Aziza El-Beqqali

Microextraction in Packed Syringe/Liquid Chromatography/Electrospray Tandem Mass Spectrometry for Quantification of Acebutolol and Metoprolol in Human Plasma and Urine Samples

Abstract The aim of the present investigation was to develop a simple, fast, and sensitive method for the determination of acebutolol and metoprolol in human plasma and urine samples. The determination of acebutolol and metoprolol in plasma and urine was performed using micro extraction in packed syringe (MEPS) as a sample preparation method, online with high performance liquid chromatography and tandem mass spectrometry (LC‐MS/MS). In MEPS the sampling sorbent was 1 mg polystyrene polymer, which was inserted in a 250 µL syringe. The lower limits of quantification (LLOQ) for acebutolol and metoprolol were set to 1.0 ng/mL. The accuracy of quality control samples (QC) varied by ±10%, and precision (R.S.D.) had a deviation of 1.4–12% for plasma and urine samples. The calibration curve was obtained within the concentration range 1.0–100 ng/mL in both plasma and urine. The regression correlation coefficients (R2) for plasma and urine samples were ≥0.999 for all runs. The present method is miniaturized, fully automated, robust, and can be easily used for pharmacokinetic and pharmacodynamic studies of acebutolol and metoprolol.

Microextraction by packed sorbent for LC–MS/MS determination of drugs in whole blood samples

BACKGROUND Microextraction by packed sorbent (MEPS) is used as an online sample-preparation method. The determination of local anesthetics lidocaine, ropivacaine and bupivacaine directly in human blood was performed using MEPS online with LC-MS/MS. RESULTS The range of the calibration curves in whole blood was 10-10000 nmol/l. The lower limit of quantification was set to 10.0 nmol/l. The accuracy of the quality control samples ranged from 85 to 97%. The interday precision of the studied analytes was within the range 1-5%. The regression correlation coefficient (r(2)) was over 0.995 for all runs. The present method is rapid, reliable and robust and may be used for therapeutic drug monitoring of studied analytes in whole blood. CONCLUSION This assay allows the analysis of drugs in human blood directly. Sample preparation is simple and automated. The assay reduced the handling time and the cost, and could handle small volumes of whole blood samples (25 µl).

On-line detection of hippuric acid by microextraction with a molecularly-imprinted polysulfone membrane sorbent and liquid chromatography-tandem mass spectrometry

Destruction of sorbents during consecutive extractions using the micro-extraction by packed sorbent (MEPS) technique is a serious problem. In MEPS the complex matrix such as plasma and blood can affect the sorbent physical properties and the sorbent can be deteriorated after handling of few samples. To overcome this problem, the surface of a polysulfone membrane (PSM) was modified by a molecularly imprinted sol-gel and utilized for online extraction of a lung cancer biomarker, hippuric acid (HA), in biological matrices. The molecularly imprinted polymer membrane provided fast, sensitive, selective and robust sample preparation method for HA in biological fluids. In addition, MIP membrane could be used for up to 50 extractions without a significant change in extraction recovery. To achieve the best results, the parameters that influenced the extraction efficiency were thoroughly investigated. Moreover, for evaluating the performance of the molecularly imprinted sol-gel membrane (MISM), a non-molecularly imprinted sol-gel membrane (NISM) as a blank was prepared. The limits of detection (LOD) and quantification (LOQ) for HA in both plasma and urine samples were 0.30nmolL-1 and 1.0nmolL-1, respectively. Standard calibration curves were obtained over the range of 1-1000nmolL-1 for HA in plasma and urine samples. The coefficients of determination (R2) were ≥0.997. The extraction recoveries of HA from human plasma and urine samples were higher than 91%. The precision values for HA in plasma and urine samples were 2.2-4.8% and 1.1-6.7%, respectively.

On-Line Determination of Cyclophosphamide in Blood Samples Utilizing Microextraction by Packed Sorbent and Liquid Chromatography Tandem Mass Spectrometry (MEPS-LC-MS/MS)

Microextraction by packed sorbent (MEPS) was used to handle whole mice blood samples. MEPS was used as an online rapid sample-preparation method, followed by liquid chromatography with tandem mass spectrometry (LC- MS/MS). Cyclophosphamide in mice blood was used as a model compound. The new method reduced the handling time and the cost and could handle small volumes of whole blood samples (20 μL). The lower limit of quantification (LLOQ) was 0.1μg/mL. The accuracy of the quality-control (QC) samples ranged from 107 to 110 %. The within-day variation was within the range 2.0-7.0% (C.V.%) while the between-day variation was between 4.0 and 6.0% (C.V.%). The calibra- tion curve in whole blood was constructed within the concentration range 0.1-100 μg/mL. The coefficients of determina- tion (R 2 ) were > 0.99 (n = 3). The present method is rapid, reliable and accurate and may be used for therapeutic drug monitoring of cyclophosphamide in whole blood. The method was applied for preclinical study of cyclophosphamide in mice.

Preparation of monolithic molecularly imprinted polymer sol–gel packed tips for high-throughput bioanalysis: Extraction and quantification of l-tyrosine in human plasma and urine samples utilizing liquid chromatography and tandem mass spectrometry

In situ monolithic molecularly imprinted polymer sol-gel packed tips (MMSTs) were prepared and evaluated for the extraction of lung cancer biomarker L-tyrosine (Tyr) from human plasma and urine samples. Several extraction parameters such as the conditioning, washing and elution solutions, pH and time were investigated. The enrichment factor (EF) and extraction recovery (ER) were studied. MMST showed good selectivity and a high extraction recovery, and MMST as a sorbent showed good stability and repeatability. The method validation showed good regression correlation coefficients for plasma and urine samples (R(2)≥0.996) within the concentration range of 5-1000 and 1-1000 nmol L(-1) in plasma and urine samples, respectively. The lower limits of quantification (LLOQ) in the plasma and urine samples were 5 and 1 nmol L(-1), respectively. The between-batch precision for Tyr in plasma ranged from 1.0 to 6.0%, and in urine it was from 1.0 to 7.0%. The results show that the developed method has more facility, stability, durability and repeatability compared with previous similar methods. To the best of our knowledge, this is the first study aimed at the selective separation of Tyr as a lung cancer biomarker by MMSTs from biological matrixes and detection by LC/MS/MS.

Determination of amphetamine and methadone in human urine by microextraction by packed sorbent coupled directly to mass spectrometry: an alternative for rapid clinical and forensic analysis.

Speed and low cost, together with regulatory approval, are the most important requirements of clinical assays. Therefore, a fast and automated on-line sample preparation method is essential for the routine analysis of biological samples. Microextraction by packed sorbent is an option for optimal sample preparation due to its easy automation, minimal requirements for the sample and elution solvent volumes, elimination of evaporation and reconstitution steps, and ability to integrate sample preparation and injection into one step. The use of effective sample preparation steps circumvents the need for chromatographic separation and therefore allows more rapid and less expensive sample analysis in clinical and forensic practice. Two biologically active compounds, amphetamine and methadone, were chosen as representative drugs of abuse for the application of microextraction by packed sorbent coupled directly to mass spectrometry. The developed method was validated, with the results confirming the suitability of the combination of these techniques for the analysis of biological samples. The approach was confirmed to be appropriate for use in clinical and forensic practice with regard to cost and time requirements for analysis.

Molecularly imprinted polymer-sol-gel tablet toward micro-solid phase extraction: II. Determination of amphetamine in human urine samples by liquid chromatography–tandem mass spectrometry

Amphetamine selective molecularly imprinted sol-gel polymer tablets, MIP-tablets, for solid-phase microextraction of biofluid samples were prepared. An acetonitrile solution of deuterated amphetamine template and silane precursor, 3-(propylmethacrylate) trimethoxysilane, was soaked into the pores of polyethylene tablet substrates and polymerized by an acid-catalysed sol-gel process. Application of the resultant MIP-tablets to extract amphetamine from human urine samples followed by LC-MS/MS analysis was investigated. The extraction protocol was optimised with respect to pH of sample, addition of sodium chloride, extraction time, desorption solvent and desorption time. The final analysis method determined amphetamine in human urine with a limit of detection (LOD) of 1.0ng/mL and a lower limit of quantification (LLOQ) of 5ng/mL. Validation demonstrated accuracy of the method was 91.0-104.0% and inter-assay precision was 4.8-8.5% (RSD). Extraction recovery was 80%. The MIP-tablets could be re-used and the same tablet could be employed for more than twenty extractions.