New method for determination of fecal sterols in urine using non-chlorinated solvents

A new method has been developed to determine a number of sterols in urine using non-chlorinated solvents, namely methyl tert.-butyl ether and methanol (the MTB method). The method involves liquid-liquid extraction, saponification, reextraction, silylation and final identification and quantification by GC-FID. The sterols determined were coprostanol, epicoprostanol, cholesterol and dihydrocholesterol. 5Alpha-cholestane was used as internal standard. The limit of detection for the sterols in this experiment was 2 microg l(-1) urine. Recovery of coprostanol over the range 5-100 microg l(-1) urine by this method was between 80 and 92%.