1. Matrix effect in the analysis of drugs of abuse from urine with desorption atmospheric pressure photoionization-mass spectrometry (DAPPI-MS) and desorption electrospray ionization-mass spectrometry (DESI-MS)
- Author
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Olli Laine, Tiina J. Kauppila, Pekka Östman, Niina Suni, Risto Kostiainen, Pia Lindfors, Tapio Kotiaho, and Ilkka Ojanperä
- Subjects
Electrospray ,Spectrometry, Mass, Electrospray Ionization ,Ion suppression in liquid chromatography–mass spectrometry ,010402 general chemistry ,Mass spectrometry ,01 natural sciences ,Biochemistry ,Gas Chromatography-Mass Spectrometry ,Analytical Chemistry ,Matrix (chemical analysis) ,Benzodiazepines ,Environmental Chemistry ,Humans ,Sample preparation ,Desorption atmospheric pressure photoionization ,Spectroscopy ,Desorption electrospray ionization ,Chemical ionization ,Chromatography ,Chemistry ,010401 analytical chemistry ,Forensic Medicine ,0104 chemical sciences ,Analgesics, Opioid ,Substance Abuse Detection ,Atmospheric Pressure ,Solvents - Abstract
We have studied the matrix effect within direct analysis of benzodiazepines and opioids from urine with desorption electrospray ionization-mass spectrometry (DESI-MS) and desorption atmospheric pressure photoionization-mass spectrometry (DAPPI-MS). The urine matrix was found to affect the ionization mechanism of the opioids in DAPPI-MS favoring proton transfer over charge exchange reaction. The sensitivity for the drugs in solvent matrix was at the same level with DESI-MS and DAPPI-MS (LODs 0.05–6 μg mL−1) but the decrease in sensitivity due to the urine matrix was higher with DESI (typically 20–160-fold) than with DAPPI (typically 2–15-fold) indicating better matrix tolerance of DAPPI over DESI. Also in MS/MS mode, DAPPI provided better sensitivity than DESI for the drugs in urine. The feasibility of DAPPI-MS/MS was then studied in screening the same drugs from five authentic, forensic post mortem urine samples. A reference measurement with gas chromatography-mass spectrometry (GC–MS) (including pretreatment) revealed 16 findings from the samples, whereas with DAPPI-MS/MS after sample pretreatment, 15 findings were made. Sample pretreatment was found necessary, since only eight findings were made from the same samples untreated.
- Published
- 2011