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Microextraction in packed syringe (MEPS) for liquid and gas chromatographic applications. Part II—Determination of ropivacaine and its metabolites in human plasma samples using MEPS with liquid chromatography/tandem mass spectrometry
Author(s) -
AbdelRehim Mohamed,
Altun Zeki,
Blomberg Lars
Publication year - 2004
Publication title -
journal of mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.475
H-Index - 121
eISSN - 1096-9888
pISSN - 1076-5174
DOI - 10.1002/jms.731
Subject(s) - chromatography , chemistry , sample preparation , analyte , calibration curve , mass spectrometry , solid phase extraction , extraction (chemistry) , ion suppression in liquid chromatography–mass spectrometry , gas chromatography , liquid chromatography–mass spectrometry , tandem mass spectrometry , analytical chemistry (journal) , calibration , detection limit , statistics , mathematics
A new technique for sample preparation on‐line with liquid chromatographic/tandem mass spectrometric (LC/MS/MS) assay was developed. Microextraction in a packed syringe (MEPS) is a new miniaturized, solid‐phase extraction technique that can be connected on‐line to gas or liquid chromatography without any modifications. In MEPS ∼1 mg of the solid packing material is inserted into a syringe (100–250 µl) as a plug. Sample preparation takes place on the packed bed. The bed can be coated to provide selective and suitable sampling conditions. The new method is very promising, very easy to use, fully automated, of low cost and rapid in comparison with previously used methods. This paper presents the development and validation of a method for MEPS on‐line with LC/MS/MS. Ropivacaine and its metabolites (PPX and 3‐OH‐ropivacaine) in human plasma samples were used as model substances. The method was validated and the calibration curves were evaluated by means of quadratic regression and weighted by the inverse of the concentration, 1/ x , for the calibration range 2–2000 n M . The applied polymer could be used more than 100 times before the syringe was discarded. The extraction recovery was between 40 and 60%. The results showed high correlation coefficients ( R 2 > 0.999) for all analytes in the calibration range studied. The accuracy, expressed as a percentage variation from the nominal concentration values, ranged from 0 to 6%. The precision, expressed as the relative standard deviation, at three different concentrations (quality control samples) was consistently about 2–10%. The limit of quantification was 2 n M . Copyright © 2004 John Wiley & Sons, Ltd.