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On‐line desalting and determination of morphine, morphine‐3‐glucuronide and morphine‐6‐glucuronide in microdialysis and plasma samples using column switching and liquid chromatography/tandem mass spectrometry
Author(s) -
Bengtsson Jörgen,
Jansson Britt,
HammarlundUdenaes Margareta
Publication year - 2005
Publication title -
rapid communications in mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.528
H-Index - 136
eISSN - 1097-0231
pISSN - 0951-4198
DOI - 10.1002/rcm.2035
Subject(s) - chemistry , microdialysis , chromatography , morphine , glucuronide , liquid chromatography–mass spectrometry , tandem mass spectrometry , mass spectrometry , pharmacology , metabolite , biochemistry , extracellular , medicine
A sensitive and reproducible method for the determination of morphine and the metabolites morphine‐3‐glucuronide (M3G) and morphine‐6‐glucuronide (M6G) was developed. The method was validated for perfusion fluid used in microdialysis as well as for sheep and human plasma. A C18 guard column was used to desalt the samples before analytical separation on a ZIC HILIC (hydrophilic interaction chromatography) column and detection with tandem mass spectrometry (MS/MS). The mobile phases were 0.05% trifluoroacetic acid (TFA) for desalting and acetonitrile/5 mM ammonium acetate (70:30) for separation. Microdialysis samples (5 µL) were directly injected onto the system. The lower limits of quantification (LLOQ) for morphine, M3G and M6G were 0.50, 0.22 and 0.55 ng/mL, respectively, and the method was linear from LLOQ to 200 ng/mL. For plasma, a volume of 100 µL was precipitated with acetonitrile containing internal standards (deuterated morphine and metabolites). The supernatant was evaporated and reconstituted in 0.05% TFA before the desalting process. The LLOQs for sheep plasma were 2.0 and 3.1 ng/mL and the ranges were 2.0–2000 and 3.1–3100 ng/mL for morphine and M3G, respectively. For human plasma, the LLOQs were 0.78, 1.49 and 0.53 ng/mL and the ranges were 0.78–500, 1.49–1000 and 0.53–500 ng/mL for morphine, M3G and M6G, respectively. Copyright © 2005 John Wiley & Sons, Ltd.