Determination of Bromide Ion Concentration in Urine Using a Head-space Gas Chromatography and an Ion Chromatography

―Biological Monitoring for Methyl Bromide Exposure―

Abstract

A head-space gas chromatography (GC) and an ion chromatography coupled with a conductive detector (IC) were used to evaluate levels of bromide ion in urine. The GC method followed by methylation with dimethyl sulfate, showed higher accuracy (27% of relative standard deviation) and lower minimum detection limit (0.4 mg/ℓ ) compared to the IC procedure of those values which were 8.7% and 1.0 mg/ℓ. The correlation coefficient between the analytical results of 15 urinary samples by the two methods was 0.793. The bromide ion concentrations detected in 36 urine samples of workers exposed to methyl bromide were averaged at 13.3±7.7mg/ℓ. The average bromide ion of the non-exposed group was 7.1 ± 2.1 mg/ℓ (n = 6). Exposed methyl bromide concentrations of workers were monitored with passive samplers during their work shifts (8 hr). No significant correlation between exposed methyl bromide and bromide ion concentrations in urine was observed.