A combination of micro-porous membrane liquid-gas extraction and solid-phase trapping for ultra trace determination of XXXX in urine.

@entity7935 @entity1568 @entity3928
A method was developed for the determination of @entity7935 in urine. The sample was pumped through the donor channel of a membrane extraction unit with a micro-porous membrane, separating the donor channel from an identical acceptor channel purged with @entity1568 . The analyte reached the acceptor channel by diffusion through the membrane and was then swept by the carrier to a solid sorbent tube, where it was trapped. The analyte was subsequently thermally desorbed and analyzed by gas chromatography (GC) with @entity3928 ( @entity3928 ). After optimization, the recovery was close to quantitative, or 95%. Purging the membrane unit with pure water in between the samples eliminated any memory effects. The linearity was good in the concentration range examined (20-4000 ng l(-1)), with a correlation coefficient of 0.9996. The repeatability at 50 ng l(-1) and 400 ng l(-1) was 1.4% and 1.2%, respectively. The limit of detection was 12 ng l(-1) and the limit of quantification 35 ng l(-1). This enables assessment of @entity7935 exposures of occupationally exposed subjects, of smokers and the majority of the general population. The developed method can be easily automated.
