title: Reusable solid-phase microextraction coating for direct immersion whole-blood analysis and extracted blood spot sampling coupled with liquid chromatography-tandem mass spectrometry and direct analysis in real time-tandem mass spectrometry.
abstract: Three different biocompatible polymers were tested and evaluated in order to improve the whole-blood biocompatibility of previously developed C18-polyacrylonitrile (C18-PAN) thin-film solid-phase microextraction (SPME) coating. Among all methods of modification, UV-dried thin PAN-over C18-PAN provided the best results. This coating presented reusable properties and reproducible extraction efficiency for at least 30 direct extractions of diazepam from whole blood [relative standard deviation (RSD) = 12% using external calibration and 4% using isotope dilution calibration]. The amount of absolute recovery for direct immersion analysis and based on the free concentration of diazepam in blood matrix was about 4.8% (desorption efficiency = 98%). The limit of quantitation (LOQ) for the developed solid-phase microextraction liquid chromatography-tandem mass spectrometry (SPME-LC-MS/MS) method for direct whole-blood analysis was 0.5 ng/mL. The optimized modification of the coating was then used for an extracted blood spot (EBS) sampling approach, a new sampling method which is introduced to address the limitations of dried blood spot sampling. EBS was evaluated using LC-MS/MS and direct analysis in real time (DART)-MS/MS, where, for a 5 μL blood spot, LOQs of 0.2 and 1 μg/mL, respectively, were achieved for extraction of diazepam.
authors.affiliation: Department of Chemistry, University of Waterloo, 200 University Avenue West, Waterloo, Ontario, N2L 3G1, Canada.
authors.forename: Fatemeh S
authors.initials: FS
authors.lastname: Mirnaghi
authors.forename: Janusz
authors.initials: J
authors.lastname: Pawliszyn
mesh_terms: D001672:Biocompatible Materials / Q000737:chemistry; D001774:Blood Chemical Analysis / Q000295:instrumentation; D002853:Chromatography, Liquid / Q000295:instrumentation; D003975:Diazepam / Q000031:analogs & derivatives / Q000097:blood*; D006801:Humans; D012680:Sensitivity and Specificity; D052617:Solid Phase Microextraction / Q000295:instrumentation; D053719:Tandem Mass Spectrometry / Q000295:instrumentation; D013997:Time Factors
chemical_list: D001672:Biocompatible Materials; D003975:Diazepam