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- El Beqqali, Aziza, et al.
(författare)
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Determination of AZD6118 in dog plasma samples utilizing microextraction by packed sorbent and liquid chromatography-electrospray ionization tandem mass spectrometry
- 2017
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Ingår i: Journal of chromatography. B. - : Elsevier BV. - 1570-0232 .- 1873-376X. ; 1043, s. 20-24
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Tidskriftsartikel (refereegranskat)abstract
- In this work, for the first time, a method has been developed for the determination of AZD6118, a candidate drug, in dog plasma samples. The method is based on microextraction by packed sorbent (MEPS) of the drug prior to liquid chromatography-electrospray ionization tandem mass spectrometry assay. Various important factors affecting MEPS performance were optimized, and under the optimized condition, a linear calibration curve in the concentration range of 20-25,000 nmol L-1 with a coefficient of determination over 0.99 was obtained. The back-calculated values of the calibration points showed good agreement with the theoretical concentrations (coefficients of variation percent between 0.3-3.8). The lower limit of quantification and limit of detection were 20.0 and 2.9 nmol L-1, respectively. The repeatability and accuracy of the method was evaluated by determination of quality control samples at three concentration levels (low, medium and high) using the developed method, and the results (coefficients of variation values were between 1.9% and 3.2%, relative recoveries ranged between 93.5-102.1%) confirm that a powerful method has been developed for the extraction and determination of the investigated drug in dog plasma.
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- El-Beqqali, Aziza, 1966-, et al.
(författare)
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Determination of dopamine and serotonin in human urine samples utilizing microextraction online with liquid chromatography/electrospray tandem mas spectrometry
- 2007
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Ingår i: Journal of Separation Science. - : Wiley. - 1615-9306 .- 1615-9314. ; 30:3, s. 421-424
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Tidskriftsartikel (refereegranskat)abstract
- A specific LC-MS-MS method for the determination of dopamine and serotonin (5-hydroxytryptamine; 5HT) in human urine is described. The analytes were extracted from urine and preconcentrated by microextraction in a packed syringe (MEPS). The new method is very promising, very easy to use, fully automated, of low cost, and rapid in comparison to previously used methods. The method was validated and the standard curves were evaluated by means of quadratic regression and weighted by the inverse of the concentration: 1/x for the calibration range 50–4000 μg/L. The MEPS applied polymer (silica-C8) could be used more than 300 times. The extraction recovery was about 50%. The results showed close correlation coefficients (r2 A0.999) for all analytes in the calibration range studied. The accuracy of MEPS-LC-MS-MS was 100–101% for dopamine and 99–100% for 5HT. The interday precision (n = 3 days), expressed as the RSD%, was 6.0–7.7% for dopamine and 6.1–11% for 5HT. MEPS reduced the handling time by 12 times compared to a published method.
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- El-Beqqali, Aziza, et al.
(författare)
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Fast and sensitive environmental analysis utilizing microextraction in packed syringe online with gas chromatography-mass spectrometry - Determination of polycyclic aromatic hydrocarbons in water
- 2006
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Ingår i: Journal of Chromatography A. - : Elsevier BV. - 0021-9673 .- 1873-3778. ; 1114:2, s. 234-238
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Tidskriftsartikel (refereegranskat)abstract
- A new sensitive, selective, fast and accurate technique for online sample preparation was developed. Microextraction in a packed syringe (MEPS) is a new miniaturised, solid-phase extraction (SPE) technique that can be connected online to GC or LC without any modifications. In MEPS approximately 1 mg of the solid packing material is inserted into a syringe (100-250 ml) 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. It is very easy to use, fully automated, of low cost and rapid in comparison with previously used methods. The determination of polycyclic hydrocarbons (PAHs) in water was performed using MEPS as sample preparation method online with gas chromatography and mass spectrometry (MEPS-GC-MS). The results from MEPS as sample preparation were compared with other techniques such as stir bar sorptive extraction (SBSE) and solid-phase microextraction (SPME). The method was validated and the standard curves were evaluated by the means of quadratic regression and weighted by inverse of the concentration: 1/x for the calibration range 5-1000 ng/L. The MEPS applied polymer (silica-C8) could be used more than 400 times before the syringe was discarded. The extraction recovery was about 70%. The results showed close correlation coefficients (R > 0.998) for all analytes in the calibration range studied. The accuracy of MEPS-GC-MS was between 90 and 113% and the inter-day precision (n = 3 days), expressed as the relative standard deviation (RSD%), was 8-16%. MEPS reduced the handling time by 30 and 100 times compared to SPME and SBSE, respectively.
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- El-Beqqali, Aziza, et al.
(författare)
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Microextraction in packed syringe/liquid chromatography/electrospray tandem mass spectrometry for quantification of acebutolol and metoprolol in human plasma and urine samples
- 2007
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Ingår i: Journal of Liquid Chromatography & Related Technologies. - : Informa UK Limited. - 1082-6076 .- 1520-572X. ; 30:4, s. 575-586
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Tidskriftsartikel (refereegranskat)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 mu L 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 (R-2) 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.
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- El-Beqqali, Aziza, 1966-, et al.
(författare)
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Molecularly imprinted polymer-sol-gel tablet toward micro-solid phase extraction : I. Determination of methadone in human plasma utilizing liquid chromatography-tandem mass spectrometry
- 2016
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Ingår i: Analytica Chimica Acta. - : Elsevier BV. - 0003-2670 .- 1873-4324. ; 936, s. 116-122
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Tidskriftsartikel (refereegranskat)abstract
- In the present work molecularly imprinted sol-gel tablet (MIP-Tablet) was prepared. The MIP-sol-gel was prepared as a thin layer on polyethylene material in a tablet form. Methadone-d9 was selected as the template and 3-(propylmethacrylate)-trimethoxysilane was used as precursor. MIP-Tablet was applied for micro-solid phase extraction (μ-SPE). The MIP-Tablet was used for the determination of methadone in human plasma samples utilizing liquid chromatography-tandem mass spectrometry; and each tablet could be used twenty times. The extraction time was 10 min while desorption time was 6 min. Factors affecting the extraction efficiency such as desorption solvents, sample pH, salt addition, extraction time, desorption time and adsorption capacity were investigated. The calibration curves were obtained within the range of 5-5000 ng/mL using methadone in human plasma samples. The coefficients of determination (r(2)) values were >= 0.999 for all runs and the extraction recovery was >80%. The accuracy values for quality control samples varied from +3.6 to +9.7% and the inter-day precision (RSD %) values were ranged from 5.0 to 8.0%. The limit of detection was 1.0 ng/mL and the lower limit of quantification was 5 ng/mL utilizing methadone in human plasma samples.
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- El-Beqqali, Aziza, et al.
(författare)
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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
- 2017
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Ingår i: Journal of chromatography. B. - : Elsevier BV. - 1570-0232 .- 1873-376X. ; 1063, s. 130-135
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Tidskriftsartikel (refereegranskat)abstract
- Amphetamine selective molecularly imprinted sol-gel polymer tablets, MIP-tablets, for solid-phase micro extraction 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 1.0 ng/mL and a lower limit of quantification (LLOQ) of 5 ng/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.
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