Solid-phase micro-extraction in bioanalysis, exemplified by lidocaine determination

Solid-phase micro-extraction (SPME) is a never sample preparation technique that can be used for gaseous, liquid or solid samples in conjunction with GC, HPLC or CE (e.g. [1]). The use of SPME for the analysis of drugs in biofluids is also becoming popular (e.g. [2]). The principle is that a fused silica fibre coated with a polymer such as polydimethylsiloxane (PDMS) is put directly into the sample or placed in the headspace above it (e.g. [3]), analyte desorption is done thermally (for GC) or with liquid. As a model compound to study conditions we have investigated lidocaine in human urine using GC or LC [4] and, with attention to protein binding, in plasma mainly using GC [5].