Determination of phenothiazine derivatives in human urine by using ionic liquid-based dynamic liquid-phase microextraction coupled with liquid chromatography.

A simple and rapid method for the determination of seven phenothiazines derivatives (chlorpromazine, promethazine, levomepromazine, prochlorperazine, trifluoperazine, fluphenazine and thioridazine) in human urine samples is presented. The analytes are extracted from the sample in 50 microL of the ionic liquid 1-butyl-3-methyl-imidazolium hexafluorophosphate working in an automatic flow system under dynamic conditions. The chemical affinity between the extractant and the analytes allows a good isolation of the drugs from the sample matrix achieving at the same time their preconcentration. The separation and detection of the extracted compounds is accomplished by liquid chromatography and UV detection. The proposed method is a valuable alternative for the analysis of these drugs in urine within the concentration range 0.07-10 microg mL(-1). Limits of detection were in the range from 21 ng mL(-1) (thioridazine) to 60 ng mL(-1) (levomepromazine). The repeatability of the proposed method expressed as RSD (n=5) varied between 2.2% (levomepromazine) and 3.9% (chlorpromazine).