Chemometric assisted solid-phase microextraction for the determination of anti-inflammatory and antiepileptic drugs in river water by liquid chromatography diode array detection

VERA CANDIOTI, LUCIANA; GIL GARCÍA, MARIA DOLORES; MARTINEZ GALERA, MARIA; GOICOECHEA, HÉCTOR C

JOURNAL OF CHROMATOGRAPHY - A

Elsevier

Año: 2008 vol. 1211 p. 22 - 32

0021-9673

In the present work, an analytical method for the simultaneous determination of seven non steroidalanti-inflammatory drugs (naproxen, ketoprofen, diclofenac, piroxicam, indomethacin, sulindac and diflunisal)and the anticonvulsant carbamazepine is reported. The method involves preconcentration andclean-up by solid-phase microextraction using polydimethylsiloxane/divinylbenzene fibers, followed byliquid chromatography with diode array detection analysis. Parameters that affect the efficiency of thesolid-phase microextraction step such as soaking solvent, soaking period, desorption period, stirring rate,extraction time, sample pH, ionic strength, organic solvent and temperature were investigated using aPlackett–Burman screening design. Then, the factors presenting significant positive effects on the analyticalresponse (soaking period, stirring rate, stirring time) were considered in a further central compositedesign to optimize the operational conditions for the SPME procedure. Additionally, multiple responsesimultaneous optimization by using the desirability function was used to find the optimum experimentalconditions for the on-line solid-phase microextraction of analytes in river water samples coupled toliquid chromatography and diode array detection. The best results were obtained using a soaking periodof 5 min, stirring rate of 1400rpm and stirring time of 44 min. The use of solid-phase microextractiontechnique avoided matrix effect and allowed to quantify the analytes in river water samples by usingMilli-Q based calibration graphs. Recoveries ranging from 71.6% to 122.8% for all pharmaceuticals provedthe accuracy of the proposedmethod in river water samples. Method detection limits (MDLs) were in therange of 0.5–3.0gL−1 and limits of quantitation (LOQs)were between 1.0 and 4.0gL−1 for pharmaceuticalcompounds in river water samples. The expanded uncertainty associated to the measurement of theconcentration ranged between 8.5% and 29.0% for 20gL−1 of each analyte and between 9.0% and 29.5%for the average of different concentration levels. The main source of uncertainty was the calibration stepin both cases