and reproducibility of the technique permitted the quantitation of individual protein concentrations in milk samples, which agreed with ranges reported in the literature. CZE may be well suited for routine use by dairies and regulatory agencies, since it allows the determination of milk proteins in less than 60 min. PMID:9725120

  10. Ultraminiaturized assay for rapid, low cost detection and quantification of clinical and biochemical samples.

    PubMed

    Parween, Shahila; Nahar, Pradip

    2016-04-01

    Herein, we report a simple, sensitive, rapid and low-cost ultraminiaturized assay technique for quantitative detection of 1 μl of clinical or biochemical sample on a novel ultraminiaturized assay plate (UAP). UAP is prepared by making tiny cavities on a polypropylene sheet. As UAP cannot immobilize a biomolecule through absorption, we have activated the tiny cavities of UAP by 1-fluoro-2-nitro-4-azidobenzene in a photochemical reaction. Activated UAP (AUAP) can covalently immobilize any biomolecule having an active nucleophilic group such as amino group. Efficacy of AUAP is demonstrated by detecting human IgE, antibody of hepatitis C virus core antigen and oligonucleotides. Quantification is performed by capturing the image of the colored assay solution and digitally quantifying the image by color saturation without using costly NanoDrop spectrophotometer. Image - based detection of human IgE and an oligonucleotide shows an excellent correlation with absorbance - based assay (recorded in a NanoDrop spectrophotometer); it is validated by Pearson's product-moment correlation with correlation coefficient of r = 0.9545088 and r = 0.9947444 respectively. AUAP is further checked by detecting hepatitis C virus Ab where strong correlation of color saturation with absorbance with respect to concentration is observed. Ultraminiaturized assay successfully detects target oligonucleotides by perfectly hybridizing with their respective complementary oligonucleotide probes but not with a random oligonucleotide. Ultraminiaturized assay technique has substantially reduced the requirement of reagents by 100 times and assay timing by 50 times making it a potential alternative to conventional method. PMID:26973054

  11. Doped colorimetric assay liposomes

    DOEpatents

    Charych, Deborah; Stevens, Raymond C.

    2001-01-01

    The present invention provides compositions comprising colorimetric assay liposomes. The present invention also provides methods for producing colorimetric liposomes and calorimetric liposome assay systems. In preferred embodiments, these calorimetric liposome systems provide high levels of sensitivity through the use of dopant molecules. As these dopants allow the controlled destabilization of the liposome structure, upon exposure of the doped liposomes to analyte(s) of interest, the indicator color change is facilitated and more easily recognized.

  12. Rapid and in vivo quantification of cellular lipids in Chlorella vulgaris using near-infrared Raman spectrometry.

    PubMed

    Lee, Tsung-Hua; Chang, Jo-Shu; Wang, Hsiang-Yu

    2013-02-19

    A rapid and noninvasive quantification method for cellular lipids in Chlorella vulgaris is demonstrated in this study. This method applied near-infrared Raman spectroscopy to monitor the change of signal intensities at 1440 cm(-1) and 2845-3107 cm(-1) along the nitrogen depletion period, and calibration curves relating signal intensity and cellular lipid abundance were established. The calibration curves show that signal intensity at 2845-3107 cm(-1) and cellular lipid abundance were highly correlated. When the calibration curve was applied on the lipid quantification of two unknown samples, the differences between lipid abundances estimated by the calibration curve and measured by gas chromatography were less than 2 wt %. Carotenoids produced a strong and broad peak near 1440 cm(-1), and it weakened the correlation between signal intensity and lipid abundance. The consistency of detection and effects of cellular contents and water on the Raman spectrogram of Chlorella vulgaris were also addressed. The sample pretreatment only involved centrifugation, and the time required for lipid quantification was shortened to less than 1.5 h. The rapid detection has great potential in high-throughput screening of microalgae and also provides valuable information for monitoring the quality of microalgae culture and determining parameters for the mass production of biodiesel from microalgae. PMID:23331037

  13. Potential of visible and near infrared spectroscopy and pattern recognition for rapid quantification of notoginseng powder with adulterants.

    PubMed

    Nie, Pengcheng; Wu, Di; Sun, Da-Wen; Cao, Fang; Bao, Yidan; He, Yong

    2013-01-01

    Notoginseng is a classical traditional Chinese medical herb, which is of high economic and medical value. Notoginseng powder (NP) could be easily adulterated with Sophora flavescens powder (SFP) or corn flour (CF), because of their similar tastes and appearances and much lower cost for these adulterants. The objective of this study is to quantify the NP content in adulterated NP by using a rapid and non-destructive visible and near infrared (Vis-NIR) spectroscopy method. Three wavelength ranges of visible spectra, short-wave near infrared spectra (SNIR) and long-wave near infrared spectra (LNIR) were separately used to establish the model based on two calibration methods of partial least square regression (PLSR) and least-squares support vector machines (LS-SVM), respectively. Competitive adaptive reweighted sampling (CARS) was conducted to identify the most important wavelengths/variables that had the greatest influence on the adulterant quantification throughout the whole wavelength range. The CARS-PLSR models based on LNIR were determined as the best models for the quantification of NP adulterated with SFP, CF, and their mixtures, in which the rP values were 0.940, 0.939, and 0.867 for the three models respectively. The research demonstrated the potential of the Vis-NIR spectroscopy technique for the rapid and non-destructive quantification of NP containing adulterants. PMID:24129019

  14. Potential of Visible and Near Infrared Spectroscopy and Pattern Recognition for Rapid Quantification of Notoginseng Powder with Adulterants

    PubMed Central

    Nie, Pengcheng; Wu, Di; Sun, Da-Wen; Cao, Fang; Bao, Yidan; He, Yong

    2013-01-01

    Notoginseng is a classical traditional Chinese medical herb, which is of high economic and medical value. Notoginseng powder (NP) could be easily adulterated with Sophora flavescens powder (SFP) or corn flour (CF), because of their similar tastes and appearances and much lower cost for these adulterants. The objective of this study is to quantify the NP content in adulterated NP by using a rapid and non-destructive visible and near infrared (Vis-NIR) spectroscopy method. Three wavelength ranges of visible spectra, short-wave near infrared spectra (SNIR) and long-wave near infrared spectra (LNIR) were separately used to establish the model based on two calibration methods of partial least square regression (PLSR) and least-squares support vector machines (LS-SVM), respectively. Competitive adaptive reweighted sampling (CARS) was conducted to identify the most important wavelengths/variables that had the greatest influence on the adulterant quantification throughout the whole wavelength range. The CARS-PLSR models based on LNIR were determined as the best models for the quantification of NP adulterated with SFP, CF, and their mixtures, in which the rP values were 0.940, 0.939, and 0.867 for the three models respectively. The research demonstrated the potential of the Vis-NIR spectroscopy technique for the rapid and non-destructive quantification of NP containing adulterants. PMID:24129019

  15. RNA-Skim: a rapid method for RNA-Seq quantification at transcript level

    PubMed Central

    Zhang, Zhaojun; Wang, Wei

    2014-01-01

    Motivation: RNA-Seq technique has been demonstrated as a revolutionary means for exploring transcriptome because it provides deep coverage and base pair-level resolution. RNA-Seq quantification is proven to be an efficient alternative to Microarray technique in gene expression study, and it is a critical component in RNA-Seq differential expression analysis. Most existing RNA-Seq quantification tools require the alignments of fragments to either a genome or a transcriptome, entailing a time-consuming and intricate alignment step. To improve the performance of RNA-Seq quantification, an alignment-free method, Sailfish, has been recently proposed to quantify transcript abundances using all k-mers in the transcriptome, demonstrating the feasibility of designing an efficient alignment-free method for transcriptome quantification. Even though Sailfish is substantially faster than alternative alignment-dependent methods such as Cufflinks, using all k-mers in the transcriptome quantification impedes the scalability of the method. Results: We propose a novel RNA-Seq quantification method, RNA-Skim, which partitions the transcriptome into disjoint transcript clusters based on sequence similarity, and introduces the notion of sig-mers, which are a special type of k-mers uniquely associated with each cluster. We demonstrate that the sig-mer counts within a cluster are sufficient for estimating transcript abundances with accuracy comparable with any state-of-the-art method. This enables RNA-Skim to perform transcript quantification on each cluster independently, reducing a complex optimization problem into smaller optimization tasks that can be run in parallel. As a result, RNA-Skim uses <4% of the k-mers and <10% of the CPU time required by Sailfish. It is able to finish transcriptome quantification in <10 min per sample by using just a single thread on a commodity computer, which represents >100 speedup over the state-of-the-art alignment-based methods, while delivering

  16. A high throughput solubility assay for drug discovery using microscale shake-flask and rapid UHPLC-UV-CLND quantification.

    PubMed

    Lin, Baiwei; Pease, Joseph H

    2016-04-15

    The rapid determination of key physical properties of lead compounds is essential to the drug discovery process. Solubility is one of the most important properties since good solubility is needed not only for obtaining reliable in vitro and in vivo assay results in early discovery but also to ensure sufficient concentration of the drug being in circulation to get the desired therapeutic exposure at the target of interest. In order for medicinal chemists to tune solubility of lead compounds, a rapid assay is needed to provide solubility data that is accurate and predictive so that it can be reliably used for designing the next generation of compounds with improved properties. To ensure speed and data quality, we developed a high throughput solubility assay that utilizes a single calibration UHPLC-UV-CLND method and a 24h shake-flask format for rapid quantification. A set of 46 model compounds was used to demonstrate that the method is accurate, reproducible and predictive. Here we present development of the assay, including evaluation of quantification method, filtration membranes, equilibrium times, DMSO concentrations, and buffer conditions. A comparison of thermodynamic solubility results to our high throughput 24h shake-flask solubility assay results is also discussed. PMID:26855285

  17. Rapid testing and quantification of Salmonella in ileocaecal lymph nodes of Austrian pigs slaughtered for consumption.

    PubMed

    Mann, Evelyne; Wagner, Martin; Schmoll, Friedrich; Slaghuis, Jörg; Schönenbrücher, Holger; Mester, Patrick

    2014-10-01

    Traditionally, quantitative microbial risk assessment (QMRA) is based on culture-dependent technologies. However, molecular quantification could forge additional, detailed information. A prerequisite of quantitative real-time PCR in animal science is a tissue preparation method where large volumes of tissue material can be reduced and particularly target cells can be concentrated. An easy-to-use sample preparation method for food (Matrix-Lysis) was recently adapted to tissues and now permits quantification of target cells from up to 5 g of organic matrix. The aim of this study was to examine the suitability of Matrix-Lysis for quantification of Salmonella in porcine ileocaecal lymph nodes (ICLNs). After demonstrating constant recovery rates, ICLNs from 540 pigs were examined for Salmonella spp. with Matrix-Lysis. Samples were also analysed using ISO 6579:2002, a combined enrichment/qPCR method and a lateral flow test. It could be shown that qPCR coupled with Matrix-Lysis can contribute to QMRA in food safety by enabling reproducible quantitative data, even at low contamination rates. PMID:25048837

  18. Rapid Quantification of Methamphetamine: Using Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy (ATR-FTIR) and Chemometrics

    PubMed Central

    Hughes, Juanita; Ayoko, Godwin; Collett, Simon; Golding, Gary

    2013-01-01

    In Australia and increasingly worldwide, methamphetamine is one of the most commonly seized drugs analysed by forensic chemists. The current well-established GC/MS methods used to identify and quantify methamphetamine are lengthy, expensive processes, but often rapid analysis is requested by undercover police leading to an interest in developing this new analytical technique. Ninety six illicit drug seizures containing methamphetamine (0.1%–78.6%) were analysed using Fourier Transform Infrared Spectroscopy with an Attenuated Total Reflectance attachment and Chemometrics. Two Partial Least Squares models were developed, one using the principal Infrared Spectroscopy peaks of methamphetamine and the other a Hierarchical Partial Least Squares model. Both of these models were refined to choose the variables that were most closely associated with the methamphetamine % vector. Both of the models were excellent, with the principal peaks in the Partial Least Squares model having Root Mean Square Error of Prediction 3.8, R2 0.9779 and lower limit of quantification 7% methamphetamine. The Hierarchical Partial Least Squares model had lower limit of quantification 0.3% methamphetamine, Root Mean Square Error of Prediction 5.2 and R2 0.9637. Such models offer rapid and effective methods for screening illicit drug samples to determine the percentage of methamphetamine they contain. PMID:23936058

  19. [Evaluation of Basic Performance of "Point Strip ferritin-3000" for Simple and Rapid Quantification of Serum Ferritin].

    PubMed

    Shibusa, Kotoe; Hatayama, Mayumi; Toki, Yasumichi; Yamamoto, Masayo; Ito, Satoshi; Shindo, Motohiro; Fujiya, Mikihiro; Niizeki, Noriyasu; Tomoda, Yutaka; Kawai, Yuichi; Addo, Lynda; Ikuta, Katsuya

    2015-12-01

    Serum ferritin is an excellent marker for total iron content in the body and is essential for the diagnosis of iron deficiency or iron overload. Recently, a simple and rapid method, which utilizes immunochromatography for the quantification of serum ferritin, was developed. However, the range of measurement in previous reagents was limited (10-500 ng/mL). This range is rather narrow and is not fully helpful for the diagnosis of iron overload which sometimes occurs as a result of prolonged transfusions, or for monitoring iron contents during iron chelation therapy against iron overload. In the present study we evaluated the basic performance of the newly developed "Point Strip ferritin-3000", which can measure serum ferritin in the range of 300-3,000 ng/mL. Coefficient of variation (CV) s of within and inter-day assays were in the ranges of 7.3-11.1% and 2.1-5.2%, respectively. Using 87 serum samples obtained from the patients with written informed consents, the correlation coefficient was calculated to be 0.93 compared to the control method. In addition, the quantification of serum ferritin by "Point Strip ferritin-3000" was not influenced by bilirubin, hemoglobin, chyle, rheumatoid factor, or ascorbic acid. From our data, "Point Strip ferritin-3000" is reliable reagent in the range of 300-3,000 ng/mL, and is therefore considered to be useful for the diagnosis of iron overload, as well as for monitoring iron contents during iron chelation therapy. In addition, this quantification method can be easily performed using a small desktop equipment without any special technique, making this system applicable for epidemiological surveys and clinical studies. PMID:27089653

  20. Rapid quantification of low level polymorph content in a solid dose form using transmission Raman spectroscopy.

    PubMed

    Griffen, Julia A; Owen, Andrew W; Burley, Jonathan; Taresco, Vincenzo; Matousek, Pavel

    2016-09-01

    This proof of concept study demonstrates the application of transmission Raman spectroscopy (TRS) to the non-invasive and non-destructive quantification of low levels (0.62-1.32% w/w) of an active pharmaceutical ingredient's polymorphic forms in a pharmaceutical formulation. Partial least squares calibration models were validated with independent validation samples resulting in prediction RMSEP values of 0.03-0.05% w/w and a limit of detection of 0.1-0.2% w/w. The study further demonstrates the ability of TRS to quantify all tablet constituents in one single measurement. By analysis of degraded stability samples, sole transformation between polymorphic forms was observed while excipient levels remained constant. Additionally, a beam enhancer device was used to enhance laser coupling to the sample, which allowed comparable prediction performance at 60 times faster rates (0.2s) than in standard mode. PMID:27218440

  1. Rapid turbidimetric assay for quantification of fusidic acid in a dermatological cream.

    PubMed

    Curbete, Mariane Machado; Salgado, Hérida Regina Nunes

    2016-06-01

    Fusidic acid is an antibiotic steroid widely used for the treatment of serious infections caused by methicillin-resistant Staphylococcus aureus (MRSA) strains. Microbiological methods are indispensable to determine the mean percentage of antimicrobial in medicaments during manufacturing and quality control processes. The aim of this study was to develop and validate a microbiological method for the quantification of fusidic acid in dermatological cream by turbidimetry, using Staphylococcus epidermidis (ATCC 12228) and casoy broth as the culture medium. The validation parameters were in accordance with ICH specifications and demonstrated accuracy, precision, selectivity, and robustness, with linear ranges from 0.25 to 2.25μgmL(-1). This method is an alternative to the diffusion agar assay currently employed to quantify fusidic acid in dermatological cream, since it is sensitive, fast, and more economical. PMID:27130089

  2. Quantification of Primary Dendritic and Secondary Eutectic Nucleation Undercoolings in Rapidly Solidified Hypo-Eutectic Al-Cu Droplets

    NASA Astrophysics Data System (ADS)

    Bogno, A.-A.; Khatibi, P. Delshad; Henein, H.; Gandin, Ch.-A.

    2016-09-01

    This paper reports on the quantification of primary dendritic and secondary eutectic nucleation undercoolings during rapid solidification of impulse atomized hypo-eutectic Al-Cu droplets. The procedure consists in determining the eutectic fraction of each investigated droplet from the fraction of intermetallic Al2Cu obtained by Rietveld refinement analysis of neutrons scattering data. The corresponding eutectic nucleation undercooling is then deduced from the metastable phase diagram of the alloy. The primary dendritic nucleation undercooling is subsequently determined using semi-empirical coarsening models of secondary dendrite arms. The two nucleation undercoolings are finally used as input variables to run a microsegregation model for binary alloys. The fractions of eutectic computed by the microsegregation model compare very favorably with the experimental results.

  3. Quantification of Primary Dendritic and Secondary Eutectic Nucleation Undercoolings in Rapidly Solidified Hypo-Eutectic Al-Cu Droplets

    NASA Astrophysics Data System (ADS)

    Bogno, A.-A.; Khatibi, P. Delshad; Henein, H.; Gandin, Ch.-A.

    2016-06-01

    This paper reports on the quantification of primary dendritic and secondary eutectic nucleation undercoolings during rapid solidification of impulse atomized hypo-eutectic Al-Cu droplets. The procedure consists in determining the eutectic fraction of each investigated droplet from the fraction of intermetallic Al2Cu obtained by Rietveld refinement analysis of neutrons scattering data. The corresponding eutectic nucleation undercooling is then deduced from the metastable phase diagram of the alloy. The primary dendritic nucleation undercooling is subsequently determined using semi-empirical coarsening models of secondary dendrite arms. The two nucleation undercoolings are finally used as input variables to run a microsegregation model for binary alloys. The fractions of eutectic computed by the microsegregation model compare very favorably with the experimental results.

  4. Development of a real-time PCR assay for rapid detection and quantification of Alexandrium minutum (a Dinoflagellate).

    PubMed

    Galluzzi, Luca; Penna, Antonella; Bertozzini, Elena; Vila, Magda; Garcés, Esther; Magnani, Mauro

    2004-02-01

    The marine dinoflagellate genus Alexandrium includes a number of species which produce neurotoxins responsible for paralytic shellfish poisoning (PSP), which in humans may cause muscular paralysis, neurological symptoms, and, in extreme cases, death. A. minutum is the most widespread toxic PSP species in the western Mediterranean basin. The monitoring of coastal waters for the presence of harmful algae also normally involves microscopic examinations of phytoplankton populations. These procedures are time consuming and require a great deal of taxonomic experience, thus limiting the number of specimens that can be analyzed. Because of the genetic diversity of different genera and species, molecular tools may also help to detect the presence of target microorganisms in marine field samples. In this study, we developed a real-time PCR-based assay for rapid detection of all toxic species of the Alexandrium genus in both fixative-preserved environmental samples and cultures. Moreover, we developed a real-time quantitative PCR assay for the quantification of A. minutum cells in seawater samples. Alexandrium genus-specific primers were designed on the 5.8S rDNA region. Primer specificity was confirmed by using BLAST and by amplification of a representative sample of the DNA of other dinoflagellates and diatoms. Using a standard curve constructed with a plasmid containing the ITS1-5.8S-ITS2 A. minutum sequence and cultured A. minutum cells, we determined the absolute number of 5.8S rDNA copies per cell. Consequently, after quantification of 5.8S rDNA copies in samples containing A. minutum cells, we were also able to estimate the number of cells. Several fixed A. minutum bloom sea samples from Arenys Harbor (Catalan Coast, Spain) were analyzed using this method, and quantification results were compared with standard microscopy counting methods. The two methods gave comparable results, confirming that real-time PCR could be a valid, fast alternative procedure for the

  5. A Rapid Molecular Test for Determining Yersinia pestis Susceptibility to Ciprofloxacin by the Quantification of Differentially Expressed Marker Genes.

    PubMed

    Steinberger-Levy, Ida; Shifman, Ohad; Zvi, Anat; Ariel, Naomi; Beth-Din, Adi; Israeli, Ofir; Gur, David; Aftalion, Moshe; Maoz, Sharon; Ber, Raphael

    2016-01-01

    Standard antimicrobial susceptibility tests used to determine bacterial susceptibility to antibiotics are growth dependent and time consuming. The long incubation time required for standard tests may render susceptibility results irrelevant, particularly for patients infected with lethal bacteria that are slow growing on agar but progress rapidly in vivo, such as Yersinia pestis. Here, we present an alternative approach for the rapid determination of antimicrobial susceptibility, based on the quantification of the changes in the expression levels of specific marker genes following exposure to growth-inhibiting concentrations of the antibiotic, using Y. pestis and ciprofloxacin as a model. The marker genes were identified by transcriptomic DNA microarray analysis of the virulent Y. pestis Kimberley53 strain after exposure to specific concentrations of ciprofloxacin for various time periods. We identified several marker genes that were induced following exposure to growth-inhibitory concentrations of ciprofloxacin, and we confirmed the marker expression profiles at additional ciprofloxacin concentrations using quantitative RT-PCR. Eleven candidate marker transcripts were identified, of which four mRNA markers were selected for a rapid quantitative RT-PCR susceptibility test that correctly determined the Minimal Inhibitory Concentration (MIC) values and the categories of susceptibility of several Y. pestis strains and isolates harboring various ciprofloxacin MIC values. The novel molecular susceptibility test requires just 2 h of antibiotic exposure in a 7-h overall test time, in contrast to the 24 h of antibiotic exposure required for a standard microdilution test. PMID:27242774

  6. A Rapid Molecular Test for Determining Yersinia pestis Susceptibility to Ciprofloxacin by the Quantification of Differentially Expressed Marker Genes

    PubMed Central

    Steinberger-Levy, Ida; Shifman, Ohad; Zvi, Anat; Ariel, Naomi; Beth-Din, Adi; Israeli, Ofir; Gur, David; Aftalion, Moshe; Maoz, Sharon; Ber, Raphael

    2016-01-01

    Standard antimicrobial susceptibility tests used to determine bacterial susceptibility to antibiotics are growth dependent and time consuming. The long incubation time required for standard tests may render susceptibility results irrelevant, particularly for patients infected with lethal bacteria that are slow growing on agar but progress rapidly in vivo, such as Yersinia pestis. Here, we present an alternative approach for the rapid determination of antimicrobial susceptibility, based on the quantification of the changes in the expression levels of specific marker genes following exposure to growth-inhibiting concentrations of the antibiotic, using Y. pestis and ciprofloxacin as a model. The marker genes were identified by transcriptomic DNA microarray analysis of the virulent Y. pestis Kimberley53 strain after exposure to specific concentrations of ciprofloxacin for various time periods. We identified several marker genes that were induced following exposure to growth-inhibitory concentrations of ciprofloxacin, and we confirmed the marker expression profiles at additional ciprofloxacin concentrations using quantitative RT-PCR. Eleven candidate marker transcripts were identified, of which four mRNA markers were selected for a rapid quantitative RT-PCR susceptibility test that correctly determined the Minimal Inhibitory Concentration (MIC) values and the categories of susceptibility of several Y. pestis strains and isolates harboring various ciprofloxacin MIC values. The novel molecular susceptibility test requires just 2 h of antibiotic exposure in a 7-h overall test time, in contrast to the 24 h of antibiotic exposure required for a standard microdilution test. PMID:27242774

  7. Fractal circuit sensors enable rapid quantification of biomarkers for donor lung assessment for transplantation

    PubMed Central

    Sage, Andrew T.; Besant, Justin D.; Mahmoudian, Laili; Poudineh, Mahla; Bai, Xiaohui; Zamel, Ricardo; Hsin, Michael; Sargent, Edward H.; Cypel, Marcelo; Liu, Mingyao; Keshavjee, Shaf; Kelley, Shana O.

    2015-01-01

    Biomarker profiling is being rapidly incorporated in many areas of modern medical practice to improve the precision of clinical decision-making. This potential improvement, however, has not been transferred to the practice of organ assessment and transplantation because previously developed gene-profiling techniques require an extended period of time to perform, making them unsuitable in the time-sensitive organ assessment process. We sought to develop a novel class of chip-based sensors that would enable rapid analysis of tissue levels of preimplantation mRNA markers that correlate with the development of primary graft dysfunction (PGD) in recipients after transplant. Using fractal circuit sensors (FraCS), three-dimensional metal structures with large surface areas, we were able to rapidly (<20 min) and reproducibly quantify small differences in the expression of interleukin-6 (IL-6), IL-10, and ATP11B mRNA in donor lung biopsies. A proof-of-concept study using 52 human donor lungs was performed to develop a model that was used to predict, with excellent sensitivity (74%) and specificity (91%), the incidence of PGD for a donor lung. Thus, the FraCS-based approach delivers a key predictive value test that could be applied to enhance transplant patient outcomes. This work provides an important step toward bringing rapid diagnostic mRNA profiling to clinical application in lung transplantation. PMID:26601233

  8. New protocol for the rapid quantification of exopolysaccharides in continuous culture systems of acidophilic bioleaching bacteria.

    PubMed

    Michel, Caroline; Bény, Claire; Delorme, Fabian; Poirier, Laurence; Spolaore, Pauline; Morin, Dominique; d'Hugues, Patrick

    2009-02-01

    In this study, we investigate exopolysaccharide production by a bacterial consortium during the bioleaching of a cobaltiferrous pyrite. Whereas comparable studies have looked at exopolysaccharide production in batch systems, this study focuses on a continuous system comprising a series of four stirred bioreactors and reveals the difficulties in quantifying biomolecules in complex media such as bioleached samples. We also adapted the phenol/sulphuric acid method to take into account iron interference, thus establishing a new protocol for sugar quantification in bioleached samples characterised by low pH (1.4) and high iron concentration (2 g l(-1)). This allows sugar analysis without any prior sample preparation step; only a small amount of sample is needed (0.5 ml) and sample preparation is limited to a single filtration step. We found that free exopolysaccharides represented more than 80% of the total sugars in the bioreactors, probably because stirring creates abrasive conditions and detaches sugars bound to pyrite or bacteria and that they were produced mainly in the first two reactors where bioleaching activity was greatest. However, we could not establish any direct link between the measured exopolysaccharide concentration and bioleaching activity. Exopolysaccharides could have another role (protection against stress) in addition to that in bacterial attachment. PMID:19130051

  9. Development of an assay for rapid detection and quantification of Verticillium dahliae in soil.

    PubMed

    Bilodeau, Guillaume J; Koike, Steven T; Uribe, Pedro; Martin, Frank N

    2012-03-01

    ABSTRACT Verticillium dahliae is responsible for Verticillium wilt on a wide range of hosts, including strawberry, on which low soil inoculum densities can cause significant crop loss. Determination of inoculum density is currently done by soil plating but this can take 6 to 8 weeks to complete and delay the grower's ability to make planting decisions. To provide a faster means for estimating pathogen populations in the soil, a multiplexed TaqMan real-time polymerase chain reaction (PCR) assay based on the ribosomal DNA (rDNA) intergenic spacer (IGS) was developed for V. dahliae. The assay was specific for V. dahliae and included an internal control for evaluation of inhibition due to the presence of PCR inhibitors in DNA extracted from soil samples. An excellent correlation was observed in regression analysis (R(2) = 0.96) between real-time PCR results and inoculum densities determined by soil plating in a range of field soils with pathogen densities as low as 1 to 2 microsclerotia/g of soil. Variation in copy number of the rDNA was also evaluated among isolates by SYBR Green real-time PCR amplification of the V. dahliae-specific amplicon compared with amplification of several single-copy genes and was estimated to range from ≈24 to 73 copies per haploid genome, which translated into possible differences in results among isolates of ≈1.8 cycle thresholds. Analysis of the variation in results of V. dahliae quantification among extractions of the same soil sample indicated that assaying four replicate DNA extractions for each field sample would provide accurate results. A TaqMan assay also was developed to help identify colonies of V. tricorpus on soil plates. PMID:22066673

  10. Rapid Quantification of Hepatitis B Virus DNA by Automated Sample Preparation and Real-Time PCR

    PubMed Central

    Stelzl, Evelyn; Muller, Zsofia; Marth, Egon; Kessler, Harald H.

    2004-01-01

    Monitoring of hepatitis B virus (HBV) DNA in serum by molecular methods has become the standard for assessment of the replicative activity of HBV. Several molecular assays for the detection and quantification of HBV DNA have been described. However, they usually lack automated sample preparation. Moreover, those assays, which are based on PCR, are limited by a short dynamic range (2 to 3 log units). In the present study, the use of RealArt HBV LC PCR Reagents in conjunction with automated extraction on the COBAS AMPLIPREP analyzer was evaluated. Members of an HBV proficiency program panel were tested; linearity, interassay, and intra-assay variations were determined. The performance of the assay in a routine clinical laboratory was evaluated with a total of 117 clinical specimens. When members of the HBV proficiency program panel were tested by the new molecular assay, the results were found to be within ±0.5 log unit of the results obtained by reference laboratories. Determination of linearity resulted in a quasilinear curve over more than 6 log units. The interassay variation of the RealArt HBV LC PCR Reagents by use of the automated sample preparation protocol ranged from 16 to 73%, and the intra-assay variation ranged from 9 to 40%. When clinical samples were tested by the new assay with the automated sample preparation protocol and the results were compared with those obtained by the COBAS AMPLICOR HBV MONITOR Test with manual sample preparation, the results for 76% of all samples with positive results by both tests were found to be within ±0.5 log unit and the results for another 18% were found to be within between 0.5 and 1.0 log unit. In conclusion, the real-time PCR assay with automated sample preparation proved to be suitable for the routine molecular laboratory and required less hands-on time. PMID:15184417

  11. Rapid imaging, detection and quantification of Giardia lamblia cysts using mobile-phone based fluorescent microscopy and machine learning.

    PubMed

    Koydemir, Hatice Ceylan; Gorocs, Zoltan; Tseng, Derek; Cortazar, Bingen; Feng, Steve; Chan, Raymond Yan Lok; Burbano, Jordi; McLeod, Euan; Ozcan, Aydogan

    2015-03-01

    Rapid and sensitive detection of waterborne pathogens in drinkable and recreational water sources is crucial for treating and preventing the spread of water related diseases, especially in resource-limited settings. Here we present a field-portable and cost-effective platform for detection and quantification of Giardia lamblia cysts, one of the most common waterborne parasites, which has a thick cell wall that makes it resistant to most water disinfection techniques including chlorination. The platform consists of a smartphone coupled with an opto-mechanical attachment weighing ~205 g, which utilizes a hand-held fluorescence microscope design aligned with the camera unit of the smartphone to image custom-designed disposable water sample cassettes. Each sample cassette is composed of absorbent pads and mechanical filter membranes; a membrane with 8 μm pore size is used as a porous spacing layer to prevent the backflow of particles to the upper membrane, while the top membrane with 5 μm pore size is used to capture the individual Giardia cysts that are fluorescently labeled. A fluorescence image of the filter surface (field-of-view: ~0.8 cm(2)) is captured and wirelessly transmitted via the mobile-phone to our servers for rapid processing using a machine learning algorithm that is trained on statistical features of Giardia cysts to automatically detect and count the cysts captured on the membrane. The results are then transmitted back to the mobile-phone in less than 2 minutes and are displayed through a smart application running on the phone. This mobile platform, along with our custom-developed sample preparation protocol, enables analysis of large volumes of water (e.g., 10-20 mL) for automated detection and enumeration of Giardia cysts in ~1 hour, including all the steps of sample preparation and analysis. We evaluated the performance of this approach using flow-cytometer-enumerated Giardia-contaminated water samples, demonstrating an average cyst capture

  12. Specific ionic effect for simple and rapid colorimetric sensing assays of amino acids using gold nanoparticles modified with task-specific ionic liquid.

    PubMed

    Wu, Datong; Cai, Pengfei; Tao, Zhihao; Pan, Yuanjiang

    2016-01-01

    In this study, a novel task-specific ionic liquid functionalized gold nanoparticle (TSIL-GNP) was successfully prepared and applied in the recognition of amino acids. Particularly, the surface of GNP was modified with the ionic liquid containing carbamido and ester group via thiol, which was characterized by Fourier transform infrared spectroscopy (FTIR) and transmission electron microscopy (TEM). The stability of this material in aqueous solution improves apparently and can remain unchanged for more than three months. The effect of pH was also discussed in this study. Attractive ionic interaction would effectively weaken intensity of the covalent coupling between the metal ion and the functional groups of amino acids. Thus, TSIL-GNP was successfully applied to recognizing serine, aspartic acid, lysine, arginine, and histidine in the presence of Cu(2+) through distinctive color changes. Suspension would be generated once a spot of cysteine was added into the GNPs solution. Results indicated that it had a good linear relationship between extinction coefficients and concentration of amino acids in a wide range of 10(-3)-10(-6) M. Moreover, the proposed strategy was successfully used to analyze the histidine in urinary samples. In brief, TSIL-GNP is a suitable substrate for discrimination of five amino acids in a rapid and simple way without sophisticated instruments. PMID:26703268

  13. Rapid onsite detection of bacterial spores of biothreat importance by paper-based colorimetric method using erbium-pyrocatechol violet complex.

    PubMed

    Shivakiran, M S; Venkataramana, M; Lakshmana Rao, P V

    2016-01-01

    Dipicolinic acid (DPA) is an important chemical marker for the detection of bacterial spores. In this study, complexes of lanthanide series elements such as erbium, europium, neodymium, and terbium were prepared with pyrocatechol violet and effectively immobilized the pyrocatechol violet (PV)-metal complex on a filter paper using polyvinyl alcohol. These filter paper strips were employed for the onsite detection of bacterial spores. The test filter papers were evaluated quantitatively with different concentrations of DPA and spores of various bacteria. Among the four lanthanide ions, erbium displayed better sensitivity than the other ions. The limit of detection of this test for DPA was 60 μM and 5 × 10(6) spores. The effect of other non-spore-forming bacteria and interfering chemicals on the test strips was also evaluated. The non-spore-forming bacteria did not have considerable effect on the test strip whereas chemicals such as EDTA had significant effects on the test results. The present test is rapid and robust, capable of providing timely results for better judgement to save resources on unnecessary decontamination procedures during false alarms. PMID:26603759

  14. Quantification of anthropogenic and natural changes in oil sands mining infrastructure land based on RapidEye and SPOT5

    NASA Astrophysics Data System (ADS)

    Zhang, Ying; Guindon, Bert; Lantz, Nicholas; Shipman, Todd; Chao, Dennis; Raymond, Don

    2014-06-01

    Natural resources development, spanning exploration, production and transportation activities, alters local land surface at various spatial scales. Quantification of these anthropogenic changes, both permanent and reversible, is needed for compliance assessment and for development of effective sustainable management strategies. Multi-spectral high resolution imagery data from SPOT5 and RapidEye were used for extraction and quantification of the anthropogenic and natural changes for a case study of Alberta bitumen (oil sands) mining located in the Western Boreal Plains near Fort McMurray, Canada. Two test sites representative of the major Alberta bitumen production extraction processes, open pit and in situ extraction, were selected. A hybrid change detection approach, combining pixel- and object-based target detection and extraction, is proposed based on Change Vector Analysis (CVA). The extraction results indicate that the changed infrastructure landscapes of these two sites have different footprints linked with their differing oil sands production processes. Pixel- and object-based accuracy assessments have been applied for validation of the change detection results. For manmade disturbances, except for those fine linear features such as the seismic lines, accuracies of about 80% have been achieved at the pixel level while, at the object level, these rise to 90-95%. Since many disturbance features are transient, a new landscape index, entitled the Re-growth Index, has been formulated at single object level specifically to monitor restoration of these features to their natural state. It is found that the temporal behaviour of the Re-growth Index in an individual patch varies depending on the type of natural land cover. In addition, the Re-growth Index is also useful for assessing the detectability of disturbed sites.

  15. Semiautomatic and rapid quantification of heartbeat parameters in Drosophila using optical coherence tomography imaging

    NASA Astrophysics Data System (ADS)

    Guo, Shou-Yuan; Liao, Fang-Tsu; Su, Ming-Tsan; Chang, Cheng-Yi; Su, Hong-Ren; Huang, Jyun-Cin; Kuo, Wen-Chuan

    2013-02-01

    We report a semiautomatic algorithm that is specialized for rapid analysis of beat-to-beat contraction-relaxation parameters of the heart in Drosophila. The presented algorithm adapts the general graph theoretical image segmentation algorithm and a histogram-based thresholding algorithm, which can measure many cardiac parameters, including heart rate, heart period, diastolic and systolic intervals, and end-diastolic and end-systolic areas. Additionally, dynamic cardiac functions, such as arrhythmia index and percent fractional shortening, can be automatically calculated for all the recorded heartbeats over significant periods of time.

  16. Rapid Quantification of 3D Collagen Fiber Alignment and Fiber Intersection Correlations with High Sensitivity

    PubMed Central

    Sun, Meng; Bloom, Alexander B.; Zaman, Muhammad H.

    2015-01-01

    Metastatic cancers aggressively reorganize collagen in their microenvironment. For example, radially orientated collagen fibers have been observed surrounding tumor cell clusters in vivo. The degree of fiber alignment, as a consequence of this remodeling, has often been difficult to quantify. In this paper, we present an easy to implement algorithm for accurate detection of collagen fiber orientation in a rapid pixel-wise manner. This algorithm quantifies the alignment of both computer generated and actual collagen fiber networks of varying degrees of alignment within 5°°. We also present an alternative easy method to calculate the alignment index directly from the standard deviation of fiber orientation. Using this quantitative method for determining collagen alignment, we demonstrate that the number of collagen fiber intersections has a negative correlation with the degree of fiber alignment. This decrease in intersections of aligned fibers could explain why cells move more rapidly along aligned fibers than unaligned fibers, as previously reported. Overall, our paper provides an easier, more quantitative and quicker way to quantify fiber orientation and alignment, and presents a platform in studying effects of matrix and cellular properties on fiber alignment in complex 3D environments. PMID:26158674

  17. Rapid Quantification of 3D Collagen Fiber Alignment and Fiber Intersection Correlations with High Sensitivity.

    PubMed

    Sun, Meng; Bloom, Alexander B; Zaman, Muhammad H

    2015-01-01

    Metastatic cancers aggressively reorganize collagen in their microenvironment. For example, radially orientated collagen fibers have been observed surrounding tumor cell clusters in vivo. The degree of fiber alignment, as a consequence of this remodeling, has often been difficult to quantify. In this paper, we present an easy to implement algorithm for accurate detection of collagen fiber orientation in a rapid pixel-wise manner. This algorithm quantifies the alignment of both computer generated and actual collagen fiber networks of varying degrees of alignment within 5°°. We also present an alternative easy method to calculate the alignment index directly from the standard deviation of fiber orientation. Using this quantitative method for determining collagen alignment, we demonstrate that the number of collagen fiber intersections has a negative correlation with the degree of fiber alignment. This decrease in intersections of aligned fibers could explain why cells move more rapidly along aligned fibers than unaligned fibers, as previously reported. Overall, our paper provides an easier, more quantitative and quicker way to quantify fiber orientation and alignment, and presents a platform in studying effects of matrix and cellular properties on fiber alignment in complex 3D environments. PMID:26158674

  18. Device for rapid quantification of human carotid baroreceptor-cardiac reflex responses

    NASA Technical Reports Server (NTRS)

    Sprenkle, J. M.; Eckberg, D. L.; Goble, R. L.; Schelhorn, J. J.; Halliday, H. C.

    1986-01-01

    A new device has been designed, constructed, and evaluated to characterize the human carotid baroreceptor-cardiac reflex response relation rapidly. This system was designed for study of reflex responses of astronauts before, during, and after space travel. The system comprises a new tightly sealing silicon rubber neck chamber, a stepping motor-driven electrodeposited nickel bellows pressure system, capable of delivering sequential R-wave-triggered neck chamber pressure changes between +40 and -65 mmHg, and a microprocessor-based electronics system for control of pressure steps and analysis and display of responses. This new system provokes classic sigmoid baroreceptor-cardiac reflex responses with threshold, linear, and saturation ranges in most human volunteers during one held expiration.

  19. TREND: a tool for rapid online research literature analysis and quantification.

    PubMed

    Landers, Richard N

    2008-08-01

    The Research Explicator for oNline Databases (TREND) tool was developed out of a need to quantify large research literatures rapidly and objectively on the basis of online research database output. By parsing such output with TREND, a researcher can in minutes extract the most commonly cited articles, the most frequently published authors, a distribution of publication dates, and a variety of other information from a research literature several thousand articles in size. This tool thus enables an increase in productivity both for researchers venturing into new areas of interest and for advisors and instructors putting together core reading lists. The processing of citations from articles represents a unique challenge, however, because deviations from strict APA formatting cause problems that are sometimes difficult to correct mechanically. A case study of one particularly troublesome citation (Baron & Kenny, 1986) is presented. Usage and implications are discussed. PMID:18697661

  20. Quantification of cell viability and rapid screening anti-cancer drug utilizing nanomechanical fluctuation.

    PubMed

    Wu, Shangquan; Liu, Xiaoli; Zhou, Xiarong; Liang, Xin M; Gao, Dayong; Liu, Hong; Zhao, Gang; Zhang, Qingchuan; Wu, Xiaoping

    2016-03-15

    Cancer is a serious threat to human health. Although numerous anti-cancer drugs are available clinically, many have shown toxic side effects due to poor tumor-selectivity, and reduced effectiveness due to cancers rapid development of resistance to treatment. The development of new highly efficient and practical methods to quantify cell viability and its change under drug treatment is thus of significant importance in both understanding of anti-cancer mechanism and anti-cancer drug screening. Here, we present an approach of utilizing a nanomechanical fluctuation based highly sensitive microcantilever sensor, which is capable of characterizing the viability of cells and quantitatively screening (within tens of minutes) their responses to a drug with the obvious advantages of a rapid, label-free, quantitative, noninvasive, real-time and in-situ assay. The microcantilever sensor operated in fluctuation mode was used in evaluating the paclitaxel effectiveness on breast cancer cell line MCF-7. This study demonstrated that the nanomechanical fluctuations of the microcantilever sensor are sensitive enough to detect the dynamic variation in cellular force which is provided by the cytoskeleton, using cell metabolism as its energy source, and the dynamic instability of microtubules plays an important role in the generation of the force. We propose that cell viability consists of two parts: biological viability and mechanical viability. Our experimental results suggest that paclitaxel has little effect on biological viability, but has a significant effect on mechanical viability. This new method provides a new concept and strategy for the evaluation of cell viability and the screening of anti-cancer drugs. PMID:26406457

  1. Rapid guided wave delamination detection and quantification in composites using global-local sensing

    NASA Astrophysics Data System (ADS)

    Tian, Zhenhua; Yu, Lingyu; Leckey, Cara

    2016-08-01

    This paper presents a rapid guided ultrasonic wave inspection approach through global inspection by phased array beamforming and local damage evaluation via wavenumber analysis. The global-local approach uses a hybrid system consisting of a PZT wafer and a non-contact laser vibrometer. The overall inspection is performed in two steps. First, a phased array configured by a small number of measurements performs beamforming and beamsteering over the entire plate in order to detect and locate the presence of the damage. A local area is identified as target damage area for the second step. Then a high density wavefield measurement is taken over the target damage area and a spatial wavenumber imaging is performed to quantitatively evaluate the damage. The two-step inspection has been applied to locate and quantify impact-induced delamination damage in a carbon fiber reinforced polymer composite plate. The detected delamination location, size and shape agree well with those of an ultrasonic C-scan. For the test case studied in this work the global-local approach reduced the total composite inspection (damage detection and characterization) time by ∼97% compared to using a full scan approach.

  2. Rapid and simple UPLC-MS/MS method for precise phytochelatin quantification in alga extracts.

    PubMed

    Bräutigam, Anja; Wesenberg, Dirk; Preud'homme, Hugues; Schaumlöffel, Dirk

    2010-09-01

    Quantitative phytochelatin (PC) analysis is, due to oxidation sensitivity of the PCs, matrix effects, and time consuming sample preparation, still a challenging analytical task. In this study, a rapid, simple, and sensitive method for precise determination of native PCs in crude extracts of the green alga Chlamydomonas reinhardtii was developed. Algae were exposed 48 h to 70 μM Cd. Coupling of ultra performance liquid chromatography and electrospray ionization tandem mass spectrometry with multi-reaction mode transitions for detection permitted the required short-time, high-resolution separation and detection specificity. Thus, under optimized chromatographic conditions, 10 thiol peptides were baseline-separated within 7 min. Relative detection limits in the nanomolar range in microliter sample volumes were achieved (corresponding to absolute detection limits at femtomole level). Next to glutathione (GSH), the most abundant cadmium-induced PCs in C. reinhardtii, namely CysGSH, PC(2), PC(3), CysPC(2), and CysPC(3), were quantified with high reproducibility at concentrations between 15 and 198 nmol g(-1) fresh weight. The biological variation of PC synthesis of nine independently grown alga cultures was determined to be on average 13.7%. PMID:20632163

  3. Electromechanical transducer for rapid detection, discrimination and quantification of lung cancer cells

    NASA Astrophysics Data System (ADS)

    Ali, Waqas; Jalvhei Moghaddam, Fatemeh; Usman Raza, Muhammad; Bui, Loan; Sayles, Bailey; Kim, Young-Tae; Iqbal, Samir M.

    2016-05-01

    Tumor cells are malignant derivatives of normal cells. There are characteristic differences in the mechanophysical properties of normal and tumor cells, and these differences stem from the changes that occur in the cell cytoskeleton during cancer progression. There is a need for viable whole blood processing techniques for rapid and reliable tumor cell detection that do not require tagging. Micropore biosensors have previously been used to differentiate tumor cells from normal cells and we have used a micropore-based electromechanical transducer to differentiate one type of tumor cells from the other types. This device generated electrical signals that were characteristic of the cell properties. Three non-small cell lung cancer (NSCLC) cell lines, NCl-H1155, A549 and NCI-H460, were successfully differentiated. NCI-H1155, due to their comparatively smaller size, were found to be the quickest in translocating through the micropore. Their translocation through a 15 μm micropore caused electrical pulses with an average translocation time of 101 ± 9.4 μs and an average peak amplitude of 3.71 ± 0.42 μA, whereas translocation of A549 and NCI-H460 caused pulses with average translocation times of 126 ± 17.9 μs and 148 ± 13.7 μs and average peak amplitudes of 4.58 ± 0.61 μA and 5.27 ± 0.66 μA, respectively. This transformation of the differences in cell properties into differences in the electrical profiles (i.e. the differences in peak amplitudes and translocation times) with this electromechanical transducer is a quantitative way to differentiate these lung cancer cells. The solid-state micropore device processed whole biological samples without any pre-processing requirements and is thus ideal for point-of-care applications.

  4. Rapid TaqMan-Based Quantification of Chlorophyll d-Containing Cyanobacteria in the Genus Acaryochloris

    PubMed Central

    Behrendt, Lars; Nielsen, Jeppe L.; Sørensen, Søren J.; Larkum, Anthony W. D.; Winther, Jakob R.

    2014-01-01

    Reports of the chlorophyll (Chl) d-containing cyanobacterium Acaryochloris have accumulated since its initial discovery in 1996. The majority of this evidence is based on amplification of the gene coding for the 16S rRNA, and due to the wide geographical distribution of these sequences, a global distribution of Acaryochloris species was suggested. Here, we present a rapid, reliable, and cost-effective TaqMan-based quantitative PCR (qPCR) assay that was developed for the specific detection of Acaryochloris species in complex environmental samples. The TaqMan probe showed detection limits of ∼10 16S rRNA gene copy numbers based on standard curves consisting of plasmid inserts. DNA from five Acaryochloris strains, i.e., MBIC11017, CCMEE5410, HICR111A, CRS, and Awaji-1, exhibited amplification efficiencies of >94% when tested in the TaqMan assay. When used on complex natural communities, the TaqMan assay detected the presence of Acaryochloris species in four out of eight samples of crustose coralline algae (CCA), collected from temperate and tropical regions. In three out of these TaqMan-positive samples, the presence of Chl d was confirmed via high-performance liquid chromatography (HPLC), and corresponding cell estimates of Acaryochloris species amounted to 7.6 × 101 to 3.0 × 103 per mg of CCA. These numbers indicate a substantial contribution of Chl d-containing cyanobacteria to primary productivity in endolithic niches. The new TaqMan assay allows quick and easy screening of environmental samples for the presence of Acaryochloris species and is an important tool to further resolve the global distribution and significance of this unique oxyphototroph. PMID:24632258

  5. Sensitive and rapid RT-qPCR quantification of pathogenic Candida species in human blood.

    PubMed

    Ogata, Kiyohito; Matsuda, Kazunori; Tsuji, Hirokazu; Nomoto, Koji

    2015-10-01

    For accurate diagnosis and appropriate treatment of candidiasis, we developed a highly sensitive quantitative RT-PCR (RT-qPCR) system for five Candida species that have been reported to be the major causes of bloodstream fungal infection (Candida albicans, Candida glabrata, Candida tropicalis, Candida parapsilosis, and Candida krusei), together with a system for all pathogenic Candida species. Cells of each fungal species spiked into human peripheral blood (PB) were specifically detected at a lower detection limit of 10(0) cell/1 mL PB by this system using the newly developed specific primer sets targeting 18S or 26S rRNA of the five Candida species, together with the existing group primer set. The total count of the five Candida spp. as the sum of those obtained by using the five species primer sets was equivalent to the count obtained by using the group primer set, indicating that the group set covered the major five Candida spp. in human blood with the same degree of accuracy as the species primer sets. The RT-qPCR counts of the Candida species were in good agreement with CFU counts obtained by their culture on CHROMagar™, with a lower detection limit of 10(0)cell/mL of PB. Candida rRNA molecules were stably stored for at least 7 days at 4°C by keeping the blood specimens in an RNA stabilizing reagent. These results strongly suggest that this sensitive system is useful for accurate and rapid diagnosis of Candida bloodstream infections. PMID:26232708

  6. Rapid extraction, identification and quantification of oral hypoglycaemic drugs in serum and hair using LC-MS/MS.

    PubMed

    Binz, Tina M; Villani, Nicholas; Neels, Hugo; Schneider, Serge

    2012-11-30

    A sensitive and accurate LC-MS/MS method for the identification and quantification of 5 oral anti-diabetics (glipizide, glibenclamide, gliclazide, gliquidone and metformin) in serum and hair was developed using glibornuride as the internal standard. We have developed a rapid and robust extraction procedure by using acetonitrile for serum protein precipitation and methanol for the extraction of anti-diabetics from hair. Anti-diabetics (ADs) were separated by UPLC over a C18 column and detection was performed on a Waters Xevo TQ MS mass spectrometer in positive ionization mode using electrospray ionization. Each AD was identified by three specific ion transitions in multiple reaction monitoring (MRM) mode. The method was validated according to international guidelines. For all compounds the variation coefficient (CV) was <20%, and accuracies ranged from 85 to 115% in serum and hair. The limits of detection (LODs) were <1.5 ng/mL for all ADs in serum and <3.59 pg/mg in hair. Recoveries varied from 56.41% (gliclazide) to 67.58% (glipizide) in serum and from 68% (gliclazide) to 91.2% (metformin) in hair. The method was successfully applied to quantify ADs in serum of 33 patients and in hair of 15 patients. PMID:22940189

  7. Rapid method for quantification of seven synthetic pigments in colored Chinese steamed buns using UFLC-MS/MS without SPE.

    PubMed

    Gao, He-Gang; Gong, Wen-Jie; Zhao, Yong-Gang

    2015-01-01

    Synthetic pigments are still used instead of natural pigments in many foods and their residues in food could be an important risk to human health. A simple and rapid analytical method combining the low-cost extraction protocol with ultra-fast liquid chromatography-tandem quadrupole mass spectrometry (UFLC-MS/MS) was developed for the simultaneous determination of seven synthetic pigments used in colored Chinese steamed buns. For the first time, ethanol/ammonia solution/water (7:2:1, v/v/v) was used as extraction solution for the synthetic pigments in colored Chinese steamed buns. The results showed that the property of the extraction solution used in this method was more effective than critic acid solution, which is used in the polyamide adsorption method. The limits of quantification for the seven synthetic pigments ranged from 0.15 to 0.50 μg/kg. The present method was successfully applied to samples of colored Chinese steamed buns for food-safety risk monitoring in Zhejiang Province, China. The results found sunset yellow pigment in six out of 300 colored Chinese steamed buns (from 0.50 to 32.6 μg/kg). PMID:25765275

  8. Electromechanical transducer for rapid detection, discrimination and quantification of lung cancer cells.

    PubMed

    Ali, Waqas; Moghaddam, Fatemeh Jalvhei; Raza, Muhammad Usman; Bui, Loan; Sayles, Bailey; Kim, Young-Tae; Iqbal, Samir M

    2016-05-13

    Tumor cells are malignant derivatives of normal cells. There are characteristic differences in the mechanophysical properties of normal and tumor cells, and these differences stem from the changes that occur in the cell cytoskeleton during cancer progression. There is a need for viable whole blood processing techniques for rapid and reliable tumor cell detection that do not require tagging. Micropore biosensors have previously been used to differentiate tumor cells from normal cells and we have used a micropore-based electromechanical transducer to differentiate one type of tumor cells from the other types. This device generated electrical signals that were characteristic of the cell properties. Three non-small cell lung cancer (NSCLC) cell lines, NCl-H1155, A549 and NCI-H460, were successfully differentiated. NCI-H1155, due to their comparatively smaller size, were found to be the quickest in translocating through the micropore. Their translocation through a 15 μm micropore caused electrical pulses with an average translocation time of 101 ± 9.4 μs and an average peak amplitude of 3.71 ± 0.42 μA, whereas translocation of A549 and NCI-H460 caused pulses with average translocation times of 126 ± 17.9 μs and 148 ± 13.7 μs and average peak amplitudes of 4.58 ± 0.61 μA and 5.27 ± 0.66 μA, respectively. This transformation of the differences in cell properties into differences in the electrical profiles (i.e. the differences in peak amplitudes and translocation times) with this electromechanical transducer is a quantitative way to differentiate these lung cancer cells. The solid-state micropore device processed whole biological samples without any pre-processing requirements and is thus ideal for point-of-care applications. PMID:27023745

  9. Development of a colorimetric sensor array for squid spoilage assessment.

    PubMed

    Zaragozá, Patricia; Fuentes, Ana; Ruiz-Rico, María; Vivancos, José-Luis; Fernández-Segovia, Isabel; Ros-Lis, José V; Barat, José M; Martínez-Máñez, Ramón

    2015-05-15

    The aim of this work was to develop and evaluate a rapid, easy-to-use optoelectronic system for the shelf-life assessment of squid in cold storage. For this purpose, an optoelectronic nose was designed, which consisted of an array containing six sensing materials prepared by combining different dyes and two inorganic supports (aluminium oxide and silica gel). Samples were packaged with the colorimetric array and kept in cold storage for 12 days. Squid spoilage was monitored simultaneously by the colorimetric array and by the physico-chemical and microbial analyses during storage. Samples exceeded the acceptability limits for microbial counts on the third day. PCA analysis carried out with CIELab showed that the colorimetric array was able to discriminate between fresh squid fit for consumption and spoiled squid. The statistical models obtained by PLS, with the optoelectronic nose, successfully predicted CO2 and O2 content in the headspace as well as microbial growth. PMID:25577086

  10. Quantification of rapid environmental redox processes with quick-scanning x-ray absorption spectroscopy (Q-XAS).

    PubMed

    Ginder-Vogel, Matthew; Landrot, Gautier; Fischel, Jason S; Sparks, Donald L

    2009-09-22

    Quantification of the initial rates of environmental reactions at the mineral/water interface is a fundamental prerequisite to determining reaction mechanisms and contaminant transport modeling and predicting environmental risk. Until recently, experimental techniques with adequate time resolution and elemental sensitivity to measure initial rates of the wide variety of environmental reactions were quite limited. Techniques such as electron paramagnetic resonance and Fourier transform infrared spectroscopies suffer from limited elemental specificity and poor sensitivity to inorganic elements, respectively. Ex situ analysis of batch and stirred-flow systems provides high elemental sensitivity; however, their time resolution is inadequate to characterize rapid environmental reactions. Here we apply quick-scanning x-ray absorption spectroscopy (Q-XAS), at sub-second time-scales, to measure the initial oxidation rate of As(III) to As(V) by hydrous manganese(IV) oxide. Using Q-XAS, As(III) and As(V) concentrations were determined every 0.98 s in batch reactions. The initial apparent As(III) depletion rate constants (t < 30 s) measured with Q-XAS are nearly twice as large as rate constants measured with traditional analytical techniques. Our results demonstrate the importance of developing analytical techniques capable of analyzing environmental reactions on the same time scale as they occur. Given the high sensitivity, elemental specificity, and time resolution of Q-XAS, it has many potential applications. They could include measuring not only redox reactions but also dissolution/precipitation reactions, such as the formation and/or reductive dissolution of Fe(III) (hydr)oxides, solid-phase transformations (i.e., formation of layered-double hydroxide minerals), or almost any other reaction occurring in aqueous media that can be measured using x-ray absorption spectroscopy. PMID:19805269

  11. Rapid, simple and highly sensitive LC-ESI-MS/MS method for the quantification of tamsulosin in human plasma.

    PubMed

    Ramakrishna, N V S; Vishwottam, K N; Manoj, S; Koteshwara, M; Wishu, S; Varma, D P

    2005-12-01

    A simple, rapid, sensitive and specific liquid chromatography-tandem mass spectrometry method was developed and validated for quantification of tamsulosin (I), a highly selective alpha1-adrenoceptor antagonist used for the treatment of patients with symptomatic benign prostatic hyperplasia. The analyte and internal standard, mosapride (II) were extracted by liquid-liquid extraction with diethyl ether-dichloromethane (70:30, v/v) using a Glas-Col Multi-Pulse Vortexer. The chromatographic separation was performed on a reverse phase Waters symmetry C18 column with a mobile phase of 0.03% formic acid-acetonitrile (30:70, v/v). The protonated analyte was quantitated in positive ionization by multiple reaction monitoring with a mass spectrometer. The mass transitions m/z 409.1 solidus in circle 228.1 and m/z 422.3 solidus in circle 198.3 were used to measure I and II, respectively. The assay exhibited a linear dynamic range of 0.1-50.0 ng/mL for tamsulosin in human plasma. The lower limit of quantitation was 100 pg/mL with a relative standard deviation of less than 10%. Acceptable precision and accuracy were obtained for concentrations over the standard curve ranges. A run time of 2.0 min for each sample made it possible to analyze a throughput of more than 400 human plasma samples per day. The validated method has been successfully used to analyze human plasma samples for application in pharmacokinetic, bioavailability or bioequivalence studies. PMID:15828055

  12. Individual Colorimetric Observer Model

    PubMed Central

    Asano, Yuta; Fairchild, Mark D.; Blondé, Laurent

    2016-01-01

    This study proposes a vision model for individual colorimetric observers. The proposed model can be beneficial in many color-critical applications such as color grading and soft proofing to assess ranges of color matches instead of a single average match. We extended the CIE 2006 physiological observer by adding eight additional physiological parameters to model individual color-normal observers. These eight parameters control lens pigment density, macular pigment density, optical densities of L-, M-, and S-cone photopigments, and λmax shifts of L-, M-, and S-cone photopigments. By identifying the variability of each physiological parameter, the model can simulate color matching functions among color-normal populations using Monte Carlo simulation. The variabilities of the eight parameters were identified through two steps. In the first step, extensive reviews of past studies were performed for each of the eight physiological parameters. In the second step, the obtained variabilities were scaled to fit a color matching dataset. The model was validated using three different datasets: traditional color matching, applied color matching, and Rayleigh matches. PMID:26862905

  13. A versatile targeted metabolomics method for the rapid quantification of multiple classes of phenolics in fruits and beverages.

    PubMed

    Vrhovsek, Urska; Masuero, Domenico; Gasperotti, Mattia; Franceschi, Pietro; Caputi, Lorenzo; Viola, Roberto; Mattivi, Fulvio

    2012-09-12

    Compelling evidence of the health benefits of phenolic compounds and their impact on food quality have stimulated the development of analytical methods for the identification and quantification of these compounds in different matrices in recent years. A targeted metabolomics method has been developed for the quantification of 135 phenolics, such as benzoates, phenylpropanoids, coumarins, stilbenes, dihydrochalcones, and flavonoids, in fruit and tea extracts and wine using UPLC/QqQ-MS/MS. Chromatography was optimized to achieve separation of the compounds over a period of 15 min, and MRM transitions were selected for accurate quantification. The method was validated by studying the detection and quantification limits, the linearity ranges, and the intraday and interday repeatability of the analysis. The validated method was applied to the analysis of apples, berries, green tea, and red wine, providing a valuable tool for food quality evaluation and breeding studies. PMID:22468648

  14. A rapid and accurate quantification method for real-time dynamic analysis of cellular lipids during microalgal fermentation processes in Chlorella protothecoides with low field nuclear magnetic resonance.

    PubMed

    Wang, Tao; Liu, Tingting; Wang, Zejian; Tian, Xiwei; Yang, Yi; Guo, Meijin; Chu, Ju; Zhuang, Yingping

    2016-05-01

    The rapid and real-time lipid determination can provide valuable information on process regulation and optimization in the algal lipid mass production. In this study, a rapid, accurate and precise quantification method of in vivo cellular lipids of Chlorella protothecoides using low field nuclear magnetic resonance (LF-NMR) was newly developed. LF-NMR was extremely sensitive to the algal lipids with the limits of the detection (LOD) of 0.0026g and 0.32g/L in dry lipid samples and algal broth, respectively, as well as limits of quantification (LOQ) of 0.0093g and 1.18g/L. Moreover, the LF-NMR signal was specifically proportional to the cellular lipids of C. protothecoides, thus the superior regression curves existing in a wide detection range from 0.02 to 0.42g for dry lipids and from 1.12 to 8.97gL(-1) of lipid concentration for in vivo lipid quantification were obtained with all R(2) higher than 0.99, irrespective of the lipid content and fatty acids profile variations. The accuracy of this novel method was further verified to be reliable by comparing lipid quantification results to those obtained by GC-MS. And the relative standard deviation (RSD) of LF-NMR results were smaller than 2%, suggesting the precision of this method. Finally, this method was successfully used in the on-line lipid monitoring during the algal lipid fermentation processes, making it possible for better understanding of the lipid accumulation mechanism and dynamic bioprocess control. PMID:26948045

  15. Smartphone spectrometer for colorimetric biosensing.

    PubMed

    Wang, Yi; Liu, Xiaohu; Chen, Peng; Tran, Nhung Thi; Zhang, Jinling; Chia, Wei Sheng; Boujday, Souhir; Liedberg, Bo

    2016-05-23

    We report on a smartphone spectrometer for colorimetric biosensing applications. The spectrometer relies on a sample cell with an integrated grating substrate, and the smartphone's built-in light-emitting diode flash and camera. The feasibility of the smartphone spectrometer is demonstrated for detection of glucose and human cardiac troponin I, the latter in conjunction with peptide-functionalized gold nanoparticles. PMID:27163736

  16. Rapid Quantification of Melamine in Different Brands/Types of Milk Powders Using Standard Addition Net Analyte Signal and Near-Infrared Spectroscopy.

    PubMed

    Tang, Bang-Cheng; Cai, Chen-Bo; Shi, Wei; Xu, Lu

    2016-01-01

    Multivariate calibration (MVC) and near-infrared (NIR) spectroscopy have demonstrated potential for rapid analysis of melamine in various dairy products. However, the practical application of ordinary MVC can be largely restricted because the prediction of a new sample from an uncalibrated batch would be subject to a significant bias due to matrix effect. In this study, the feasibility of using NIR spectroscopy and the standard addition (SA) net analyte signal (NAS) method (SANAS) for rapid quantification of melamine in different brands/types of milk powders was investigated. In SANAS, the NAS vector of melamine in an unknown sample as well as in a series of samples added with melamine standards was calculated and then the Euclidean norms of series standards were used to build a straightforward univariate regression model. The analysis results of 10 different brands/types of milk powders with melamine levels 0~0.12% (w/w) indicate that SANAS obtained accurate results with the root mean squared error of prediction (RMSEP) values ranging from 0.0012 to 0.0029. An additional advantage of NAS is to visualize and control the possible unwanted variations during standard addition. The proposed method will provide a practically useful tool for rapid and nondestructive quantification of melamine in different brands/types of milk powders. PMID:27525154

  17. Rapid Quantification of Melamine in Different Brands/Types of Milk Powders Using Standard Addition Net Analyte Signal and Near-Infrared Spectroscopy

    PubMed Central

    2016-01-01

    Multivariate calibration (MVC) and near-infrared (NIR) spectroscopy have demonstrated potential for rapid analysis of melamine in various dairy products. However, the practical application of ordinary MVC can be largely restricted because the prediction of a new sample from an uncalibrated batch would be subject to a significant bias due to matrix effect. In this study, the feasibility of using NIR spectroscopy and the standard addition (SA) net analyte signal (NAS) method (SANAS) for rapid quantification of melamine in different brands/types of milk powders was investigated. In SANAS, the NAS vector of melamine in an unknown sample as well as in a series of samples added with melamine standards was calculated and then the Euclidean norms of series standards were used to build a straightforward univariate regression model. The analysis results of 10 different brands/types of milk powders with melamine levels 0~0.12% (w/w) indicate that SANAS obtained accurate results with the root mean squared error of prediction (RMSEP) values ranging from 0.0012 to 0.0029. An additional advantage of NAS is to visualize and control the possible unwanted variations during standard addition. The proposed method will provide a practically useful tool for rapid and nondestructive quantification of melamine in different brands/types of milk powders. PMID:27525154

  18. SynPAnal: software for rapid quantification of the density and intensity of protein puncta from fluorescence microscopy images of neurons.

    PubMed

    Danielson, Eric; Lee, Sang H

    2014-01-01

    Continuous modification of the protein composition at synapses is a driving force for the plastic changes of synaptic strength, and provides the fundamental molecular mechanism of synaptic plasticity and information storage in the brain. Studying synaptic protein turnover is not only important for understanding learning and memory, but also has direct implication for understanding pathological conditions like aging, neurodegenerative diseases, and psychiatric disorders. Proteins involved in synaptic transmission and synaptic plasticity are typically concentrated at synapses of neurons and thus appear as puncta (clusters) in immunofluorescence microscopy images. Quantitative measurement of the changes in puncta density, intensity, and sizes of specific proteins provide valuable information on their function in synaptic transmission, circuit development, synaptic plasticity, and synaptopathy. Unfortunately, puncta quantification is very labor intensive and time consuming. In this article, we describe a software tool designed for the rapid semi-automatic detection and quantification of synaptic protein puncta from 2D immunofluorescence images generated by confocal laser scanning microscopy. The software, dubbed as SynPAnal (for Synaptic Puncta Analysis), streamlines data quantification for puncta density and average intensity, thereby increases data analysis throughput compared to a manual method. SynPAnal is stand-alone software written using the JAVA programming language, and thus is portable and platform-free. PMID:25531531

  19. SynPAnal: Software for Rapid Quantification of the Density and Intensity of Protein Puncta from Fluorescence Microscopy Images of Neurons

    PubMed Central

    Danielson, Eric; Lee, Sang H.

    2014-01-01

    Continuous modification of the protein composition at synapses is a driving force for the plastic changes of synaptic strength, and provides the fundamental molecular mechanism of synaptic plasticity and information storage in the brain. Studying synaptic protein turnover is not only important for understanding learning and memory, but also has direct implication for understanding pathological conditions like aging, neurodegenerative diseases, and psychiatric disorders. Proteins involved in synaptic transmission and synaptic plasticity are typically concentrated at synapses of neurons and thus appear as puncta (clusters) in immunofluorescence microscopy images. Quantitative measurement of the changes in puncta density, intensity, and sizes of specific proteins provide valuable information on their function in synaptic transmission, circuit development, synaptic plasticity, and synaptopathy. Unfortunately, puncta quantification is very labor intensive and time consuming. In this article, we describe a software tool designed for the rapid semi-automatic detection and quantification of synaptic protein puncta from 2D immunofluorescence images generated by confocal laser scanning microscopy. The software, dubbed as SynPAnal (for Synaptic Puncta Analysis), streamlines data quantification for puncta density and average intensity, thereby increases data analysis throughput compared to a manual method. SynPAnal is stand-alone software written using the JAVA programming language, and thus is portable and platform-free. PMID:25531531

  20. A rapid Fourier-transform infrared (FTIR) spectroscopic method for direct quantification of paracetamol content in solid pharmaceutical formulations

    NASA Astrophysics Data System (ADS)

    Mallah, Muhammad Ali; Sherazi, Syed Tufail Hussain; Bhanger, Muhammad Iqbal; Mahesar, Sarfaraz Ahmed; Bajeer, Muhammad Ashraf

    2015-04-01

    A transmission FTIR spectroscopic method was developed for direct, inexpensive and fast quantification of paracetamol content in solid pharmaceutical formulations. In this method paracetamol content is directly analyzed without solvent extraction. KBr pellets were formulated for the acquisition of FTIR spectra in transmission mode. Two chemometric models: simple Beer's law and partial least squares employed over the spectral region of 1800-1000 cm-1 for quantification of paracetamol content had a regression coefficient of (R2) of 0.999. The limits of detection and quantification using FTIR spectroscopy were 0.005 mg g-1 and 0.018 mg g-1, respectively. Study for interference was also done to check effect of the excipients. There was no significant interference from the sample matrix. The results obviously showed the sensitivity of transmission FTIR spectroscopic method for pharmaceutical analysis. This method is green in the sense that it does not require large volumes of hazardous solvents or long run times and avoids prior sample preparation.

  1. Quantification of whey proteins by reversed phase-HPLC and effectiveness of mid-infrared spectroscopy for their rapid prediction in sweet whey.

    PubMed

    Sturaro, Alba; De Marchi, Massimo; Masi, Antonio; Cassandro, Martino

    2016-01-01

    In the dairy industry, membrane filtration is used to reduce the amount of whey waste and, simultaneously, to recover whey proteins (WP). The composition of WP can strongly affect the filtration treatment of whey, and rapid determination of WP fractions would be of interest for dairy producers to monitor WP recovery. This study aimed to develop mid-infrared spectroscopy (MIRS) prediction models for the rapid quantification of protein in sweet whey, using a validated rapid reversed phase (RP)-HPLC as a reference method. Quantified WP included α-lactalbumin (α-LA), β-lactoglobulin (β-LG) A and B, bovine serum albumin, caseinomacropeptides, and proteose peptone. Validation of RP-HPLC was performed by calculating the relative standard deviation (RSD) in repeatability and reproducibility tests for WP retention time and peak areas. Samples of liquid whey (n=187) were analyzed by RP-HPLC and scanned through MIRS to collect spectral information (900 to 4,000 cm(-1)); statistical analysis was carried out through partial least squares regression and random cross-validation procedure. Retention times in RP-HPLC method were stable (RSD between 0.03 and 0.80%), whereas the RSD of peak area (from 0.25 to 8.48%) was affected by WP relative abundance. Higher coefficients of determination in validation for MIRS model were obtained for protein fractions present in whey in large amounts, such as β-LG (0.58), total identified WP (0.58), and α-LA (0.56). Results of this study suggest that MIRS is an easy method for rapid quantification of detail protein in sweet whey, even if better resolution was achieved with the method based on RP-HPLC. The prediction of WP in sweet whey by MIRS might be used for screening and for classifying sweet whey according to its total and individual WP contents. PMID:26585472

  2. A colorimetric sensor array of porous pigments.

    PubMed

    Lim, Sung H; Kemling, Jonathan W; Feng, Liang; Suslick, Kenneth S

    2009-12-01

    The development of a low-cost, simple colorimetric sensor array capable of the detection and identification of toxic gases is reported. This technology uses a disposable printed array of porous pigments in which metalloporphyrins and chemically-responsive dyes are immobilized in a porous matrix of organically modified siloxanes (ormosils) and printed on a porous membrane. The printing of the ormosil into the membrane is highly uniform and does not lessen the porosity of the membrane, as shown by scanning electron microscopy. When exposed to an analyte, these pigments undergo reactions that result in well-defined color changes due to strong chemical interactions: ligation to metal ions, Lewis or Brønsted acid-base interactions, hydrogen bonding, etc. Striking visual identification of 3 toxic gases has been shown at the IDLH (immediately dangerous to life and health) concentration, at the PEL (permissible exposure level), and at a level well below the PEL. Identification and quantification of analytes were achieved using the color change profiles, which were readily distinguishable in a hierarchical clustering analysis (HCA) dendrogram, with no misclassifications in 50 trials. PMID:19918616

  3. A colorimetric sensor array of porous pigments

    PubMed Central

    Lim, Sung H.; Kemling, Jonathan W.; Feng, Liang

    2010-01-01

    The development of a low-cost, simple colorimetric sensor array capable of detection and identification of toxic gases is reported. This technology uses a disposable printed array of porous pigments in which metalloporphyrins and chemically responsive dyes are immobilized in a porous matrix of organically modified siloxanes (ormosils) and printed on a porous membrane. The printing of the ormosil into the membrane is highly uniform and does not lessen the porosity of the membrane, as shown by scanning electron microscopy. When exposed to an analyte, these pigments undergo reactions that result in well-defined color changes due to strong chemical interactions: ligation to metal ions, Lewis or Bronsted acid-base interactions, hydrogen bonding, etc. Striking visual identification of 3 toxic gases has been shown at the IDLH (immediately dangerous to life and health), at the PEL (permissible exposure level), and at a level well below the PEL. Identification and quantification of analytes were achieved using the color change profiles, which were readily distinguishable in a hierarchical clustering analysis (HCA) dendrogram, with no misclassifications in 50 trials. PMID:19918616

  4. Colorimetric characterization of LED luminaires

    NASA Astrophysics Data System (ADS)

    Costa, C. L. M.; Vieira, R. R.; Pereira, R. C.; Silva, P. V. M.; Oliveira, I. A. A.; Sardinha, A. S.; Viana, D. D.; Barbosa, A. H.; Souza, L. P.; Alvarenga, A. D.

    2015-01-01

    The Optical Metrology Division of Inmetro - National Institute of Metrology, Quality and Technology has recently started the colorimetric characterization of lamps by implementing Correlated Color Temperature (CCT) and Color Rendering Index (CRI) measurements of incandescent lamps, followed by the CFL, and LED lamps and luminaires. Here we present the results for the verification of the color characterization of samples of SSL luminaires for public as well as indoor illumination that are sold in Brazil.

  5. Rapid quantification of major reaction products formed during thermochemical pretreatment of lignocellulosic biomass using GC-MS.

    PubMed

    Humpula, James F; Chundawat, Shishir P S; Vismeh, Ramin; Jones, A Daniel; Balan, Venkatesh; Dale, Bruce E

    2011-04-15

    Accurate quantification of reaction products formed during thermochemical pretreatment of lignocellulosic biomass would lead to a better understanding of plant cell wall deconstruction for production of cellulosic biofuels and biochemicals. However, quantification of some process byproducts, most notably acetamide, acetic acid and furfural, present several analytical challenges using conventional liquid chromatography methods. Therefore, we have developed a high-throughput gas chromatography based mass spectrometric (GC-MS) method in order to quantify relevant compounds without requiring time-consuming sample derivatization prior to analysis. Solvent extracts of untreated, ammonia fiber expansion (AFEX) treated and dilute-acid treated corn stover were analyzed by this method. Biomass samples were extracted with acetone using an automated solvent extractor, serially diluted and directly analyzed using the proposed GC-MS method. Acetone was the only solvent amongst water, methanol and acetonitrile that did not contain detectable background levels of the target compounds or facilitate a buildup of plant-derived residues in the GC injector, which decreased analytical reproducibility. Quantitative results were based on the method of standard addition and external standard calibration curves. PMID:21444255

  6. Rapid and sensitive quantification of C3- and C6-phosphoesters in starch by fluorescence-assisted capillary electrophoresis.

    PubMed

    Verbeke, Jeremy; Penverne, Christophe; D'Hulst, Christophe; Rolando, Christian; Szydlowski, Nicolas

    2016-11-01

    Phosphate groups are naturally present in starch at C3- or C6-position of the glucose residues and impact the structure of starch granules. Their precise quantification is necessary for understanding starch physicochemical properties and metabolism. Nevertheless, reliable quantification of Glc-3-P remains laborious and time consuming. Here we describe a capillary electrophoresis method for simultaneous measurement of both Glc-6-P and Glc-3-P after acid hydrolysis of starch. The sensitivity threshold was estimated at the fg scale, which is compatible with the analysis of less than a μg of sample. The method was validated by analyzing antisense potato lines deficient in SBEs, GWD or GBSS. We show that Glc-3-P content is altered in the latter and that these variations do not correlate with modifications in Glc-6-P content. We anticipate the method reported here to be an efficient tool for high throughput study of starch phosphorylation at both C3- and C6-position. PMID:27516330

  7. Development of a SYBR Green quantitative polymerase chain reaction assay for rapid detection and quantification of infectious laryngotracheitis virus.

    PubMed

    Mahmoudian, Alireza; Kirkpatrick, Naomi C; Coppo, Mauricio; Lee, Sang-Won; Devlin, Joanne M; Markham, Philip F; Browning, Glenn F; Noormohammadi, Amir H

    2011-06-01

    Infectious laryngotracheitis is an acute viral respiratory disease of chickens with a worldwide distribution. Sensitive detection of the causative herpesvirus is particularly important because it can persist in the host at a very low copy number and be transmitted to other birds. Quantification of viral genome copy number is also useful for clinical investigations and experimental studies. In the study presented here, a quantitative polymerase chain reaction (qPCR) assay was developed using SYBR Green chemistry and the viral gene UL15a to detect and quantify infectious laryngotracheitis virus (ILTV) in ILTV-inoculated chicken embryos or naturally infected birds. The specificity of the assay was confirmed using a panel of viral and bacterial pathogens of poultry. The sensitivity of the assay was compared with two conventional PCR assays, virus titration and an antigen-detecting enzyme-linked immunosorbent assay. The qPCR developed in this study was highly sensitive and specific, and has potential for quantification of ILTV in tissues from naturally and experimentally infected birds and embryos. PMID:21711182

  8. Rapid and Thiol-Specific High-Throughput Assay for Simultaneous Relative Quantification of Total Thiols, Protein Thiols, and Nonprotein Thiols in Cells

    PubMed Central

    2015-01-01

    Thiol groups in biological molecules play a significant role in various physiological functions and pathological conditions. Thiols are divided into two major groups: protein thiols and nonprotein thiols. Numerous methods have been reported for thiol assays. Most of these methods have been developed for glutathione, the principal nonprotein thiol, despite the fact that cellular protein thiols are more abundant than glutathione. Further, these methods usually involve a process of biological sample preparation followed by a separation method, and they are time-consuming. We reported previously a series of thiol-specific fluorogenic benzofurazan sulfides. These nonfluorescent benzofurazan sulfides react rapidly and specifically with a thiol to form a strong fluorescent thiol adduct. The rapid reaction, thiol-specific and fluorogenic nature of the sulfides successfully yielded an application of one of the sulfides for relative quantitation of total thiols in live cells through fluorescence microscopy. In this work, we employed the same compound to develop the first high-throughput method for simultaneous monitoring of protein thiols, nonprotein thiols, and total thiols in cells in a 96-well plate on a fluorescence microplate reader at λex = 430 nm and λem = 520 nm, respectively. The method is rapid and sensitive, and has been validated by an HPLC thiol assay method. The method can detect thiols with cell concentrations as low as 500 cells/well. We also demonstrated that the method can readily monitor changes in cellular thiol levels. Although the method cannot provide an absolute quantification for thiols because fluorescence intensity of different thiol adducts varies, it provides an accurate measurement of relative quantification, relative to the control. The method will be a valuable tool in thiol-related biomedical/pharmaceutical research. PMID:25423115

  9. Hand-Held Reader for Colorimetric Sensor Arrays.

    PubMed

    Askim, Jon R; Suslick, Kenneth S

    2015-08-01

    An inexpensive hand-held device for analysis of colorimetric sensor arrays (CSAs) has been developed. The device makes use of a contact image sensor (CIS), technology commonly used in business card scanners, to rapidly collect low-noise colorimetric data for chemical sensing. The lack of moving parts and insensitivity to vibration allow for lower noise and improved scan rates compared to other digital imaging techniques (e.g., digital cameras, flatbed scanners); signal-to-noise ratios are a factor of 3-10 higher than currently used methods, and scan rates are up to 250 times faster without compromising sensitivity. The device is capable of real-time chemical analysis at scan rates up to 48 Hz. PMID:26177346

  10. Capillary electrophoresis coupled with inductively coupled mass spectrometry as an alternative to cloud point extraction based methods for rapid quantification of silver ions and surface coated silver nanoparticles

    PubMed Central

    Qu, Haiou; Mudalige, Thilak K.; Linder, Sean W.

    2016-01-01

    Speciation and accurate quantification of ionic silver and metallic silver nanoparticles are critical to investigate silver toxicity and to determine the shelf-life of products that contain nano silver under various storage conditions. We developed a rapid method for quantification of silver ions and silver nanoparticles using capillary electrophoresis (CE) interfaced with inductively-coupled plasma mass spectrometry (ICPMS). The addition of 2-mercaptopropionylglycine (tiopronin) to the background electrolyte was used to facilitate the chromatographic separation of ionic silver and maintain the oxidation state of silver. The obtained limits of detection were 0.05 μg kg−1 of silver nanoparticles and 0.03 μg kg−1 of ionic silver. Nanoparticles of varied sizes (10–110 nm) with different surface coating, including citrate acid, lipoic acid, polyvinylpyrrolidone and bovine serum albumin (BSA) were successfully analyzed. Particularly good recoveries (>93%) were obtained for both ionic silver and silver nanoparticle in the presence of excess amount of BSA. The method was further tested with six commercially available dietary supplements which varied in concentration and matrix components. The summed values of silver ions and silver nanoparticles correlated well with the total silver concentration determined by ICPMS after acid digestion. This method can serve as an alternative to cloud point extraction technique when the extraction efficiency for protein coated nanoparticles is low. PMID:26724893

  11. Capillary electrophoresis coupled with inductively coupled mass spectrometry as an alternative to cloud point extraction based methods for rapid quantification of silver ions and surface coated silver nanoparticles.

    PubMed

    Qu, Haiou; Mudalige, Thilak K; Linder, Sean W

    2016-01-15

    Speciation and accurate quantification of ionic silver and metallic silver nanoparticles are critical to investigate silver toxicity and to determine the shelf-life of products that contain nano silver under various storage conditions. We developed a rapid method for quantification of silver ions and silver nanoparticles using capillary electrophoresis (CE) interfaced with inductively-coupled plasma mass spectrometry (ICPMS). The addition of 2-mercaptopropionylglycine (tiopronin) to the background electrolyte was used to facilitate the chromatographic separation of ionic silver and maintain the oxidation state of silver. The obtained limits of detection were 0.05 μg kg(-1) of silver nanoparticles and 0.03 μg kg(-1) of ionic silver. Nanoparticles of varied sizes (10-110 nm) with different surface coating, including citrate acid, lipoic acid, polyvinylpyrrolidone and bovine serum albumin (BSA) were successfully analyzed. Particularly good recoveries (>93%) were obtained for both ionic silver and silver nanoparticle in the presence of excess amount of BSA. The method was further tested with six commercially available dietary supplements which varied in concentration and matrix components. The summed values of silver ions and silver nanoparticles correlated well with the total silver concentration determined by ICPMS after acid digestion. This method can serve as an alternative to cloud point extraction technique when the extraction efficiency for protein coated nanoparticles is low. PMID:26724893

  12. Rapid Quantification of Drug Resistance Gene Expression in Candida albicans by Reverse Transcriptase LightCycler PCR and Fluorescent Probe Hybridization

    PubMed Central

    Frade, Joao P.; Warnock, David W.; Arthington-Skaggs, Beth A.

    2004-01-01

    We developed a rapid, sensitive, and reproducible assay to quantify Candida albicans ACT1, CDR1, CDR2, ERG11, and MDR1 mRNA using a two-step reverse transcription and LightCycler real-time PCR (RT-LightCycler PCR) method with sequence-specific hybridization probes. We compared RT-LightCycler PCR with Northern hybridization for quantitative analysis of gene expression in isolates with various fluconazole susceptibilities. Specificity of each LightCycler PCR was verified by LightCycler melting curve analysis and agarose gel electrophoresis of amplified products. Correlation of quantification results between RT-LightCycler PCR and Northern hybridization yielded correlation coefficients of ≥0.91 for all genes except MDR1 (0.74). In this case, reduced correlation was due to the inability of Northern hybridization to accurately quantify the high MDR1 expression in a susceptible dose-dependent isolate which was shown by RT-LightCycler PCR to overexpress MDR1 >200-fold relative to the other isolates tested. In four isolates, low levels of CDR2 mRNA were detected by RT-LightCycler PCR but were undetectable by Northern hybridization. mRNA quantification by RT-LightCycler PCR correlates with Northern hybridization and offers additional advantages, including increased sensitivity and speed of analysis, along with lower RNA concentration requirements and an increased dynamic range of signal detection. PMID:15131174

  13. Rapid quantification of tilidine, nortilidine, and bisnortilidine in urine by automated online SPE-LC-MS/MS.

    PubMed

    Köhler, Christoph; Grobosch, Thomas; Binscheck, Torsten

    2011-04-01

    The opioid tilidine is a prodrug which is hepatically metabolized to active nortilidine and bisnortilidine. Due to the increasing abuse of tilidine by drug users and the lack of a specific immunoassay, we developed an analytical method for the quantification of tilidine, nortilidine, and bisnortilidine in urine suitable for screening. In a following step, this method was used to establish data on excretion kinetics of the substances in order to evaluate the time window of detection after a single oral dose of tilidine/naloxone and also was applied to authentic urine samples from correctional facilities. Urine samples were mixed with internal standard solution and extracted on a weak cation exchanger at pH 6 using a Symbiosis Pico system. The chromatographic separation was achieved within a 3.5-min run time on a Phenylhexyl column (50 × 2.0 mm, 5 μm) via gradient elution (methanol and 0.2% formic acid) at a flow rate of 0.50 mL/min. The ESI-MS/MS was performed on a QTrap 3,200 in positive multiple reaction monitoring mode using two mass transitions per analyte. Validating the method resulted in a lower limit of quantification of 1.0 μg/L followed by a linear calibration range to 100 μg/L for each analyte (r(2) > 0.99). The analytical method allowed the detection of a single dose of a commercially available tilidine solution up to 7 days after administration. Using this highly sensitive method, 55 of 3,665 urine samples were tested positive. PMID:21140136

  14. Colorimetric and fluorimetric assays to quantitate micromolar concentrations of transition metals.

    PubMed

    McCall, K A; Fierke, C A

    2000-09-10

    Transition metal ions, although maintained at low concentrations, play diverse important roles in many biological processes. Two assays useful for the rapid quantification of a range of first-row transition metal ions have been developed. The colorimetric assay extends the 4-(2-pyridylazo)resorcinol assay of Hunt et al. (J. Biol. Chem. 255, 14793 (1984)) to measure nanomole quantities of Co(2+), Ni(2+), and Cu(2+) as well as Zn(2+). The fluorimetric assay takes advantage of the coordination of a number of metal ions (Mn(2+), Co(2+), Ni(2+), Cu(2+), Zn(2+), Cd(2+)) by Fura-2 and can also be used to measure nanomole quantities of these ions. The assays developed here have the advantage of not requiring the extensive sample preparation necessary for other methodologies, such as atomic absorption spectroscopy and inductively coupled plasma emission spectroscopy (ICPES), while being comparable in accuracy to the detection limits of ICPES for the first-row transition metal ions. To demonstrate the effectiveness of these assays, we determined the affinity of carbonic anhydrase II (CA II), a prototypical zinc enzyme, for Ni(2+) and Cd(2+). These data indicate that CA II binds transition metals with high affinity and is much more selective for Zn(2+) over Ni(2+) or Cd(2+) than most small-molecule chelators or other metalloenzymes. PMID:10964414

  15. Quantification of oxyresveratrol analog trans-2,4,3',5'-tetramethoxystilbene in rat plasma by a rapid HPLC method: application in a pre-clinical pharmacokinetic study.

    PubMed

    Lin, Hai-Shu; Choo, Qiu-Yi; Ho, Paul C

    2010-12-01

    A rapid HPLC method was developed and validated for the quantification of oxyresveratrol analog trans-2,4,3',5'-tetramethoxystilbene (oxyresveratrol tetramethyl ether, OTE) in rat plasma. Chromatographic separation was achieved on an RP-HPLC column, which was protected by a guard column through a 12 min gradient delivery of a mixture of acetonitrile-water at 50°C. The UV absorbance at 325 nm was recorded. The retention time of OTE and trans-stilbene (internal standard) was about 7.7 and 8.4 min, respectively. The calibration curves were linear (R(2) ≥ 0.9986) with a lower limit of quantification of 15 ng/mL. The intra- and inter-day variations, in terms of RSD, were all lower than 9.8% while the intra-day and inter-day bias ranged from -8.3 to +9.2%. The pharmacokinetics of OTE was assessed in rats using 2-hydroxypropyl-β-cyclodextrin as a dosing vehicle. After intravenous administration, OTE possessed a long terminal elimination half-life (t(1/2) (λz) = 481 ± 137 min) and slow clearance (Cl = 29.1 ± 3.7 mL/min/kg). Upon oral administration, OTE was rapidly absorbed. However, it only displayed minimal plasma exposure and its absolute oral bioavailability (F) was as low as 4.5 ± 3.2%. Fortunately, the levels of OTE after single oral administration were sufficient to inhibit human cytochrome P450 1B1. PMID:21077256

  16. Colorimetric Solid-Phase Extractor

    NASA Technical Reports Server (NTRS)

    2003-01-01

    The heart of a colorimetric solid phase extractor (CSPE) test kit quickly measures the concentration of the biocides silver or iodine in astronauts' drinking water to determine whether concentrations are safe. When 10 milliliters (ml) of water is drawn through the disk, the disk will turn color (yellow in this picture for iodine) indicating the presence of the biocides. The device could someday be used to test water safety at reservoirs and water treatment plants on Earth. (photo credit: Microanalytical Instrumentation Center, Iowa State University).

  17. Development of a barcode-style lateral flow immunoassay for the rapid semi-quantification of gliadin in foods.

    PubMed

    Yin, Hsin-Yi; Chu, Pei-Tzu; Tsai, Wen-Che; Wen, Hsiao-Wei

    2016-02-01

    In this work, a barcode-style lateral flow immunoassay is developed using two cut-off values (10 and 50 mg kg(-1) gliadin) to provide a semi-quantification for identifying "gluten-free" and "very low gluten" foods, based on the international Codex Alimentarius Standard. This developed assay exhibits favorable specificity in differentiating wheat from seven commonly used grains, with only a slight cross-reaction with barely. The intra-assay and inter-assay CV values of this assay were 1.5-1.7% and 2.5-4.5%, respectively, revealing high reproducibility. In the analysis of 48 food samples, the results of this assay closely agreed with those obtained using AOAC-approved ELISA or strip kits, as the Cohen's kappa coefficients for both comparisons exceeded 0.8. Thus, this developed assay can be used to quickly estimate the gliadin content in foods in order to protect people with wheat allergy or celiac disease from the accidental ingestion of gliadin. PMID:26304432

  18. Rapid quantification of miglustat in human plasma and cerebrospinal fluid by liquid chromatography coupled with tandem mass spectrometry.

    PubMed

    Guitton, Jérôme; Coste, Sylvie; Guffon-Fouilhoux, Nathalie; Cohen, Sabine; Manchon, Monique; Guillaumont, Marc

    2009-01-15

    Miglustat (OGT 918) is an iminosugar recently introduced in therapeutic as potential alternative therapy in disorders found in several diseases such as Tay-Sachs, Gaucher or Niemann-Pick diseases. A highly sensitive liquid-chromatography-electrospray tandem mass spectrometry (LC-MS/MS) assay was developed for the quantification of miglustat in human plasma and cerebrospinal fluid (CSF). The sample preparation consists in a simple protein precipitation with a mixture of acetonitrile/methanol (75/25) which yields 100% recovery. The isocratic separation utilizes an Atlantis Hilic (3 microm, 150 mm x 2.1 mm) column, with a mobile phase of acetonitrile/water/ammonium acetate buffer (75/10/15, v/v/v) delivered at 230 microl/min. Selected reaction monitoring (SRM) mode was used with the transitions m/z 220-->158 for the miglustat and m/z 208-->m/z 146 for the miglitol (internal standard). Good linearity was observed in a range from 125 to 2500 ng/ml and from 50 to 1000 ng/ml, for plasma and CSF, respectively. The within-run precision of the assay was less than 6%, and the between-run run precision was less than 6.5%, for six replicates at each of three concentrations and evaluated on three separated days for both plasma and CSF mediums. Assay accuracy was in the range of 98-106.5%. Stability of miglustat was reported under a variety of storage conditions. The miglustat concentrations in two children are presented to demonstrate the clinical interest of this new method. PMID:19095507

  19. Rapid quantification of buprenorphine-glucuronide and norbuprenorphine-glucuronide in human urine by LC-MS-MS.

    PubMed

    Hegstad, S; Khiabani, H Z; Øiestad, E L; Berg, T; Christophersen, A S

    2007-05-01

    A liquid chromatography-tandem mass spectrometry (LC-MS-MS) method was developed and validated for the determination of buprenorphine-glucuronide (BUP-G) and norbuprenorphine-glucuronide (NBUP-G) in human urine. The method included a dilution step followed by filtration through a Mini-Uniprep Filter and direct injection onto the LC column. The analytes were quantified in multiple reactions monitoring mode using one transition ion. Norbuprenorpine-d(3) (NBUP-d(3)) was used as the internal standard. The concentration ranges were 6-161 ng/mL for BUP-G and 12-295 ng/mL for NBUP-G. Recoveries determined after filtration for the analytes were 75%. The between-day precision of the method was in the range of 4.8-11%. The limits of quantification were found to be 4.6 ng/mL for BUP-G and 11.8 ng/mL for NBUP-G. Approximately 1000 samples from law enforcement, prison inmates, probation services, and hospitals were analyzed by the presented method. The ratios of drug glucuronides versus creatinine were calculated for a selection of samples (n = 151), where there was information on treatment with buprenorphine between 16 and 20 mg/day. The majority (86%) of the samples had a ratio of BUP-G/creatinine below 570 microg/g, and 76% of the samples had NBUP-G/creatinine lower than 1060 microg/g. The LC-MS-MS method proved to be robust and specific for the determination of BUP-G and NBUP-G in urine. PMID:17555645

  20. A Rapid Protocol of Crude RNA/DNA Extraction for RT-qPCR Detection and Quantification of 'Candidatus Phytoplasma prunorum'

    PubMed Central

    Minguzzi, Stefano; Terlizzi, Federica; Lanzoni, Chiara; Poggi Pollini, Carlo; Ratti, Claudio

    2016-01-01

    Many efforts have been made to develop a rapid and sensitive method for phytoplasma and virus detection. Taking our cue from previous works, different rapid sample preparation methods have been tested and applied to Candidatus Phytoplasma prunorum (‘Ca. P. prunorum’) detection by RT-qPCR. A duplex RT-qPCR has been optimized using the crude sap as a template to simultaneously amplify a fragment of 16S rRNA of the pathogen and 18S rRNA of the host plant. The specific plant 18S rRNA internal control allows comparison and relative quantification of samples. A comparison between DNA and RNA contribution to qPCR detection is provided, showing higher contribution of the latter. The method presented here has been validated on more than a hundred samples of apricot, plum and peach trees. Since 2013, this method has been successfully applied to monitor ‘Ca. P. prunorum’ infections in field and nursery. A triplex RT-qPCR assay has also been optimized to simultaneously detect ‘Ca. P. prunorum’ and Plum pox virus (PPV) in Prunus. PMID:26742106

  1. Development of a Rapid Cartilage Damage Quantification Method for the Lateral Tibiofemoral Compartment Using Magnetic Resonance Images: Data from the Osteoarthritis Initiative

    PubMed Central

    Zhang, Ming; Driban, Jeffrey B.; Price, Lori Lyn; Lo, Grace H.; Miller, Eric; McAlindon, Timothy E.

    2015-01-01

    The purpose of this study was to expand and validate the cartilage damage index (CDI) to detect cartilage damage in the lateral tibiofemoral compartment. We used an iterative 3-step process to develop and validate the lateral CDI: development (100 knees), testing (80 knees), and validation (100 knees). The validation set included 100 knees from the Osteoarthritis Initiative that was enriched to include all grades of lateral joint space narrowing (JSN, 0–3). Measurement of the CDI was rapid at 7.4 (s.d. 0.73) minutes per knee pair (baseline and follow-up of one knee). The intratester reliability is good (intraclass correlation coefficient (3, 1 model) = 0.86 to 0.98). At baseline, knees with greater KL grade and lateral JSN had a lower mean CDI (i.e., greater cartilage damage). Baseline lateral CDI is associated with both lateral JSW (r = 0.81 to 0.85, p < 0.01) and HKA (r = −0.30 to −0.33, p < 0.05). The SRM is good (lateral femur SRM = −0.76; lateral tibia SRM = −0.73; lateral tibiofemoral total SRM = −0.87). The lateral tibiofemoral CDI quantification allows for rapid evaluation and is reliable and responsive, with good construct validity. It may be an efficient method to measure lateral tibiofemoral articular cartilage in large clinical and epidemiologic studies. PMID:26713316

  2. A Rapid Protocol of Crude RNA/DNA Extraction for RT-qPCR Detection and Quantification of 'Candidatus Phytoplasma prunorum'.

    PubMed

    Minguzzi, Stefano; Terlizzi, Federica; Lanzoni, Chiara; Poggi Pollini, Carlo; Ratti, Claudio

    2016-01-01

    Many efforts have been made to develop a rapid and sensitive method for phytoplasma and virus detection. Taking our cue from previous works, different rapid sample preparation methods have been tested and applied to Candidatus Phytoplasma prunorum ('Ca. P. prunorum') detection by RT-qPCR. A duplex RT-qPCR has been optimized using the crude sap as a template to simultaneously amplify a fragment of 16S rRNA of the pathogen and 18S rRNA of the host plant. The specific plant 18S rRNA internal control allows comparison and relative quantification of samples. A comparison between DNA and RNA contribution to qPCR detection is provided, showing higher contribution of the latter. The method presented here has been validated on more than a hundred samples of apricot, plum and peach trees. Since 2013, this method has been successfully applied to monitor 'Ca. P. prunorum' infections in field and nursery. A triplex RT-qPCR assay has also been optimized to simultaneously detect 'Ca. P. prunorum' and Plum pox virus (PPV) in Prunus. PMID:26742106

  3. Adobe photoshop quantification (PSQ) rather than point-counting: A rapid and precise method for quantifying rock textural data and porosities

    NASA Astrophysics Data System (ADS)

    Zhang, Xuefeng; Liu, Bo; Wang, Jieqiong; Zhang, Zhe; Shi, Kaibo; Wu, Shuanglin

    2014-08-01

    Commonly used petrological quantification methods are visual estimation, counting, and image analyses. However, in this article, an Adobe Photoshop-based analyzing method (PSQ) is recommended for quantifying the rock textural data and porosities. Adobe Photoshop system provides versatile abilities in selecting an area of interest and the pixel number of a selection could be read and used to calculate its area percentage. Therefore, Adobe Photoshop could be used to rapidly quantify textural components, such as content of grains, cements, and porosities including total porosities and different genetic type porosities. This method was named as Adobe Photoshop Quantification (PSQ). The workflow of the PSQ method was introduced with the oolitic dolomite samples from the Triassic Feixianguan Formation, Northeastern Sichuan Basin, China, for example. And the method was tested by comparing with the Folk's and Shvetsov's "standard" diagrams. In both cases, there is a close agreement between the "standard" percentages and those determined by the PSQ method with really small counting errors and operator errors, small standard deviations and high confidence levels. The porosities quantified by PSQ were evaluated against those determined by the whole rock helium gas expansion method to test the specimen errors. Results have shown that the porosities quantified by the PSQ are well correlated to the porosities determined by the conventional helium gas expansion method. Generally small discrepancies (mostly ranging from -3% to 3%) are caused by microporosities which would cause systematic underestimation of 2% and/or by macroporosities causing underestimation or overestimation in different cases. Adobe Photoshop could be used to quantify rock textural components and porosities. This method has been tested to be precise and accurate. It is time saving compared with usual methods.

  4. Rapid, absolute, and simultaneous quantification of specific pathogenic strain and total bacterial cells using an ultrasensitive dual-color flow cytometer.

    PubMed

    Yang, Lingling; Wu, Lina; Zhu, Shaobin; Long, Yao; Hang, Wei; Yan, Xiaomei

    2010-02-01

    This paper describes a rapid and sensitive strategy for the absolute and simultaneous quantification of specific pathogenic strain and total bacterial cells in a mixture. A laboratory-built compact, high-sensitivity, dual channel flow cytometer (HSDCFCM) was modified to enable dual fluorescence detection. A bacterial cell mixture comprising heat-killed pathogenic Escherichia coli E. coli O157:H7 and harmless E. coli DH5alpha was used as a model system. Pathogenic E. coli O157:H7 cells were selectively labeled by red fluorescent probe via antibody-antigen interaction, and all bacterial cells were stained with membrane-permeable nucleic acid dye that fluoresces green. When each individual bacterium passes through the interrogating laser beam, E. coli O157:H7 emits both red and green fluorescence, while E. coli DH5alpha exhibits only green fluorescence. Because the fluorescence burst generated from each individual bacterial cell was easily distinguished from the background, accurate enumeration and consequently absolute quantification were achieved for both pathogenic and total bacterial cells. By using this strategy, accurate counting of bacteria at a density above 1.0 x 10(5) cells/mL can be accomplished with 1 min of data acquisition time after fluorescent staining. Excellent correlation between the concentrations measured by the HSDCFCM and the conventional plate-counting method were obtained for pure-cultured E. coli O157:H7 (R(2) = 0.9993) and E. coli DH5alpha (R(2) = 0.9998). Bacterial cell mixtures with varying proportions of E. coli O157:H7 and E. coli DH5alpha were measured with good ratio correspondence. We applied the established approach to detecting artificially contaminated drinking water samples; E. coli O157:H7 of 1.0 x 10(2) cells/mL were accurately quantified upon sample enrichment. It is believed that the proposed method will find wide applications in many fields demanding bacterial identification and quantification. PMID:20039721

  5. Rapid detection and quantification of tumor marker carbohydrate antigen 72-4 (CA72-4) using a superparamagnetic immunochromatographic strip.

    PubMed

    Chen, Yanrong; Wang, Kan; Liu, Zongrui; Sun, Rongjin; Cui, Daxiang; He, Jinghua

    2016-03-01

    Rapid and quantitative detection of biomarkers with high sensitivity and specificity has become a common practice in the clinical diagnosis and treatment of cancer. Herein, a quantitative lateral flow immunoassay (LFIA) based on superparamagnetic nanoparticles (SPMNPs) was developed for detection of carbohydrate antigen 72-4 (CA72-4) in human serum. This direct and rapid method did not involve any sample preparation and was accomplished using a test strip in which a sandwich reaction was performed. Probes on the conjugate pad were prepared by coupling monoclonal antibody CC49 specific to CA72-4 onto SPMNPs. Coupled monoclonal antibody B72.3 and goat anti-mouse IgG were loaded onto a nitrocellulose (NC) membrane, serving as the test and control lines, respectively. Initially, results were evaluated by macroscopic observation. Afterwards, the magnetic signal strength of the reaction area was quantified using a magnetic assay reader (MAR). Several parameters that may influence the detection sensitivity were studied and optimized. Under optimal conditions, the proposed method was capable of detecting as low as 0.38 IU/mL of CA72-4 in 20 min and had a wide detection linearity range (0-100 IU/mL). We evaluated 100 clinical samples (70 positive and 30 negative) to assess the validity of these test strips, which exhibited high sensitivity (99 %) and specificity (97 %). The results indicated a high rate of accuracy (98.4-102 %) and a low relative standard deviation according to the average recovery test. In conclusion, the test strips based on SPMNP probes are a rapid, sensitive, and quantitative method for the detection of CA72-4 and possess great potential in point-of-care testing (POCT). Graphical Abstract Schematic illustration of the strategy for CA72-4 detection and quantification using a superparamagnetic immunochromatographic strip. PMID:26825343

  6. Application of a rapid scanning plasma emission detector and gas chromatography for multi-element quantification of halogenated hydrocarbons.

    PubMed

    Zerezghi, M; Mulligan, K J; Caruso, J A

    1984-08-01

    A microwave induced plasma emission detector is used as an element-selective detector for gas chromatography. The spectrometer, which is fitted with a rapid scanning galvanometer mirror, is used to scan a pre-selected spectral window to provide information in the multi-element mode. This information is used to determine the per mole response of some elements as a function of molecular structure. Despite the low microwave powers employed, the response per mole appears to be independent of the molecular structure. Detection limits and linear dynamic ranges are determined by narrowing the spectral coverage to increase the sensitivity. Calibration curves are linear over several orders of magnitude and detection limits are at the pg/sec levels. PMID:6480798

  7. Photoacoustic and Colorimetric Visualization of Latent Fingerprints.

    PubMed

    Song, Kai; Huang, Peng; Yi, Chenglin; Ning, Bo; Hu, Song; Nie, Liming; Chen, Xiaoyuan; Nie, Zhihong

    2015-12-22

    There is a high demand on a simple, rapid, accurate, user-friendly, cost-effective, and nondestructive universal method for latent fingerprint (LFP) detection. Herein, we describe a combination imaging strategy for LFP visualization with high resolution using poly(styrene-alt-maleic anhydride)-b-polystyrene (PSMA-b-PS) functionalized gold nanoparticles (GNPs). This general approach integrates the merits of both colorimetric imaging and photoacoustic imaging. In comparison with the previous methods, our strategy is single-step and does not require the signal amplification by silver staining. The PSMA-b-PS functionalized GNPs have good stability, tunable color, and high affinity for universal secretions (proteins/polypeptides/amino acids), which makes our approach general and flexible for visualizing LFPs on different substrates (presumably with different colors) and from different people. Moreover, the unique optical property of GNPs enables the photoacoustic imaging of GNPs-deposited LFPs with high resolution. This allows observation of level 3 hyperfine features of LFPs such as the pores and ridge contours by photoacoustic imaging. This technique can potentially be used to identify chemicals within LFP residues. We believe that this dual-modality imaging of LFPs will find widespread use in forensic investigations and medical diagnostics. PMID:26528550

  8. Development of a colony lift immunoassay to facilitate rapid detection and quantification of Escherichia coli O157:H7 from agar plates and filter monitor membranes.

    PubMed

    Ingram, D T; Lamichhane, C M; Rollins, D M; Carr, L E; Mallinson, E T; Joseph, S W

    1998-07-01

    E. coli O157:H7 is a food-borne adulterant that can cause hemorrhagic ulcerative colitis and hemolytic uremic syndrome. Faced with an increasing risk of foods contaminated with E. coli O157:H7, food safety officials are seeking improved methods to detect and isolate E. coli O157:H7 in hazard analysis and critical control point systems in meat- and poultry-processing plants. A colony lift immunoassay was developed to facilitate the positive identification and quantification of E. coli O157:H7 by incorporating a simple colony lift enzyme-linked immunosorbent assay with filter monitors and traditional culture methods. Polyvinylidene difluoride (PVDF) membranes (Millipore, Bedford, Mass.) were prewet with methanol and were used to make replicates of every bacterial colony on agar plates or filter monitor membranes that were then reincubated for 15 to 18 h at 36 +/- 1 degree C, during which the colonies not only remained viable but were reestablished. The membranes were dried, blocked with blocking buffer (Kirkegaard and Perry Laboratories [KPL], Gaithersburg, Md.), and exposed for 7 min to an affinity-purified horseradish peroxidase-labeled goat anti-E. coli O157 antibody (KPL). The membranes were washed, exposed to a 3,3',5,5'-tetramethylbenzidine membrane substrate (TMB; KPL) or aminoethyl carbazole (AEC; Sigma Chemical Co., St. Louis, Mo.), rinsed in deionized water, and air dried. Colonies of E. coli O157:H7 were identified by either a blue (via TMB) or a red (via AEC) color reaction. The colored spots on the PVDF lift membrane were then matched to their respective parent colonies on the agar plates or filter monitor membranes. The colony lift immunoassay was tested with a wide range of genera in the family Enterobacteriaceae as well as different serotypes within the E. coli genus. The colony lift immunoassay provided a simple, rapid, and accurate method for confirming the presence of E. coli O157:H7 colonies isolated on filter monitors or spread plates by

  9. Surfactant-based ionic liquids for extraction of phenolic compounds combined with rapid quantification using capillary electrophoresis.

    PubMed

    Huang, Fangzhi; Berton, Paula; Lu, Chengfei; Siraj, Noureen; Wang, Chun; Magut, Paul K S; Warner, Isiah M

    2014-09-01

    A rapid liquid phase extraction employing a novel hydrophobic surfactant-based room temperature ionic liquid (RTIL), tetrabutylphosphonium dioctyl sulfosuccinate ([4C4 P][AOT]), coupled with capillary electrophoretic-UV (CE-UV) detection is developed for removal and determination of phenolic compounds. The long-carbon-chain RTIL used is sparingly soluble in most solvents and can be used to replace volatile organic solvents. This fact, in combination with functional-surfactant-anions, is proposed to reduce the interfacial energy of the two immiscible liquid phases, resulting in highly efficient extraction of analytes. Several parameters that influence the extraction efficiencies, such as extraction time, RTIL type, pH value, and ionic strength of aqueous solutions, were investigated. It was found that, under acidic conditions, most of the investigated phenols were extracted from aqueous solution into the RTIL phase within 12 min. Good linearity was observed over the concentration range of 0.1-80.0 μg/mL for all phenols investigated. The precision of this method, expressed as RSD, was determined to be within 3.4-5.3% range. The LODs (S/N = 3) of the method were in the range of 0.047-0.257 μg/mL. The proposed methodology was successfully applied to determination of phenols in real water samples. PMID:24798689

  10. A study on the use of near-infrared spectroscopy for the rapid quantification of major compounds in Tanreqing injection

    NASA Astrophysics Data System (ADS)

    Li, Wenlong; Cheng, Zhiwei; Wang, Yuefei; Qu, Haibin

    2013-01-01

    In this paper we describe the strategy used in the development and validation of a near infrared spectroscopy method for the rapid determination of baicalin, chlorogenic acid, ursodeoxycholic acid (UDCA), chenodeoxycholic acid (CDCA), and the total solid contents (TSCs) in the Tanreqing injection. To increase the representativeness of calibration sample set, a concentrating-diluting method was adopted to artificially prepare samples. Partial least square regression (PLSR) was used to establish calibration models, with which the five quality indicators can be determined with satisfied accuracy and repeatability. In addition, the slope/bias (S/B) method was used for the models transfer between two different types of NIR instruments from the same manufacturer, which is contributing to enlarge the application range of the established models. With the presented method, a great deal of time, effort and money can be saved when large amounts of Tanreqing injection samples need to be analyzed in a relatively short period of time, which is of great significance to the traditional Chinese medicine (TCM) industries.

  11. Two novel methods for rapid detection and quantification of DNMT3A R882 mutations in acute myeloid leukemia.

    PubMed

    Mancini, Melissa; Hasan, Syed Khizer; Ottone, Tiziana; Lavorgna, Serena; Ciardi, Claudia; Angelini, Daniela F; Agostini, Francesca; Venditti, Adriano; Lo-Coco, Francesco

    2015-03-01

    DNMT3A mutations represent one of the most frequent gene alterations detectable in acute myeloid leukemia with normal karyotype. Although various recurrent somatic mutations of DNMT3A have been described, the most common mutation is located at amino acid R882 in the methyltransferase domain of the gene. DNMT3A mutations have been reported to be stable during disease progression and are associated with unfavorable outcome in acute myeloid leukemia patients with normal karyotype. Because of their prognostic significance and high stability during disease evolution, DNMT3A mutations might represent highly informative biomarkers for minimal residual disease monitoring. We describe a new rapid diagnostic RT-PCR assay based on TauI restriction enzyme reaction to identify DNMT3A R882 mutations at diagnosis. In addition, we developed a sensitive and specific test based on peptide nucleic acid real-time PCR technology to monitor DNMT3A R882H mutation. We identified 24 DNMT3A R882H mutated patients out of 134 acute myeloid leukemia screened samples and we analyzed in these patients the kinetics of minimal residual disease after induction and consolidation therapy. This assay may be useful to better assess response to therapy in patients with acute myeloid leukemia bearing the DNMT3A R882H mutation. PMID:25554589

  12. QuShape: Rapid, accurate, and best-practices quantification of nucleic acid probing information, resolved by capillary electrophoresis

    PubMed Central

    Karabiber, Fethullah; McGinnis, Jennifer L.; Favorov, Oleg V.; Weeks, Kevin M.

    2013-01-01

    Chemical probing of RNA and DNA structure is a widely used and highly informative approach for examining nucleic acid structure and for evaluating interactions with protein and small-molecule ligands. Use of capillary electrophoresis to analyze chemical probing experiments yields hundreds of nucleotides of information per experiment and can be performed on automated instruments. Extraction of the information from capillary electrophoresis electropherograms is a computationally intensive multistep analytical process, and no current software provides rapid, automated, and accurate data analysis. To overcome this bottleneck, we developed a platform-independent, user-friendly software package, QuShape, that yields quantitatively accurate nucleotide reactivity information with minimal user supervision. QuShape incorporates newly developed algorithms for signal decay correction, alignment of time-varying signals within and across capillaries and relative to the RNA nucleotide sequence, and signal scaling across channels or experiments. An analysis-by-reference option enables multiple, related experiments to be fully analyzed in minutes. We illustrate the usefulness and robustness of QuShape by analysis of RNA SHAPE (selective 2′-hydroxyl acylation analyzed by primer extension) experiments. PMID:23188808

  13. Identification of Escherichia coli O157 by Using a Novel Colorimetric Detection Method with DNA Microarrays

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Shiga toxin-producing Escherichia coli O157:H7 is a leading cause of foodborne illness worldwide. To evaluate better methods to rapidly detect and genotype E. coli O157 strains, the present study evaluated the use of ampliPHOX, a novel colorimetric detection method based on photopolymerization, for...

  14. Zinc Biosorption by Seaweed Illustrated by the Zincon Colorimetric Method and the Langmuir Isotherm

    ERIC Educational Resources Information Center

    Areco, Maria Mar; dos Santos Afonso, Maria; Valdman, Erika

    2007-01-01

    An experiment is conducted to promote biotechnology knowledge that is an emerging technology on cleaning treatment, showing the potential of seaweed to remove heavy-metal ions from solution. The rapid and accurate determination of zinc in aqueous solution by the zincon colorimetric method gives an interesting and simple experiment for any…

  15. Rapid diagnosis and quantification of Francisella tularensis in organs of naturally infected common squirrel monkeys (Saimiri sciureus).

    PubMed

    Abril, Carlos; Nimmervoll, Helena; Pilo, Paola; Brodard, Isabelle; Korczak, Bozena; Markus, Seiler; Miserez, Raymond; Frey, Joachim

    2008-02-01

    Francisella tularensis, a small Gram-negative facultative intracellular bacterium, is the causative agent of tularaemia, a severe zoonotic disease transmitted to humans mostly by vectors such as ticks, flies and mosquitoes. The disease is endemic in many parts of the northern hemisphere. Among animals, the most affected species belong to rodents and lagomorphs, in particular hares. However, in the recent years, many cases of tularaemia among small monkeys in zoos were reported. We have developed a real-time PCR that allows to quantify F. tularensis in tissue samples. Using this method, we identified the spleen and the kidney as the most heavily infected organ containing up to 400 F. tularensis bacteria per simian host cell in two common squirrel monkeys (Saimiri sciureus) from a zoo that died of tularaemia. In other organs such as the brain, F. tularensis was detected at much lower titres. The strain that caused the infection was identified as F. tularensis subsp. holarctica biovar I, which is susceptible to erythromycin. The high number of F. tularensis present in soft organs such as spleen, liver and kidney represents a high risk for persons handling such carcasses and explains the transmission of the disease to a pathologist during post-mortem analysis. Herein, we show that real-time PCR allows a reliable and rapid diagnosis of F. tularensis directly from tissue samples of infected animals, which is crucial in order to attempt accurate prophylactic measures, especially in cases where humans or other animals have been exposed to this highly contagious pathogen. PMID:17875369

  16. Novel, Rapid Identification, and Quantification of Adulterants in Extra Virgin Olive Oil Using Near-Infrared Spectroscopy and Chemometrics.

    PubMed

    Azizian, Hormoz; Mossoba, Magdi M; Fardin-Kia, Ali Reza; Delmonte, Pierluigi; Karunathilaka, Sanjeewa R; Kramer, John K G

    2015-07-01

    A new, rapid Fourier transform near infrared (FT-NIR) spectroscopic procedure is described to screen for the authenticity of extra virgin olive oils (EVOO) and to determine the kind and amount of an adulterant in EVOO. To screen EVOO, a partial least squares (PLS1) calibration model was developed to estimate a newly created FT-NIR index based mainly on the relative intensities of two unique carbonyl overtone absorptions in the FT-NIR spectra of EVOO and other mixtures attributed to volatile (5280 cm(-1)) and non-volatile (5180 cm(-1)) components. Spectra were also used to predict the fatty acid (FA) composition of EVOO or samples spiked with an adulterant using previously developed PLS1 calibration models. Some adulterated mixtures could be identified provided the FA profile was sufficiently different from those of EVOO. To identify the type and determine the quantity of an adulterant, gravimetric mixtures were prepared by spiking EVOO with different concentrations of each adulterant. Based on FT-NIR spectra, four PLS1 calibration models were developed for four specific groups of adulterants, each with a characteristic FA composition. Using these different PLS1 calibration models for prediction, plots of predicted vs. gravimetric concentrations of an adulterant in EVOO yielded linear regression functions with four unique sets of slopes, one for each group of adulterants. Four corresponding slope rules were defined that allowed for the determination of the nature and concentration of an adulterant in EVOO products by applying these four calibration models. The standard addition technique was used for confirmation. PMID:26050093

  17. Development of a Taqman real-time PCR assay for rapid detection and quantification of Vibrio tapetis in extrapallial fluids of clams

    PubMed Central

    Richard, Gaëlle G.; Le Bris, Cédric; Paillard, Christine

    2015-01-01

    The Gram-negative bacterium Vibrio tapetis is known as the causative agent of Brown Ring Disease (BRD) in the Manila clam Venerupis (=Ruditapes) philippinarum. This bivalve is the second most important species produced in aquaculture and has a high commercial value. In spite of the development of several molecular methods, no survey has been yet achieved to rapidly quantify the bacterium in the clam. In this study, we developed a Taqman real-time PCR assay targeting virB4 gene for accurate and quantitative identification of V. tapetis strains pathogenic to clams. Sensitivity and reproducibility of the method were assessed using either filtered sea water or extrapallial fluids of clam injected with the CECT4600T V. tapetis strain. Quantification curves of V. tapetis strain seeded in filtered seawater (FSW) or extrapallial fluids (EF) samples were equivalent showing reliable qPCR efficacies. With this protocol, we were able to specifically detect V. tapetis strains down to 1.125 101 bacteria per mL of EF or FSW, taking into account the dilution factor used for appropriate template DNA preparation. This qPCR assay allowed us to monitor V. tapetis load both experimentally or naturally infected Manila clams. This technique will be particularly useful for monitoring the kinetics of massive infections by V. tapetis and for designing appropriate control measures for aquaculture purposes. PMID:26713238

  18. Rapid and selective quantification of L-theanine in ready-to-drink teas from Chinese market using SPE and UPLC-UV.

    PubMed

    Chen, Guoqiang; Wang, Yun; Song, Weiqi; Zhao, Bo; Dou, Yuling

    2012-11-15

    An ultra performance liquid chromatography (UPLC) method combined with solid phase extraction (SPE) sample pre-treatment was developed and validated for the rapid quantification of L-theanine in ready-to-drink (RTD) teas. UPLC analysis of twenty-seven RTD teas from the Chinese market revealed that the L-theanine levels in various types of RTD teas were significantly different. RTD green teas were found to contain highest mean L-theanine level (37.85±20.54 mg/L), followed by jasmine teas (36.60±12.08 mg/L), Tieguanying teas (18.54±3.46 mg/L) black teas (16.89±6.56), Pu-erh teas (11.31±0.90 mg/L) and oolong teas (3.85±2.27 mg/L). The ratio of total polyphenols content to L-theanine content could be used as a featured parameter for differentiating RTD teas. L-theanine in RTD teas could be a reliable quality parameter that is complementary to total polyphenols. PMID:22868106

  19. Sensitive and rapid analytical method for the quantification of glucosamine in human plasma by ultra high performance liquid chromatography with tandem mass spectrometry.

    PubMed

    Yang, Wen; Zheng, Xiaohong; Simpemba, Ernest; Ma, Pengcheng; Ding, Li

    2015-06-01

    A highly sensitive and rapid ultra high performance liquid chromatography with tandem mass spectrometry method has been developed and validated for the determination of glucosamine in human plasma using miglitol as the internal standard. Special attention was paid to achieve the high throughput and sensitivity of the established method, and the absence of a matrix effect on the analytes. The sample preparation procedure involved a simple deproteinization step. The chromatographic separation was achieved on a Waters ACQUITY HSS Cyano column using a mixture of acetonitrile/2 mM ammonium acetate solution containing 0.03% formic acid (80:20, v/v) as the mobile phase with a very short run time of 1.5 min. This method was validated over the concentration range of 10-3000 ng/mL for glucosamine. The intra- and inter-batch precision was <13.9% for the low, medium, and high quality control samples. The established method is highly sensitive with a lower limit of quantification of 10 ng/mL, low enough to determine the circadian rhythm on endogenous glucosamine level in human plasma, which has not been reported in detail until now. The method was successfully applied to characterize the pharmacokinetic profile of glucosamine in healthy volunteers following a single oral administration of 750 or 1500 mg glucosamine hydrochloride. PMID:25802209

  20. Combination of crossflow ultrafiltration, monolithic affinity filtration, and quantitative reverse transcriptase PCR for rapid concentration and quantification of model viruses in water.

    PubMed

    Pei, Lu; Rieger, Martin; Lengger, Sandra; Ott, Sonja; Zawadsky, Claudia; Hartmann, Nils Marten; Selinka, Hans-Christoph; Tiehm, Andreas; Niessner, Reinhard; Seidel, Michael

    2012-09-18

    We present a rapid and effective adsorption-elution method based on monolithic affinity filtration (MAF) for the concentration and purification of waterborne viruses. The MAF column consists of a hydrolyzed macroporous epoxy-based polymer. High recoveries were achieved by columns for the bacterial virus (bacteriophage) MS2 110 (±19)%, as model organism, as well as for human adenoviruses 42.4 (±3.4)% and murine noroviruses 42.6 (±1.9)%. This new concentration and purification method was combined with crossflow ultrafiltration (CUF). Because of the adsorption of the examined viruses to the macroporous surface of the MAF column at pH 3, concentrated matrix components by CUF can be removed. Bacteriophages MS2 were spiked in tap water and concentrated with the new CUF-MAF concentration method by a volumetric factor of 10(4) within 33 min. Furthermore, the detection limit for quantification of bacteriophage MS2 by quantitative reverse transcriptase PCR (qRT-PCR) could be improved from 79.47 to 0.0056 GU mL(-1) by a factor of 1.4 × 10(4). In a first study, we have shown that this method could also be applied for river water containing naturally MS2 and MS2-like phages. PMID:22917471

  1. A rapid and sensitive LC-MS/MS method for quantification of 3,29-dibenzoyl rarounitriol in rat plasma: application to a pharmacokinetic study.

    PubMed

    Zhao, Chengliang; Zhang, Nan; Chen, Bin; Song, Youxin; Zhu, Naiqiang; Zhao, Long; Liu, Changjian; Meng, Xiangwei

    2015-08-01

    A rapid, sensitive and high-throughput liquid chromatography-tandem mass spectrometry was established and validated to assay the concentrations of 3,29-dibenzoyl rarounitriol in rat plasma. Plasma samples were processed by liquid-liquid extraction with ethyl acetate and separated on a Hypersil Gold C18 column (50 × 4.6 mm, 3 µm) at an isocratic flow rate of 0.5 mL/min using methanol-10 mm ammonium acetate-formic acid (90:10:0.1, v/v/v) as mobile phase. The total run time was 5 min for each sample. MS/MS detection was accomplished in selected reaction monitoring mode with positive electrospray ionization. The calibration curve was linear over the concentration range of 0.125-50 ng/mL with lower limit of quantification of 0.125 ng/mL. The intra- and inter-day precisions were <10.1% in terms of coefficient of variation, and the accuracy was within ±11.7% in terms of relative error. The developed method was successfully applied to a pharmacokinetic study of 3,29-dibenzoyl rarounitriol following intragastric administration of 3.65 mg/kg to Wistar rats. PMID:25611485

  2. Simple and rapid determination of phthalates using microextraction by packed sorbent and gas chromatography with mass spectrometry quantification in cold drink and cosmetic samples.

    PubMed

    Kaur, Ramandeep; Heena; Kaur, Ripneel; Rani, Susheela; Malik, Ashok Kumar

    2016-03-01

    A simple and rapid method using microextraction by packed sorbent coupled with gas chromatography and mass spectrometry has been developed for the analysis of five phthalates, namely, diethyl phthalate, benzyl-n-butyl phthalate, dicyclohexyl phthalate, di-n-butyl phthalate, and di-n-propyl phthalate, in cold drink and cosmetic samples. The various parameters that influence the microextraction by packed sorbent performance such as extraction cycle (extract-discard), type and amount of solvent, washing solvent, and pH have been studied. The optimal conditions of microextraction using C18 as the packed sorbent were 15 extraction cycles with water as washing solvent and 3 × 10 μL of ethyl acetate as the eluting solvent. Chromatographic separation was also optimized for injection temperature, flow rate, ion source, interface temperature, column temperature gradient and mass spectrometry was evaluated using the scan and selected ion monitoring data acquisition mode. Satisfactory results were obtained in terms of linearity with R(2) >0.9992 within the established concentration range. The limit of detection was 0.003-0.015 ng/mL, and the limit of quantification was 0.009-0.049 ng/mL. The recoveries were in the range of 92.35-98.90% for cold drink, 88.23-169.20% for perfume, and 88.90-184.40% for cream. Analysis by microextraction by packed sorbent promises to be a rapid method for the determination of these phthalates in cold drink and cosmetic samples, reducing the amount of sample, solvent, time and cost. PMID:26683135

  3. Highly Sensitive Colorimetric Detection of Ochratoxin A by a Label-Free Aptamer and Gold Nanoparticles

    PubMed Central

    Luan, Yunxia; Chen, Jiayi; Li, Cheng; Xie, Gang; Fu, Hailong; Ma, Zhihong; Lu, Anxiang

    2015-01-01

    A label-free aptamer-based assay for the highly sensitive and specific detection of Ochratoxin A (OTA) was developed using a cationic polymer and gold nanoparticles (AuNPs). The OTA aptamer was used as a recognition element for the colorimetric detection of OTA based on the aggregation of AuNPs by the cationic polymer. By spectroscopic quantitative analysis, the colorimetric assay could detect OTA down to 0.009 ng/mL with high selectivity in the presence of other interfering toxins. This study offers a new alternative in visual detection methods that is rapid and sensitive for OTA detection. PMID:26690477

  4. Rapid analysis and quantification of fluorescent brighteners in wheat flour by Tri-step infrared spectroscopy and computer vision technology

    NASA Astrophysics Data System (ADS)

    Guo, Xiao-Xi; Hu, Wei; Liu, Yuan; Gu, Dong-Chen; Sun, Su-Qin; Xu, Chang-Hua; Wang, Xi-Chang

    2015-11-01

    Fluorescent brightener, industrial whitening agent, has been illegally used to whitening wheat flour. In this article, computer vision technology (E-eyes) and colorimetry were employed to investigate color difference among different concentrations of fluorescent brightener in wheat flour using DMS as an example. Tri-step infrared spectroscopy (Fourier transform-infrared spectroscopy coupled with second derivative infrared spectroscopy (SD-IR) and two dimensional correlation infrared spectroscopy (2DCOS-IR)) was used to identify and quantitate DMS in wheat flour. According to color analysis, the whitening effect was significant when added with less than 30 mg/g DMS but when more than 100 mg/g, the flour began greenish. Thus it was speculated that the concentration of DMS should be below 100 mg/g in real flour adulterant with DMS. With the increase of the concentration, the spectral similarity of wheat flour with DMS to DMS standard was increasing. SD-IR peaks at 1153 cm-1, 1141 cm-1, 1112 cm-1, 1085 cm-1 and 1025 cm-1 attributed to DMS were regularly enhanced. Furthermore, it could be differentiated by 2DOS-IR between DMS standard and wheat flour added with DMS low to 0.05 mg/g and the bands in the range of 1000-1500 cm-1 could be an exclusive range to identify whether wheat flour contained DMS. Finally, a quantitative prediction model based on IR spectra was established successfully by Partial least squares (PLS) with a concentration range from 1 mg/g to 100 mg/g. The calibration set gave a determination coefficient of 0.9884 with a standard error (RMSEC) of 5.56 and the validation set presented a determination coefficient of 0.9881 with a standard error of 5.73. It was demonstrated that computer vision technology and colorimetry were effective to estimate the content of DMS in wheat flour and the Tri-step infrared macro-fingerprinting combined with PLS was applicable for rapid and nondestructive fluorescent brightener identification and quantitation.

  5. A rapid and highly sensitive UPLC-MS-MS method for the quantification of zolpidem tartrate in human EDTA plasma and its application to pharmacokinetic study.

    PubMed

    Reddy, Dendhi Chandrapal; Bapuji, Akula Tukaram; Rao, Vepakomma Suryanarayana; Himabindu, Vurimindi; Ravinder, Sreedasyam

    2012-07-01

    A rapid and high sensitive liquid chromatography-tandem mass spectrometry (LC-MS-MS) method was developed and validated for the quantification of zolpidem in human EDTA plasma using ondansetron (IS) as an internal standard. The analyte and IS were extracted from human plasma using ethyl acetate and separated on a C18 column (Inertsil-ODS, 5 µm, 4.6 × 50 mm) interfaced with a triple quadrupole tandem mass spectrometer. The mobile phase, which consisted of a mixture of methanol and 20 mM ammonium formate (pH 5.00 ± 0.05; 75:25 v/v), was injected at a flow rate of 0.40 mL/min. The retention times of zolpidem and IS were approximately 1.76 and 1.22. The LC run time was 3 min. The electrospray ionization source was operated in positive ion mode. Multiple reaction monitoring used the [M + H](+) ions m/z 308.13 → 235.21 for zolpidem and m/z 294.02 → 170.09 for the ondansetron, respectively. Five freeze-thaw cycles was established at -20 and -70°C.The linearity of the response/concentration curve was established in human EDTA plasma over the concentration range 0.10-149.83 ng/mL. The lower detection limit [(signal-to-noise (S/N) > 3] was 0.04 ng/mL and the lower limit of quantification (S/N > 10) was 0.10 ng/mL. This LC-MS-MS method was validated with intra-batch and inter-batch precision of 0.52-8.66.The intra-batch and inter-batch accuracy was 96.66-106.11. Recovery of zolpidem in human plasma was 87.00% and IS recovery was 81.60%. The primary pharmacokinetic parameters were T(max) (h) = (1.25 ± 0.725), C(max) (ng/mL) (127.80 ± 34.081), AUC(0→t), = (665.37 ± 320.982) and AUC(0→∞), 686.03 ± 342.952, respectively. PMID:22689921

  6. Gold nanoparticles based colorimetric nanodiagnostics for cancer and infectious diseases

    NASA Astrophysics Data System (ADS)

    Valentini, Paola; Persano, Stefano; Cecere, Paola; Sabella, Stefania; Pompa, Pier Paolo

    2014-03-01

    Traditional in vitro diagnostics requires specialized laboratories and costly instrumentation, both for the amplification of nucleic acid targets (usually achieved by PCR) and for the assay readout, often based on fluorescence. We are developing hybrid nanomaterials-based sensors for the rapid and low-cost diagnosis of various disease biomarkers, for applications in portable platforms for diagnostics at the point-of-care. To this aim, we exploited the size and distancedependent optical properties of gold nanoparticles (AuNPs) to achieve colorimetric detection. Moreover, in order to avoid the complexity of thermal cycles associated to traditional PCR, the design of our systems includes signal amplification schemes, achieved by the use of enzymes (nucleases, helicase) or DNAzymes. Focused on instrument-free and sensitive detection, we carefully combined the intrinsic sensitivity by multivalency of functionalized AuNPs with isothermal and non-stringent enzyme-aided reaction conditions, controlled AuNPs aggregates, universal reporters and magnetic microparticles, the latter used both as a substrate and as a means for the colorimetric detection. We obtained simple and robust assays for the sensitive (pM range or better) naked-eye detection of cancer or infectious diseases (HPV, HCV) biomarkers, requiring no instrumentation except for a simple heating plate. Finally, we are also developing non-medical applications of these bio-nanosensors, such as in the development of on-field rapid tests for the detection of pollutants and other food and water contaminants.

  7. [Detection of viable metabolically active yeast cells using a colorimetric assay].

    PubMed

    Růzicka, F; Holá, V

    2008-02-01

    The increasing concern of yeasts able to form biofilm brings about the need for susceptibility testing of both planktonic and biofilm cells. Detection of viability or metabolic activity of yeast cells after exposure to antimicrobials plays a key role in the assessment of susceptibility testing results. Colorimetric assays based on the color change of the medium in the presence of metabolically active cells proved suitable for this purpose. In this study, the usability of a colorimetric assay with the resazurin redox indicator for monitoring the effect of yeast inoculum density on the reduction rate was tested. As correlation between the color change rate and inoculum density was observed, approximate quantification of viable cells was possible. The assay would be of relevance to antifungal susceptibility testing in both planktonic and biofilm yeasts. PMID:18318392

  8. Rapid quantification of Escherichia coli in food and media using bacteriophage T7 amplification and liquid chromatography-multiple reaction monitoring tandem mass spectrometry.

    PubMed

    Banu, Mazlina; Ng, Daniel; Zheng, Lu; Goh, Lin-Tang; Bi, Xuezhi; Ow, Dave Siak-Wei

    2014-12-20

    Conventional microbiological assays have been a valuable tool for specific enumeration of indicative bacteria of relevance to food and public health, but these culture-based methods are time-consuming and require tedious biochemical and morphological identification. In this work, we exploit the ability of bacteriophage T7 to specifically infect Escherichia coli and amplify nearly a 100-fold in 1–2 h. Bacteriophage amplification is integrated with liquid chromatography-multiple reaction monitoring tandem mass spectrometry (LC-MRM–MS/MS) for quantitation of phage-specific peptides. Heavy isotopic 15N labeled T7 is introduced as the inoculum phage and internal standard. Quantification is performed by determining the ratio of phage-specific peptides over the internal standard which value is proportional to E. coli numbers. A broad dynamic range of 6-log orders ranging from 3.0 × 10(3) to 3.0 × 10(9) CFU/ml is attained in LB, while between 4.1 × 10(4)–2.7 × 10(9) CFU/ml and 1.9 × 10(3)–3.0 × 10(7) CFU/ml was enumerated respectively in coconut water and apple juice. With this method, viable E. coli are quantified in 4 h with a detection limit of 3.0 × 10(3) CFU/ml, 4.1 × 10(4) CFU/ml and 1.9 × 10(3) CFU/ml in LB, coconut water and apple juice, respectively. This method has potential as a rapid tool for detection of fecal contamination during food bioprocessing and distribution to safeguard public health. PMID:25456056

  9. Rapid and sensitive screening and selective quantification of antibiotics in human urine by two-dimensional ultraperformance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry.

    PubMed

    Wang, He-Xing; Wang, Bin; Zhou, Ying; Jiang, Qing-Wu

    2014-12-01

    A rapid and sensitive method for the screening and selective quantification of antibiotics in urine by two-dimensional ultraperformance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry was developed. This method allowed the injection of 200 μL urine extract. The 200-μL injection volume used in this method increased the absolute sensitivity for target antibiotics in solvent by an average 13.3 times, with a range from 8.4 to 28.5 times, compared with the 10-μL conventional injection volume. A 96-well solid phase extraction procedure was established to eliminate the contamination on the chromatographic column resulting from the large-volume injection and increase the throughput of sample preparation. Fourteen target antibiotics from six common categories (β-lactams, quinolones, tetracyclines, macrolides, sulfonamides, and chloramphenicols) were selected as model compounds, and a database containing an additional 74 antibiotics was compiled for posttarget screening. The limit of detection of the target antibiotics, defined as a signal-to-noise ratio of 3, ranged from 0.04 to 1.99 ng/mL. The mean interday recoveries ranged between 79.6 and 121.3 %, with a relative standard deviation from 2.9 to 18.3 % at three spiking levels of 20 ng/mL, 50 ng/mL, and 100 ng/mL. This method was successfully applied in 60 real urine samples from schoolchildren aged 8-11 years, and four target antibiotics (azithromycin, sulfadiazine, trimethoprim, and oxytetracycline) and two posttarget antibiotics (sulfadimidine and cefaclor) were found in the urine samples. This method can be used as a large-scale biomonitoring tool for exposure of the human population to antibiotics. PMID:25354887

  10. High-throughput and rapid quantification of lipids by nanoflow UPLC-ESI-MS/MS: application to the hepatic lipids of rabbits with nonalcoholic fatty liver disease.

    PubMed

    Byeon, Seul Kee; Lee, Jong Cheol; Chung, Bong Chul; Seo, Hong Seog; Moon, Myeong Hee

    2016-07-01

    A rapid and high-throughput quantification method (approximately 300 lipids within 20 min) was established using nanoflow ultrahigh-pressure liquid chromatography-tandem mass spectrometry (nUPLC-ESI-MS/MS) with selective reaction monitoring (SRM) and applied to the quantitative profiling of the hepatic lipids of rabbits with different metabolic conditions that stimulate the development of nonalcoholic fatty liver disease (NAFLD). Among the metabolic conditions of rabbits in this study [inflammation (I), high-cholesterol diet (HC), and high-cholesterol diet combined with inflammation (HCI)], significant perturbation in hepatic lipidome (>3-fold and p < 0.01) was observed in the HC and HCI groups, while no single lipid showed a significant change in group I. In addition, this study revealed a dramatic increase (>2-fold) in relatively high-abundant monohexosylceramides (MHCs), sphingomyelins (SMs), and triacylglycerols (TGs) in both the HC and HCI groups, especially in MHCs as all 11 MHCs increased by larger than 3- to 12-fold. As the levels of the relatively high-abundant lipids in the above classes increased, the total lipidome level of each class increased significantly by approximately 2-fold to 5-fold. Other classes of lipids also generally increased, which was likely induced by the increase in mitogenic and nonapoptotic MHCs and SMs, as they promote cell proliferation. On the other hand, a slight decrease in the level of apoptotic ceramides (Cers) was observed, which agreed with the general increase in total lipid level. As distinct changes in hepatic lipidome were observed from HC groups, this suggests that HC or HCI is highly associated with NAFLD but not inflammation alone itself. Graphical Abstract Schematic of lipidomic analysis from hepatic tissue using nanoflow LC-ESI-MS/MS and nUPLC-ESI-MS/MS. PMID:27178550

  11. Multiplexed Colorimetric Solid-Phase Extraction

    NASA Technical Reports Server (NTRS)

    Gazda, Daniel B.; Fritz, James S.; Porter, Marc D.

    2009-01-01

    Multiplexed colorimetric solid-phase extraction (MC-SPE) is an extension of colorimetric solid-phase extraction (C-SPE) an analytical platform that combines colorimetric reagents, solid phase extraction, and diffuse reflectance spectroscopy to quantify trace analytes in water. In CSPE, analytes are extracted and complexed on the surface of an extraction membrane impregnated with a colorimetric reagent. The analytes are then quantified directly on the membrane surface using a handheld diffuse reflectance spectrophotometer. Importantly, the use of solid-phase extraction membranes as the matrix for impregnation of the colorimetric reagents creates a concentration factor that enables the detection of low concentrations of analytes in small sample volumes. In extending C-SPE to a multiplexed format, a filter holder that incorporates discrete analysis channels and a jig that facilitates the concurrent operation of multiple sample syringes have been designed, enabling the simultaneous determination of multiple analytes. Separate, single analyte membranes, placed in a readout cartridge create unique, analyte-specific addresses at the exit of each channel. Following sample exposure, the diffuse reflectance spectrum of each address is collected serially and the Kubelka-Munk function is used to quantify each water quality parameter via calibration curves. In a demonstration, MC-SPE was used to measure the pH of a sample and quantitate Ag(I) and Ni(II).

  12. A Colorimetric Bioassay for Perchlorate

    NASA Astrophysics Data System (ADS)

    Heinnickel, M. L.; Smith, S.; Coates, J. D.

    2007-12-01

    Recognition of perchlorate (ClO4-) as a widespread contaminant across the United States and its potential adverse affects towards human health has motivated the EPA to place ClO4- on its contaminant candidate list for drinking water supplies. While a federal MCL has not yet been set, a recommended public health goal of 1 ppb (μg.L-1) was established by the US EPA in 2002. To date, methods of detection require use of sensitive ion chromatographic equipment that are expensive, time consuming, and require highly trained personnel for use. Our studies are focused on the development of a highly sensitive, simple, and robust colorimetric bioassay based on the primary enzyme involved in microbial ClO4- reduction, the perchlorate reductase (Pcr). A previously published assay used reduced methyl viologen (MV, the dye is reduced with sodium hydrosulfite) as an electron donor to demonstrate Pcr activity. The assay directly correlates the amount of MV oxidized with the amount of ClO4- reduced by assuming a transfer of four electrons. To test this assumption, we compared actual concentrations of MV oxidized to ClO4- reduced in this assay. ClO4- concentrations were determined using a Dionex ICS-500 ion chromatography system, while MV concentrations were determined using a standard curve generated at 578 nm. Comparisons between the two revealed that twelve molecules of MV were oxidized for each molecule of ClO4- reduced. The oxidation of these additional eight MV molecules is explained by the interaction of the dye with chlorite (the product of the Pcr reaction) and other contaminants that could be present in the enzyme prep. This unsettling result indicated this assay would be problematic for the detection of ClO4- in soil, which has many chemicals that could react with MV. To improve upon this assay, we have tried to reduce ClO4- using less reactive dyes and reductants. The reductants ascorbic acid, NADH, and dithiothreitol drive Pcr catalyzed ClO4- reduction, however, they

  13. Colorimetric Immunoassay for Detection of Tumor Markers

    PubMed Central

    Yin, Yongmei; Cao, Ya; Xu, Yuanyuan; Li, Genxi

    2010-01-01

    Tumor markers are substances, usually proteins, produced by the body in response to cancer growth, or by the cancer tissue itself. They can be detected in blood, urine, or tissue samples, and the discovery and detection of tumor markers may provide earlier diagnosis of cancer and improved therapeutic intervention. Colorimetric immunoassays for tumor marker detection have attracted considerable attention, due to their simplicity and high efficiency. The traditionally used colorimetric immunoassays for the detection of tumor markers are based on enzyme-linked immunosorbent assays, and the great achievement of nanotechnology has further opened opportunities for the development of such kind of immunoassays. This paper will summarize recent advances in the field of colorimetric immunoassays for detecting tumor markers, which is aimed to provide an overview in this field, as well as experimental guidance for the learner. PMID:21614193

  14. Sensitiveness of the colorimetric estimation of titanium

    USGS Publications Warehouse

    Wells, R.C.

    1911-01-01

    The accuracy of the colorimetric estimation of titanium is practically constant over concentrations ranging from the strongest down to those containing about 1.5 mg. TiO2 in 100 cc. The change in concentration required to produce a perceptible difference in intensity between two solutions, at favorable concentrations, was found to be about 6.5 per cent, which does not differ much from the results of others with chromium and copper solutions. With suitable precautions, such as comparing by substitution and taking the mean of several settings or of the two perceptibly different extremes, the accuracy of the colorimetric comparisons appears to be about 2 per cent.

  15. Reactive Arrays of Colorimetric Sensors for Metabolite and Steroid Identification.

    PubMed

    Batres, Gary; Jones, Talia; Johnke, Hannah; Wilson, Mark; Holmes, Andrea E; Sikich, Sharmin

    2014-12-31

    The work described herein examines a rapid mix-and-measure method called DETECHIP suitable for screening of steroids and metabolites. The addition of steroids and metabolites to reactive arrays of colorimetric sensors generated characteristic color "fingerprints" that were used to identify the analyte. A color analysis tool was used to identify the analyte pool that now includes biologically relevant analytes. The mix-and-measure arrays allowed the detection of disease metabolites, orotic acid and argininosuccinic acid; and the steroids androsterone, 1,4-androstadiene, testosterone, stanozolol, and estrone. The steroid 1,4-androstadiene was also detected by this method while dissolved in synthetic urine. Some of the steroids, such as androstadiene, stanozolol, and androsterone were co-dissolved with (2-hydroxypropyl)-β-cyclodextrin in order to increase solubility in aqueous buffered solutions. The colorimetric arrays do not intend to eliminate ELISA or mass spectroscopy based screening, but to possibly provide an alternative analytical detection method for steroids and metabolites. PMID:25019034

  16. Development of a new colorimetric assay for lipoxygenase activity.

    PubMed

    Lu, Weiqiang; Zhao, Xue; Xu, Zhongyu; Dong, Ningning; Zou, Shien; Shen, Xu; Huang, Jin

    2013-10-15

    Lipoxygenases (LOXs) are a family of non-heme iron-containing dioxygenases that catalyze the hydroperoxidation of lipids, containing a cis,cis-1,4-pentadiene structure. A rapid and reliable colorimetric assay for determination of the activity of three human functional lipoxygenase isoforms (5-lipoxygenase, platelet 12-lipoxygenase, and 15-lipoxygenase-1) is developed in this article. In the new assay, LOX-derived lipid hydroperoxides oxidize the ferrous ion (Fe²⁺) to the ferric ion (Fe³⁺), the latter of which binds with thiocyanate (SCN⁻) to generate a red ferrithiocyanate (FTC) complex. The absorbance of the FTC complex can be easily measured at 480 nm. Because 5-LOX can be stimulated by many cofactors, the effects of its cofactors (Ca²⁺, ATP, dithiothreitol, glutathione, L-α-phosphatidylcholine, and ethylenediaminetetraacetic acid) on the color development of the FTC complex are also determined. The assay is adaptive for purified LOXs and cell lysates containing active LOXs. We use the new colorimetric assay in a 96-well format to evaluate several well-known LOX inhibitors, the IC₅₀ values of which are in good agreement with previously reported data. The reliability and reproducibility of the assay make it useful for in vitro screening for inhibitors of LOXs and, therefore, should accelerate drug discovery for clinical application. PMID:23811155

  17. Development of a Tunable LED-Based Colorimetric Source

    PubMed Central

    Brown, Steven W.; Santana, Carlos; Eppeldauer, George P.

    2002-01-01

    A novel, spectrally tunable light-source utilizing light emitting diodes (LEDs) for radiometric, photometric, and colorimetric applications is described. The tunable source can simulate standard sources and can be used as a transfer source to propagate photometric and colorimetric scales from calibrated reference instruments to test artifacts with minimal increase in uncertainty. In this prototype source, 40 LEDs with 10 different spectral distributions were mounted onto an integrating sphere. A voltage-to-current control circuit was designed and implemented, enabling independent control of the current sent to each set of four LEDs. The LEDs have been characterized for stability and dependence on drive current. The prototype source demonstrates the feasibility of development of a spectrally tunable LED source using LEDs with up to 40 different spectral distributions. Simulations demonstrate that such a source would be able to approximate standard light-source distributions over the visible spectral range—from 380 nm to 780 nm—with deviations on the order of 2 %. The tunable LED source can also simulate spectral distributions of special sources such as discharge lamps and display monitors. With this tunable source, a test instrument can be rapidly calibrated against a variety of different source distributions tailored to the anticipated uses of the artifact. Target uncertainties for the calibration of test artifacts are less than 2 % in luminance and 0.002 in chromaticity for any source distribution.

  18. Rapid Identification and Quantification of Natural Antioxidants in the Seeds of Rhubarb from Different Habitats in China Using Accelerated Solvent Extraction and HPLC-DAD-ESI-MSn-DPPH Assay.

    PubMed

    Tan, Liang; Geng, Dan-dan; Hu, Feng-zu; Dong, Qi

    2016-01-01

    In this study, the 10 accessions of rhubarb seeds from different habitats in China were investigated. Lipids were removed using petroleum ether, and the effective components were then separated using accelerated solvent extraction with 80% aqueous methanol. An off-line 2,2-diphenyl-1-picrylhydrazyl (DPPH) free-radical scavenging method was used as the marker to evaluate the total antioxidant capability of extracts. On-line high-performance liquid chromatography-diode-array detectors-electrospray ionization-tandem mass spectrometry (HPLC-DAD-ESI-MS(n)) and HPLC-DAD-DPPH assays were developed for rapid identification and quantification of individual free-radical scavengers in extracts of rhubarb seeds. Ten free-radical scavengers from methanolic extracts of the rhubarb seeds were screened, five of which were identified and quantitatively analyzed: epicatechin, myricetin, hyperoside, quercitrin and quercetin. All were identified in rhubarb seeds for the first time and can be regarded as the major potent antioxidants in rhubarb seeds due to representing most of the total free-radical scavenging activity. Preliminary analysis of structures was performed for another five antioxidants. Based on our validation results, the developed method can be used for rapid separation, convenient identification and quantification of the multiple antioxidative constituents in rhubarb seeds, featuring good quantification parameters, accuracy and precision. The results are important to clarify the material basis and therapeutic mechanism of rhubarb seeds. PMID:26206792

  19. Colorimetric determination of tobramycin in parenteral solutions.

    PubMed

    Das Gupta, V

    1988-06-01

    A colorimetric method based on a reaction between tobramycin and alkaline copper sulphate solution has been proposed to quantify tobramycin in injections. The excipients present and normal saline did not interfere with the assay procedure. A tobramycin sample which was decomposed using either sulphuric acid or sodium hydroxide solution indicated fairly good stability on both sides of the pH scale. PMID:3209627

  20. Nucleic acid-coupled colorimetric analyte detectors

    DOEpatents

    Charych, Deborah H.; Jonas, Ulrich

    2001-01-01

    The present invention relates to methods and compositions for the direct detection of analytes and membrane conformational changes through the detection of color changes in biopolymeric materials. In particular, the present invention provide for the direct colorimetric detection of analytes using nucleic acid ligands at surfaces of polydiacetylene liposomes and related molecular layer systems.

  1. Visualizing Capsaicinoids: Colorimetric Analysis of Chili Peppers

    ERIC Educational Resources Information Center

    Thompson, Robert Q.; Chu, Christopher; Gent, Robin; Gould, Alexandra P.; Rios, Laura; Vertigan, Theresa M.

    2012-01-01

    A colorimetric method for total capsaicinoids in chili pepper ("Capsicum") fruit is described. The placental material of the pepper, containing 90% of the capsaicinoids, was physically separated from the colored materials in the pericarp and extracted twice with methanol, capturing 85% of the remaining capsaicinoids. The extract, evaporated and…

  2. Colorimetric determination of o-phenylenediamine in water samples based on the formation of silver nanoparticles as a colorimetric probe

    NASA Astrophysics Data System (ADS)

    Li, Nan; Gu, Yu; Gao, Mengmeng; Wang, Zilu; Xiao, Deli; Li, Yun; Lin, Rui; He, Hua

    2015-04-01

    A simple, rapid and cost-effective method for visual colorimetric detection of o-phenylenediamine (OPD) based on the formation of silver nanoparticles (AgNPs) has been developed in this paper. Silver ions can be reduced to AgNPs by OPD in a few minutes, causing changes in absorption spectra and color of the reaction system. Therefore, colorimetric detection of OPD could be realized by a UV-vis spectrophotometer or even the naked eye. Results showed that the absorption intensity of AgNPs at 416 nm exhibited a good linear correlation (R2 = 0.998) with OPD concentration in the range from 10-6 to 8 × 10-5 mol L-1 and the detection limit (3 σ/S) was calculated to be 1.61 × 10-7 mol L-1. Furthermore, as low as 4 × 10-6 mol L-1 OPD can be visualized by the naked eye without the requirement of any complicated or expensive instruments. This proposed method has been successfully applied to determine OPD in water samples, and may provide an innovative platform in the development of sensors for guiding environmental monitoring in the future.

  3. Paper-based tuberculosis diagnostic devices with colorimetric gold nanoparticles

    NASA Astrophysics Data System (ADS)

    Tsai, Tsung-Ting; Shen, Shu-Wei; Cheng, Chao-Min; Chen, Chien-Fu

    2013-08-01

    A colorimetric sensing strategy employing gold nanoparticles and a paper assay platform has been developed for tuberculosis diagnosis. Unmodified gold nanoparticles and single-stranded detection oligonucleotides are used to achieve rapid diagnosis without complicated and time-consuming thiolated or other surface-modified probe preparation processes. To eliminate the use of sophisticated equipment for data analysis, the color variance for multiple detection results was simultaneously collected and concentrated on cellulose paper with the data readout transmitted for cloud computing via a smartphone. The results show that the 2.6 nM tuberculosis mycobacterium target sequences extracted from patients can easily be detected, and the turnaround time after the human DNA is extracted from clinical samples was approximately 1 h.

  4. A Wash-Free Homogeneous Colorimetric Immunoassay Method

    PubMed Central

    Liu, Huiqiao; Rong, Pengfei; Jia, Hongwei; Yang, Jie; Dong, Bo; Dong, Qiong; Yang, Cejun; Hu, Pengzhi; Wang, Wei; Liu, Haitao; Liu, Dingbin

    2016-01-01

    Rapid and convenient biosensing platforms could be beneficial to timely diagnosis and treatment of diseases in virtually any care settings. Sandwich immunoassays, the most commonly used methods for protein detection, often rely on expensive tags such as enzyme and tedious wash and incubation procedures operated by skilled labor. In this report, we revolutionized traditional sandwich immunoassays by providing a wash-free homogeneous colorimetric immunoassay method without requirement of any separation steps. The proposed strategy was realized by controlling the growth of gold nanoparticles (AuNPs) to mediate the interparticle spacing in the protein-AuNP oligomers. We have demonstrated the successful in vitro detection of cancer biomarker in serum samples from patients with high clinical sensitivity and specificity. PMID:26722373

  5. Hybrid nanosensor for colorimetric and ultrasensitive detection of nuclease contaminations

    NASA Astrophysics Data System (ADS)

    Cecere, Paola; Valentini, Paola; Pompa, Pier Paolo

    2016-04-01

    Nucleases are ubiquitous enzymes that degrade DNA or RNA, thus they can prejudice the good outcome of molecular biology experiments involving nucleic acids. We propose a colorimetric test for the naked-eye detection of nuclease contaminations. The system uses an hybrid nanosensor, based on gold nanoparticles functionalized with DNA probes. Our assay is rapid, instrument-free, simple and low-cost. Moreover, it reaches sensitivity equal or better than those of commercial kits, and presents a lot of advantageous aspects. Therefore, it is very competitive, with a real market potential. This test will be relevant in routine process monitoring in scientific laboratories, and in quality control in clinical laboratories and industrial processes, allowing the simultaneous detection of nucleases with different substrate specificities and large-scale screening.

  6. Optimized enzymatic colorimetric assay for determination of hydrogen peroxide (H2O2) scavenging activity of plant extracts

    PubMed Central

    Fernando, Chamira Dilanka; Soysa, Preethi

    2015-01-01

    The classical method to determine hydrogen peroxide (H2O2) scavenging activity of plant extracts is evaluated by measuring the disappearance of H2O2 at a wavelength of 230 nm. Since this method suffers from the interference of phenolics having strong absorption in the UV region, a simple and rapid colorimetric assay was developed where plant extracts are introduced to H2O2, phenol and 4-aminoantipyrine reaction system in the presence of horseradish peroxidase (HRP). This reaction yields a quinoneimine chromogen which can be measured at 504 nm. Decrease in the colour intensity reflects the H2O2 scavenged by the plant material. • Optimum conditions determined for this assay were 30 min reaction time, 37 °C, pH 7, enzyme concentration of 1 U/ml and H2O2 concentration of 0.7 mM. The limit of detection (LOD) and limit of quantitation (LOQ) were 136 μM and 411 μM, respectively. • Half maximal effective concentration required to scavenge 50% of H2O2 in the system (EC50 value) calculated for several plant extracts and standard antioxidants resulted in coefficient of variance (CV%) of the EC50 values less than 3.0% and correlation coefficient values (R2) > 0.95 for all dose response curves obtained. • This method is convenient and very precise which is suitable for the rapid quantification of H2O2 scavenging ability of standard antioxidants and natural antioxidants present in plant extracts. PMID:26285798

  7. Colorimetric detection of Shewanella oneidensis based on immunomagnetic capture and bacterial intrinsic peroxidase activity

    PubMed Central

    Wen, Junlin; Zhou, Shungui; Chen, Junhua

    2014-01-01

    Rapid detection and enumeration of target microorganisms is considered as a powerful tool for monitoring bioremediation process that typically involves cleaning up polluted environments with functional microbes. A novel colorimetric assay is presented based on immunomagnetic capture and bacterial intrinsic peroxidase activity for rapidly detecting Shewanella oneidensis, an important model organism for environmental bioremediation because of its remarkably diverse respiratory abilities. Analyte bacteria captured on the immunomagnetic beads provided a bacterial out-membrane peroxidase-amplified colorimetric readout of the immunorecognition event by oxidizing 3, 3′, 5, 5′-tetramethylbenzidine (TMB) in the present of hydrogen peroxide. The high-efficiency of immunomagnetic capture and signal amplification of peroxidase activity offers an excellent detection performance with a wide dynamic range between 5.0 × 103 and 5.0 × 106 CFU/mL toward target cells. Furthermore, this method was demonstrated to be feasible in detecting S. oneidensis cells spiked in environmental samples. The proposed colorimetric assay shows promising environmental applications for rapid detection of target microorganisms. PMID:24898751

  8. Colorimetric detection of Shewanella oneidensis based on immunomagnetic capture and bacterial intrinsic peroxidase activity

    NASA Astrophysics Data System (ADS)

    Wen, Junlin; Zhou, Shungui; Chen, Junhua

    2014-06-01

    Rapid detection and enumeration of target microorganisms is considered as a powerful tool for monitoring bioremediation process that typically involves cleaning up polluted environments with functional microbes. A novel colorimetric assay is presented based on immunomagnetic capture and bacterial intrinsic peroxidase activity for rapidly detecting Shewanella oneidensis, an important model organism for environmental bioremediation because of its remarkably diverse respiratory abilities. Analyte bacteria captured on the immunomagnetic beads provided a bacterial out-membrane peroxidase-amplified colorimetric readout of the immunorecognition event by oxidizing 3, 3', 5, 5'-tetramethylbenzidine (TMB) in the present of hydrogen peroxide. The high-efficiency of immunomagnetic capture and signal amplification of peroxidase activity offers an excellent detection performance with a wide dynamic range between 5.0 × 103 and 5.0 × 106 CFU/mL toward target cells. Furthermore, this method was demonstrated to be feasible in detecting S. oneidensis cells spiked in environmental samples. The proposed colorimetric assay shows promising environmental applications for rapid detection of target microorganisms.

  9. An organic indicator functionalized graphene oxide nanocomposite-based colorimetric assay for the detection of sarcosine

    NASA Astrophysics Data System (ADS)

    Xue, Zhonghua; Yin, Bo; Wang, Hui; Li, Mengqian; Rao, Honghong; Liu, Xiuhui; Zhou, Xinbin; Lu, Xiaoquan

    2016-03-01

    Rapid detection of sarcosine is a key requirement for both diagnosis and treatment of disease. We report here a simple yet sensitive colorimetric nanocomposite platform for rapid detection of sarcosine in alkaline media. The approach exploited the benefits of a rapid color-producing reaction between an organic indicator, 1,2-naphthoquinone-4-sulphonic acid sodium salt (NQS), and the analyte of sarcosine species as well as the good catalytic ability of graphene oxide (GO) to the formation of highly colored products due to its good water dispersibility, extremely large surface area and facile surface modification. As a result, a NQS functionalized GO nanocomposite through π-π stacking has been demonstrated to be useful as a highly efficient catalyst system for the selective and sensitive colorimetric determination of sarcosine by providing a nanocomposite-amplified colorimetric response. Meanwhile, the strategy offered excellent selectivity toward sarcosine species against other amino acids as well as a satisfying detection limit of 0.73 μM. More importantly, by using an electrochemical method, a credible sensing mechanism of GO nanocomposite-based colorimetric platform for a special analyte determination can be easily verified and elucidated, which also provides an attractive alternative to conventional characterization strategies.Rapid detection of sarcosine is a key requirement for both diagnosis and treatment of disease. We report here a simple yet sensitive colorimetric nanocomposite platform for rapid detection of sarcosine in alkaline media. The approach exploited the benefits of a rapid color-producing reaction between an organic indicator, 1,2-naphthoquinone-4-sulphonic acid sodium salt (NQS), and the analyte of sarcosine species as well as the good catalytic ability of graphene oxide (GO) to the formation of highly colored products due to its good water dispersibility, extremely large surface area and facile surface modification. As a result, a NQS

  10. A gold nanoparticles-based colorimetric test to detect single nucleotide polymorphisms for improvement of personalized therapy of psoriasis

    NASA Astrophysics Data System (ADS)

    Marsella, Alessandra; Valentini, Paola; Tarantino, Paolo; Congedo, Maurizio; Pompa, Pier Paolo

    2016-04-01

    We report a simple, rapid and low-cost test, based on gold nanoparticles, for the naked-eye colorimetric detection of a signature of single nucleotide polymorphisms (SNPs) relevant for the personalized medicine of psoriasis patients. We validated the colorimetric assay on real-world DNA samples from a cohort of 30 psoriasis patients and we compared the results, in double-blind, with those obtained with two state-of-the-art instrumental techniques, namely reverse dot blotting and direct sequencing, finding 100% agreement. We demonstrated high accuracy, sensitivity and specificity of the colorimetric test that can be easily adapted for the genotypization of different SNPs, important for the pharmacogenomics of various diseases, and in other fields, such as food traceability and population structure analysis.

  11. Colorimetric characterization models based on colorimetric characteristics evaluation for active matrix organic light emitting diode panels.

    PubMed

    Gong, Rui; Xu, Haisong; Tong, Qingfen

    2012-10-20

    The colorimetric characterization of active matrix organic light emitting diode (AMOLED) panels suffers from their poor channel independence. Based on the colorimetric characteristics evaluation of channel independence and chromaticity constancy, an accurate colorimetric characterization method, namely, the polynomial compensation model (PC model) considering channel interactions was proposed for AMOLED panels. In this model, polynomial expressions are employed to calculate the relationship between the prediction errors of XYZ tristimulus values and the digital inputs to compensate the XYZ prediction errors of the conventional piecewise linear interpolation assuming the variable chromaticity coordinates (PLVC) model. The experimental results indicated that the proposed PC model outperformed other typical characterization models for the two tested AMOLED smart-phone displays and for the professional liquid crystal display monitor as well. PMID:23089779

  12. A one-tube multiplexed colorimetric strategy based on plasmonic nanoparticles combined with non-negative matrix factorization.

    PubMed

    Liu, Yizhen; Fang, Wei; Wu, Zitong; Zhou, Guohua; Yi, Wen; Zhou, Xiaodong; Shen, Aiguo; Hu, Jiming

    2014-10-01

    Herein, a one-tube colorimetric platform has been developed for the simultaneous determination of two analytes (DNA as model object) in one tube with picomolar sensitivity. SPR-active nanoparticles are used to encode reporter probes sensitive to oligonucleotides associated with hepatitis A virus Vall7 polyprotein gene (HVA) and hepatitis B virus surface-antigen gene (HVB) respectively and magnetic beads (MBs) serve as the removal tool. In this mixed nanoparticles based biosensor, the addition of target analytes could change the concentration of each nanoparticle, leading to different colors of the supernatant. The influence of spectral overlap has been eliminated by a non-negative matrix factorization (NMF). With the assistance of NMF, the limit of detection (LOD) can be determinated as pM level without amplification. On the whole, this nanosensor boasts the advantages of high sensitivity and low sample consumption. Simultaneous colorimetric detection and quantification of two molecules in one tube are demonstrated. PMID:25059165

  13. Loop-Mediated Isothermal Amplification (LAMP) for Rapid Detection and Quantification of Dehalococcoides Biomarker Genes in Commercial Reductive Dechlorinating Cultures KB-1 and SDC-9

    PubMed Central

    Kanitkar, Yogendra H.; Stedtfeld, Robert D.; Steffan, Robert J.; Hashsham, Syed A.

    2016-01-01

    Real-time quantitative PCR (qPCR) protocols specific to the reductive dehalogenase (RDase) genes vcrA, bvcA, and tceA are commonly used to quantify Dehalococcoides spp. in groundwater from chlorinated solvent-contaminated sites. In this study, loop-mediated isothermal amplification (LAMP) was developed as an alternative approach for the quantification of these genes. LAMP does not require a real-time thermal cycler (i.e., amplification is isothermal), allowing the method to be performed using less-expensive and potentially field-deployable detection devices. Six LAMP primers were designed for each of three RDase genes (vcrA, bvcA, and tceA) using Primer Explorer V4. The LAMP assays were compared to conventional qPCR approaches using plasmid standards, two commercially available bioaugmentation cultures, KB-1 and SDC-9 (both contain Dehalococcoides species). DNA was extracted over a growth cycle from KB-1 and SDC-9 cultures amended with trichloroethene and vinyl chloride, respectively. All three genes were quantified for KB-1, whereas only vcrA was quantified for SDC-9. A comparison of LAMP and qPCR using standard plasmids indicated that quantification results were similar over a large range of gene concentrations. In addition, the quantitative increase in gene concentrations over one growth cycle of KB-1 and SDC-9 using LAMP was comparable to that of qPCR. The developed LAMP assays for vcrA and tceA genes were validated by comparing quantification on the Gene-Z handheld platform and a real-time thermal cycler using DNA isolated from eight groundwater samples obtained from an SDC-9-bioaugmented site (Tulsa, OK). These assays will be particularly useful at sites subject to bioaugmentation with these two commonly used Dehalococcoides species-containing cultures. PMID:26746711

  14. Discrimination of honeys using colorimetric sensor arrays, sensory analysis and gas chromatography techniques.

    PubMed

    Tahir, Haroon Elrasheid; Xiaobo, Zou; Xiaowei, Huang; Jiyong, Shi; Mariod, Abdalbasit Adam

    2016-09-01

    Aroma profiles of six honey varieties of different botanical origins were investigated using colorimetric sensor array, gas chromatography-mass spectrometry (GC-MS) and descriptive sensory analysis. Fifty-eight aroma compounds were identified, including 2 norisoprenoids, 5 hydrocarbons, 4 terpenes, 6 phenols, 7 ketones, 9 acids, 12 aldehydes and 13 alcohols. Twenty abundant or active compounds were chosen as key compounds to characterize honey aroma. Discrimination of the honeys was subsequently implemented using multivariate analysis, including hierarchical clustering analysis (HCA) and principal component analysis (PCA). Honeys of the same botanical origin were grouped together in the PCA score plot and HCA dendrogram. SPME-GC/MS and colorimetric sensor array were able to discriminate the honeys effectively with the advantages of being rapid, simple and low-cost. Moreover, partial least squares regression (PLSR) was applied to indicate the relationship between sensory descriptors and aroma compounds. PMID:27041295

  15. Visual Screening and Colorimetric Determination of Clenbuterol and Ractopamine Using Unmodified Gold Nanoparticles as Probe.

    PubMed

    Luo, Yeli; Liu, Xin; Guo, Jiajia; Gao, Hanting; Li, Ying; Xu, Jingyue; Shen, Fei; Sun, Chunyan

    2016-01-01

    In this paper, a sensitive method for the colorimetric detection of clenbuterol and ractopamine using citrate-stabilized gold nanoparticles (AuNPs) as probe was developed. The concentration of clenbuterol and ractopamine could be determined with naked eyes or a UV-vis spectrometer. By optimizing the influence of NaHSO₄ and incubation time, clenbuterol could be detected in the linear range of 0.1-4 µg/mL with the detection limit of 0.0158 µg/mL, and ractopamine could be detected in the linear range of 1-9 µg/mL with the detection limit of 0.0229 µg/mL. The proposed method could be successfully applied to detect clenbuterol and ractopamine in pig urines by a simple pre-treatment with excellent recoveries. The proposed colorimetric assay exhibits good reproducibility and accuracy, providing a simple and rapid method for the analysis of clenbuterol and ractopamine. PMID:27398486

  16. Comparison of a gas chromatographic and colorimetric method for the determination of plasma paracetamol.

    PubMed

    Chambers, R E; Jones, K

    1976-07-01

    Plasma paracetamol levels have generally been determined either by gas chromatography (Stewart and Willis, 1975), which relies on complex equipment, or by spectrophotometry (Knepil, 1974), which can be time-consuming. The introduction by Glynn and Kendal (1975) of a simple colorimetric method based on the reaction of paracetamol with nitrous acid to give 2-nitro-4-acetamidophenol appears to have overcome these disadvantages, thereby providing a suitable procedure for the rapid measurement of plasma paracetamol in cases of overdose. The method was reported to be specific for paracetamol, no interference being caused either by the sulphate and glucuronide conjugates of paracetamol or by a large number of other commonly found drugs. This communication presents the results of a study in which plasma paracetamol levels determined by the colorimetric method were compared with those determined by an established gas chromatographic technique. PMID:952476

  17. Rapid quantification of a cleavable antibody-conjugated drug by liquid chromatography/tandem mass spectrometry with microwave-assisted enzymatic cleavage.

    PubMed

    Xu, Ling; Packer, Laura E; Qian, Mark G; Wu, Jing-Tao

    2016-09-01

    Antibody-drug conjugates (ADCs) play an increasingly important role for targeted cancer treatment. One class of ADCs has attracted particular interest in drug development. These ADCs employ a cleavable chemistry linkage for drugs and utilize the reduced interchain disulfide cysteine residues for conjugation. In this work, a novel bioanalytical method for the quantification of a cleavable antibody-conjugated drug in plasma was developed, qualified, and implemented. This novel method significantly improves throughput by combining a microwave-assisted, enzymatic cleavage of conjugated drugs from ADCs with a 96-well based sample preparation procedure to immunocapture ADCs in plasma. The released drug is subsequently quantified using a LC/MS/MS method. Our results represent a high-throughput, generic, and sensitive quantification method for antibody-conjugated microtubule inhibitors (such as MMAE) for preclinical PK/PD studies. The linear range of the standard curve for antibody conjugated drug (MMAE) was from 2.01 to 2010ng/mL with an excellent linearity (r(2)>0.997). The intra-run precision was below 8.14% and accuracy was from -7.71% to -1.08%. No matrix effect or carryover was observed for this method. This method was successfully used to measure the level of conjugated drug in a preclinical PK/PD study in mice. PMID:27281578

  18. Rapid and sensitive quantification of levoglucosan in aerosols by high-performance anion-exchange chromatography with positive electrospray ionization mass spectrometry (HPAEC-positive ESI-MS)

    NASA Astrophysics Data System (ADS)

    Asakawa, Daichi; Furuichi, Yuko; Yamamoto, Atsushi; Oku, Yuichiro; Funasaka, Kunihiro

    2015-12-01

    A convenient quantification method for underivatized levoglucosan, which is a tracer for biomass burning influenced particulate matter (PM), has been established using high-performance anion-exchange chromatography (HPAEC) coupled to positive electrospray ionization mass spectrometry ((+)ESI-MS). Levoglucosan was chromatographically separated from its isomers (mannosan and galactosan) and detected selectively with positive ESI-MS. Limits of detection and quantification for this method were 0.40 and 1.3 ng mL-1, respectively. A comparison of simultaneous measurements by this method and conventional derivatization gas chromatography/mass spectrometry showed a good linearity with a slope of 1.008 and a determination coefficient of 0.9932. The developed method was applied to ambient suspended particulate matter hourly collected by continuous particulate monitors at 10 stations. The hourly concentration of levoglucosan during August 9-11, 2011, was 1.7-918 ng m-3 and its distribution indicated the transportation of biomass burning aerosols of a forest fire. This is the first report of horizontal distribution of the hourly levoglucosan concentration in Japan.

  19. New two dimensional liquid-phase colorimetric assay based on old iodine-starch complexation for the naked-eye quantitative detection of analytes.

    PubMed

    Nie, Jinfang; Brown, Tom; Zhang, Yun

    2016-06-14

    A new type of quantitative point-of-care liquid-phase colorimetric assay (LPCA) termed as two dimensional (2D) LPCA is designed using old iodine-starch complexation reaction firstly discovered in 1814. The naked-eye 2D LPCA's utility is well demonstrated with the simple, low-cost, portable detection and quantification of model analytes in buffer and/or human serum samples without the use of external electronic readers. PMID:27074248

  20. QUANTIFICATION AND INTERPRETATION OF TOTAL PETROLEUM HYDROCARBONS IN SEDIMENT SAMPLES BY A GC/MS METHOD AND COMPARISON WITH EPA 418.1 AND A RAPID FIELD METHOD

    EPA Science Inventory

    ABSTRACT: Total Petroleum hydrocarbons (TPH) as a lumped parameter can be easily and rapidly measured or monitored. Despite interpretational problems, it has become an accepted regulatory benchmark used widely to evaluate the extent of petroleum product contamination. Three cu...

  1. A rapid method for the simultaneous quantification of the major tocopherols, carotenoids, free and esterified sterols in canola (Brassica napus) oil using normal phase liquid chromatography.

    PubMed

    Flakelar, Clare L; Prenzler, Paul D; Luckett, David J; Howitt, Julia A; Doran, Gregory

    2017-01-01

    A normal phase high performance liquid chromatography (HPLC) method was developed to simultaneously quantify several prominent bioactive compounds in canola oil vis. α-tocopherol, γ-tocopherol, δ-tocopherol, β-carotene, lutein, β-sitosterol, campesterol and brassicasterol. The use of sequential diode array detection (DAD) and tandem mass spectrometry (MS/MS) allowed direct injection of oils, diluted in hexane without derivatisation or saponification, greatly reducing sample preparation time, and permitting the quantification of both free sterols and intact sterol esters. Further advantages over existing methods included increased analytical selectivity, and a chromatographic run time substantially less than other reported normal phase methods. The HPLC-DAD-MS/MS method was applied to freshly extracted canola oil samples as well as commercially available canola, palm fruit, sunflower and olive oils. PMID:27507459

  2. Development and validation of a reliable and rapid LC-MS/MS method for simultaneous quantification of sacubitril and valsartan in rat plasma and its application to a pharmacokinetic study.

    PubMed

    Chunduri, Raja Haranadha Babu; Dannana, Gowri Sankar

    2016-09-01

    A selective, sensitive and rapid liquid chromatographic method with electrospray ionization tandem mass spectrometric detection has been developed and validated for simultaneous quantification of sacubitril and valsartan in rat plasma using telmisartan as internal standard (IS). The analytes were extracted by deprotenization of 50 μL of plasma sample using 200 μL of acetonitrile. In a short chromatographic run of 1.50 min run time, separation was achieved on a Hypersil Gold C18 column using a mobile phase composed of 0.1% formic acid in Milli-Q water-0.1% formic acid in acetonitrile in gradient elution mode. The quantification of target compounds was performed in a positive electrospray ionization mode and multiple reaction monitoring. Response was a linear function of concentration in the ranges of 0.5-20,000 ng/mL for both analytes, with r(2)  > 0.9997. The intra- and inter-day precision and accuracy results were <15% and acceptable as per US Food and Drug Administration guidelines. Stability of compounds were established in a battery of stability studies, i.e. bench-top, autosampler and long-term storage stability as well as freeze-thaw cycles. The validated method can be used as a routine method to support pharmacokinetic studies. Copyright © 2016 John Wiley & Sons, Ltd. PMID:26876742

  3. Development of a rapid column-switching LC-MS/MS method for the quantification of THCCOOH and THCCOOH-glucuronide in whole blood for assessing cannabis consumption frequency.

    PubMed

    Hädener, Marianne; Weinmann, Wolfgang; Schürch, Stefan; König, Stefan

    2016-03-01

    The concentration of 11-nor-9-carboxy-Δ(9)-tetrahydrocannabinol (THCCOOH) in whole blood is used as a parameter for assessing the consumption behavior of cannabis consumers. The blood level of THCCOOH-glucuronide might provide additional information about the frequency of cannabis use. To verify this assumption, a column-switching liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the rapid and direct quantification of free and glucuronidated THCCOOH in human whole blood was newly developed. The method comprised protein precipitation, followed by injection of the processed sample onto a trapping column and subsequent gradient elution to an analytical column for separation and detection. The total LC run time was 4.5 min. Detection of the analytes was accomplished by electrospray ionization in positive ion mode and selected reaction monitoring using a triple-stage quadrupole mass spectrometer. The method was fully validated by evaluating the following parameters: linearity, lower limit of quantification, accuracy and imprecision, selectivity, extraction efficiency, matrix effect, carry-over, dilution integrity, analyte stability, and re-injection reproducibility. All acceptance criteria were analyzed and the predefined criteria met. Linearity ranged from 5.0 to 500 μg/L for both analytes. The method was successfully applied to whole blood samples from a large collective of cannabis consumers, demonstrating its applicability in the forensic field. PMID:26781107

  4. Rapid Quantification of Bacteria in Infected Root Canals Using Fluorescence Reagents and a Membrane Filter: A Pilot Study on Its Clinical Application to the Evaluation of the Outcomes of Endodontic Treatment

    PubMed Central

    Sato, Takuichi; Yamaki, Keiko; Ishida, Naoko; Shoji, Megumi; Sato, Emika; Abiko, Yuki; Hashimoto, Kazuhiro; Takeuchi, Yasuhisa; Matsuyama, Junko; Shimauchi, Hidetoshi; Takahashi, Nobuhiro

    2012-01-01

    Objective. The bacterial examination has been performed during the course of the root canal treatment. In the present pilot study, the new developed method, using fluorescence reagents and a membrane filter, was applied to the detection and quantification of bacteria in infected root canals, in order to evaluate the outcomes of the treatment. Methods. Six infected root canals with periapical lesions from 5 subjects were included. Informed consent was obtained from all subjects (age ranges, 23–79 years). Samples from infected root canals were collected at the beginning of the treatment (termed #25 First), the end of the first day of treatment (termed #55 First), and the next appointment day (termed #55 Second). Then, the bacterial count (CFU) was measured using fluorescence reagents (4′,6′-diamidino-2-phenylindole and propidium iodide) and the polycarbonate membrane filter by Bioplorer. Results. The mean ± SD of CFU in the sample of “#25 First” was (1.0 ± 1.4) × 105. As the root canal treatment progressed, the CFU decreased as 7.9 × 103 (#55 First) and 4.3 × 102 (#55 Second). Conclusion. In the present pilot study, rapid detection and quantification of bacteria in infected root canals were found to be successfully performed using fluorescence reagents and a membrane filter (Bioplorer analysis). PMID:22693506

  5. Development and validation of a rapid and sensitive LC-ESI-MS/MS method for ondansetron quantification in human plasma and its application in comparative bioavailability study.

    PubMed

    Moreira, Roberto F; Salvadori, Myriam C; Azevedo, Cristina P; Oliveira-Silva, Diogo; Borges, Diego C; Moreno, Ronílson A; Sverdloff, Carlos E; Borges, Ney C

    2010-11-01

    The validation of a high throughput and specific method using a high-performance liquid chromatography coupled to electrospray (ES+) ionization tandem triple quadrupole mass spectrometric (LC-ESI-MS/MS) method for ondansetron quantification in human plasma is described. Human plasma samples were extracted by liquid-liquid extraction (LLE) using methyl tert-butyl ether and analyzed by LC-ESI-MS/MS. The limit of quantification was 0.2 ng/mL and the method was linear in the range 0.2-60 ng/mL. The intra-assay precisions ranged from 1.6 to 7.7%, while inter-assay precisions ranged from 2.1 to 5.1%. The intra-assay accuracies ranged from 97.5 to 108.2%, and the inter-assay accuracies ranged from 97.3 to 107.0%. The analytical method was applied to evaluate the relative bioavailability of two pharmaceutical formulations containing 8 mg of ondansetron each in 25 healthy volunteers using a randomized, two-period crossover design. The geometric mean and respective 90% confidence interval (CI) of ondansetron test/reference percent ratios were 90.15% (81.74-99.44%) for C(max) and 93.11% (83.01-104.43%) for AUC(₀-t). Based on the 90% confidence interval of the individual ratios (test formulation/reference formulation) for C(max) and AUC(₀-inf), it was concluded that the test formulation is bioequivalent to the reference one with respect to the rate and extent of absorption of ondansetron. PMID:20954214

  6. Reversible colorimetric probes for mercury sensing.

    PubMed

    Coronado, Eugenio; Galán-Mascarós, José R; Martí-Gastaldo, Carlos; Palomares, Emilio; Durrant, James R; Vilar, Ramón; Gratzel, M; Nazeeruddin, Md K

    2005-09-01

    The selectivity and sensitivity of two colorimetric sensors based on the ruthenium complexes N719 [bis(2,2'-bipyridyl-4,4'-dicarboxylate)ruthenium(II) bis(tetrabutylammonium) bis(thiocyanate)] and N749 [(2,2':6',2' '-terpyridine-4,4',4' '-tricarboxylate)ruthenium(II) tris(tetrabutylammonium) tris(isothiocyanate)] are described. It was found that mercury ions coordinate reversibly to the sulfur atom of the dyes' NCS groups. This interaction induces a color change in the dyes at submicromolar concentrations of mercury. Furthermore, the color change of these dyes is selective for mercury(II) when compared with other ions such as lead(II), cadmium(II), zinc(II), or iron(II). The detection limit for mercury(II) ions--using UV-vis spectroscopy--in homogeneous aqueous solutions is estimated to be approximately 20 ppb for N719 and approximately 150 ppb for N749. Moreover, the sensor molecules can be adsorbed onto high-surface-area mesoporous metal oxide films, allowing reversible heterogeneous sensing of mercury ions in aqueous solution. The results shown herein have important implications in the development of new reversible colorimetric sensors for the fast, easy, and selective detection and monitoring of mercuric ions in aqueous solutions. PMID:16131215

  7. Using the iPhone as a device for a rapid quantitative analysis of trinitrotoluene in soil.

    PubMed

    Choodum, Aree; Kanatharana, Proespichaya; Wongniramaikul, Worawit; Daeid, Niamh Nic

    2013-10-15

    Mobile 'smart' phones have become almost ubiquitous in society and are typically equipped with a high-resolution digital camera which can be used to produce an image very conveniently. In this study, the built-in digital camera of a smart phone (iPhone) was used to capture the results from a rapid quantitative colorimetric test for trinitrotoluene (TNT) in soil. The results were compared to those from a digital single-lens reflex (DSLR) camera. The colored product from the selective test for TNT was quantified using an innovative application of photography where the relationships between the Red Green Blue (RGB) values and the concentrations of colorimetric product were exploited. The iPhone showed itself to be capable of being used more conveniently than the DSLR while providing similar analytical results with increased sensitivity. The wide linear range and low detection limits achieved were comparable with those from spectrophotometric quantification methods. Low relative errors in the range of 0.4 to 6.3% were achieved in the analysis of control samples and 0.4-6.2% for spiked soil extracts with good precision (2.09-7.43% RSD) for the analysis over 4 days. The results demonstrate that the iPhone provides the potential to be used as an ideal novel platform for the development of a rapid on site semi quantitative field test for the analysis of explosives. PMID:24054571

  8. Colorimetric and ultrasensitive bioassay based on a dual-amplification system using aptamer and DNAzyme.

    PubMed

    Tang, Longhua; Liu, Yang; Ali, Md Monsur; Kang, Dong Ku; Zhao, Weian; Li, Jinghong

    2012-06-01

    Rapid detection of ultralow amount of biomarkers in a biologically complex mixture remains a major challenge. Herein, we report a novel aptamer-based protein detection assay that integrates two signal amplification processes, namely, polymerase-mediated rolling-circle amplification (RCA) and DNA enzyme-catalyzed colorimetric reaction. The target biomarker is captured in a sandwich assay by primary aptamer-functionalized microbeads (MBs) and a secondary aptamer that is connected to a RCA primer/circular template complex. RCA reaction, which amplifies the single biomarker binding events by a factor of hundreds to thousands (the first amplification) produces a long DNA molecule containing multiple DNAzyme units. The peroxidase-like DNAzyme catalyzes the oxidation of 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (the second amplification), which generates a blue-green colorimetric signal. This new biosensing platform permits the ultrasensitive, label-free, colorimetric detection of biomarker in real time. Using platelet-derived growth factor B-chain (PDGF-BB) as a model system, we demonstrated that our assay can detect a protein marker specifically in a serum-containing medium, at a concentration as low as 0.2 pg/mL in ∼2 h, which rivals traditional assays such as ELISA. We anticipate this simple methodology for biomarker detection can find utility in point-of-care applications. PMID:22533853

  9. Optimization of Polydiacetylene-Coated Superparamagnetic Magnetite Biosensor for Colorimetric Detection of Biomarkers.

    PubMed

    Chan, Terence; Verma, Mohit S; Gu, Frank X

    2015-04-01

    Biosensors for point-of-care testing of critical illnesses are urgently needed, especially in many areas of poor healthcare infrastructure. Polydiacetylene-based sensors are ideal because of their unique colorimetric properties where blue to red color shifts can be observed with the naked eye. In this work, a colorimetric biosensor capable of simple, rapid magnetic separation is optimized, using horse IgG as a model antibody, to obtain higher sensitivity. Composed of a unique combination of polydiacetylene and superparamagnetic iron oxide, the biosensor is fabricated at varying ratios of polydiacetylene to demonstrate optimization of color responsiveness. At increasing polydiacetylene ratios, improved color responsiveness and aqueous dispersion are observed, but the magnetic separation efficiency starts to suffer. The optimal color response is obtained at 90 wt% polydiacetylene. In addition, a 50 times improved lower detection limit of 0.01 mg/mL horse IgG is achieved, a relevant biomarker concentration for diagnosing sepsis. This platform provides a promising colorimetric biosensor for point-of-care use. PMID:26353474

  10. Rapid Quantification of Four Anthocyanins in Red Grape Wine by Hydrophilic Interaction Liquid Chromatography/Triple Quadrupole Linear Ion Trap Mass Spectrometry.

    PubMed

    Sun, Yongming; Xia, Biqi; Chen, Xiangzhun; Duanmu, Chuansong; Li, Denghao; Han, Chao

    2015-01-01

    The identification and quantification of four anthocyanins (cyanidin-3-O-glucoside, peonidin-3-O-glucoside, delphinidin-3-O-glucoside, and malvidin-3-O-glucoside) in red grape wine were carried out by hydrophilic interaction liquid chromatography/triple quadrupole linear ion trap MS (HILIC/QTrap-MS/MS). Samples were diluted directly and separated on a Merck ZIC HILIC column with 20 mM ammonium acetate solution-acetonitrile mobile phase. Quantitative data acquisition was carried out in the multiple reaction monitoring mode. Additional identification and confirmation of target compounds were performed using the enhanced product ion mode of the linear ion trap. The LOQs were in the range 0.05-1.0 ng/mL. The average recoveries were in the range 94.6 to 104.5%. The HILIC/QTrap-MS/MS platform offers the best sensitivity and specificity for characterization and quantitative determination of the four anthocyanins in red grape wines and fulfills the quality criteria for routine laboratory application. PMID:26651575

  11. Rapid quantification of conjugated and unconjugated bile acids and C27 precursors in dried blood spots and small volumes of serum.

    PubMed

    Janzen, N; Sander, S; Terhardt, M; Das, A M; Sass, J O; Kraetzner, R; Rosewich, H; Rosevich, H; Peter, M; Sander, J

    2010-06-01

    The aim of the study was to develop a method for fast and reliable diagnosis of peroxisomal diseases and to facilitate differential diagnosis of cholestatic hepatopathy. For the quantification of bile acids and their conjugates as well as C(27) precursors di- and trihydroxycholestanoic acid (DHCA, THCA), in small pediatric blood samples we combined HPLC separation on a reverse-phase C18 column with ESI-MS/MS analysis in the negative ion mode. Analysis was done with good precision (CV 3,7%-11.1%) and sufficient sensitivity (LOQ: 11-91 nmol/L) without derivatization. Complete analysis of 17 free and conjugated bile acids from dried blood spots and 10 microL serum samples, respectively, was performed within 12 min. Measurement of conjugated primary bile acids plus DHCA and THCA as well as ursodeoxycholic acid was done in 4.5 min. In blood spots of healthy newborns, conjugated primary bile acids were found in the range of 0.01 to 2.01 micromol/L. Concentrations of C(27) precursors were below the detection limit in normal controls. DHCA and THCA were specifically elevated in cases of peroxysomal defects and one Zellweger patient. PMID:20093478

  12. Rapid quantification of imidazolium-based ionic liquids by hydrophilic interaction liquid chromatography: Methodology and an investigation of the retention mechanisms.

    PubMed

    Hawkins, Cory A; Rud, Anna; Guthrie, Margaret L; Dietz, Mark L

    2015-06-26

    The separation of nine N,N'-dialkylimidazolium-based ionic liquids (ILs) by an isocratic hydrophilic interaction high-performance liquid chromatographic method using an unmodified silica column was investigated. The chosen analytical conditions using a 90:10 acetonitrile-ammonium formate buffer mobile phase on a high-purity, unmodified silica column were found to be efficient, robust, and sensitive for the determination of ILs in a variety of solutions. The retention window (k' = 2-11) was narrower than that of previous methods, resulting in a 7-min runtime for the nine IL homologues. The lower limit of quantification of the method, 2-3 μmol L(-1), was significantly lower than those reported previously for HPLC-UV methods. The effects of systematically modifying the IL cation alkyl chain length, column temperature, and mobile-phase water and buffer content on solute retention were examined. Cation exchange was identified as the dominant retention mechanism for most of the solutes, with a distinct (single methylene group) transition to a dominant partitioning mode at the highest solute polarity. PMID:25979537

  13. Beetroot-pigment-derived colorimetric sensor for detection of calcium dipicolinate in bacterial spores.

    PubMed

    Gonçalves, Letícia Christina Pires; Da Silva, Sandra Maria; DeRose, Paul C; Ando, Rômulo Augusto; Bastos, Erick Leite

    2013-01-01

    In this proof-of-concept study, we describe the use of the main red beet pigment betanin for the quantification of calcium dipicolinate in bacterial spores, including Bacillus anthracis. In the presence of europium(III) ions, betanin is converted to a water-soluble, non-luminescent orange 1∶1 complex with a stability constant of 1.4 × 10(5) L mol(-1). The addition of calcium dipicolinate, largely found in bacterial spores, changes the color of the aqueous solution of [Eu(Bn)(+)] from orange to magenta. The limit of detection (LOD) of calcium dipicolinate is around 2.0 × 10(-6) mol L(-1) and the LOD determined for both spores, B. cereus and B. anthracis, is (1.1 ± 0.3)× 10(6) spores mL(-1). This simple, green, fast and low cost colorimetric assay was selective for calcium dipicolinate when compared to several analogous compounds. The importance of this work relies on the potential use of betalains, raw natural pigments, as colorimetric sensors for biological applications. PMID:24019934

  14. Development of an extraction method based on new porous organogel materials coupled with liquid chromatography-mass spectrometry for the rapid quantification of bisphenol A in urine.

    PubMed

    ter Halle, Alexandra; Claparols, Catherine; Garrigues, Jean Christophe; Franceschi-Messant, Sophie; Perez, Emile

    2015-10-01

    A new method based on the use of porous organogel materials in combination with liquid chromatography-tandem mass spectrometry (LC-MS-MS) was assessed for the quantification of trace contaminants in complex matrices. As a demonstration of the use of these new materials, the contaminant chosen as a model was bisphenol A (BPA) and its extraction was investigated in urine. Organogel materials consist of an organic solvent immobilized by an organogelator. The composition of the organogel materials was optimized in terms of extraction efficiency and compatibility with LC-MS-MS. Porosity was introduced into the organogel by means of the particulate leaching method using sugar crystals. This new absorbing material is simple to use; the extraction method is reduced to a few steps. The originality of the method lies in the complete dissolution of the material for analysis by LC-MS-MS. The matrix effect of the organogel components was studied and was found to be minimal in atmospheric-pressure chemical ionization (APCI) compared to electrospray ionization (ESI) in negative mode. The influence of matrix components on the extraction was investigated by working with different media (acidified water, synthetic urine, horse urine and human urine). The partition coefficient was not affected within the margin of error (±0.1). After optimization, bisphenol A recoveries from urine samples reached 80%. The actual concentration factor was 10. The relative standard deviation (RSD, n=6) for the extraction and determination of BPA in horse urine spiked at 10ngmL(-1) was 9%. Tests with spiked human urine showed that the extraction performances were the same as with the solutions tested previously. The use of porous organogel allowed a fast, simple, sensitive, robust, green method to be developed for the determination of trace contaminants in complex matrices. PMID:26342874

  15. Development of a rapid HPLC-UV method for simultaneous quantification of protodioscin and rutin in white and green asparagus spears.

    PubMed

    Lee, Eun Jin; Yoo, Kil Sun; Patil, Bhimanagouda S

    2010-01-01

    Asparagus (Asparagus officinalis L.) spears are rich in bioactive compounds such as protodioscin, a saponin, and rutin, a flavonoid. Protodioscin and rutin are routinely quantified separately, and an approach permitting simultaneous measurement would significantly improve speed of analysis. We have optimized an extraction procedure and modified a method of high-performance liquid chromatography by coupling to an ultraviolet detector to simultaneously analyze protodioscin and rutin in asparagus extracts. An acidic ethanol solvent was more efficient than methanol, acetonitrile, or water in coextraction of protodioscin and rutin. Protodioscin and rutin were detected at 210 nm, with retention times of 12.6 min and 7.9 min, respectively. The method was validated by high linear correlations between 3.13 and 1000.0 μg/mL for protodioscin (r(2)= 0.9999), and between 0.3 and 1087.5 μg/mL for rutin (r(2)= 0.9997). The limit(s) of detection and quantification for protodioscin were 1.6 μg/mL and 3.13 μg/mL, respectively, and for rutin 0.2 μg/mL and 0.3 μg/mL, respectively. White asparagus spears and the crown of the plants were revealed to be rich sources of protodioscin and contained 2.59 to 10.4 mg/g dry weight. Green asparagus spears, particularly the upper portion, were rich in rutin and contained between 1.51 and 7.29 mg/g dry weight. PMID:21535581

  16. Colorimetric calibration of coupled infrared simulation system

    NASA Astrophysics Data System (ADS)

    Zhang, Ying; Fei, Jindong; Gao, Yang; Du, Jian

    2015-10-01

    In order to test 2-color infrared sensors, a coupled infrared simulation system can generate radiometric outputs with wavelengths that range from less than 3 microns to more than 12 microns. There are two channels in the coupled simulation system, optically combined by a diachronic beam combiner. Each channel has an infrared blackbody, a filter, a diaphragm, and diaphragm-motors. The system is projected to the sensor under testing by a collimator. This makes it difficult to calibrate the system with only one-band thermal imager. Errors will be caused in the radiance levels measured by the narrow band thermal imager. This paper describes colorimetric temperature measurement techniques that have been developed to perform radiometric calibrations of these infrared simulation systems above. The calibration system consists of two infrared thermal imagers; one is operated at the wavelength range of MW-IR, and the other at the range of LW-IR.

  17. Sensitive colorimetric cytotoxicity measurement using alarmar blue.

    PubMed

    Page, B; Page, M

    1995-01-01

    Cytotoxicity testing of anticancer drugs requires techniques which are sensitive, reproductible and applicable to large scale testing using automated instruments. End point staining of cells or viability stains are reliable but they are often not sensitive enough or not suitable for automation. We have already described a fluorometric cytotoxicity assay using a non fluorescent substrate, Alarmar Blue, which upon reduction in living cells, yields a fluorescent product. This assay is sensitive and highly reproductible but it is limited since automated fluorescent plate readers are not found frequently in laboratories. The conditions are now described for using Alamar Blue as a substrate in a colorimetric cytotoxicity assay. This new economical assay could be used with advantage for large scale screening of cytotoxic agents in microtitration plates. PMID:21597689

  18. Accurate colorimetric feedback for RGB LED clusters

    NASA Astrophysics Data System (ADS)

    Man, Kwong; Ashdown, Ian

    2006-08-01

    We present an empirical model of LED emission spectra that is applicable to both InGaN and AlInGaP high-flux LEDs, and which accurately predicts their relative spectral power distributions over a wide range of LED junction temperatures. We further demonstrate with laboratory measurements that changes in LED spectral power distribution with temperature can be accurately predicted with first- or second-order equations. This provides the basis for a real-time colorimetric feedback system for RGB LED clusters that can maintain the chromaticity of white light at constant intensity to within +/-0.003 Δuv over a range of 45 degrees Celsius, and to within 0.01 Δuv when dimmed over an intensity range of 10:1.

  19. A novel coumarin Schiff-base as a Ni(II) ion colorimetric sensor.

    PubMed

    Wang, Lingyun; Ye, Decheng; Cao, Derong

    2012-05-01

    A novel coumarin Schiff base compound (L) prepared from 7-diethylaminocoumarin-3-aldehyde and 3-amino-7-hydroxycoumarin was synthesized and evaluated as a chemoselective Ni(2+) sensor. Addition of Ni(2+) to CH(3)CN solution of L resulted in a rapid color change from yellow to red together with a large red shift from 465 to 516 nm. Moreover, other common alkali-, alkaline earth-, transition- and rare earth metal ions induced no or minimal spectral changes. Experimental results indicated that L could be used as a potential Ni(2+) colorimetric and naked-eye chemosensor in CH(3)CN solution. PMID:22306449

  20. Colorimetric assay of noramidopyrine methanesulfonate sodium in formulations and in blood and urine samples.

    PubMed

    Diab, A H

    1977-04-01

    A simple, rapid, specific and sensitive colorimetric method is proposed for the quantitative estimation of noramido-pyrine methanesulfonate sodium in different dosage forms as well as in blood and urine samples. The method is based on the reaction of 3-sulfonic-5-amino-alpha-naphthol with formaldehyde liberated from noramidopyrine methanesulfonate sodium after treatment with conc. sulfuric acid where a yellow colour appeared immediately which turned to blue on dilution with water. The blue colour obeyed Beer's law (10--400 microgram) and remained stable for more than 1 h. The effect of other drugs, tablet excipients, parentral vehicles and suppository bases was studied. PMID:896911

  1. Chloride accelerated Fenton chemistry for the ultrasensitive and selective colorimetric detection of copper.

    PubMed

    Shan, Zhi; Lu, Mingsheng; Wang, Li; MacDonald, Bruce; MacInnis, Judy; Mkandawire, Martin; Zhang, Xu; Oakes, Ken D

    2016-02-01

    A highly selective, ultrasensitive (visual and instrumental detection limits of 40 nM and 0.1 nM, respectively), environmentally-friendly, simple and rapid colorimetric sensor was developed for the detection of copper(II) in water. This sensor is based on a novel signal-amplification mechanism involving reactive halide species (RHSs) including chlorides or bromides, which accelerate copper Fenton reactions oxidizing the chromogenic substrate to develop colour. The results of this study expand our understanding of copper-based Fenton chemistry. PMID:26685747

  2. Hemicyanine-based colorimetric chemosensors: Different recognition mechanisms for CN- sensing

    NASA Astrophysics Data System (ADS)

    Gwon, Seon-Yeong; Lee, Eun-Mi; Kim, Sung-Hoon

    2012-10-01

    Simple hemicyanine dyes were synthesized by a classical condensation reaction. The structures of these dyes were characterized by 1H NMR spectroscopy, elemental analysis, and FAB-Mass spectrometry. The sensing behavior of the hemicyanines towards a selection of anions was investigated by UV-vis absorption spectroscopy. These structurally simple dyes displayed a rapid response and high selectivity for cyanide ion over other common anions in the DMSO/H2O solution. Different sensing mechanism of the dyes to cyanide ion were confirmed by 1H NMR studies, together with theoretical calculations based on DFT and PPP-MO methods. These dyes show no colorimetric response for other anions investigated.

  3. Rapid separation and concentration of food-borne pathogens in food samples prior to quantification by viable-cell counting and real-time PCR.

    PubMed

    Fukushima, Hiroshi; Katsube, Kazunori; Hata, Yukiko; Kishi, Ryoko; Fujiwara, Satomi

    2007-01-01

    Buoyant density gradient centrifugation has been used to separate bacteria from complex food matrices, as well as to remove compounds that inhibit rapid detection methods, such as PCR, and to prevent false-positive results due to DNA originating from dead cells. Applying a principle of buoyant density gradient centrifugation, we developed a method for rapid separation and concentration following filtration and low- and high-speed centrifugation, as well as flotation and sedimentation buoyant density centrifugation, for 12 food-borne pathogens (Salmonella enterica, Escherichia coli, Yersinia enterocolitica, Campylobacter jejuni, Vibrio cholerae O139, Vibrio parahaemolyticus O3K6, Vibrio vulnificus, Providencia alcalifaciens, Aeromonas hydrophila, Bacillus cereus, Staphylococcus aureus, and Clostridium perfringens) in 13 different food homogenates. This method can be used prior to real-time quantitative PCR (RTi-qPCR) and viable-cell counting. Using this combined method, the target organisms in the food samples theoretically could be concentrated 250-fold and detected at cell concentrations as low as 10(1) to 10(3) CFU/g using the RTi-qPCR assay, and amounts as small as 10(0) to 10(1) CFU/g could be isolated using plate counting. The combined separation and concentration methods and RTi-qPCR confirmed within 3 h the presence of 10(1) to 10(2) CFU/g of Salmonella and C. jejuni directly in naturally contaminated chicken and the presence of S. aureus directly in remaining food items in a poisoning outbreak. These results illustrated the feasibility of using these assays for rapid inspection of bacterial food contamination during a real-world outbreak. PMID:17056684

  4. Multi-class, multi-residue analysis of trace veterinary drugs in milk by rapid screening and quantification using ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry.

    PubMed

    Zhang, Yaqian; Li, Xiang; Liu, Xiaomao; Zhang, Jinjie; Cao, Yanzhong; Shi, Zhihong; Sun, Hanwen

    2015-12-01

    A simple and rapid multi-class multi-residue analytical method was developed for the screening and quantification of veterinary drugs in milk by ultra-performance liquid chromatography coupled to quadrupole time-of-flight mass spectrometry (UPLC-QTOF-MS). A total of 90 veterinary drugs investigated belonged to almost 20 classes including lincomycins, macrolides, sulfonamides, quinolones, tetracyclines, β-agonists, β-lactams, sedatives, β-receptor antagonists, sex hormones, glucocorticoids, nitroimidazoles, benzimidazoles, nitrofurans, and some others. A modified quick, easy, cheap, effective, rugged, and safe (QuEChERS) procedure was developed for the sample preparation without the solid-phase extraction step. The linearity, sensitivity, accuracy, repeatability, and reproducibility of the method were fully validated. The response of the detector was linear for each target compound in a wide concentration range with a correlation coefficient (R(2)) of 0.9973 to 0.9999 (among them R(2)>0.999 for 73 of 90 analytes). The range of the limit of quantification for these compounds in the milk ranged from 0.10 to 17.30μg/kg. The repeatability and reproducibility were in the range of 2.11 to 9.62% and 2.76 to 13.9%, respectively. The average recoveries ranged from 72.62 to 122.2% with the RSD (n=6) of 1.30 to 9.61% at 3 concentration levels. For the screening method, the data of the precursor and product ions of the target analytes were simultaneously acquired under the all ions MS/MS mode in a single run. An accurate mass database for the confirmation and identification of the target compounds was established. The applicability of the screening method was verified by applying to real milk samples. The proposed analytical method allows the identification and confirmation of the target veterinary drugs at trace levels employing quick analysis time. Certain veterinary drugs were detected in some cases. PMID:26506545

  5. Ferromagnetic particles as a rapid and robust sample preparation for the absolute quantification of seven eicosanoids in human plasma by UHPLC-MS/MS.

    PubMed

    Suhr, Anna Catharina; Bruegel, Mathias; Maier, Barbara; Holdt, Lesca Miriam; Kleinhempel, Alisa; Teupser, Daniel; Grimm, Stefanie H; Vogeser, Michael

    2016-06-01

    We used ferromagnetic particles as a novel technique to deproteinize plasma samples prior to quantitative UHPLC-MS/MS analysis of seven eicosanoids [thromboxane B2 (TXB2), prostaglandin E2 (PGE2), PGD2, 5-hydroxyeicosatetraenoic acid (5-HETE), 11-HETE, 12-HETE, arachidonic acid (AA)]. A combination of ferromagnetic particle enhanced deproteination and subsequent on-line solid phase extraction (on-line SPE) realized quick and convenient semi-automated sample preparation-in contrast to widely used manual SPE techniques which are rather laborious and therefore impede the investigation of AA metabolism in larger patient cohorts. Method evaluation was performed according to a protocol based on the EMA guideline for bioanalytical method validation, modified for endogenous compounds. Calibrators were prepared in ethanol. The calibration curves were found to be linear in a range of 0.1-80ngmL(-1) (TXB2, PGE2, PGD2), 0.05-40ngmL(-1) (5-HETE, 11-HETE), 0.5-400ngmL(-1) (12-HETE) and 25-9800ngmL(-1) (AA). Regarding all analytes and all quality controls, the resulting precision data (inter-assay 2.6 %-15.5 %; intra-assay 2.5 %-15.1 %, expressed as variation coefficient) as well as the accuracy results (inter-assay 93.3 %-125 %; intra-assay 91.7 %-114 %) were adequate. Further experiments addressing matrix effect, recovery and robustness, yielded also very satisfying results. As a proof of principle, the newly developed LC-MS/MS assay was employed to determine the capacity of AA metabolite release after whole blood stimulation in healthy blood donors. For this purpose, whole blood specimens of 5 healthy blood donors were analyzed at baseline and after a lipopolysaccharide (LPS) induced blood cell activation. In several baseline samples some eicosanoids levels were below the Lower Limit of Quantification. However, in the stimulated samples all chosen eicosanoids (except PGD2) could be quantified. These results, in context with those obtained in validation, demonstrate the

  6. Evaluation of a PCR/DNA Probe Colorimetric Membrane Assay for Identification of Campylobacter spp. in Human Stool Specimens

    PubMed Central

    Collins, Evelyn; Glennon, Maura; Hanley, Shirley; Murray, Anne-Marie; Cormican, Martin; Smith, Terry; Maher, Majella

    2001-01-01

    DNA was extracted from 50 human stool specimens using the QIAamp DNA stool minikit. PCR amplification was followed by post-PCR hybridization to DNA probes specific for the Campylobacter genus, Campylobacter jejuni, and Campylobacter coli in a colorimetric membrane assay. Thirty-two of 38 culture-positive specimens were PCR/DNA probe positive for C. jejuni. The assay is rapid and simple and can be applied to stool specimens for the detection of Campylobacter. PMID:11682549

  7. ELISA-PLA: A novel hybrid platform for the rapid, highly sensitive and specific quantification of proteins and post-translational modifications.

    PubMed

    Tong, Qing-He; Tao, Tao; Xie, Li-Qi; Lu, Hao-Jie

    2016-06-15

    Detection of low-abundance proteins and their post-translational modifications (PTMs) remains a great challenge. A conventional enzyme-linked immunosorbent assay (ELISA) is not sensitive enough to detect low-abundance PTMs and suffers from nonspecific detection. Herein, a rapid, highly sensitive and specific platform integrating ELISA with a proximity ligation assay (PLA), termed ELISA-PLA, was developed. Using ELISA-PLA, the specificity was improved by the simultaneous and proximate recognition of targets through multiple probes, and the sensitivity was significantly improved by rolling circle amplification (RCA). For GFP, the limit of detection (LOD) was decreased by two orders of magnitude compared to that of ELISA. Using site-specific phospho-antibody and pan-specific phospho-antibody, ELISA-PLA was successfully applied to quantify the phosphorylation dynamics of ERK1/2 and the overall tyrosine phosphorylation level of ERK1/2, respectively. ELISA-PLA was also used to quantify the O-GlcNAcylation of AKT, c-Fos, CREB and STAT3, which is faster and more sensitive than the conventional immunoprecipitation and western blotting (IP-WB) method. As a result, the sample consumption of ELISA-PLA was reduced 40-fold compared to IP-WB. Therefore, ELISA-PLA could be a promising platform for the rapid, sensitive and specific detection of proteins and PTMs. PMID:26866564

  8. Quantification of rifampicin in human plasma and cerebrospinal fluid by a highly sensitive and rapid liquid chromatographic–tandem mass spectrometric method

    PubMed Central

    Srivastava, Abhishek; Waterhouse, David; Ardrey, Alison; Ward, Stephen A.

    2012-01-01

    A highly sensitive and rapid liquid chromatography tandem mass spectrometry (LC–MS/MS) method has been developed to measure the levels of the antitubercular drug rifampicin (RIF) in human plasma and cerebrospinal fluid (CSF). The analyte and internal standard (IS) were isolated from plasma and CSF by a simple organic solvent based precipitation of proteins followed by centrifugation. Detection was carried out by electrospray positive ionization mass spectrometry in the multiple-reaction monitoring (MRM) mode. The assay was linear in the concentration range 25–6400 ng/mL with intra- and inter-day precision of <7% and <8%, respectively. The validated method was applied to the study of RIF pharmacokinetics in human CSF and plasma over 25 h period after a 10 mg/kg oral dose. PMID:22709606

  9. Transformation of microcystins to 2-methyl-3-methoxy-4-phenylbutyric acid by room temperature ozone oxidation for rapid quantification of total microcystins.

    PubMed

    Zhang, L L; Yu, R P; Wang, L P; Wu, S F; Song, Q J

    2016-04-20

    Microcystins (MCs) are cyanobacterial hepatotoxins capable of accumulation into animal tissues. To determine the total microcystins in water, a novel analytical method, including ozonolysis, methylation of 2-methyl-3-methoxy-4-phenylbutyric acid (MMPB) with methylchloroformate (MCF) and gas chromatography mass spectrometry (GC-MS) detection was developed. The results show that MCs can be oxidized by ozone to produce MMPB at ambient temperature, proving ozonation is an effective, rapid and green method for the transformation of MCs to MMPB without secondary pollution. The oxidation conditions as well as the esterification process were optimized and, subsequently applied to analysis of environmental samples. The method shows wide linear range and high sensitivity with a detection limit of 0.34 μg L(-1). The established method was successfully applied to the analysis of microcystins in water samples. PMID:26975781

  10. Ultrafast colorimetric determination of predominant protein structure evolution with gold nanoplasmonic particles

    NASA Astrophysics Data System (ADS)

    Kim, Hye Young; Choi, Inhee

    2016-01-01

    The intracellular and extracellular accumulation of disordered proteins and aggregated proteins occurs in many protein conformational diseases, such as aging-related neurodegeneration and alcoholic liver diseases. However, the conventional methods to study protein structural changes are limited for the rapid detection and monitoring of protein aggregation because of long incubation times (i.e., usually several days), complicated sample pretreatment steps, and expensive instrumentation. Here, we describe an ultrafast colorimetric method for the real-time monitoring of protein structure evolution and the determination of predominant structures via nanoparticle-assisted protein aggregation. During the aggregation process, nanoparticles act as nucleation cores, which form networks depending on the structures of the protein aggregates, and accelerate the kinetics of the protein aggregation. Simultaneously, these nanoparticles exhibit colorimetric responses according to their embedded shapes (e.g., fibrillar and amorphous) on the protein aggregates. We observed distinct spectral shifts and concomitant colorimetric responses of concentration- and type-dependent protein aggregation with the naked eye within a few minutes (<2 min) under acidic conditions. Moreover, the morphological transitions from small aggregates to larger aggregates of nanoparticle-assisted protein aggregates were visualized with dark-field microscope imaging, which show a similar trend with that of protein aggregates formed without the aid of nanoparticles. Finally we show that our proposed method can be utilized to screen the protein aggregation propensity under a variety of conditions such as different pH levels, high temperature, and chemicals. These findings suggest that the proposed method is an easy way to study the molecular biophysics of protein aggregation and to rapidly screen anti-aggregation drugs for protein conformational diseases.The intracellular and extracellular accumulation of

  11. Rapid quantification of the toxic alga Prymnesium parvum in natural samples by use of a specific monoclonal antibody and solid-phase cytometry.

    PubMed

    West, N J; Bacchieri, R; Hansen, G; Tomas, C; Lebaron, P; Moreau, H

    2006-01-01

    The increasing incidence of harmful algal blooms around the world and their associated health and economic effects require the development of methods to rapidly and accurately detect and enumerate the target species. Here we describe use of a solid-phase cytometer to detect and enumerate the toxic alga Prymnesium parvum in natural samples, using a specific monoclonal antibody and indirect immunofluorescence. The immunoglobulin G antibody 16E4 exhibited narrow specificity in that it recognized several P. parvum strains and a Prymnesium nemamethecum strain but it did not cross-react with P. parvum strains from Scandinavia or any other algal strains, including species of the closely related genus Chrysochromulina. Prymnesium sp. cells labeled with 16E4 were readily detected by the solid-phase cytometer because of the large fluorescence signal and the signal/noise ratio. Immunofluorescence detection and enumeration of cultured P. parvum cells preserved with different fixatives showed that the highest cell counts were obtained when cells were fixed with either glutaraldehyde or formaldehyde plus the cell protectant Pluronic F-68, whereas the use of formaldehyde alone resulted in significantly lower counts. Immunofluorescence labeling and analysis with the solid-phase cytometer of fixed natural samples from a bloom of P. parvum occurring in Lake Colorado in Texas gave cell counts that were close to those obtained by the traditional method of counting using light microscopy. These results show that a solid-phase cytometer can be used to rapidly enumerate natural P. parvum cells and that it could be used to detect other toxic algae, with an appropriate antibody or DNA probe. PMID:16391128

  12. Dual-Modal Colorimetric/Fluorescence Molecular Probe for Ratiometric Sensing of pH and Its Application.

    PubMed

    Wu, Luling; Li, Xiaolin; Huang, Chusen; Jia, Nengqin

    2016-08-16

    As traditional pH meters cannot work well for minute regions (such as subcellular organelles) and in harsh media, molecular pH-sensitive devices for monitoring pH changes in diverse local heterogeneous environments are urgently needed. Here, we report a new dual-modal colorimetric/fluorescence merocyanine-based molecular probe (CPH) for ratiometric sensing of pH. Compared with previously reported pH probes, CPH bearing the benzyl group at the nitrogen position of the indolium group and the phenol, which is used as the acceptor for proton, could respond to pH changes immediately through both the ratiometric fluorescence signal readout and naked-eye colorimetric observation. The sensing process was highly stable and reversible. Most importantly, the suitable pKa value (6.44) allows CPH to presumably accumulate in lysosomes and become a lysosome-target fluorescent probe. By using CPH, the intralysosomal pH fluctuation stimulated by antimalaria drug chloroquine was successfully tracked in live cells through the ratiometric fluorescence images. Additionally, CPH could be immobilized on test papers, which exhibited a rapid and reversible colorimetric response to acid/base vapor through the naked-eye colorimetric analysis. This proof-of-concept study presents the potential application of CPH as a molecular tool for monitoring intralysosomal pH fluctuation in live cells, as well as paves the way for developing the economic, reusable, and fast-response optical pH meters for colorimetric sensing acid/base vapor with direct naked-eye observation. PMID:27431089

  13. Simple and Rapid Determination of Ferulic Acid Levels in Food and Cosmetic Samples Using Paper-Based Platforms

    PubMed Central

    Tee-ngam, Prinjaporn; Nunant, Namthip; Rattanarat, Poomrat; Siangproh, Weena; Chailapakul, Orawon

    2013-01-01

    Ferulic acid is an important phenolic antioxidant found in or added to diet supplements, beverages, and cosmetic creams. Two designs of paper-based platforms for the fast, simple and inexpensive evaluation of ferulic acid contents in food and pharmaceutical cosmetics were evaluated. The first, a paper-based electrochemical device, was developed for ferulic acid detection in uncomplicated matrix samples and was created by the photolithographic method. The second, a paper-based colorimetric device was preceded by thin layer chromatography (TLC) for the separation and detection of ferulic acid in complex samples using a silica plate stationary phase and an 85:15:1 (v/v/v) chloroform: methanol: formic acid mobile phase. After separation, ferulic acid containing section of the TLC plate was attached onto the patterned paper containing the colorimetric reagent and eluted with ethanol. The resulting color change was photographed and quantitatively converted to intensity. Under the optimal conditions, the limit of detection of ferulic acid was found to be 1 ppm and 7 ppm (S/N = 3) for first and second designs, respectively, with good agreement with the standard HPLC-UV detection method. Therefore, these methods can be used for the simple, rapid, inexpensive and sensitive quantification of ferulic acid in a variety of samples. PMID:24077320

  14. Establishing a TaqMan-Based Real-Time PCR Assay for the rapid detection and quantification of the newly emerged duck tembusu virus

    PubMed Central

    2011-01-01

    To establish an accurate, rapid, and a quantifiable method for the detection of the newly emerged duck Tembusu virus (DTMUV) that recently caused a widespread infectious disease in ducks in China, we developed a TaqMan-based real-time PCR assay by using E gene-specific primers and a TaqMan probe. This real-time PCR assay was 100 times more sensitive than the conventional PCR. The reproducibility and specificity of the real-time PCR assay were confirmed using plasmids containing E genes or RNAs and DNAs extracted from well-known viruses causing duck diseases. The reliability of this real-time PCR assay was confirmed in 19 of the 24 swab samples, 22 of the 24 tissue samples collected from experimentally infected ducks, as well as 15 of the 21 clinical samples collected from sick ducks since they were verified as DTMUV-positive. The results reveal that the newly established real-time PCR assay might be a useful diagnostic method for epidemiologically investigating and closely observing the newly emerged DTMUV. PMID:21978536

  15. Flow cytometry-assisted quantification of γH2AX expression has potential as a rapid high-throughput biodosimetry tool.

    PubMed

    Achel, Daniel G; Serafin, Antonio M; Akudugu, John M

    2016-08-01

    Large-scale radiological events require immediate and accurate estimates of doses received by victims, and possibly the first responders, to assist in treatment decisions. Although there are numerous efforts worldwide to develop biodosimetric tools to adequately handle triage needs during radiological incidents, such endeavours do not seem to actively involve sub-Saharan Africa which currently has a significant level of nuclear-related activity. To initiate a similar interest in Africa, ex vivo radiation-induced γH2AX expression in peripheral blood lymphocytes from fourteen healthy donors was assessed using flow cytometry. While the technique shows potential for use as a rapid high-throughput biodosimetric tool for radiation absorbed doses up to 5 Gy, significant inter-individual differences in γH2AX expression emerged. Also, female donors exhibited higher levels of γH2AX expression than their male counterparts. To address these shortcomings, gender-based in-house dose-response curves for γH2AX induction in lymphocytes 2, 4, and 6 h after X-ray irradiation are proposed for the South African population. The obtained results show that γH2AX is a good candidate biomarker for biodosimetry, but might need some refinement and validation through further studies involving a larger cohort of donors. PMID:27262315

  16. Rapid quantification of bacteria and viruses in influent, settled water, activated sludge and effluent from a wastewater treatment plant using flow cytometry.

    PubMed

    Ma, Lili; Mao, Guannan; Liu, Jie; Yu, Hui; Gao, Guanghai; Wang, Yingying

    2013-01-01

    As microbiological parameters are important in monitoring the correct operation of wastewater treatment plants and controlling the microbiological quality of wastewater, the abundances of total bacteria (including intact and damaged bacterial cells) and total viruses in wastewater were investigated using a combination of ultrasonication and flow cytometry. The comparisons between flow cytometry (FCM) and other cultivation-independent methods (adenosine tri-phosphate (ATP) analysis for bacteria enumeration and epifluorescence microscopy (EFM) for virus enumeration) gave very similar patterns of microbial abundance changes, suggesting that FCM is suitable for targeting and obtaining reliable counts for bacteria and viruses in wastewater samples. The main experimental results obtained were: (1) effective removal of total bacteria in wastewater, with a decrease from an average concentration of 1.74 × 10(8)counts ml(-1) in raw wastewater to 3.91 × 10(6)counts ml(-1) in the effluent, (2) compared to influent raw wastewater, the average concentration of total viruses in the treated effluent (3.94 × 10(8)counts ml(-1)) exhibited no obvious changes, (3) the applied FCM approach is a rapid, easy, and convenient tool for understanding the microbial dynamics and monitoring microbiological quality in wastewater treatment processes. PMID:24185058

  17. Rapid and efficient method for the quantification of lychnopholide in rat plasma by liquid chromatography-tandem mass spectrometry for pharmacokinetic application.

    PubMed

    Lachi-Silva, Larissa; Sousa, João Paulo Barreto; Montanha, Maiara Camotti; Sy, Sherwin K B; Lopes, João Luis Callegari; Silva, Denise Brentan; Lopes, Norberto Peporine; Diniz, Andréa; Kimura, Elza

    2016-07-01

    Lychnopholide is a sesquiterpene lactone usually obtained from Lychnophora and Eremanthus species and has pharmacological activities that include anti-inflammatory and anti-tumor. Lychnopholide isolated from Eremanthus matogrossenssis was analyzed in this study. The aims of this study were to develop and validate an analytical methodology by LC-MS/MS and to quantify lychnopholide in rat plasma. Chromatographic separation was achieved on a C18 column using isocratic elution with the mobile phase consisting of methanol and water (containing 0.1% formic acid) at a flow rate of 0.4 mL/min. The detection was performed in multiple-reaction monitoring mode using electrospray ionization in positive mode. The method validation was performed in accordance with regulatory guidelines and the results met the acceptance criteria. The linear range of detection was 10-200 ng/mL (r > 0.9961). The intra- and inter-day assay variability were <6.2 and <11.7%, respectively. The extraction recovery was approximately 63% using liquid-liquid extraction with chloroform. Lychnopholide was detected in plasma up to 60 min after intravenous administration in rats. This rapid and sensitive method for the analysis of the sesquiterpene lactone lychnopholide in rat plasma can be applied to pharmacokinetic studies of this compound. Copyright © 2016 John Wiley & Sons, Ltd. PMID:26577838

  18. Quantification of Gas-Wall Partitioning in Teflon Environmental Chambers Using Rapid Bursts of Low-Volatility Oxidized Species Generated in Situ.

    PubMed

    Krechmer, Jordan E; Pagonis, Demetrios; Ziemann, Paul J; Jimenez, Jose L

    2016-06-01

    Partitioning of gas-phase organic compounds to the walls of Teflon environmental chambers is a recently reported phenomenon than can affect the yields of reaction products and secondary organic aerosol (SOA) measured in laboratory experiments. Reported time scales for reaching gas-wall partitioning (GWP) equilibrium (τGWE) differ by up to 3 orders of magnitude, however, leading to predicted effects that vary from substantial to negligible. A new technique is demonstrated here in which semi- and low-volatility oxidized organic compounds (saturation concentration c* < 100 μg m(-3)) were photochemically generated in rapid bursts in situ in an 8 m(3) environmental chamber, and then their decay in the absence of aerosol was measured using a high-resolution chemical ionization mass spectrometer (CIMS) equipped with an "inlet-less" NO3(-) ion source. Measured τGWE were 7-13 min (rel. std. dev. 33%) for all compounds. The fraction of each compound that partitioned to the walls at equilibrium follows absorptive partitioning theory with an equivalent wall mass concentration in the range 0.3-10 mg m(-3). Measurements using a CIMS equipped with a standard ion-molecule reaction region showed large biases due to the contact of compounds with walls. On the basis of these results, a set of parameters is proposed for modeling GWP in chamber experiments. PMID:27138683

  19. Quantification of forest carbon degradation in Nicaragua using RapidEye remote sensing data: El Cuá and Wiwili case studies

    NASA Astrophysics Data System (ADS)

    Argoty, F. N.; Cifuentes, M.; Imbach, P. A.; Vilchez, S.; Casanoves, F.; Ibrahim, M.; Vierling, L. A.

    2012-12-01

    Forest degradation and deforestation affect ecosystem function and climate regulation services such as carbon storage. Historically, Central America has been a deforestation and forest degradation hotspot. Wiwili and El Cuá municipalities in northern Nicaragua are no exception, where subsistence agriculture and cattle ranch expansion have driven deforestation and other wood extraction activities, leading to various levels of forest degradation. Reduction of Emissions from forest Degradation and Deforestation (REDD) projects are proposed as a tool to slow the degradation and loss of carbon stocks by restoring carbon to its natural levels in order to mitigate carbon dioxide emissions that cause global warming. REDD projects require baseline estimations of current carbon stocks and forest degradation status. We estimated carbon stocks across a forest degradation gradient based on common biophysical variables and commercially available (RapidEye) remote sensing data. We measured 80 temporary forest plots (50x20m) for aboveground biomass to sample a gradient of forest degradation at two municipalities (El Cuá and Wiwili) in northern Nicaragua. We measured biomass in trees (≥10 cm DBH), saplings (5-9.9 cm DBH), other growth forms (ferns, palms and woody vines), and large detritus (snags and downed wood). Biomass was estimated by a range of allometric models and a constant conversion factor (0.47) was applied to calculate aboveground carbon stocks. Remote sensing data from a RapidEye scene for 02/2010 provided data for 5 spectral bands and 19 vegetation indexes at 6 m spatial resolution. Precipitation, temperature, altitude, slope, canopy cover, and aspect were also used as input variables for carbon modeling. We tested linear mixed models, generalized additive mixed models and regression tree approaches to explain carbon stocks based on vegetation indexes and biophysical variables. Additionally, we grouped plots into low (17-168 Mg C ha-1), medium (168-302 Mg C ha-1

  20. Rapid, online quantification of H2S in JP-8 fuel reformate using near-infrared cavity-enhanced laser absorption spectroscopy.

    PubMed

    Dong, Feng; Junaedi, Christian; Roychoudhury, Subir; Gupta, Manish

    2011-06-01

    One of the key challenges in reforming military fuels for use with fuel cells is their high sulfur content, which can poison the fuel cell anodes. Sulfur-tolerant fuel reformers can convert this sulfur into H(2)S and then use a desulfurizing bed to remove it prior to the fuel cell. In order to optimize and verify this desulfurization process, a gas-phase sulfur analyzer is required to measure H(2)S at low concentrations (<1 ppm(v)) in the presence of other reforming gases (e.g., 25-30% H(2), 10-15% H(2)O, 15% CO, 5% CO(2), 35-40% N(2), and trace amounts of light hydrocarbons). In this work, we utilize near-infrared cavity-enhanced optical absorption spectroscopy (off-axis ICOS) to quantify H(2)S in a JP-8 fuel reformer product stream. The sensor provides rapid (2 s), highly precise (±0.1 ppm(v)) measurements of H(2)S in reformate gases over a wide dynamic range (0-1000 ppm(v)) with a low detection limit (3σ = ±0.09 ppm(v) in 1 s) and minimal cross-interferences from other present species. It simultaneously quantifies CO(2) (±0.2%), CH(4) (±150 ppm(v)), C(2)H(4) (±30 ppm(v)), and H(2)O (±300 ppm(v)) in the reformed gas for a better characterization of the fuel reforming process. Other potential applications of this technology include measurement of coal syngas and H(2)S in natural gas. By including additional near-infrared, distributive feedback diode lasers, the instrument can also be extended to other reformate species, including CO and H(2). PMID:21486070

  1. Evaluation of a rapid method for the simultaneous quantification of ribavirin, sofosbuvir and its metabolite in rat plasma by UPLC-MS/MS.

    PubMed

    Shi, Xiaojun; Zhu, Dedong; Lou, Jie; Zhu, Bo; Hu, Ai-rong; Gan, Dongmei

    2015-10-01

    A rapid and sensitive ultra performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method for the determination of ribavirin, sofosbuvir and its metabolite GS-331007 in rat plasma was established. The analytes and the internal standard (midazolam) were separated on an Acquity UPLC BEH C18 chromatography column (2.1mm×50mm, 1.7μm) using gradient elution with a mobile phase of acetonitrile and 0.1% formic acid in water at a flow rate of 0.4mL/min. The detection was performed on a triple quadrupole tandem mass spectrometer by multiple reaction monitoring (MRM) mode to monitor the precursor-to-product ion transitions of m/z 245.1→113.1 for ribavirin, m/z 530.3→243.1 for sofosbuvir, m/z 261.5→113.1 for GS-331007 and m/z 326.2→291.1 for midazolam (IS) using a positive electrospray ionization interface. The method was validated over a concentration range of 5-1000ng/mL for ribavirin, 10-2000ng/mL for sofosbuvir and 10-2000ng/mL for GS-331007. Total time for each chromatograph was 3.0min. The intra- and inter-day precision and accuracy of the quality control samples at low, medium, and high concentration levels exhibited relative standard deviations (RSD) <10.0% and the accuracy values ranged from -10.6% to 11.6%. The method was successfully applied to a pharmacokinetic study of ribavirin, sofosbuvir and GS-331007 in rats. PMID:26363369

  2. Development of a real-time PCR assay (SYBR Green I) for rapid identification and quantification of scyphomedusae Aurelia sp.1 planulae

    NASA Astrophysics Data System (ADS)

    Wang, Jianyan; Zhen, Yu; Mi, Tiezhu; Yu, Zhigang; Wang, Guoshan

    2015-07-01

    The complicated life cycle of Aurelia spp., comprising benthic asexually-reproducing polyps and sexually-reproducing medusae, makes it hard for researchers to identify and track them, especially for early stage individuals, such as planulae. To solve this problem, we developed a real-time PCR assay (SYBR Green I) to identify planulae in both cultured and natural seawater samples. Species-specific primers targeting Aurelia sp.1 mitochondrial 16S rDNA (mt 16S rDNA) regions were designed. Using a calibration curve constructed with plasmids containing the Aurelia sp.1 mt 16S rDNA fragment and a standard curve for planulae, the absolute number of mt 16S rDNA copies per planula was determined and from that the total number of planulae per sample was estimated. For the field samples, a 100-fold dilution of the sample DNA combined with a final concentration of 0.2 μg/μL BSA in the PCR reaction mixture was used to remove real-time PCR inhibitors. Samples collected in Jiaozhou Bay from July to September 2012 were subsequently analyzed using this assay. Peak Aurelia sp.1 planula abundance occurred in July 2012 at stations near Hongdao Island and Qingdao offshore; abundances were very low in August and September. The real-time PCR assay (SYBR Green I) developed here negates the need for traditional microscopic identification, which is laborious and time-consuming, and can detect and quantify jellyfish planulae in field plankton samples rapidly and specifically.

  3. Colorimetric Sensor Array for White Wine Tasting

    PubMed Central

    Chung, Soo; Park, Tu San; Park, Soo Hyun; Kim, Joon Yong; Park, Seongmin; Son, Daesik; Bae, Young Min; Cho, Seong In

    2015-01-01

    A colorimetric sensor array was developed to characterize and quantify the taste of white wines. A charge-coupled device (CCD) camera captured images of the sensor array from 23 different white wine samples, and the change in the R, G, B color components from the control were analyzed by principal component analysis. Additionally, high performance liquid chromatography (HPLC) was used to analyze the chemical components of each wine sample responsible for its taste. A two-dimensional score plot was created with 23 data points. It revealed clusters created from the same type of grape, and trends of sweetness, sourness, and astringency were mapped. An artificial neural network model was developed to predict the degree of sweetness, sourness, and astringency of the white wines. The coefficients of determination (R2) for the HPLC results and the sweetness, sourness, and astringency were 0.96, 0.95, and 0.83, respectively. This research could provide a simple and low-cost but sensitive taste prediction system, and, by helping consumer selection, will be able to have a positive effect on the wine industry. PMID:26213946

  4. Basic design principles of colorimetric vision systems

    NASA Astrophysics Data System (ADS)

    Mumzhiu, Alex M.

    1998-10-01

    Color measurement is an important part of overall production quality control in textile, coating, plastics, food, paper and other industries. The color measurement instruments such as colorimeters and spectrophotometers, used for production quality control have many limitations. In many applications they cannot be used for a variety of reasons and have to be replaced with human operators. Machine vision has great potential for color measurement. The components for color machine vision systems, such as broadcast quality 3-CCD cameras, fast and inexpensive PCI frame grabbers, and sophisticated image processing software packages are available. However the machine vision industry has only started to approach the color domain. The few color machine vision systems on the market, produced by the largest machine vision manufacturers have very limited capabilities. A lack of understanding that a vision based color measurement system could fail if it ignores the basic principles of colorimetry is the main reason for the slow progress of color vision systems. the purpose of this paper is to clarify how color measurement principles have to be applied to vision systems and how the electro-optical design features of colorimeters have to be modified in order to implement them for vision systems. The subject of this presentation far exceeds the limitations of a journal paper so only the most important aspects will be discussed. An overview of the major areas of applications for colorimetric vision system will be discussed. Finally, the reasons why some customers are happy with their vision systems and some are not will be analyzed.

  5. Performance evaluation of a colorimetric hydrazine dosimeter

    NASA Astrophysics Data System (ADS)

    Brenner, Karen P.; Rose-Pehrsson, Susan L.

    1994-06-01

    A dosimeter for real-time, colorimetric detection of hydrazine in air has been developed. The passive badge consists of a dosimeter card containing a vanillin solution coated on a thin paper substrate. The active patch consists of a thick cellulose substrate coated with a vanillin solution. When placed in a plastic sample holder attached to a personnel pump, up to 5 L/min can be drawn through the active badge substrate. Through a condensation reaction, vanillin reacts with hydrazine to form a colored product that absorbs in the visible region. The hydrazone formed in the reaction is yellow; its intensity is proportional to the dose. When exposed passively to hydrazine, the experimental detection limit is less than 20 ppb-hrs. Extrapolated results indicate a detection limit of less than 5 ppb-hrs for long sampling periods. Actively sampling of hydrazine vapors gives an experimental detection limit of less than 100 ppb-L at a sample rate of 5 L/min. Relative humidity effects on badge response were minor. High humidity enhanced the color development on the vanillin badge; while low humidity had no effect on badge response. Interference testing of the dosimeters revealed a tobacco smoke interference. Preliminary shelf life tests indicated no decrease in sensitivity to hydrazine when stored at room temperature for 6 months.

  6. A rapid and sensitive LC-MS/MS method for quantification of quercetin-3-O-β-d-glucopyranosyl-7-O-β-d-gentiobioside in plasma and its application to a pharmacokinetic study.

    PubMed

    He, Xin; Tao, Guizhou; Gao, Hang; Li, Keyan; Zhang, Yazhuo; Sun, Limin; Zhang, Yingjie

    2016-09-01

    A rapid and sensitive LC-MS/MS method with good accuracy and precision was developed and validated for the pharmacokinetic study of quercetin-3-O-β-d-glucopyranosyl-7-O-β-d-gentiobioside (QGG) in Sprague-Dawley rats. Plasma samples were simply precipitated by methanol and then analyzed by LC-MS/MS. A Venusil® ASB C18 column (2.1 × 50 mm, i.d. 5 μm) was used for separation, with methanol-water (50:50, v/v) as the mobile phase at a flow rate of 300 μL/min. The optimized mass transition ion-pairs (m/z) for quantitation were 787.3/301.3 for QGG, and 725.3/293.3 for internal standard. The linear range was 7.32-1830 ng/mL with an average correlation coefficient of 0.9992, and the limit of quantification was 7.32 ng/mL. The intra- and inter-day precision and accuracy were less than ±15%. At low, medium and high quality control concentrations, the recovery and matrix effect of the analyte and IS were in the range of 89.06-92.43 and 88.58-97.62%, respectively. The method was applied for the pharmacokinetic study of QGG in Sprague-Dawley rats. Copyright © 2016 John Wiley & Sons, Ltd. PMID:26848536

  7. Analysis of the Precursor rRNA Fractions of Rapidly Growing Mycobacteria: Quantification by Methods That Include the Use of a Promoter (rrnA P1) as a Novel Standard†

    PubMed Central

    Menéndez, María del Carmen; Rebollo, María José; Núñez, María del Carmen; Cox, Robert A.; García, María Jesús

    2005-01-01

    Mycobacterial species are able to control rRNA production through variations in the number and strength of promoters controlling their rrn operons. Mycobacterium chelonae and M. fortuitum are members of the rapidly growing mycobacterial group. They carry a total of five promoters each, encoded, respectively, by one and two rrn operons per genome. Quantification of precursor rrn transcriptional products (pre-rrn) has allowed detection of different promoter usage during cell growth. Bacteria growing in several culture media with different nutrient contents were compared. Balanced to stationary phases were analyzed. Most promoters were found to be used at different levels depending on the stage of bacterial growth and the nutrient content of the culture medium. Some biological implications are discussed. Sequences of the several promoters showed motifs that could be correlated to their particular level of usage. A product corresponding to the first rrnA promoter in both species, namely, rrnA P1, was found to contribute at a low and near-constant level to pre-rRNA synthesis, regardless of the culture medium used and the stage of growth analyzed. This product was used as a standard to quantitate rRNA gene expression by real-time PCR when M. fortuitum infected macrophages. It was shown that this bacterium actively synthesizes rRNA during the course of infection and that one of its rrn operons is preferentially used under such conditions. PMID:15629925

  8. A rapid and reliable UPLC-MS/MS method for the identification and quantification of fourteen synthetic anti-diabetic drugs in adulterated Chinese proprietary medicines and dietary supplements.

    PubMed

    Li, Ning; Cui, Mei; Lu, Xiumei; Qin, Feng; Jiang, Kun; Li, Famei

    2010-11-01

    An ultraperformance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was developed for simultaneous qualitative and quantitative analysis of 14 synthetic anti-diabetic drugs in adulterated Chinese proprietary medicines (CPMs) and dietary supplements. The samples were prepared by ultrasonic extraction with methanol and separated on a C₁₈ column with mobile phase consisting of acetonitrile and water (both containing 0.10% formic acid). Gradient elution was applied with a flow rate of 0.20 mL/min. Two transitions from protonated molecules were monitored for each synthetic anti-diabetic drug in positive mode of electrospray ionization (ESI). The two transitions, the peak area ratio of the two transitions and the retention time were used for identification. The more intensive transition was used for quantification. The analysis time was 6 min per sample. Satisfactory linear relationships were estimated between the peak area and the concentration with correlation coefficients higher than 0.995. The limit of detection ranged from 0.03 to 5.45 ng/mL. The relative standard deviation of intra-day precision was below 7.6%, the RSD of inter-day precision was below 15% and the relative error of accuracy was between -10 and 7.8%. The proposed method is rapid, selective, reliable and was successfully applied to the analysis of 30 real samples of 22 CPMs and eight dietary supplements from the local market in China. PMID:20954219

  9. Rapid Detection and Quantification of RNA of Ebola and Marburg Viruses, Lassa Virus, Crimean-Congo Hemorrhagic Fever Virus, Rift Valley Fever Virus, Dengue Virus, and Yellow Fever Virus by Real-Time Reverse Transcription-PCR

    PubMed Central

    Drosten, Christian; Göttig, Stephan; Schilling, Stefan; Asper, Marcel; Panning, Marcus; Schmitz, Herbert; Günther, Stephan

    2002-01-01

    Viral hemorrhagic fevers (VHFs) are acute infections with high case fatality rates. Important VHF agents are Ebola and Marburg viruses (MBGV/EBOV), Lassa virus (LASV), Crimean-Congo hemorrhagic fever virus (CCHFV), Rift Valley fever virus (RVFV), dengue virus (DENV), and yellow fever virus (YFV). VHFs are clinically difficult to diagnose and to distinguish; a rapid and reliable laboratory diagnosis is required in suspected cases. We have established six one-step, real-time reverse transcription-PCR assays for these pathogens based on the Superscript reverse transcriptase-Platinum Taq polymerase enzyme mixture. Novel primers and/or 5′-nuclease detection probes were designed for RVFV, DENV, YFV, and CCHFV by using the latest DNA database entries. PCR products were detected in real time on a LightCycler instrument by using 5′-nuclease technology (RVFV, DENV, and YFV) or SybrGreen dye intercalation (MBGV/EBOV, LASV, and CCHFV). The inhibitory effect of SybrGreen on reverse transcription was overcome by initial immobilization of the dye in the reaction capillaries. Universal cycling conditions for SybrGreen and 5′-nuclease probe detection were established. Thus, up to three assays could be performed in parallel, facilitating rapid testing for several pathogens. All assays were thoroughly optimized and validated in terms of analytical sensitivity by using in vitro-transcribed RNA. The ≥95% detection limits as determined by probit regression analysis ranged from 1,545 to 2,835 viral genome equivalents/ml of serum (8.6 to 16 RNA copies per assay). The suitability of the assays was exemplified by detection and quantification of viral RNA in serum samples of VHF patients. PMID:12089242

  10. A selectively fluorescein-based colorimetric probe for detecting copper(II) ion.

    PubMed

    Zhang, Li; Zhang, Xianhong

    2014-12-10

    A novel fluorescein derivative 3-bromo-5-methylsalicylaldehyde fluorescein hydrazone (BMSFH) has been synthesized by reacting fluorescein hydrazide with 3-bromo-5-methylsalicylaldehyde and was developed as a new colorimetric probe for detection of Cu(2+). In the presence of Cu(2+) the BMSFH exhibits a rapid color change from colorless to yellow together with an obvious new band appeared at 502nm in the UV-vis absorption spectra. However, other common alkali-, alkaline earth-, transition- and rare earth metal ions induced no or minimal spectral changes. This change is attributed to BMSFH via coordination with Cu(2+) in a 1:1 stoichiometry and this binding to Cu(2+) is reversible, as indicated by the bleaching of the color when the Cu(2+) is extracted with EDTA. Experimental results indicate that the BMSFH can provide a rapid, selective and sensitive response to Cu(2+) with a linear dynamic range 3.0-330μmol/L and can be used as a potential Cu(2+) colorimetric probe in aqueous solution. PMID:24929315