High-performance liquid chromatography with a 3α-hydroxysteroid dehydrogenase postcolumn reactor and isoluminol-microperoxidase chemiluminescence detection

Chemiluminescence in drug assay

The phenomenon of chemiluminescence allows the development of simple analytical procedures using low cost instrumentation which can be easily controlled by computers. The sensitivity of the methods is excellent, and selectivity is improved by high-performance liquid chromatographic separation. A broad area of chemiluminometric applications is drug analysis, which is reviewed in this paper.

Determination of conjugated bile acids in human urine by high-performance liquid chromatography with chemiluminescence detection

A qualitative and quantitative analysis of the conjugated 1 beta- and 6 alpha-hydroxy bile acids, including common bile acids, in human urine using high-performance liquid chromatography with chemiluminescence detection is described. After extraction of urine with C18 silica cartridges, the bile acids were separated into non-conjugated, glycine, taurine and sulphate fractions by ion-exchange chromatography on a lipophilic gel. Solvolysis of the sulphate was carried out by treatment with trifluoroethanol in acetone containing hydrochloric acid, and the liberated amino acid conjugates were fractionated again. The individual bile acids were separated on a reversed-phase C18 column (Bile Pak II), with detection by an immobilized 3 alpha-hydroxysteroid dehydrogenase enzyme reactor and chemiluminescence reaction of the generated NADH using 1-methoxy-5-methylphenazinium methylsulphate-isoluminol-microperoxidase system. The assay method showed the detection limits ranging from 8 to 250 pmol for the bile acids tested. Analysis of urine samples obtained from newborns, non-pregnant women and women in late pregnancy showed a large difference in bile acid composition and conjugation mode, suggesting that bile acid metabolism is different during fetal and neonatal periods.