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

Abstract

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 microL) 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 microL 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.

Improved hydrophilic interaction chromatography method for the identification and quantification of glucosinolates

“…The system is much more robust and flexible than previous methods, giving better separation of a greater range of glucosinolates, with much longer column life. With our oldest sulfoalkylbetaine zwitterionic column we have already made well over 500 injections with no loss in peak geometry, and others report successfully using them for as many as 3000 injections [25]. A.…”

Morphine Brain Pharmacokinetics at Very Low Concentrations Studied with Accelerator Mass Spectrometry and Liquid Chromatography-Tandem Mass Spectrometry

“…The morphine concentration in the samples was recalculated from the [ 14 C]morphine concentrations obtained from AMS as they were mixed in fixed proportions. Bengtsson et al (2005), with minor adjustments, was used for the analysis of medium-and high-concentration plasma and microdialysis samples of morphine using electrospray ionization. The method was linear between 0.5 and 200 ng/ml for microdialysis samples with a coefficient of variation Ͻ13.8% and an accuracy of 95 to 104%.…”

“…The method was linear between 0.5 and 200 ng/ml for microdialysis samples with a coefficient of variation Ͻ13.8% and an accuracy of 95 to 104%. For sheep plasma, the method was linear between 2 and 2000 ng/ml with a coefficient of variation Ͻ6.0% and accuracy of 98 to 106% (Bengtsson et al, 2005). For the microdialysis samples, 5 l of the microdialysate was injected directly into the system.…”

Mise au point et validation d’une méthode de dosage simultané de la morphine et de ses métabolites glucuronoconjugués totaux par chromatographie liquide d’interactions hydrophiles

“…Les méthodes de dosage spécifique de la M3G et de la M6G décrites dans la littérature mettent en oeuvre des phases stationnaires zwittérioniques (ZIC-HILIC : zwitterionic ion chromatography and hydrophilic interaction liquid chromatography) dont les groupements fonctionnels permettent des interactions électrostatiques faibles [17,18]. Les mécanismes d'échanges d'ions entre ces phases stationnaires et les groupements acide carboxylique des métabolites glucuronoconjugués de la morphine (figure 1), caractérisés par des constantes d'acidité différentes (tableau I), permettent alors de séparer spécifiquement les deux isomères [16].…”