University of North Florida
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Stuart Chalk, Ph.D.
Department of Chemistry
University of North Florida
Phone: 1-904-620-1938
Fax: 1-904-620-3535
Website: @unf

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Classification: Biological tissue -> liver -> cow

Citations 12

"Determination Of Nickel And Cobalt In Natural Waters And Biological Material By Reductive Chronopotentiometric Stripping Analysis In A Flow System Without Sample Deoxygenation"
Anal. Chim. Acta 1985 Volume 175, Issue 1 Pages 79-88
H. Eskilsson and C. Haraldsson, D. Jagner

Abstract: Samples (100 ml) of natural waters, or portions (0.5 to 5 ml) of acid digests of seawater sediments or bovine liver, were mixed with 3 M NH3 - HCl buffer (pH 9.2) and 0.1 M dimethylglyoxime(I) solution in ethanol; Co(III) species formed during acid digestion were reduced with NaBH4. Electroanalysis was performed in a thin-layer flow cell with a vitreous-carbon working electrode. The microprocessor-controlled operational sequence included(I) plating of a mercury film on to the carbon electrode;(II) potentiostatic adsorption (at -0.5 V vs. the SCE) of the Ni(II) - and Co(II) - I complexes on to the mercury film; (iii) constant-current reduction of the metal ions in a 5 M CaCl2 medium and simultaneous recording of the working-electrode potential vs. time; (iv) chemical removal of the mercury film; and (v) cleaning of the vitreous-carbon surface. To determine Co in presence of a large excess of Ni, an adsorption potential of -0.75 V vs. the SCE was used. Detection limits (after 70 s of adsorption) were 8.6 ng L-1 for Ni(II) and 10.5 ng L-1 for Co(II).
Nickel Cobalt Potentiometric stripping analysis Electrode Sample preparation Interferences

"Metal Speciation By Supercritical-fluid Extraction With Online Detection By Atomic Absorption Spectrometry"
Anal. Chem. 1994 Volume 66, Issue 22 Pages 3900-3907
Jin Wang and William D. Marshall

Abstract: A silica flame-in-tube interface is described for the AAS detection of As, Cd, Cu, Mn, Pb, Se or Zn in the eluate from a SFE apparatus. It consisted of a heated optical tube placed within the optical beam of the spectrometer, a flame tube fitted with H2 and O2 gas entry ports and a sample introduction tube. The analyte metal in an aqueous medium was complexed in situ with tetrabutylammonium dibutyldithiocarbamate and the derivative was mobilized into supercritical CO2. The superheated extractor eluate was nebulized into the upper region of a diffuse flame in the interface flame tube and introduced into the optical tube for analysis. The optimal flame conditions were slightly reducing for aqueous and CO2 mobile phases but slightly oxidizing for a methanolic mobile phase. The detection limits of the metals were in the sub ng to low pg range when a standard was flow-injected into the mobile phase. The recoveries of 5 or 10 µg/ml of Cu, Mn and Pb were 92-94.4% with RSD of 0.1%; the RSD for the cumulative area under the AAS response curve was appreciably more variable. The differences in the rates of mobilization of analyte metal from different matrices was studied using fresh and freeze-dried bovine liver.
Arsenic Cadmium Copper Manganese Lead Selenium Zinc Sample preparation Spectrophotometry Speciation Solvent extraction

"Flame Atomic Absorption Spectrometric Determination Of Cadmium And Copper In Biological Reference Materials Using Online Sorbent Extraction Preconcentration"
Fresenius J. Anal. Chem. 1992 Volume 344, Issue 12 Pages 535-540
Shukun Xu, Michael Sperling and Bernhard Welz

Abstract: Animal or plant tissue reference material (0.5 g) was subjected to acid digestion and the residue was diluted with HNO3. Urine samples for analysis were diluted with water before addition of HNO3. The solution was loaded into a flow injection manifold where it was merged with a stream of 0.05% diethylammonium-NN-diethyldithiocarbamate. The complex formed was extracted online on a conical 100 µL micro-column of RP-C 18 sorbent and the chelates were eluted with methanol directly into the nebulizer - burner system of the spectrometer. Small air segments introduced before and after elution prevented the eluent from mixing with the sample solution and increased sensitivity. A sampling frequency of 85 h-1 was achieved, with a sample loading time of 30 s at a flow rate of 4.0 mL min-1. The enrichment factor for Cd and Cu was 20 and the detection limits were 0.15 and 0.2 µg L-1 for Cd and Cu, respectively. The coefficient of variation were 2.3% for 10 µL L-1 of Cd and 1.4% for 45 µg L-1 of Cu (n = 11). The procedure was suitable for the determination of Cu in biological materials and for Cd in urine. Low recoveries were obtained for Cd in samples containing high levels of Cu and/or Fe. Cadmium and copper at the µg/g to ng/g level in plant and animal tissue reference materials, and at the µg/L level in urine were determined by flame atomic absorption spectrometry using online sorbent extraction pre-concentration based on flow injection techniques. Bonded silica reversed phase sorbent with octadecyl functional groups (RP-C 18), packed in a 100 µL column, was used to collect the diethylammonium-N,N-diethyldithiocarbamate (DDTC) complex formed online in the sample digests at low pH. Methanol was used to elute the analyte chelates directly into the nebulizer-burner system of the spectrometer. Small air segments introduced before and after elution prevented the eluent from mixing with the sample solution and increased the sensitivity. A sampling frequency of 85/h could be obtained with a sample loading time of 30 s at a flow rate of 4.0 mL/min. The enrichment factor for both elements was 20 and the enhancement factors, including the effect of the organic solvent and with the flow spoiler removed, were 126 and 114 for cadmium and copper, respectively. The detection limits (3s) were 0.15 µg/L for cadmium and 0.2 µg/L for copper. The precision was 2.3% and 1.4% RSD for 10 µg/L Cd and 45 µg/L Cu, respectively. (n = 11). Results for the determination of cadmium and copper in various biological reference materials were typically in good agreement with certified values. Low recoveries were observed, however, for cadmium in samples containing high levels of copper and/or iron, such as bovine liver.
Cadmium Copper Sample preparation Spectrophotometry Sample preparation Reference material Air segmentation Preconcentration C18 Solid phase extraction

"Simultaneous Determination Of Copper, Lead, Cadmium, And Zinc In Previously Lyophilized Biological Tissues Using Flow Injection Analysis/anodic Stripping Voltammetry"
Electroanalysis 1994 Volume 6, Issue 10 Pages 894-902
A Izquierdo, M. D. Luque de Castro, M. Valcárcel

Abstract: Improvements in three main aspects of the analysis of metal traces in biological tissues are proposed, namely: (a) lyophilization of the samples both to preserve them and to favor the digestion process; (b) digestion of the lyophilized tissues using an effective and fast procedure; and (c) automatic determination of the target analytes by flow-injection analysis/anodic stripping voltammetry (FIA/ASV). After optimization of these steps, the overall procedure was successfully applied to the simultaneous determination of copper, lead, cadmium, and zinc in certified reference materials (CRMs) and fresh bovine liver samples with good results. Finally, the performance of the method was validated by a statistical study using parameters of the certification campaign of the CRMs; the results obtained being within, or close to, the confidence levels of the certification campaign.
Copper Lead Cadmium Zinc Voltammetry Simultaneous analysis

"Hydride-generation Flow Injection Using Graphite Furnace Detection - Emphasis On Determination Of Tin"
Spectrochim. Acta B 1992 Volume 47, Issue 5 Pages 701-709
Zhang Li, Susan McIntosh, Glen R. Carnrick and Walter Slavin*

Abstract: Hydride-forming analytes were separated from large volume of matrix by trapping the hydrides on a Pd-coated L'vov platform at low temperature before analysis by AAS. The Pd-treated stabilized-temp. platform furnace was used for in situ trapping and atomization of the analyte, and was at least 80% efficient for As, Bi, Ge, Sb, Se, Sn and Te. The method was tested by determining Sn in steel, river sediment, orchard leaves and bovine liver standard reference materials. The detection limit for Sn was 7 ng l-1, and the coefficient of variation was 31.5% at the 1.0 ng level. Other hydride-forming elements did not interfere.
Arsenic Bismuth Germanium Antimony Selenium Tellurium Tin Spectrophotometry Interferences Volatile generation Reference material Volatile generation

"Determination Of Heavy Metals By Inductively Coupled Plasma Mass Spectrometry After Online Separation And Preconcentration"
Spectrochim. Acta B 1998 Volume 53, Issue 11 Pages 1527-1539
Valderi L. Dressler, Dirce Pozebon and Adilson J. Curtius*

Abstract: A method for the determination of Cu, As, Se, Cd, In, Hg, Tl, Pb and Bi in waters and in biological materials by inductively coupled plasma mass spectrometry, after an online separation, is described. The matrix separation and analyte pre-concentration is accomplished by retention of the analytes complexed with the ammonium salt of O,O-di-Et dithiophosphoric acid in a HNO3 solution on C18 immobilized on silica in a minicolumn. Methanol, as eluent, is introduced in the conventional pneumatic nebulizer of the instrument. To use the best compromise conditions, concerning the ligand and acid concentrations, the analytes were determined in two sep. groups. The enrichment factors were at 5-61, depending on the analyte. The limits of detection varied from 0.43 ng L-1 for Bi to 33 ng L-1 for Cu. The sample consumption is only 2.3 mL for each group and the sampling frequency is 21 h-1. The accuracy was tested by analyzing five certified reference materials: water, riverine water, urine, bovine muscle and bovine liver. The agreement between obtained and certified concentrations was very good, except for As. The relatively small volume of methanol, used as eluent, minimizes the problems produced by the introduction of organic solvent into the plasma.
Metals, heavy Copper Arsenic Selenium Cadmium Indium Mercury Thallium Lead Bismuth Mass spectrometry Interferences Method comparison Reference material Preconcentration C18 Silica Ion pair formation

"Determination Of Total Phosphorus In Biological Samples By Flow Injection Analysis With Spectrophotometric Detection"
Bull. Chem. Soc. Jpn. 1993 Volume 66, Issue 3 Pages 966-968
Edison Munaf, Wenzhi Hu and Hiroki Haraguchi

Abstract: Sample (8 to 40 g) was digested using 40 mL of 1 M HClO4, shaken vigorously and centrifuged at 3000 rpm for 5 min. A 20 mL portion of the supernatant solution was adjusted to pH 6.5 with 1.5 M potassium hydrogen carbonate and a 20 µL portion of this solution was injected into a carrier stream which merged with a stream (100 µL min-1) of 4% potassium peroxodisulfate solution and passed through a PTFE reaction coil (8 m x 0.5 mm) at 140°C. The mixture then merged with a stream (100 µL min-1) of 2% ammonium molybdate solution containing 0.36% ascorbic acid and 1.5 M H2SO4 and passed through a second PTFE coil (5 m x 0.5 mm) before the absorbance was measured at 880 nm. The calibration graph was rectilinear for 0.5 to 20 µg mL-1 of P; the detection limit was 16 ng mL-1. The method was used to determine P in chicken heart, eggs of salmon and yellowtail fish and in livers of cow, pig, chicken and fish.
Phosphorus Sample preparation Spectrophotometry PPB Heated reaction

"Separation And Determination Of Copper And Zinc By Ion Chromatography Using 2-(2-benzoxazolylazo)-1-naphthol As A Post-column Derivatization Reagent"
Bunseki Kagaku 1998 Volume 47, Issue 11 Pages 861-866
Shin-ichiro Okawa, Kazuhiko Yamazaki and Tosimi Ishikawa

Abstract: An ion chromatography method using post-column derivatization with 2-(2-benzoxazolylazo)-1-naphthol(α-BOAN) in a nonionic surfactant solution of Brij35 was established for the separation and determination of Cu(II) and Zn(II). The optimum conditions for determining the elements were: an eluent containing 0.25 mol L-1 lactic acid (pH 3.1) at a flow rate of 1 mL min-1; for post-column derivatization, 2 x 10^-4 mol L-1 α-BOAN solution containing 4%(v/v) dioxane, 4%(w/v) Brij35 and sodium tetraborate at a flow rate of 0.3 mL min-1; pH at the drain of 3.3 ± 0.1; analytical column, a Shim-pack IC-C1 (5.0 mm i.d x 150 mm); oven temperature of 40°C; an injection volume of 0.02 mL; and detection at 565 nm. A linear relationship was observed between the peak hight and the amt. of elements within ranges of 80-240 and 400-2000 ppb for Cu and Zn, respectively. The relative standard deviations for the measurements (n = 7) of 120 ppb Cu and 800 ppb Zn were 2.2 and 2.0%, respectively. The detection limits of 16 ppb Cu and 195 ppb Zn (S/N = 3) were obtained. The present method was applied to the separation and determination of Cu(II) and Zn(II) in the Rice Flour (NIST SRM1568a) and Bovine Liver (NIST SRM1577b) with satisfactory results. Cu(II) and Zn(II) in rice from Australia, Thailand, China, and the U.S.A. are also determined by this method.
Copper Zinc HPIC Spectrophotometry Post-column derivatization Reference material Method comparison Optimization

"Determination Of Trace Platinum By Flow Injection Analysis - Adsorptive Stripping Voltammetry And Catalytic Polarographic Hydrogen Wave"
Fenxi Huaxue 1990 Volume 18, Issue 1 Pages 20-24
Wei Guizhen Lu Zongpeng* Alan M.Bond

Abstract: Platinum solution (0.1 µg mL-1; 100 µL) is injected into the flow injection analyzer. and reacts in a stream (0.27 mL min-1) of 0.002% hydrazine sulfate - 0.36 M H2SO4 and 0.04% formaldehyde - 0.36 M H2SO4. Detection is by adsorptive stripping voltammetry at -0.3 V for 60 s and measurement of the catalytic hydrogen wave at -0.8 V. Recoveries were 93.7 to 100% with a coefficient of variation of 5%. The calibration graph was rectilinear for 10 pg to 1 ng of Pt. Twenty samples can be run per hour. The method was applied in the analysis of urine, fish meal, milk powder, ox liver, minerals and organoplatinum compounds.
Platinum Voltammetry Polarography Catalysis Calibration

"Determination Of N-methylcarbamate Pesticides In Liver By Liquid Chromatography"
J. AOAC Int. 1989 Volume 72, Issue 4 Pages 586-592
Ali MS

Abstract: A 21-g portion of bovine, porcine or duck liver was extracted with 200 mL of CH2Cl2 and the extract was dried (Na2SO4). After evaporation to 1 to 2 ml, the residue was dissolved in CH2Cl2 - cyclohexane (1:1; 7.5 ml) and cleaned up by gel-permeation chromatography on a column (60 x 2.5 cm) containing 60 g of BioBeads SX-3 resin (200 to 400 mesh), with CH2Cl2 - cyclohexane (1:1) as mobile phase (5.0 mL min-1). The eluate was evaporated and the residue was dissolved in CH2Cl2 and further cleaned up on an Aminopropyl Bond Elut cartridge, before transfer of residue to methanol and HPLC. Analysis was on a column (25 cm x 4.6 mm) of Zorbax C-8 (5 µm), with aqueous 12 to 70% acetonitrile over 30 min, then over 1 min to aqueous 80% acetonitrile (held for 8 min) as mobile phase (1.5 mL min-1). Post-column derivatization with phthalaldehyde was followed by fluorescence detection of 10 carbamate derivatives at 418 nm (excitation at 340 nm). Recovery was >80% with coefficient of variation of 17%; detection limits were 5 to 10 ppb.
Carbamates, N-methyl HPLC Fluorescence Sample preparation Post-column derivatization

"Continuous-flow Vapor Generation For Inductively Coupled Argon Plasma Spectrometric Analysis. 2. Arsenic"
J. AOAC Int. 1991 Volume 74, Issue 3 Pages 516-521
Tracy ML, Littlefield ES, Moller G.

Abstract: Biological tissue, blood or water, is wet ashed in a 10 mL test tube on a programmed heating block with HNO3, H2SO4 and HClO4 at up to 310°C (details given). The cooled digest is treated with HCl and KI and the As present is reduced by NaBH4 to arsine in a simplified continuous-flow manifold. A standard pneumatic nebulizer effects the gas - liquid separation of AsH3 which is quantified by ICP-AES at 193.756 nm. The detection limit was 0.4 to 0.6 µg L-1 of As. Mean coefficient of variation were 1.2% for analysis of water samples (n = 27) and 2% for analysis of liver samples (n = 12). Recoveries ranged from 99 to 104% for tap water, bovine liver and rice flour.
Arsenic Spectrophotometry Heated reaction Nebulizer Phase separator Reference material Volatile generation

"A Rapid Enzyme Assay For ß-galactosidase Using Optically Gated Sample Introduction On A Microfabricated Chip"
Anal. Bioanal. Chem. 2004 Volume 378, Issue 7 Pages 1710-1715
Hongwei Xu, Andrew G. Ewing

Abstract: The ability to perform enzyme assays on microchips is demonstrated using optically gated sample introduction. The hydrolysis of fluorescein mono-β-d-galactopyranoside (FMG) by β-d-galactosidase (β-Gal) is continuously monitored using a microchip for 5 to 10 min. The outcome of the reaction was analyzed by performing serial on-chip separations of fluorescent substrate, FMG, and product, fluorescein. Kinetic information about β-Gal has been successfully obtained by varying the concentration of FMG. β-Gal enzymes from two different sources including bovine liver and E. coli., have been examined and compared to each other and to results obtained using traditional assay methods. In addition, the competitive inhibition of β-Gal by phenylethyl β-d-thiogalactoside (PETG) and β-lactose has been studied using this technique. PETG is found to have higher inhibition than lactose in the hydrolysis. This separation-based enzyme assay technique avoids the possible fluorescence interference between FMG and fluorescein, which is a problem with the traditional plate assay method. Additionally, the amount of the enzyme and substrate required with this technique is at least four orders of magnitude lower than the traditional plate assay method. By using optically gated sample introduction, microchips allow continuous serial injections and separations without any potential switch, thus making this technique ideal as a sensor for enzyme assays. This technique should therefore be valuable for high-throughput screening in the drug discovery industry.
Enzyme, β-d-galactosidase Galactoside conjugates Fluorescence Sensor Kinetic High throughput