Determination of chloroform levels in blood using a headspace capillary gas chromatographic method

Headspace (HS) capillary gas chromatography with flame-ionization detection was developed for the determination of chloroform levels in blood. Separation of chloroform was improved significantly using a DB-WAX capillary column, without interference by other volatile substances. Sensitivity was increased by adjusting the splitter ratio to 20, without any decline in peak resolution. The HS conditions, a 50 degrees C incubation for 30 min, gave reproducible and sensitive determinations. The distribution coefficient (k) was calculated to be 8.24. The CV was 1.8% for 27.7 micrograms/mL chloroform, and the detection limit was 0.02 microgram/mL (S/N = 4) when the splitter ratio was 10. Raising HS temperature resulted in a significant decrease in k for chloroform in the absence of blood, in contrast to the relatively small effect seen in the presence of blood. Although inorganic salts showed a salting-out effect, erythrocytes and hydrophobic compounds, such as detergent and lipid, significantly suppressed the vaporization of chloroform. Chloroform was found to be distributed mainly in erythrocytes when incubated with blood overnight at 2 degrees C.