Sample records for 8-quinolinol

  1. [Synthesis and antimicrobial ivestigation of 8-quinolinols glucosaminides].


    Chupakhina, T A; Katsev, A M; Kur'ianov, V O


    In the phase transfer system solid calcium carbonate--acetonitrile per acetylated O-beta-D-glucosaminides of 8-quinolinol, 2-methyl-8-quinolinol and 5-chloro-8-quinolinol were synthesized. Zemplen deacetylation was led to corresponding trioles. Obtained O-beta-D-glucosaminides were identified with 1H-NMR spectroscopy. Antimicrobial activity of deacetylated forms has been studied in a test of inhibition of bioluminescence of marine luminescent bacteria Vibrio fischeri F1 and method of the serial breeding on the museum steams of Escherichia coli, Agrobacterium tumefaciens, Bacillus cereus, Micrococcus luteus. It was established that glycosylation decrease antimicrobial activity in comparison with non-glycosilated 8-quinolinols. PMID:23189563

  2. Redox properties of 8-quinolinol and implications for its mode of action.


    Chobot, Vladimir; Drage, Sigrid; Hadacek, Franz


    8-Quinolinol (oxine, 8-hydroxyquinoline) is a simple aromatic alkaloid with allelopathic, antibacterial, antifungal, and cytotoxic activities. Generally, it is assumed that 8-quinolinol toxicity depends on transition metal chelation that negatively affects their availability for metalloenzymes in the cell or reactive oxygen species generation (ROS), which are formed following reduction of molecular oxygen by autoxidation of the redox active metal central atom of the 8-quinolinol complex. On the contrary, beneficial effects of 8-quinolinol and its derivatives in the medication of certain degenerative diseases are known. In this context, the activity of 8-quinolinol derivatives is attributed to their antioxidant activity following iron complex formation. To address this controversial issue, we explore the possible anti- or pro-oxidant effects of 8-quinolinol and its iron complexes in the deoxyribose degradation assay, by cyclic voltammetry and in a biological assay. The antibacterial effects of 8-quinolinol and its complex with iron were evaluated on Curtobacterium flaccumfacies and Paenibacillus amylolyticus. 8-Quinolinol showed strong antioxidant activity in the deoxyribose degradation assay. This activity may not depend exclusively on iron chelation, but probably more on the notable reducing properties of 8-quinolinol; it proved to be a more efficient antioxidant than the flavonoids catechin and quercetin. By contrast, 8-quinolinol showed no pro-oxidative effects in the deoxyribose degradation assay, both in free form and in complex with iron, as it may occur with redox cyclers. Cyclic voltammetry confirmed this too. 8-Quinolinol significantly inhibited bacterial growth and respiration. Idiosyncratically, its 50:1 mixture with iron(III) ions was less active compared with free 8-quinolinol; it even caused a U-shaped nonlinear hormetic effect on growth and failed to inhibit respiration as totally as the pure mixture; the respiration was even accelerated compared with the control as a result of lower stress. Our results support the notion that complex formation with either iron or other transition metals affects the reducing power of 8-quinolinol, but, in contrast to general assumptions, this study finds no support that complex formation with iron represents the major mode of action. PMID:21615015


    Microsoft Academic Search

    W Wendlandt


    S>The thermal decomposition of the 5,7-dichloro-, 5,7dibromo- and 5,7-; diiodo-8-quinolinol chelates of La, Ce, Pr, Nd, Sm, and Y was investigated on the ; thermobalance. The chelates decomposed in the temperature range from 65 to 125 ; deg C while the oxide levels were obtained from 395 to 805 deg C. Although the ; chelate thermal stability temperatures varied little

  4. Structure, magnetic behavior, and anisotropy of homoleptic trinuclear lanthanoid 8-quinolinolate complexes.


    Chilton, Nicholas F; Deacon, Glen B; Gazukin, Olga; Junk, Peter C; Kersting, Berthold; Langley, Stuart K; Moubaraki, Boujemaa; Murray, Keith S; Schleife, Frederik; Shome, Mahasish; Turner, David R; Walker, Julia A


    Three complexes of the form [Ln(III)3(OQ)9] (Ln = Gd, Tb, Dy; OQ = 8-quinolinolate) have been synthesized and their magnetic properties studied. The trinuclear complexes adopt V-shaped geometries with three bridging 8-quinolinolate oxygen atoms between the central and peripheral eight-coordinate metal atoms. The magnetic properties of these three complexes differ greatly. Variable-temperature direct-current (dc) magnetic susceptibility measurements reveal that the gadolinium and terbium complexes display weak antiferromagnetic nearest-neighbor magnetic exchange interactions. This was quantified in the isotropic gadolinium case with an exchangecoupling parameter of J = -0.068(2) cm(-1). The dysprosium compound displays weak ferromagnetic exchange. Variable-frequency and -temperature alternating-current magnetic susceptibility measurements on the anisotropic cases reveal that the dysprosium complex displays single-molecule-magnet behavior, in zero dc field, with two distinct relaxation modes of differing time scales within the same molecule. Analysis of the data revealed anisotropy barriers of Ueff = 92 and 48 K for the two processes. The terbium complex, on the other hand, displays no such behavior in zero dc field, but upon application of a static dc field, slow magnetic relaxation can be observed. Ab initio and electrostatic calculations were used in an attempt to explain the origin of the experimentally observed slow relaxation of the magnetization for the dysprosium complex. PMID:24520896

  5. Electrochemistry of oxo-technetium(V) complexes containing Schiff base and 8-quinolinol ligands

    SciTech Connect

    Refosco, F.; Mazzi, U.; Deutsch, E.; Kirchhoff, J.R.; Heineman, W.R.; Seeber, R.


    The electrochemistry of six-coordinate, monooxo technetium(V) complexes containing Schiff base ligands has been studied in acetonitrile and N,N'-dimethylformamide solutions. The complexes have the general formula TcOCl(L/sub B/)/sub 2/ or TcO(L/sub T/)(L/sub B/), where L/sub B/ represents a bidentate-N,O Schiff base ligand or a bidentate-N,O 8-quinolinol ligand and L/sub T/ represents a tridentate-O,N,O Schiff base ligand. Cyclic voltammetry at a platinum-disk electrode, controlled-potential coulometry, and thin-layer spectroelectrochemistry were used to probe both the oxidation and the reduction of these complexes. The results of these studies, and previously reported results on the analogous Re(V) complexes, can be understood within a single general reaction scheme. The salient features of this scheme are (i) one-electron reduction of Tc(V) to Tc(IV), (ii) subsequent loss of a ligand situated cis to the Tc/identical to/O linkage, and (iii) subsequent isomerization of this unstable Tc(IV) product to more stable complex in which the site trans to the Tc/identical to/O linkage is vacant. The Tc(IV) complexes can also be reduced to analogous Tc(III) species, which appear to undergo the same ligand loss and isomerization reactions. The technetium complexes are 400-500 mV easier to reduce than are their rhenium analogues. The 8-quinolinol ligands, and especially the 5-nitro derivative, both thermodynamically and kinetically stabilize the Tc(IV) and Tc(III) oxidation states. These electrogenerated species are unusual in that they constitute the bulk of the known examples of monomeric Tc(IV) and Tc(III) complexes containing only N- and O-donating ligands. 34 refs., 9 figs., 1 tab.

  6. Studies of the degradation mechanism of organic light-emitting diodes based on tris(8-quinolinolate)aluminum Alq and 2-tert-butyl-9,10-di(2-naphthyl)anthracene TBADN

    Microsoft Academic Search

    Viktor V. Jarikov; Denis Y. Kondakov


    Previously, radical cation of tris(8-quinolinolate)aluminum (Alq•+) has been associated with the instability of Alq films subjected to holes-only electrical current. Yet, the questions remain (i) whether Alq•+ is the primary source of the intrinsic degradation of bipolar organic light-emitting diodes (OLEDs) based on Alq, (ii) whether Alq•+ reactions result in deep charge traps in holes-only devices as found in bipolar

  7. Determination of rare earth elements in seawater by inductively coupled plasma mass spectrometry with on-line column pre-concentration using 8-quinolinole-immobilized fluorinated metal alkoxide glass

    NASA Astrophysics Data System (ADS)

    Kajiya, Tasuku; Aihara, Masato; Hirata, Shizuko


    The on-line column pre-concentration technique with inductively coupled plasma mass spectrometry (ICP-MS) has been developed using micro-column of 8-quinolinole-immobilized fluorinated metal alkoxide glass (MAF-8HQ). The aim of method was to determine rare earth elements (REEs) (Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu) in seawater. A 6.4 ml of seawater sample was passed through the column for 2 min, after washing the column with ultrapure water, the adsorbed REEs were subsequently eluted into the plasma with 1.4 M nitric acid. Sample pH, sampling and eluting flow rates and acidity of eluent were optimized. Detection limits (3 ?) based on three times standard deviations of water by 8 replicates were in the range from 0.11 pg ml -1 for Y to 0.30 pg ml -1 for Tb, and the precisions by a 10 pg ml -1 REEs standard solution ( n=8) were in the range from 4.7% for Tm to 8.7% for Tb and Yb. Analysis of one sample could be processed in 7 min. The proposed method was verified by determination of REEs in the two certified reference materials (CRMs) of seawater, CASS-4 and NASS-5, and the method was also applied to determine REEs in the costal seawater of Hiroshima Bay, the Seto Inland Sea, Japan.

  8. Determination of 5-chloro-7-iodo-8-quinolinol (clioquinol) in plasma and tissues of hamsters by high-performance liquid chromatography and electrochemical detection

    Microsoft Academic Search

    G. P. Bondiolotti; C. Pollera; R. Pirola; S. R. Bareggi


    This paper describes a method of determining clioquinol levels in hamster plasma and tissue by means of HPLC and electrochemical detection. Clioquinol was separated on a Nucleosil C18 300mm×3.9mm i.d. 7?m column at 1ml\\/min using a phosphate\\/citrate buffer 0.1M (400ml) with 600ml of a methanol:acetonitrile (1:1, v\\/v) mobile phase. The retention times of clioquinol and the IS were, respectively, 11.6

  9. Cancer stem\\/progenitor cell active compound 8-quinolinol in combination with paclitaxel achieves an improved cure of breast cancer in the mouse model

    Microsoft Academic Search

    Jiangbing Zhou; Hao Zhang; Peihua Gu; Joseph B. Margolick; Deling Yin; Ying Zhang


    Increasing evidence suggests that breast cancer is caused by cancer stem cells and the cure of breast cancer requires eradication\\u000a of breast cancer stem cells. In this study, we established and characterized a sphere culture model derived from side population\\u000a cells from the human breast cancer cell line MCF7. The sphere culture could be maintained long term and was enriched


    Microsoft Academic Search

    M. E. Mitchof; J. J. Morrell

    Alder represents an abundant but underutilized resource that has little natural resistance to decay. Treated alder might be used for stakes, posts, or other nonstructural applications. The performance of alder treated with chromated copper arsenate (CCA), copper 8 quinolinolate, zinc naphthenate (ZN), or thiocyanomethylthiobenzothiazole (TCMTB) was assessed in soil block tests. CCA provided the best protection, and ZN and TCMTB

  11. 8Hydroxyquinoline anchored to silica gel via new moderate size linker: synthesis and applications as a metal ion collector for their flame atomic absorption spectrometric determination

    Microsoft Academic Search

    Anupama Goswami; Ajai K. Singh; B. Venkataramani


    The silica gel modified with (3-aminopropyl-triethoxysilane) was reacted with 5-formyl-8-hydroxyquinoline (FHOQx) to anchor 8-quinolinol ligand on the silica gel. It was characterised with cross polarisation magic angle spinning (CPMAS) NMR and diffuse reflectance infrared Fourier transformation (DRIFT) spectroscopy and used for the preconcentration of Cu(II), Pb(II), Ni(II), Fe(III), Cd(II), Zn(II) and Co(II) prior to their determination by flame atomic absorption

  12. Capillary electrophoretic assay for the stability of tris(8-quinolinolato)gallium(III) in tablet formulations.


    Foteeva, Lidia S; Stolyarova, Natalya V; Timerbaev, Andrei R; Keppler, Bernhard K


    A capillary electrophoresis (CE) method for testing the stability of a novel oral anticancer metallodrug, tris(8-quinolinolato)gallium(III) (KP46), is proposed. As both the intact drug and its eventual impurity or/and decomposition product, 8-quinolinol, are not charged (at most of the pH range), the micellar-mediated CE mode based on using micellar concentrations of sodium dodecyl sulfate was employed. The running electrolyte conditions were optimized in order to resolve the peak of KP46 from the signal of 8-quinolinol, as well as from these of tablet matrix components. The stability of KP46 in different organic and water-organic solvent systems was studied regarding its limited solubility and the following recovering experiments. The method thus developed was applied to the determination of KP46 in tablet formulations, for which sample preparation method, namely powdering and ultrasound-assisted extraction (with 50% aqueous acetone), was tested and optimized in terms of procedure time (10 min). Different in the content of the active substance (10-30%) batches of tablets stored for two years after preparation were validated and recoveries obtained at the level from 97 to 102% confirmed sufficient drug stability. This principal finding was verified by means of an independent method, gas chromatography coupled with mass spectrometry (GC-MS). PMID:18579328

  13. Homogeneous liquid-liquid solvent extraction. [Propylene carbonate-water system

    SciTech Connect

    Ting, C.S.; Williams, E.T.; Finston, H.L.


    This investigation was undertaken to extend the technique of homogeneous liquid-liquid solvent extraction into propylene carbonate. The mutual solubilities of propylene carbonate in water and vice-versa are shown in the phase diagram. The extraction of a variety of monodentate and bidentate ligand complexes with Fe(III) as a function of ligand concentration and pH were investigated. The monodentate ligands studied include, thiocyanate, chloride, bromide, benzoate, and bathophenanthrolines. The bidentate ligands studied include the various ..beta..-diketones, 8-quinolinol, and also cupferron which was studied under normal conditions, i.e., not under conditions of homogeneous extraction. The homogeneous extraction proved effective for a variety of chelate complexes and ion association complexes of iron giving, in all cases, very rapid extraction as compared with the slow rate of conventional extraction methods.

  14. Phosphorescent white organic light-emitting diodes by electron transporting layer engineering.


    Lee, Seok Jae; Koo, Ja Ryong; Lee, Dong Hyung; Lee, Ho Won; Lee, Kum Hee; Yoon, Seung Soo; Kim, Young Kwan


    The authors describe the fabrication of white organic light-emitting diodes (WOLEDs) with dual electron transporting layers (D-ETL) using 2,9-dimethyl-4,7-diphenyl-1,10-phenanhroline/ 4,7-diphenyl-1,10-phenanthroline (BPhen) and bis-(2-methyl-8-quinolinolate)-4-(phenylphenolato) aluminum/BPhen. Stepwise D-ETL easily transports electrons easily to the emitting layer and reduces the leakage of electrons. Therefore, WOLEDs with D-ETL show higher external quantum efficiency (EQE) when compared to a control WOLED with a single ETL device. The optimized WOLEDs showed a peak EQE of 13.0%, luminous efficiency of 27.4 cd/A, and Commission Internationale de L'Eclairage coordinates of (0.40, 0.39) at 1000 cd/m2. PMID:25942876

  15. Recognizing acute health effects of substitute fungicides: are first-aid reports effective?


    Teschke, K; Hertzman, C; Wiens, M; Dimich-Ward, H; Hershler, R; Ostry, A; Kelly, S J


    Recently, many British Columbia sawmills stopped using traditional chlorophenate anti-sapstain fungicides and substituted 2-(thiocyanomethylthio) benzothiazole (TCMTB) and copper-8-quinolinolate (Copper 8). We conducted a cross-sectional study with two aims: to ascertain which acute health effects, if any, were associated with the use of the substitute fungicides; and to determine the effectiveness of first-aid records as a means of detecting acute health outcomes. Workers in five coastal sawmills were asked to complete a self-administered questionnaire about symptoms considered potentially related and unrelated to fungicide exposure, and about injuries commonly reported in sawmills. In addition, we collected first-aid records from the mills, and asked senior workers to estimate the duration of exposure to fungicides for each job. Symptoms found to be consistently elevated in TCMTB mills included dry skin around the eyes, blood-stained mucus from the nose, nose bleed, peeling skin, burning or itching skin, and skin redness or rash. No symptoms were consistently elevated in the Copper 8 mills. Symptoms related to TCMTB exposure were recorded only 12 times in first-aid logs during the study period (versus 335 questionnaire self-reports). This low symptom-recording frequency may be a function of established patterns of first-aid use in which illness symptoms are reported less frequently than injuries. PMID:1585948

  16. Photocontrolled nitric oxide release from two nitrosylruthenium isomer complexes and their potential biomedical applications

    NASA Astrophysics Data System (ADS)

    Liu, Jiao; Duan, Qingqing; Wang, Jianru; Song, Zhen; Qiao, Xiaoyan; Wang, Hongfei


    Nitric oxide (NO) has key regulatory roles in various biological and medical processes. The control of its local concentration, which is crucial for obtaining the desired effect, can be achieved with exogenous NO donors. Release of NO from metal-nitrosyl complexes upon exposure to light is a strategy that could allow for the site-specific delivery of the reactive species NO to physiological targets. The photodissociation of NO from two nitrosylruthenium(II) isomer complexes {cis- and trans-[Ru(OAc)2NO]} was demonstrated by matrix-assisted laser desorption ionization time-of-flight mass spectrometry spectra, and electron paramagnetic resonance spectra further prove the photoinduced NO release by spin trapping of NO free radicals upon photoirradiation. Real-time NO release was quantitatively measured by electrochemistry with an NO-specific electrode. The quantitative control of NO release from [Ru(OAc)2NO] in aqueous solutions was done by photoirradiation at different wavelengths. Both isomers show photoinduced damage on plasmid DNA, but the trans isomer has higher cytotoxicity and photocytotoxicity activity against the HeLa tumor cell line than that of the cis isomer. Nitrosylruthenium(II) complex, with 8-quinolinol derivatives as ligands, has a great potential as a photoactivated NO donor reagent for biomedical applications.

  17. Efficient deep-blue organic light-emitting diodes with a 1,4-(dinaphthalen-2-yl)-naphthalene.


    Seo, Ji Hoon; Lee, Seok Jae; Hyung, Gun Woo; Lee, Kum Hee; Park, Jung Keun; Yoon, Seung Soo; Kim, Young Kwan


    Deep-blue organic light-emitting diodes (OLEDs) with nearly 5% external quantum efficiency were demonstrated using a 1,4-(dinaphthalen-2-yl)-naphthalene (DNN) host. The 4,4'-bis(9-ethyl-3-carbazovinylene)-1,1'-biphenyl (BCzVBi) dopant that was used in this experiment effectively accepted energy from the DNN host via Förster energy transfer because the photoluminescence spectrum of the DNN host showed better spectra overlap with the ultraviolet-visible (UV-vis) absorption spectrum of the BCzVBi dopant than the photoluminescence spectrum of the 2-methyl-9,10-bis(naphthalen-2-yl)anthracene host did. Moreover, the DNN host had a higher energy bandgap (3.5 eV) than the BCzVBi dopant did (3.0 eV), while the MADN host had the same energy bandgap as the BCzVBi dopant. The optimized deep-blue device also had ETL of bis-(2-methyl-8-quinolinolate)-4-(phenylphenolato)aluminium which showed smoother sigma of 0.6 nm and higher Tg of 92 degrees than those of 4,7-diphenyl-1,10-phenanthroline (14.8 nm and 62 degrees C). The deep-blue device exhibited a peak current efficiency of 5.68 cd/A, a peak external quantum efficiency of 4.89%, and Commission Internationale d' Eclairage coordinates of (0.15, 0.13). PMID:22121612

  18. Ultrafast energy transfer in oligofluorene-aluminum bis(8-hydroxyquinoline)acetylacetone coordination polymers.


    Montes, Victor A; Zyryanov, Grigory V; Danilov, Evgeny; Agarwal, Neeraj; Palacios, Manuel A; Anzenbacher, Pavel


    Understanding the excited-state dynamics in conjugated systems can lead to their better utilization in optical sensors, organic photovoltaics (OPVs), and organic light-emitting diodes (OLEDs). We present the synthesis of self-assembled coordination polymers comprising two types of fluorescent moieties: discrete fluorene oligomers of a well-defined length (n = 1-9) connected via aluminum(III) bis(8-quinolinolate)acetylacetone joints. Due to their well-defined structure, these materials allowed for a detailed study of energy migration processes within the materials. Thus, femtosecond transient spectroscopy was used to study the ultrafast energy transfer from the oligofluorene to the quinolinolate moieties, which was found to proceed at a rate of 10(11) s(-1). The experimental results were found to be in agreement with the behavior predicted according to the Beljonne's improved Forster model of energy transfer. In addition, the solid-state and semiconductor properties of these coordination polymers allowed for the fabrication of OLEDs. Preliminary experiments with simple two- and three-layer devices fabricated by spin-coating yield bright yellow electroluminescence with maximum brightness of 6000 cd/m(2), with a turn-on voltage of approximately 6 V and a maximum external quantum efficiency of up to 1.2%, suggesting their potential for use in PLED applications. PMID:19146416

  19. Spectrophotometric catalytic determination of small amounts of rhenium in mineralized rocks and molybdenite

    USGS Publications Warehouse

    Simon, F.O.; Grimaldi, F.S.


    Rhenium is determined by spectrophotometry of the tellurium sol formed by the reduction of tellurate by stannous chloride under the catalytic influence of rhenium. A detailed investigation of the conditions for high sensitivity and stability at lowest concentration levels of rhenium is presented as well as the behavior of 26 ions. The method is applied to the determination of some tenths of 1 p.p.m. or more of rhenium in a 1-mg. aliquot of mineralized rocks, mixtures of molybdenite and rocks, and molybdenite concentrates. The practical quantity limit of detection is 2 ?? 10-10 gram of rhenium. Samples are decomposed with a mixture of CaO, CaCl2, and MgO. On leaching, most constituents of the sample are precipitated either as calcium salts or hydroxides, except for rhenium and a small amount of molybdenum which pass into the filtrate. Residual molybdenum is removed by extraction with 8-quinolinol in chloroform. Better than 95% recoveries are obtained with two fusions with flux.


    PubMed Central

    Bleiweis, Arnold S.; Zimmerman, Leonard N.


    Bleiweis, Arnold S. (The Pennsylvania State University, University Park), and Leonard N. Zimmerman. Properties of proteinase from Streptococcus faecalis var. liquefaciens. J. Bacteriol. 88:653–659. 1964.—The extracellular group D streptococcal proteinase is inactivated by chelating agents [ethylenediamine-tetraacetate (EDTA), o-phenanthroline, and 8-quinolinol] and mercaptans (cysteine, mercaptoethanol, and thioglycolate). The optimal inhibitory concentrations of EDTA (4 × 10?4m) and cysteine (2.5 × 10?2m) promote rapid loss of activity with 50% inactivation after 4 to 5 min. Enzyme inactivated by either EDTA or cysteine is reactivated about 80% by 4 × 10?4m Zn++. Such reactivation of EDTA-treated enzyme is prevented completely by iodoacetate (5 × 10?2m) and of cysteine-treated enzyme by oxidizing conditions, which suggests that the zinc binding-site may be a thiol. High levels of zinc (10?3m) do not allow reactivation in either case, and actually inhibit native proteinase. Ca++, Mg++, Co++, Fe++, Cu++, and Ni++ do not reactivate cysteine-treated enzyme, but Mn++ (10?4 to 8 × 10?4m) allows 27% reversal. N2-held, cysteine-treated enzyme can be spontaneously reactivated if the substrate is flushed with O2 during the assay; leakage of air or O2 into the samples before assay leads to loss of reactivatability. Native proteinase does not lose activity after dialysis for 43 hr against 0.07 m phosphate buffer. It is concluded that the group D proteinase obtained from Streptococcus faecalis var. liquefaciens is probably a zinc metalloenzyme that is unlike the thiol-activated, group A streptococcal proteinase, but similar to the mammalian carboxypeptidase A. PMID:14208503

  1. A Novel Method Applied in Determination and Assessment of Trace Amount of Lead and Cadmium in Rice from Four Provinces, China

    PubMed Central

    Li, Shan; Wang, Mei; Yang, Bingyi; Zhong, Yizhou; Feng, Le


    Heavy metal contamination of soils or water can lead to excessive lead (Pb) and cadmium (Cd) levels in rice. As cumulative poisons, consumption of Pb and Cd in contaminated rice may cause many toxic effects in humans. In the present study, Pb and Cd levels in rice samples from Hubei, Jiangxi, Heilongjiang, and Guangdong provinces in China were analyzed by cloud point extraction and graphite furnace atomic absorption spectrometry (GFAAS). The heavy metals in the rice samples were reacted with 8-quinolinol to form a complex at pH 9.0 and 40°C. Analytes were quantitatively extracted to a surfactant-rich phase (Triton X-45) after centrifugation and analyzed by GFAAS. The effects of experimental conditions, including pH, concentration of reagents, and equilibration time and temperature, on cloud point extraction were optimized efficiently using Plackett–Burman and Box–Behnken experimental designs. Under the optimum conditions, good linearity was observed in the concentration ranges of 0.5–5 µg/L for Pb and 0.05–0.50 µg/L for Cd. The limits of detection were 0.043 µg/L for Pb with a concentration factor of 24.2 in a 10 mL sample and 0.018 µg/L for Cd with a concentration factor of 18.4 in a 10 mL sample. Twenty rice samples from four provinces were analyzed successfully, and the mean levels of Pb and Cd in the rice were all below their maximum allowable concentrations in China. Comparing the tolerable daily intakes given by FAO/WHO with the mean estimated daily intakes; Pb and Cd mean daily intake through rice consumption were 0.84 µg/kg bw/day and 0.40 µg/kg bw/day, which were lower than the tolerable daily intakes. PMID:25251454

  2. 8-Hydroxyquinoline anchored to silica gel via new moderate size linker: synthesis and applications as a metal ion collector for their flame atomic absorption spectrometric determination.


    Goswami, Anupama; Singh, Ajai K; Venkataramani, B


    The silica gel modified with (3-aminopropyl-triethoxysilane) was reacted with 5-formyl-8-hydroxyquinoline (FHOQ(x)) to anchor 8-quinolinol ligand on the silica gel. It was characterised with cross polarisation magic angle spinning (CPMAS) NMR and diffuse reflectance infrared Fourier transformation (DRIFT) spectroscopy and used for the preconcentration of Cu(II), Pb(II), Ni(II), Fe(III), Cd(II), Zn(II) and Co(II) prior to their determination by flame atomic absorption spectrometry. The surface area of the modified silica gel has been found to be 227 m(2) g(-1) and the two pKa values as 3.8 and 8.0. The optimum pH ranges for quantitative sorption are 4.0-7.0, 4.5-7.0, 3.0-6.0, 5.0-8.0, 5.0-8.0, 5.0-8.0 and 4.0-7.0 for Cu, Pb, Fe, Zn, Co, Ni and Cd, respectively. All the metals can be desorbed with 2.5 mol l(-1) HCl or HNO(3). The sorption capacity for these metal ions is in range of 92-448.0 micromol g(-1) and follows the order Cd