HIGHLY SENSITIVE GAS-CHROMATOGRAPHIC ANALYSIS OF ETHANOL IN WHOLE-BLOOD, SERUM, URINE, AND FECAL SUPERNATANTS BY THE DIRECT-INJECTION METHOD

A highly sensitive, reproducible, and rapid gas chromatographic method for ethanol determination in various biological specimens (human whol e blood, serum, urine, and fecal supernatants) was developed. The meth od involves direct injection of the biological specimen into the gas c hromatograph, without any pretreatment. Contamination of the gas chrom atographic column with nonvolatile material was prevented by the use o f a glass liner in the injector. This liner, which acted as a precolum n, was partly filled with small glass beads. Injection was performed i n between the glass beads. More than 50 injections of the various biol ogical specimens could be done before the liner had to be replaced by a new one. This injection technique between glass beads allows direct injection of large sample volumes up to 10 mu L without disturbing the gas chromatographic separation. Injection of these large sample volum es made the method very sensitive. The detection limit for ethanol amo unted to 0.1 mg/L (2 mu mol/L) when using an injection volume of 5 mu L. Attention has also been paid to simultaneously monitoring ethanol, methanol, acetaldehyde, and acetone in blood and urine of control subj ects.