Simultaneous HPLC Determination of Free, Conjugated, and Sulfated Bile Acids

A novel immobilization fluorescence capillary analysis method and its applications

Fluorescence capillary analysis (FCA) realizes trace-level analysis of micro-volume samples; it is easy to operate, extremely low in analytical cost and can significantly lessen environmental pollution from analytical chemistry waste. FCA has the characteristics of green analytical chemistry and has been applied in clinical, biochemical, pharmaceutical, food safety and other fields. FCA basically involves a micro-volume glass capillary, a capillary holder and an ordinary fluorescence detector. The capillary is not only a container for chemical reaction and detection but also functions as a carrier to immobilize enzymes, gene probes or reagents; it can be used repeatedly or can be disposable. In analysis, the capillary which is modified with functional reagents sucks in a measured liquid for the reaction and is then inserted into the holder within the fluorescent detector for measurement. The immobilized FCA method has been successfully used in the determination of reduced coenzyme I, ethanol in liqueur, lactic acid in dairy products, pyruvic acid and glucose in serum, trace-level sulfated bile acid in urine, the ratio of pyruvic/lactic acid in serum, and pyruvic acid in cells as well as in DNA end-labeling and dyeing methods. Further, FCA can also be extended to capillary arrays to complete multipurpose simultaneous determinations and can be combined with mobile phones as fluorescence detectors for use in mobile health analytical technology. FCA will produce considerable social benefits in medicine, pharmacy, fermentation of food, environmental protection and other fields. Therefore, the relevant contents are presented in this tutorial review.

Simple and quantitative analysis of urinary sulfated tauro- and glycodihydroxycholic acids in infant with cholestasis by electrospray ionization mass spectrometry

Here we report a simple, sensitive, and accurate method for detecting urinary sulfated tauro- and glyco-bile acids that uses electrospray ionization mass spectrometry. The sulfated tauro- and glycodihydroxycholic acids mainly generated [M-2H](2-) negative ions at m/z 288.6 and m/z 263.6, respectively. These doubly charged ions appeared primarily in samples prepared from the urine of patients with cholestasis and were detected quantitatively. Cholestatic jaundice is the primary clinical sign of biliary atresia. The measurement of doubly charged negative ions, especially of sulfated taurodihydroxycholic acid (principally taurochenodeoxycholate-3-sulfate), is a useful screening modality for biliary atresia in neonates.

Black bear (Ursus americanus) bile composition: seasonal changes

Gallbladder contents from 8 active and 14 dormant black bears were analyzed for individual bile acids by high-performance liquid chromatography and for cholesterol, phospholipids, sodium, potassium, calcium, magnesium, zinc, iron, and copper. Only three bile acids occurring as taurine conjugates were detected: tauroursodeoxycholate, taurochenodeoxycholate, and taurocholate. The proportion of tauroursodeoxycholate to the sum of the three bile acids decreased. Calcium, cholesterol, phospholipids, magnesium, zinc, and copper concentrations were increased in dormancy. Standardized collection and handling procedures yielded more consistent data than previously available. The decrease in tauroursodeoxycholate and absence of deoxycholate and lithocholate are consistent with our working hypothesis that a marked reduction in metabolic activity of the gut flora is an integral part of the adaptation to metabolic stability of the dormant bear.

HPLC-fluorescence determination of individual free and conjugated bile acids in human serum

A method for the quantitative analysis of unconjugated and conjugated bile acids (BA) in serum of patients with primary biliary cirrhosis (PBC) before and after therapy with antibiotic or ursodeoxycholic acid (UDCA) is described. After separation of the free, glycine and taurine conjugated (F, G and T conjugated) fractions by solid-phase extraction, the isolated T conjugates were hydrolysed enzymatically using cholyglycine hydrolase. The BA fractions were derivatized using 2-bromoacetyl-6-methoxynaphthalene (Br-AMN) and detected fluorimetrically (lambda exc = 300 nm, lambda em = 460 nm). The derivatization reaction was performed under mild conditions (10 min at 40 degrees C) in an aqueous medium in the presence of tetrakis (decyl) ammonium bromide (TDeABr). The HPLC separation was achieved using an ODS column and with a mobile phase gradient mixture of A-B, where A is water and B is acetonitrile:methanol (60:40 v/v) for elution at a flow-rate of 1.2 mL/min. The reproducibility, recovery and separation of individual BA under gradient elution conditions were satisfactory, allowing a sensitive detection of each BA in serum samples with a detection limit of about 1-2 pmol.