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Acetylator phenotyping via analysis of four caffeine metabolites in human urine by micellar electrokinetic capillary chromatography with multiwavelength detection
Author(s) -
Guo Ruichen,
Thormann Wolfgang
Publication year - 1993
Publication title -
electrophoresis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.666
H-Index - 158
eISSN - 1522-2683
pISSN - 0173-0835
DOI - 10.1002/elps.1150140183
Subject(s) - micellar electrokinetic chromatography , chromatography , chemistry , urine , capillary electrophoresis , caffeine , electrokinetic phenomena , biological fluids , biology , biochemistry , endocrinology
The simultaneous analysis of 5‐acetylamino‐6‐formylamino‐3‐methyluracil (AFMU), 5‐acetylamino‐6‐amino‐3‐methyluracil (AAMU), 1‐methylxanthine (1X) and 1‐methyluric acid (1U), the four urinary metabolites of caffeine employed for acetylator phenotyping in man, by micellar electrokinetic capillary chromatography (MECC) is reported. Using on‐column fast scanning multiwavelength detection is shown to permit unambiguous identification of AAMU, AFMU, 1X and 1U in the three‐dimensional electropherograms obtained with both direct urine injection or application of extracted urine. The phenotype status of a number of healthy volunteers, some with known acetylator status, were determined using peak height ratios of AFMU/1X, (AFMU + AAMU)/1X and compared to those obtained by high performance liquid chromatography (HPLC) employing the AFMU/1X peak height ratio. Another set of MECC data was obtained after deliberate conversion of AFMU to AAMU, the results being expressed by AAMU/1X, AAMU/(1U + 1X) or AAMU/(AAMU + 1U + 1X) ratios. The data suggest that most reliable data are obtained when phenotyping is conducted under conditions of complete conversion of AFMU to AAMU. Phenotyping employing caffeine and analysis of its urinary metabolites by MECC is shown to be simple and, with automated instruments, potentially suitable for routine use and large‐scale population analysis. The agreement of MECC data obtained from three different instruments demonstrates the high level of maturity of this emerging technology.