An automated head space analysis method for xylenes and ethylbenzene in blood and water.

A sensitive, reliable method of analysis was established for water and blood samples containing xylene isomers (m-,o- & p-) and ethylbenzene by means of an automated head space sampler connected to a GC equipped with a flame ionization detector. Minimum detection limits (MDLs) were ca. 1 and 6 ng/mL, respectively, for each of the four target compounds in water and blood samples. Practical quantitation limits (PQLs) with precision values better than +/- 4% for duplicate samples were 40 and 240 ng/mL, respectively, for the individual organic compounds in water and blood. The analytical precision was < +/- 4% for concentrations above the PQL and up to 50 micrograms/mL. Calibration curves for the C2-benzene isomers in water and blood samples were linear (r2 > 0.9999) for individual analyte concentration up to ca. 50 micrograms/mL. Blank values were below the MDLs. The effect of cocontaminants on head space analyte concentration was insignificant for the anticipated range of sample composition.