Determination of carphedon in human urine by solid-phase microextraction using capillary gas chromatography with nitrogen–phosphorus detection
Carphedon is a phenyl derivative of nootropil and is effective in increasing physical endurance and cold resistance, and is used for amnesia treatment. Carphedon was extracted from human urine samples by solid-phase microextraction with a 65 µm carbowax–divinylbenzene-coated fiber. This analysis was performed by using capillary gas chromatography with nitrogen–phosphorus detection and optimized at pH 9.6, 30% NaCl, immersion time 10 min and desorption in the GC injector at 250 °C for 3 min. The regression equation for carphedon showed good linearity in the range from 0.1 to 10 µg ml–1 for human urine samples. The limit of detection was 0.01 µg ml–1. The developed method is more sensitive and simpler in sample preparation than liquid–liquid extraction and can be applied to doping analysis for stimulants.