Utility of disk solid-phase extraction for whole blood samples: analysis of some tetracyclic antidepressants by gas chromatography with nitrogen-phosphorus detection

Abstract

Four tetracyclic antidepressants, maprotiline, mianserin, mirtazapine, and setiptiline, were extracted from human whole blood and plasma samples by disk solid-phase extraction with Empore C18 cartridges. They were determined by gas chromatography (GC) with nitrogen-phosphorus detection. Recoveries of maprotiline, mianserin, mirtazapine, and setiptiline spiked into whole blood or plasma were more than 83%. Regression equations for the four drugs showed excellent linearity in the range of 25–1000 ng in 0.2 ml whole blood and in 0.5 ml plasma. The limits of detection for the drugs were 4.1–18.2 ng per 0.2 ml for whole blood and 3.4–13.5 ng per 0.5 ml for plasma. The limits of quantification for the four drugs were 25 ng in 0.2 ml whole blood and in 0.5 ml plasma. Intraday and interday coefficients of variation for the antidepressants in both human specimens were below 15%. The above data show that relatively hydrophobic and basic drugs in crude biological samples such as whole blood can be extracted by disk solid-phase extraction very efficiently and with good reproducibility, and suggest that the extraction method is also useful as pretreatments before more sophisticated detection methods such as GC-mass spectrometry (MS) and liquid chromatography-MS(-MS).