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

Abstract

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 approximately 1 mg of the solid packing material is inserted into a syringe (100-250 microl) 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 nM. 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 nM.

Screening of cocaine and its metabolites in human urine samples by direct analysis in real-time source coupled to time-of-flight mass spectrometry after online preconcentration utilizing microextraction by packed sorbent

“…This approach to sample preparation is very promising for many reasons: (1) it is easy to use, (2) it can be fully automated as an online procedure, (3) it is rapid, and (4) the cost of analysis is minimal compared with conventional solid-phase extraction. Hence, several drugs such as local anesthetics and their metabolites [1][2][3], the anticancer drugs rosco- …”

“…Sample preparation takes place on the packed bed, which can be coated to provide selective and suitable sampling conditions. This approach to sample preparation is very promising for many reasons: (1) it is easy to use, (2) it can be fully automated as an online procedure, (3) it is rapid, and (4) the cost of analysis is minimal compared with conventional solid-phase extraction. Hence, several drugs such as local anesthetics and their metabolites [1][2][3], the anticancer drugs rosco-vitine, olomoucine, busulfan, and cyclophosphamide [4 -7], the ␤-blockers acebutolol and metoprolol ␤ [8], the neurotransmitters dopamine and serotonin [9], and methadone [10] have been extracted from biological samples such as blood, plasma, or urine samples using MEPS.…”

Determination of Three Organochlorine Pesticides in Aqueous Samples by Solid-Phase Extraction Based on Natural Nano Diatomite in Packed Syringe Coupled to Gas Chromatography-Mass Spectrometry

“…Microextraction in a packed syringe (MEPS) is a rather new technique used for the extraction and preconcentration of trace amounts of analytes into a solid support sorbent packed inside two frits in a syringe or microsyringe. [12][13][14] In this technique, sample preparation takes place on a packed bed of the sorbent. The sorbent is inserted in the barrel of a 1-mL insulin syringe as a plug with two polyethylene filters on both sides.…”

“…Many materials, such as silica-based (C2, C8, C18) sorbents, [13][14][15] strong cation exchanger, 14 carboxyl purified multi-walled carbon nanotubes, 17 and polystyrene, 18,19 are used as the sorbent in MEPS. Begheri et al have applied a polyaniline nanowire network, 20 and a polydiphenylamine nanocomposite, 21 as the sorbent in a packed syringe for the preconcentration and extraction of OPPs.…”

Polymerization Inhibitors and Promoters for Unsaturated Polyester Resins; Use of Solid Phase MicroExtraction and Gas Chromatography Coupled to Mass Spectrometry for the Determination of 4-tert-Butyl Catechol and Acetylacetone

“…Sample preparation remains one of the more time-consuming and error-prone aspects of analytical chemistry. To overcome drawbacks of conventional extraction techniques, alternative miniaturized methods have been proposed both as solid phase microextraction, as Solid Phase MicroExtraction (SPME) [7][8][9], MicroExctraction by Packed Sorbent (MEPS) [10], Stir Bar Sorptive Extraction (Twister, SBSE) [11], Solid Phase Dynamic Extraction (Magic Needle, SPDE) [12], In-Tube Extraction (ITEX) [13] and liquid phase microextraction like Single-Drop MicroExtraction (SDME) [14], Hollow Fiber LiquidPhase Microextraction (HF-LPME) [15,16], Dispersive Liquid-Liquid Microextraction (DLLME) [17], Solvent Bar MicroExtraction (SBME) [18]. On-sample derivatizations applied in miniaturized extraction systems and their simultaneous GC and liquid chromatography analysis has been described for the determination of analytes in aqueous matrices [19,20].…”