Combination of aqueous and non-aqueous capillary electrophoresis with electrospray mass spectrometry for the determination of drug residues in water

The work presented in this paper deals with the combination of capillary el ectrophoresis (CE) with electrospray mass spectrometry (MS) for the determi nation of drug residues in water. CE/MS methods have been developed based o n either aqueous or non-aqueous ammonium acetate solutions as the carrier e lectrolyte for the separation of selected drugs. The different separation c onditions were compared in terms of selectivity and detection limits; both aqueous and non-aqueous CE proved to be suitable for the present analytical task, exhibiting detection limits between 3 and 93 mug/dm(3) (injected sta ndard concentration) corresponding to concentrations between 5 and 19 ng/dm (3) in the sample. A combination of liquid-liquid extraction and solid-phase extraction was in vestigated for sample pretreatment, yielding enrichment factors of 10000. T he applicability of CE/MS was demonstrated for the analysis of several rive r water samples.