Ascorbate in plasma as measured by liquid chromatography and by dichlorophenolindophenol colorimetry.

1986 ◽  
Vol 32 (6) ◽  
pp. 1004-1006 ◽  
Author(s):  
D J VanderJagt ◽  
P J Garry ◽  
W C Hunt
Keyword(s):  
Ascorbic Acid ◽  
Liquid Chromatography ◽  
Electrochemical Detection ◽  
High Performance ◽  
Colorimetric Method ◽  
Dehydroascorbic Acid ◽  
High Performance Liquid Chromatographic ◽  
Plasma Samples ◽  
Chromatographic Procedure ◽  
Liquid Chromatographic

Abstract Ascorbic acid was measured in 125 plasma samples by an automated colorimetric method involving dichlorophenolindophenol and by a "high-performance" liquid-chromatographic procedure with electrochemical detection. The two methods gave comparable results for samples with ascorbate concentrations of 1 to 20 mg/L (r = 0.97). We also measured the amount of total ascorbate (ascorbic acid + dehydroascorbic acid) in the same samples by a liquid-chromatographic procedure with precolumn derivitization of ascorbic acid. We confirmed that plasma contains little dehydroascorbic acid.

Gas Chromatographic and Gas Chromatographic-Mass Spectrometric Confirmation of 2,4- and 2,6-Toluenediamine Determined by Liquid Chromatography in Aqueous Extracts

1982 ◽  
Vol 65 (6) ◽  
pp. 1388-1394 ◽  
Author(s):  
Roger C Snyder ◽  
William C Brumley ◽  
Charles V Breder ◽  
Thomas Fazio
Keyword(s):  
Mass Spectrometry ◽  
Liquid Chromatography ◽  
High Performance ◽  
High Performance Liquid Chromatographic ◽  
Mass Spectrometric ◽  
Gas Liquid Chromatography ◽  
Aqueous Extracts ◽  
Chromatographic Procedure ◽  
Liquid Chromatographic ◽  
Chromatographic Mass

Abstract The confirmation of 2,4- and 2,6-toluenediamine (TDA) in aqueous extracts from boil-in-bags and retortable pouches is described. The extracts were initially analyzed by a high performance liquid chromatographic procedure and any apparent 2,4- and/or 2,6-TDA were quantitated. The liquid chromatographic effluent corresponding to any apparent 2,4- or 2,6-TDA was collected. TDA was then partitioned into ethyl acetate and reacted with trifluoroacetic anhydride (TFAA). The TDA-TFAA derivative formed was confirmed by gas-liquid chromatography (GLC) using a 1.2 m × 0.32 cm nickel column packed with 6% OV-17 on Superpak-20M. Results obtained from analyzing extracts of several retortable pouches and boil-in-bags showed levels of TDA migration ranging from <0.1 to 2.2 ppb (μg/L). Additional confirmation of the TDA-TFAA derivative from retortable pouches by multiple ion detection GC/mass spectrometry is also described.

Liquid-chromatographic separation of urinary 5-hydroxy-3-indoleacetic acid, with measurement at 254 nm.

1980 ◽  
Vol 26 (7) ◽  
pp. 910-912
Author(s):  
P S Draganac ◽  
S J Steindel ◽  
W G Trawick
Keyword(s):  
High Performance ◽  
Indoleacetic Acid ◽  
Colorimetric Method ◽  
Internal Standard ◽  
High Performance Liquid Chromatographic ◽  
Reversed Phase ◽  
Acetate Buffer ◽  
Nitrobenzoic Acid ◽  
Chromatographic Procedure ◽  
Liquid Chromatographic

Abstract A "high-performance" liquid-chromatographic procedure for 5-hydroxy-3-indoleacetic acid is described and compared with a colorimetric method in which 1-nitroso-2-naphthol is used. The analyte and an internal standard, p-nitrobenzoic acid, were extracted into diethyl ether from urine at pH 4.0 (acidified with HCl) to which sodium chloride had been added, and the ether was back-extracted with acetate buffer, pH 9.2. Aliquots of this extract were injected into a reversed-phase liquid-chromatographic column and eluted with pH 3.5 acetate buffer/methanol (95/5 by vol); the effluent was monitored at 254 nm. The precision (CV) of the method was 11.8% at 1.8 mg/L, 5.5% at 92 mg/L. Analytical recovery averaged 84%. The colorimetric method gave higher values for the analyte than did the chromatographic method for all patients' urines.

Liquid-chromatographic separation of urinary 5-hydroxy-3-indoleacetic acid, with measurement at 254 nm.

1980 ◽  
Vol 26 (7) ◽  
pp. 910-912 ◽  
Author(s):  
P S Draganac ◽  
S J Steindel ◽  
W G Trawick
Keyword(s):  
High Performance ◽  
Indoleacetic Acid ◽  
Colorimetric Method ◽  
Internal Standard ◽  
High Performance Liquid Chromatographic ◽  
Reversed Phase ◽  
Acetate Buffer ◽  
Nitrobenzoic Acid ◽  
Chromatographic Procedure ◽  
Liquid Chromatographic

Abstract A "high-performance" liquid-chromatographic procedure for 5-hydroxy-3-indoleacetic acid is described and compared with a colorimetric method in which 1-nitroso-2-naphthol is used. The analyte and an internal standard, p-nitrobenzoic acid, were extracted into diethyl ether from urine at pH 4.0 (acidified with HCl) to which sodium chloride had been added, and the ether was back-extracted with acetate buffer, pH 9.2. Aliquots of this extract were injected into a reversed-phase liquid-chromatographic column and eluted with pH 3.5 acetate buffer/methanol (95/5 by vol); the effluent was monitored at 254 nm. The precision (CV) of the method was 11.8% at 1.8 mg/L, 5.5% at 92 mg/L. Analytical recovery averaged 84%. The colorimetric method gave higher values for the analyte than did the chromatographic method for all patients' urines.

Determination of urinary glyoxal and methylglyoxal by high-performance liquid chromatography

2004 ◽  
Vol 42 (2) ◽  
Author(s):  
Kazuki Akira ◽  
Yui Matsumoto ◽  
Takao Hashimoto
Keyword(s):  
Liquid Chromatography ◽  
High Performance ◽  
Internal Standard ◽  
High Performance Liquid Chromatographic ◽  
Reversed Phase ◽  
Carbonyl Stress ◽  
Age Related ◽  
Highperformance Liquid Chromatography ◽  
Chromatographic Procedure ◽  
Liquid Chromatographic

AbstractCarbonyl stress compounds such as glyoxal and methylglyoxal have been recently attracting much attention because of their possible clinical significance in chronic and age-related diseases. A high-performance liquid chromatographic procedure has been developed for the simultaneous quantitation of glyoxal and methylglyoxal in human urine. The assay is based on the reaction of these compounds with 1,2-diamino-4,5-dimethoxybenzene to form fluorescent adducts, which are separated by reversed-phase highperformance liquid chromatography in a total run time of 45 minutes and quantitated fluorometrically using 2,3-pentanedione as an internal standard. Derivatization is performed for diluted urine (100–120 mOsm/kg H

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