Related Experiment Video
Updated: Aug 13, 2026
Determination of 45 Pesticides in Avocado Varieties by the QuEChERS Method and Gas Chromatography-Tandem Mass Spectrometry
Published on: December 8, 2023
Determination of quinalphos in blood and urine by direct solid-phase microextraction combined with gas
E Gallardo1, M Barroso, C Margalho
1Instituto de Medicina Legal, Servicio de Toxicología Forense, Universidad de Santiago de Compostela, San Francisco s/n, 15782 Santiago de Compostela, Spain.
Abstract:
A new method based on direct solid-phase microextraction (DI-SPME) followed by gas chromatography-mass spectrometry was developed for the purpose of determining quinalphos in blood and urine. Two types of coated fibre have been assayed and compared: carbowax/divinylbenzene (CW/DVB 65 microm) and polydimethylsiloxane (PDMS 100 microm). The main parameters affecting the SPME process such as temperature, salt addition, pH, stirring and adsorption/desorption time profiles were optimized to enhance the sensitivity of the procedure. The method was developed using only 100 microL of blood and urine. Limits of detection of the method for blood and urine matrices were, respectively, 10 and 2 ng/mL. Linearity was established over concentration ranges from 0.05 to 50 microg/mL for blood, and 0.01 to 50 microg/mL for urine, with regression coefficients ranging between 0.9991 and 0.9999. Intra- and interday precision values were less than 13%, and accuracy was within +/-15% of the nominal concentration for all studied levels in both matrices. Absolute recoveries were 14 and 26% for blood and urine, respectively.
