CAPILLARY GAS-CHROMATOGRAPHY WITH CRYOGENIC OVEN TEMPERATURE FOR HEADSPACE SAMPLES - ANALYSIS OF CHLOROFORM OR METHYLENE-CHLORIDE IN WHOLE-BLOOD

A new and sensitive gas chromatography (GC) method for measurement of chloroform or methylene chloride in whole blood is presented. Trace le vels of these analytes present in the headspace of samples were cryoge nically trapped prior to on-line GC analysis. After heating of a blood sample containing chloroform and methylene chloride (internal standar d, and vice versa) in a 7.0-mL vial at 55 degrees C for 20 min, 5 mL o f the headspace vapor was drawn into a glass syringe. All vapor was in troduced into an Rtx-Volatiles middle-bore capillary column in the spl itless mode at -30 degrees C oven temperature to trap the entire analy tes, and the oven temperature was programmed up to 280 degrees C for d etection of the compounds and for cleaning of the column. The present conditions gave sharp peaks for both chloroform and methylene chloride and very low background noises for whole blood samples. As much as 11 .5 and 20.0% of chloroform and methylene chloride, respectively, which had been added to whole blood in a vial, could be introduced into the GC column. The calibration curves showed linearity in the range of 0. 05-5.0 mu g/0.5 mL of whole blood. The detection limit was estimated t o be about 2 ng/0.5 mL. The coefficients of intraday and interday vari ations were 1.31 and 8.90% for chloroform and 1.37 and 9.03% for methy lene chloride, respectively. The data on chloroform or methylene chlor ide in rat blood after inhalation of each compound were also presented .