Use of in-tube sorptive extraction techniques for determination of benzene, toluene, ethylbenzene and xylenes in soft drinks.

A comparison is made between static headspace analysis and headspace solid-phase dynamic extraction (HS-SPDE) for the quantitative determination of trace level BTEX solvents (benzene, toluene, ethylbenzene and o-, m-, and p-xylene) in soft drinks. Two non-polar extraction phases were investigated for SPDE using an automated sampler with a gas-tight syringe equipped with a special needle coated on the inside with the extraction phase. Following adsorption onto the phase, the analytes were thermally desorbed directly into a GC-MS. The techniques were optimised and evaluated by analysis of spiked soft drink samples. The use of the SPDE device gave comparable results to the static headspace method, with lower detection limits for some compounds, and also offers advantages for applications where lower temperatures are preferred.