Comparison of electroclhemical detection methods in liquid chromatography for the determination of N-acetylcysteine in plasma

Kok, Wim Th.; Halvax, J.J.; Frei, R.W.

doi:10.1016/s0021-9673(01)83369-0

Cited by 20 publications

(5 citation statements)

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“…Because of this extensive use, different methods have been developed and described for detecting this compound in biological samples, including the electrochemical detection system [12], and gas chromatography-mass spectrometry [13]. HPLC, coupled with electrospray tandem mass spectrometry, has been used lately to quantitate MPG levels and other sulfhydryl-containing compounds in biological samples [18][19][20][21].…”

Section: Discussionmentioning

confidence: 99%

“…Applicability of this method to a plasma sample was not shown. Kok et al [12] provided a method for determining MPG by using an electrochemical detection system on a gold/mercury amalgamated electrode. Although this method offers high selectivity and sensitivity, the response is so unstable that it is not practical for clinical use.…”

Section: Discussionmentioning

confidence: 99%

“…MPG becomes oxidized to disulfide dimers and forms conjugates with other endogenous thiols [11]. Previous methods used for determining the quantitation of MPG include an electrochemical detection system [12], gas chromatography-mass spectrometry [13], and the HPLC method [14]. However, the time-consuming procedures, extensive manipulation of samples and complicated derivatization steps are common limitations of these detection methods.…”

Section: Introductionmentioning

confidence: 99%

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Liquid chromatography analysis of N-(2-mercaptopropionyl)-glycine in biological samples by ThioGlo™ 3 derivatization

Penugonda

Mare

et al. 2004

Journal of Chromatography B

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N-(2-Mercaptopropionyl)-glycine (MPG) is a synthetic aminothiol antioxidant that is used in the treatment of cystinuria, rheumatoid arthritis, liver and skin disorders. Recent studies have shown that MPG can function as a chelating, cardioprotecting and a radioprotecting agent. Several other studies have shown that it may also act as a free radical scavenger because of its thiol group. Thiol-containing compounds have been detected in biological samples by various analytical methods such as spectrophotometric and colorimetric methods. However, these methods require several milliliters of a sample, time-consuming procedures and complicated derivatization steps, as well as having high detection limits. The present study describes a rapid, sensitive and relatively simple method for detecting MPG in biological tissues by using reverse-phase HPLC. With ThioGlo 3 [3H-Naphto[2,1-b] pyran, 9-acetoxy-2-(4-(2,5-dihydro-2,5-dioxo-1H-pyrrol-1-yl) phenyl-3-oxo-)] as the reagent, highly fluorescent derivatives of thiols can be obtained that are suitable for HPLC. MPG is derivatized with ThioGlo 3 and is then detected flourimetrically by reverse phase HPLC using a C18 column as the stationary phase. Acetonitrile: Water (75:25) with acetic acid and phosphoric acid (1 mL/L) is used as the mobile phase (excitation wavelength, 365 nm; emission wavelength, 445 nm). The calibration curve for MPG is linear over a range of 10-2500 nM (r=0.999) and the coefficients of the variation of within-run and between-run precision were found to be 0.3 and 2.1%, respectively. The detection limit was 5.07 nM per 20 microL injection volume. Quantitative relative recovery of MPG in the biological samples (plasma, lung, liver, kidney and brain) ranged from 90+/-5.3 to 106.7+/-9.3 %. Based on these results, we have concluded that this method is suitable for determining MPG in biological samples.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Liquid chromatography analysis of N-(2-mercaptopropionyl)-glycine in biological samples by ThioGlo™ 3 derivatization

Penugonda

Mare

et al. 2004

Journal of Chromatography B

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“…Details on the characteristics and performance of this technique have been published (8). Indirect electrochemical detection has been shown to be advantageous in the determination of compounds with slow electrode kinetics in direct oxidation (9). Besides, electrode passivation is avoided by the moderate potential that can be applied in the reductive detection.…”

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confidence: 99%

“…Besides, electrode passivation is avoided by the moderate potential that can be applied in the reductive detection. Applications to the determination of sulfur compounds in biological samples with iodine and bromine as oxidizing reagents have been published (9,10). Since cephalosporins react with iodine only after the opening of their 8-lactam ring (11,12), bromine was used as reagent in this work.…”

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confidence: 99%

Determination of cephalosporins and decomposition products by liquid chromatography with indirect electrochemical detection

Fabre¹,

Kok²

1988

Anal. Chem.

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Identification of photochemical products of amino acids, peptides, and proteins in on‐line, postcolumn photolytic derivatization detection by HPLC‐electrochemistry

Dou

Krull

1992

Electroanalysis

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ABSTMCTIn previous studies we have developed a method for the electrochemical detection of aromatic amino acids, sulfur-containing amino acids, peptides, and proteins in HPLC by using photolytic derivatization approaches. Upon irradlation, nonelectroactive (or even inherently electroactive) amino acids and peptides can be converted to electroactive (or more electroactive) compounds, in an on-line, postcolumn manner, which can be detected electrochemically in HPLC. In the case of proteins, the same method can be used to change the electroactivity of proteins photochemically. It is important to identify these photochemically converted compounds, especially those which are electroactive, in order to understand the detection mechanisms of the method. In this paper the results of identification of electroactive photoproducts for aromatic amino acids, peptides, and proteins are presented. Mainly, these studies were carried out by HPLC and direct electrochemical detection of off-line photolyzed analytes. m Y WORDS:Photolytic derivatization, proteins, peptides, amperometric detection.In the development of on-line, postcolumn electrochemical detection (EC) of aromatic amino acids, peptides, and proteins, a photolytic derivatization approach was used to convert nonelectroactive (or even mherently eleceoactive) amino acids and peptides into electroactive (or more electroactive) compounds, in an on-line, postcolumn manner, which could then be detected electrochemically in high performance liquid chromatography (HPLC) 11-21, In the case of proteins, the electroactivity could be increased upon irradiation [31. However, the exact photoproducts of these analytes were not identified in the previous studies. The identification of these photochemically converted compounds, especially those which are electroactive, is important to our understanding of the detection mechanism(s) of the overall method. In this paper the results of attempts to identify the electroactive photoproducts for aromatic or sulfur containing amino acids, peptides, and proteins are presented. Mainly, such 'Current Address: Roche Biomedical Laboratories, Inc., 1 Roche Drive, PO Box 500, Raritan NJ 08869 USA T o whom correspondence should be addressed. studies were carried out by HPLC and direct electrochemical detection of off-line photolyzed analytes.Studies on the photochemistry of amino acids, peptides, and proteins, especially aromatic and sulfurcontaining amino acids, have been heavily reported in the literature 14-71, Both radiolysis and photolysis were used for these irradiations. Different irradiation conditions, including wavelength of UV light, pH, concentration, and under N, or 0,, were employed. In most cases the final photochemical products were identified. Although most of these literature results could be used in our research to explain the mechanisms of photolysis-electrochemical detection of the original amino acids and peptides, separate studies were carried out to identify the photoproducts of certain amino acids, peptides, or proteins in ou...

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Comparison of electroclhemical detection methods in liquid chromatography for the determination of N-acetylcysteine in plasma

Cited by 20 publications

References 9 publications

Liquid chromatography analysis of N-(2-mercaptopropionyl)-glycine in biological samples by ThioGlo™ 3 derivatization

Liquid chromatography analysis of N-(2-mercaptopropionyl)-glycine in biological samples by ThioGlo™ 3 derivatization

Determination of cephalosporins and decomposition products by liquid chromatography with indirect electrochemical detection

Identification of photochemical products of amino acids, peptides, and proteins in on‐line, postcolumn photolytic derivatization detection by HPLC‐electrochemistry

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