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
Email: schalk@unf.edu
Website: @unf

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Thiols

  • Molecular Formula: SH
  • InChI: InChI=1S/H2S/h1H2

@ ChemSpider@ NIST@ PubChem

Citations 19

"Determination Of Sulfide And Mercaptans [thiols] In Caustic Scrubbing Liquor"
Anal. Chim. Acta 1989 Volume 226, Issue 1 Pages 165-170
Wei Lei and Purnendu K. Dasgupta

Abstract: A flow injection system is described, whereby a 10 µL sample of scrubber liquid is injected into a water stream and then mixed sequentially with 0.1% of NN-dimethyl-p-phenylenediamine in 3 M HCl and 1.33% of FeCl3.6H2O in 0.2 M HCl. Dual-wavelength detection is carried out for S2- and thiols at 670 and 500 nm, respectively. At 500 nm, the calibration graphs are rectilinear for S2- and thiols for 10 mM. At 670 nm, the response for S2- is rectilinear for 5 mM, and response for thiols is negligible. The coefficient of variation for synthetic mixtures are 3%, with recoveries close to 100%. Sampling rate 60 samples h-1 should be possible.
Industrial Spectrophotometry Dual detection

"Solvent Extraction In Continuous-flow Systems With Intelligent Zone Sampling"
Anal. Chim. Acta 1989 Volume 226, Issue 2 Pages 255-269
Purnendu K. Dasgupta and Wei Lei

Abstract: A portion of extractant (50 to 100 µL) is injected into a flowing reagent stream that passes through an extraction coil of residence time 1 to 3 min, and the extractant is isolated as it flows through the loop of an injection valve, which is activated by sensing by conductivity probes or by appropriate timing. The extractant can then be injected into a second stream for further chemistry before detection of the analyte. The effects of parameters, such as the coil material, configuration and diameter, or the phase ratio and flow rate, were studied. Examples include extraction of C1 to C5 alkanethiols from gasoline, extraction of a dye from aqueous fluoricarbon surfactant solution, and extraction of alkylbenzenesulfonates from water into CHCl3 as its methylene blue ion-pair. In the latter instance, the calibration graph was rectilinear up to 5 µg mL-1 of dodecylbenzenesulfonate; the coefficient of variation for 2.5 µg mL-1 was 1.3%. The detection limit was 50 ng mL-1, and a sampling rate of 60 h-1 should be attainable.
Oil Spectrophotometry Sample preparation Zone sampling Ion pair extraction Optimization Solvent extraction

"Amperometry Of Thiols In A Flow Injection System With A Nickel Oxide Electrode"
Anal. Chim. Acta 1990 Volume 229, Issue 1 Pages 191-195
Yoshiko Arikawa and Calvin O. Huber

Abstract: The electrochemical oxidation of a series of thiols on a nickel oxide electrode surface was investigated in a flow injection system. The thiols were dissolved in phthalate buffer (pH 3.0), the injection volume was 25 µL, 0.1 M NaOH containing 0.05 mM NiSO4 was used as background electrolyte (1.0 mL min-1), and Pt auxiliary and SCE reference electrodes were sited downstream of the working electrode. The optimum applied potential was 0.46 V. Graphs of peak current vs. concentration. were rectilinear from 0.1 to 1 mM, and detection limits ranged from 0.03 to 0.2 mM. The coefficient of variation (n = 10) for 0.1 mM ethanethiol was 1.6%.
Amperometry Electrode Buffer Detection limit

"Determination Of Pharmaceutical Thiols By Liquid Chromatography With Electrochemical Detection: Use Of An Electrode With A Conductive Carbon Cement Matrix, Chemically Modified With Cobalt Phthalocyanine"
Anal. Chim. Acta 1996 Volume 332, Issue 2-3 Pages 249-255
Gabriella Favaro* and Mario Fiorani

Abstract: An electrode, prepared by doping conductive C cement with 5% cobalt phthalocyanine, was used in FIA and LC systems to detect the pharmaceutical thiols, captopril, thiopronine and penicillamine. FIA determinations were performed with phosphate buffer of pH 2 as carrier stream (1 ml/min), an injection volume of 20 µL and an applied potential of 0.6 V vs. Ag/AgCl (stainless steel counter electrode). The calibration curves were presented for 5-100 µM of each analyte. The dynamic linear range was up to ~20 µM. The detection limits were 76, 73 and 88 nM for captopril, thiopronine and penicillamine, respectively. LC determinations were performed on a 5 µm Bio-Sil C18 HL 90-5S column (15 cm x 4.6 mm i.d.) with 1 mM sodium 1-octanesulfonate in 0.01 M phosphate buffer/acetonitrile as mobile phase (1 ml/min) and gradient elution from 9:1 (held for 5 min) to 7:3 (held for 10 min) in 5 min. The working electrode was maintained at 0.6 V vs. Ag/AgCl and the injection volume was 20 µL. For thiopronine, penicillamine and captopril the retention times were 3.1, 5 and 11.3 min and the detection limits were 0.71, 1 and 2.5 µM, respectively.
Pharmaceutical LC Electrode Buffer Detector

"Manual And Flow Injection Spectrophotometric Assay Of Thiols, Based On Their S-nitrosation"
Talanta 1991 Volume 38, Issue 3 Pages 283-289
Krishna K. Verma and Kent K. Stewart*, Archana Jain, Dayashanker Gupta and Sunil K. Sanghi

Abstract: For the manual and flow injection methods (described), thiols are treated with NaNO2 and HCl, the excess of HNO2 is destroyed by addition of ammonium sulfamate, and the S-nitrosothiols are hydrolyzed with Hg(II); an azo-dye is formed by the reaction of the released HNO2 with sulfanilamide and N-(1-naphthyl)ethylenediamine. Detection is at 544 nm. Since the final step depends on the HNO2 liberated and not on the particular thiol being determined, the calibration graphs should be identical for all thiols. The manual method is about 4-fold more sensitive than the flow injection method, but the latter has a high sample rate and is less susceptible to interference by tryptophan. The method is applicable to many thiols including aromatic thiols and amino-acids, but cannot be used for many sterically hindered thiols.
Spectrophotometry Calibration Interferences

"Simultaneous Fluorimetric Determination Of Thiols And Disulfides By Liquid Chromatography With Modified Post-column Derivatization"
Anal. Chem. 1982 Volume 54, Issue 12 Pages 1951-1955
Hiroshi Nakamura, and Zenzo Tamura

Abstract: By modification of our post-column derivatization system for thiols, an HPLC method has been developed for the simultaneous fluorometric determination of biogenic thiols and disulfides. They are separated by anion-exchange chromatography with gradient elution, reacted with sodium sulfite at pH 6-7 and o-phthalaldehyde (OPA) at pH 9.4-10.5 in the presence of taurine to produce fluorescent isoindole fluorophores, and monitored with a fluorescence detector (λex = 360 nm; λem > 405 nm). Under the optimized conditions for chromatography and the post-column derivatization, 250 pmol of L-cysteine (CySH), L-cystine (CySS), glutathione (GSH), and oxidized glutathione (GSSG) and 750 pmol of 3'-dephosphocoenzyme A (DP-CoASH), coenzyme A (CoASH), and their oxidized forms (DP-CoASS and CoASS) can be determined. The relative standard deviations (n = 5) of the method are 1.35%, 4.09%, and 6.87% for the analyzes of 5 nmol of CySS and GSSG and 8.5 nmol of CoASS, respectively.
HPLC Fluorescence Post-column derivatization Simultaneous analysis

"Liquid Chromatographic Determination Of Amino- And Imino-acids And Thiols By Post-column Derivatization With 4-fluoro-7-nitrobenzofurazan"
Anal. Chem. 1983 Volume 55, Issue 11 Pages 1786-1791
Yoshihiko Watanabe and Kazuhiro Imai

Abstract: After separation by ion-exchange chromatography on Kyowa Gel 62210F (details given), amino- and imino-acids and thiols were determined by reaction with 4-fluoro-7-nitrobenzofurazan to produce highly fluorescent derivatives, which were detected at 530 nm (excitation at 470 nm) for amino- and imino-acids, and at 520 nm (excitation at 450 nm) for thiols. Detection limits were 5, 50 and 10 pmol for proline, tyrosine and cysteine, respectively. The coefficient of variation of the retention times for 18 amino- and imino-acids was 0.73%, and that of the relative peak heights for 625-pmol amounts of the acids was 3.06%. The calibration graph for each acid was rectilinear over the range 50 to 2500 pmol. The method was applied in the determination of amino- and imino-acids in blood of normal and diseased new-born humans. Results agreed with those obtained by the phthalaldehyde-derivatization method.
Human Baby Blood HPIC Fluorescence Post-column derivatization

"Sorbent Isolation And Elution With An Immiscible Eluent In Flow Injection Anlysis"
Anal. Chem. 1989 Volume 61, Issue 5 Pages 496-499
Wei Lei, Purnendu K. Dasgupta, Jorge L. Lopez, and Don C. Olson

Abstract: The use of a flow injection carrier that is immiscible with the sample matrix is illustrated. To determine thiols in gasoline, the sample is passed through a column of Amberlite IRA-401-S strongly basic anion exchanger (OH- form) on which the thiols are concentrated. A portion of aqueous NaOH (>1M) is then injected into the gasoline stream before the column, and elutes the thiols and regenerates the column. This solution enters a flow of the same NaOH, which is mixed with a stream of 1 M NaHCO3 as buffering agent; 1 mM 5,5'-dithiobis-(2-nitrobenzoic acid) is then introduced and the absorbance is measured at 450 nm. To determine aniline in benzene, the mixture is passed through a column of Rexyn-101 strongly acid cation-exchange resin (H+ form), which retains aniline. A portion of 0.1 M H2SO4 is then introduced to elute aniline from the column, and after this flow has merged with more 0.1 M H2SO4 the absorbance is measured at 280 nm. The sensing and delay circuits are illustrated. Response was rectilinear up to 2 mM for thiols and up to 10 ng mL-1 for aniline. Further possible applications are discussed.
Organic compound Oil Spectrophotometry Preconcentration Buffer Amberlite Rexyn

"Flow Injection Analysis Titrations Of Sulfide, Cysteine And Thiol-containing Drugs With Chemiluminescent Detection"
Fresenius J. Anal. Chem. 1993 Volume 345, Issue 11 Pages 723-726
I. López García, P. Viñas and J. A. Martínez Gil

Abstract: The method is based on lowering of the chemiluminescence produced by the reaction between ClO- and luminol; the optimum pH for both the chemiluminescence reaction and its suppression by S2- or a thiol is 11.2 and the optimum ClO- concentration. in the flow injection analysis system used is 0.4 mM. Sample solution is injected into a stream of ClO- solution, which passes through a silicone tube (8 cm x 2 mm) and merges with 5 mM luminol before entering a flow-through chemiluminescence detector; the overall flow rate is 6.5 mL min-1. The method has been applied to aqueous solution of pharmaceuticals. Calibration graphs obtained by plotting the chemiluminescence peak width at half height vs. log. analyte concentration. were rectilinear for 1 to 100 mM of S2- and 0.1 to 100 mM of cysteine, N-acetylcysteine, N-penicillamine, 2-mercaptopropionylglycine (tiopronin) and 2-thiouracil; some variation in the slopes was observed. No interference was caused by fructose, lactose, glucose, sucrose, maltose, caffeine, salicylic acid, tartrate, oxalate or starch in up to 10-fold amount over N-penicillamine.
Pharmaceutical Chemiluminescence Interferences Peak width Titrations

"Measurement Of Mercaptans In Gasoline"
Microchim. Acta 1989 Volume 99, Issue 1-2 Pages 35-41
Wei Lei, Purnendu K. Dasgupta, Steve D. Matza and Don C. Olson

Abstract: Portions (10 µL) of 4 mM 5,5'-dithiobis-(2-nitrobenzoic acid) and 2% ethylenediamine solution, each in methanol - acetone (4:1), are injected into a flowing stream of gasoline. The product, viz, 2-nitro-5-mercaptobenzoate, is detected at 412 nm after ~15 s. Calibration graphs were rectilinear for all of the C1 to C10 thiols examined. The system is intended for determination of 64 ppm of S.
Oil Spectrophotometry Organic phase detection

"Electrocatalytic Amperometric Detection At Polymeric Cobalt Phthalocyanine Electrodes"
Electroanalysis 1991 Volume 3, Issue 2 Pages 119-124
Xiaohe Qi, Richard P. Baldwin, Huawen Li, Thomas F. Guarr

Abstract: The cited chemically modified electrodes were prepared according to the method of Li and Guarr (cf. J. Chem. Soc., Chem. Commun., 1989, 832) with polymeric surface coverage from 1 to 10 nmol cm-2. The electrode was applied to the detection of thiol compounds under flow injection conditions with use of a Ag - AgCl reference electrode (pH 3.2), an applied potential of +0.55 V and an aqueous mobile phase containing 50% of methanol or acetonitrile. In most cases, response was rectilinear over 2 to 3 orders of magnitude of concentration. with detection limits from 0.1 pmol for N-acetylcysteine to 5 pmol for 6-mercaptopurine. The electrodes are extremely stable and can be readily adapted for HPLC conditions.
Amperometry HPLC Electrode Electrode Catalysis

"Amperometric Flow Injection Analysis Of Organic Thiols And Proteins"
Electroanalysis 1996 Volume 8, Issue 5 Pages 468-472
Achmad Hidayat, D. Brynn Hibbert *, Peter W. Alexander

Abstract: Portions (10 µL) of standard L-cysteine (I) solution was injected into a carrier stream of 100 mM phosphate buffer of pH 3.1 containing 15 µM-Hg(II) [1.5 ml/min] of a flow injection system and detected at a W electrode at -0.24 V vs. Ag/AgCl with a Pt wire auxiliary electrode. The calibration graph was linear over the range 0.25-100 µM-I with a detection limit of 0.25 µM. Silver and iodate ions were observed to interfere. Thiourea (II), glutathione (III), DNA and albumin were similarly detected, and appropriate analytical data are briefly presented. I, II, reduced-III, DL-homocysteine, DL-penicillamine and 3-mercaptopropanoic acid were resolved by HPLC on a Zorbax ODS column (25 cm x 4.6 mm i.d.), aqueous 50 mM 3-chloroacetate/methanol (99:1) of pH 2.3 as mobile phase (0.3 ml/min) and post-column reaction with 50 mM phosphate buffer of pH 2.3 containing 15 µM-Hg(II) (1 ml/min) for amperometric detection as before.
Amperometry HPLC Interferences

"Derivatization Of Thiol-containing Compounds"
J. Chromatogr. B 1994 Volume 659, Issue 1-2 Pages 227-241
Kazutake Shimada* and Kuniko Mitamura

Abstract: Derivatization reagents for thiols are reviewed with respect to their reactivity, selectivity, spectroscopic characteristics and their applicability to HPLC, with UV and electrochemical detection. The derivatization reagents contains a functional group e.g. an N-substituted maleimide, active halogen or aziridine, which react with the thiol group. Derivatization for use in FIA, TLC or GC-MS is also described. (77 references).
HPLC Spectrophotometry Electrochemical analysis GPC Mass spectrometry Post-column derivatization Review

"Pulsed Amperometric Detection Of Sulfur Compounds. 1. Initial Studies At Platinum Electrodes In Alkaline Solution"
J. Electroanal. Chem. 1986 Volume 209, Issue 1 Pages 159-169
Theresa Z. Polta and Dennis C. Johnson*

Abstract: It is shown that pulsed amperometric detection (cf. Hughes et al., Anal. Abstr., 1982, 43, 1C11) can be used for the determination of S compounds (e.g., SCN-, S2O32-, S2-, CS2, thiols, thioamides, dithiocarbamates and sulfoxides) that are adsorbed at the electrode surface. Application of the technique is exemplified by the determination of thiourea in 0.25 M NaOH as supporting electrolyte with use of a flow injection system equipped with a flow-through platinum detector (Dionex). At low analyte concentration. (C) and/or short adsorption times, the peak current (Ip) showed a rectilinear dependence upon concentration, but for high concentration. or long adsorption times rectilinear calibration graphs were obtained by plotting 1/Ip vs. 1/C. The limit of detection for thiourea was 0.38 ppm (based on a 45 µL sample).
Amperometry Electrode Electrode Theory

"Development Of Ion-selective Electrodes And Flow Injection Analysis For Sulfides And Thiols"
Anal. Proc. 1980 Volume 17, Issue 12 Pages 533-535
E. Jane Duffield, G. J. Moody, J. D. R. Thomas

Abstract: The flow injection analysis system was used to control difficulties arising in the response of Ag sulfide membrane ion-selective electrodes to sulfides and thiols due to oxidation and volatility. Reproducible flow injection emf. response peaks were obtained for S2- standards at 10^-4-10-1M.
Electrode Electrode Electrode

"Fluorescence And Chemiluminescence Detection Of Oxazole-labelled Amines And Thiols"
Biomed. Chromatogr. 1993 Volume 7, Issue 4 Pages 208-216
Toshimasa Toyo'oka *, Hitesh P. Chokshi, Richard S. Givens, Robert G. Carlson, Susan M. Lunte, Theodore Kuwana

Abstract: Fluorescence and chemiluminescence analyzes of amino acids and thiols derivatized with 2-fluoro-4,5-diphenyloxazole (DIFOX) and 2-chloro-4,5-bis(p-N,N-dimethylaminosulfonylphenyl)oxazole (SAOX-Cl) were investigated. Thirteen diphenyloxazole (DIOX)-derivatized amino acids were separated within 38 min by a linear gradient elution from 100% A [0.05 M phosphate (pH 7.0): CH3CN (75:25)] to 100% B [0.05 M phosphate (pH 7.0):CH3CN (1:1)] over 30 min and an isocratic elution of 100% B for 30 min. The detection limits (S/N = 2) with fluorescence detection were in the range of 19-64 fmol. Thiols derivatized with SAOX-Cl were separated by an isocratic elution using 0.1 M H3PO4:CH3CN (65:35) and detected fluorimetrically. The detection limits (S/N = 2) of reduced glutathione, N-acetylcysteine, 2-mercaptopropionylglycine, cysteine, homocysteine and captopril were 1.2, 1.5, 1.9, 5.7, 6.4 and 7.9 fmol, respectively. Peroxyoxalate chemiluminescence (CL) intensities of sulfonyl-5-N,N-dimethylaminonaphthalene (DNS), SAOX and DIOX derivatives were compared using three different oxalate esters (DFPO, TCPO and TDPO) by flow injection analysis. The relative chemiluminescence intensity (RCL) of SAOX-proline and DIOX-proline were 76-80% and 19-25% of DNS-proline (100%), respectively. Other SAOX and DIOX derivatives showed lower CL intensities (< 12%). Extremely low CL intensities were obtained for the fluorescent tagging reagents (< 0.11%) and their hydrolysis products (< 0.80%). Secondary amino acids and peptides, derivatized with DIFOX in aqueous media at room temperature for 1 h, were detected using DFPO/H2O2. TCPO/H2O2 and TDPO/H2O2 after separation by high performance liquid chromatography.(ABSTRACT TRUNCATED AT 250 WORDS)
Fluorescence Chemiluminescence

"Endogenous Plasma N-acetylcysteine And Single Dose Oral Bioavailability From Two Different Formulations As Determined By A New Analytical Method"
Biopharm. Drug Dispos. 1991 Volume 12, Issue 5 Pages 343-353
Bernard Gabard, Hermann Mascher

Abstract: Plasma (0.5 ml) was mixed with 0.5 mL of water and 30 µL of 10% tributyl phosphine in methanol. After 30 min at 37°C, 0.15 mL of 20% HClO4 was added and the solution was centrifuged at 2500 g. A portion (100 muwl) of the supernatant solution was analyzed by HPLC on a column (8 cm x 4 mm) of Nucleosil 120 C18 (3 µm) with ethanol - 0.1 M H3PO4 - triethylamine (40:960:1), containing glycine at 100 µg mL-1, as mobile phase (1 mL min-1). The column eluate was mixed with 0.5 M NaOH - 0.1 M H3BO3 (41:59), containing o-phthalaldehyde (10 µg mL-1), at 1 mL min-1 in a reaction tube (described) and detected at 475 nm (excitation at 325 nm). The calibration graph was rectilinear from 0.06 to 8 µM-acetylcysteine; the detection limit was 6 nM. The coefficient of variation (n = 3) were 4.4% at 60 nM and 0.1% at 8 µm. The method is specific for thiols, e.g., cysteine, glutathione, thioglycolic acid and homocysteine.
Blood Plasma HPLC Fluorescence Column Post-column derivatization

"Fluorimetric Determination Of Thiols By High Performance Liquid Chromatography With Post-column Derivatization"
Bunseki Kagaku 1981 Volume 30, Issue 5 Pages 339-341
Hiroaki TAKAHASHI, Takanori YOSHIDA, Hiroshi MEGURO

Abstract: An analytical method of thiols was reported on high performance liquid chromatography with post column derivatization. The derivatization is based on the reaction of thiols with N-(9-acridinyl)maleimide. The separation of cysteamine, cysteine, N-acetylcysteine and glutathione was achieved within 14 min on a silica column with NH2 groups (Jasco SN-01) using a mixture of 0.05 M NaH2PO4: acetonitrile (55:45) as an eluent. At the maleimide concentration of 2.7 mg/500 mL in acetonitrile, the linear relationships were obtained over the concentration range (0.0525) nmol for cysteine and (0.1100) nmol for gluta-thione respectively. The reproducibility of the injection was good with a coefficient of variation of less than 3%.
HPLC Fluorescence Post-column derivatization

"Determination Of Thiols By Hydrodynamic Modulation Voltammetry"
Bunseki Kagaku 1987 Volume 36, Issue 10 Pages 628-631
Yamaguchi, S.;Tsukamoto, T.;Senda, M.

Abstract: Square-wave hydrodynamic modulation voltammetry with a vibrating platinum-wire electrode was applied to the flow injection determination of thiols, e.g., cysteine, N-acetylcysteine, dithiothreitol, 2-mercaptoethanol and reduced glutathione. A carrier stream (0.2 mL min-1) of 0.1 M phosphate buffer (pH 3) was used. The electrode was vibrated between 0 and 60 Hz over 2 s and the modulation current vs. potential curve and the difference modulation current vs. potential curve showed a max. between +0.7 and +0.9 V vs. a SCE. The difference current measured at +0.65 V increased rectilinearly between 0 and 0.1 mM thiol. Thiols were determined at the 1 µM level with the exception of reduced glutathione, which gave an unexpectedly small modulation current.
Electrode Voltammetry