			Home About us Contact

Extraction Recoveries (extraction + recovery)

Distribution by Scientific Domains

Chemistry	93%

Selected Abstracts

Multi-residue method for the analysis of pharmaceutical compounds in sewage sludge, compost and sediments by sonication-assisted extraction and LC determination

JOURNAL OF SEPARATION SCIENCE, JSS, Issue 12 2010
Julia Martín
Abstract A method for the simultaneous determination of 16 pharmaceutical compounds in three types of sewage sludge (primary, secondary and anaerobically digested dehydrated sludge), compost and sediment samples is described. Pharmaceutical compounds evaluated were nonsteroidal anti-inflammatory drugs (acetaminophen, diclofenac, ibuprofen, ketoprofen, naproxen and salicylic acid), antibiotics (sulfamethoxazole and trimethoprim), an anti-epileptic drug (carbamazepine), a ,-blocker (propranolol), a nervous stimulant (caffeine), estrogens (17,-ethinylestradiol, 17,-estradiol, estriol and estrone) and lipid regulators (clofibric acid, metabolite of clofibrate and gemfibrozil). The method is based on the ultrasonic-assisted extraction, clean-up by SPE and analytical determination by HPLC with diode array and fluorescence detectors. The best extraction recoveries were achieved in a three-step extraction procedure with methanol and acetone as extraction solvents. Extraction recoveries of several pharmaceutical compounds as caffeine were highly dependent on the type of sample evaluated. The applicability of the method was tested by analyzing primary, secondary and anaerobically digested dehydrated sludge, compost and sediment samples from Seville (Southern Spain). Ten of the sixteen pharmaceutical compounds were detected in sludge samples and five in compost and sediment samples. The highest concentration levels were recorded for ibuprofen in sewage samples, whereas salicylic acid and 17,-ethinylestradiol were detected in all of the samples analyzed. [source]

Rapid method for determination of chlormequat residues in tomato products by ion-exchange liquid chromatography/electrospray tandem mass spectrometry

RAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 19 2002
M. Careri
A rapid method has been devised for the direct determination of chlormequat in tomato samples. No clean-up is required, and analysis uses ion-exchange liquid chromatography/tandem mass spectrometry interfaced with electrospray ionization (LC/ESI-MS/MS). A cation-exchange column was used with an aqueous ammonium acetate/acetonitrile mixture as the mobile phase under isocratic conditions. The method was validated in terms of detection limits (LOD), quantitation limits (LOQ), linearity, recovery, precision and accuracy. Good results in the low,µg kg,1 level were obtained for the LOD and LOQ of chlormequat in tomato samples. Comparison of solvent and matrix-matched calibration curves demonstrated the absence of significant matrix effects and the feasibility of using external calibration. Linearity was established over two orders of magnitude by performing homoscedasticity and Mandel fitting statistical tests. The absence of both constant and proportional systematic errors was verified by evaluating the recovery function, demonstrating good method accuracy. Excellent precision in terms of intra-day repeatability was calculated (RSD% <3.4). Extraction recoveries from tomato products were calculated, by using a labelled internal standard (d4 -chlormequat), to be in the 93,±,5,99,±,7% range. The applicability of the method to the determination of chlormequat residues in tomato products was demonstrated. Copyright © 2002 John Wiley & Sons, Ltd. [source]

Rapid and sensitive determination of strychnine and brucine in human urine by capillary electrophoresis with field-amplified sample stacking

BIOMEDICAL CHROMATOGRAPHY, Issue 2 2010
Junmei Li
Abstract A simple, rapid, sensitive and low-cost method using capillary electrophoresis (CE) coupled with field-amplified sample stacking (FASS) has been developed and validated for the simultaneous determination of strychnine and brucine residues in human urine. Before sample loading, a water plug (3.5 kPa, 3,s) was injected to contain sample cations and to permit FASS. Electrokinetic injection at a voltage (20 kV, 25,s) was then used to introduce cations. Separation was performed using 20,mM acetate buffer (pH 3.8) with an applied voltage of 20 kV. The calibration curves were linear over a range of 8.00,2.56 , 102,ng/mL (r = 0.9995) for strychnine and 10.0,3.20 × 102,ng/mL (r = 0.9999) for brucine. Extraction recoveries in urine were greater than 79.6 and 82.8% for strychnine and brucine, respectively, with an RSD of less than 4.9%. The detection limits (signal-to-noise ratio 3) for strychnine and brucine were 2.00 and 2.50,ng/mL, respectively. A urine sample from one healthy female volunteer (26 years old, 50,kg) was pretreated and analyzed. Strychnine and brucine levels in urine could be detected 24,h after administration. On these grounds, this method was feasible for application to preliminary screening of trace levels of abused drugs for both doping control and forensic analysis. Copyright © 2009 John Wiley & Sons, Ltd. [source]

Liquid chromatography with electrospray ionization mass spectrometry method for the assay of glucosamine sulfate in human plasma: validation and application to a pharmacokinetic study

BIOMEDICAL CHROMATOGRAPHY, Issue 3 2006
Tao-Min Huang
Abstract A liquid chromatography,electrospray ionization mass spectrometry (LC,ESI,MS) method was developed and validated for the assay of glucosamine sulfate in human plasma. Plasma proteins were precipitated by acetonitrile, followed by vortex mixing and centrifugation. The supernatant was transferred and derivatized with phenyl iso-thiocyanate in acetonitrile at 60°C for 40 min. Chromatographic separation was performed on a C18 column (Inertsil ODS-3 150 × 2.1 mm i.d., 5 µm, JP) with a mobile phase gradient consisting of 0.2% acetic acid (aqueous) and methanol at a flow-rate of 0.3 mL/min. MS detection using electrospray ionization (ESI) as an interface was used in single ion monitoring mode to determine positive ions at m/z 297. This method was shown to be selective and sensitive for glucosamine sulfate. The limit of detection was 35 ng/mL for glucosamine sulfate in plasma and the linear range was 0.1,20 µg/mL in plasma with a correlation coefficient (r) of 0.9991. The relative standard deviations (RSDs) of intra-day and inter-day assays were 8.7,11.4 and 9.8,12.6%, respectively. Extraction recoveries of glucosamine sulfate in plasma were greater than 73%. This method proved to be simple, reproducible and feasible for pharmacokinetic studies of glucosamine sulfate in healthy volunteers after a single oral administration (1500 mg). The pharmacokinetic parameters and relative bioavailabilities were investigated for both domestic glucosamine sulfate tablet and capsule preparations compared with an imported capsule product. Copyright © 2005 John Wiley & Sons, Ltd. [source]

Ion-pair mediated transport of angiotensin, neurotensin, and their metabolites in liquid phase microextraction under acidic conditions

JOURNAL OF SEPARATION SCIENCE, JSS, Issue 11 2005
J. Léon E. Reubsaet
Abstract This paper discusses the behaviour of angiotensin 1 and neurotensin together with their metabolites in a three-phase liquid phase microextraction under acidic conditions. Variations in donor phase, organic phase, and acceptor phase are studied with extraction recovery as response variable. It is proved that for all peptides the transport across the organic phase is mediated by heptane-1-sulphonic acid. n -Octanol gave overall best results as organic phase. A donor phase volume of 1.0 mL was chosen as a compromise between optimal recovery and robustness of the LPME device. The optimal pH of the donor phase (using acceptor phase of pH 2) was found to be different for the peptides, which opens opportunities for selective sample preparation. Decreasing the acceptor phase pH to 1.0 resulted in increased extraction recoveries. On using 1.0 mL of donor phase containing 50 mM heptane-1-sulphonic acid pH 3, n -octanol as organic phase immobilized in the pores of the fibre, and 20 ,L of acceptor phase containing 0.1 mol/L HCl, extraction recoveries up to 82% (enrichment factor = 41) were achieved. To our knowledge this is the first report on liquid phase microextraction of angiotensins and neurotensins. [source]

Simultaneous determination of parabens, triclosan and triclocarban in water by liquid chromatography/electrospray ionisation tandem mass spectrometry

RAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 12 2009
Iria González-Mariño
A method for the determination of several household biocides in water by liquid chromatography/electrospray ionisation tandem mass spectrometry (LC/ESI-MS/MS) is presented. It permits the simultaneous determination of triclosan (TCS), triclocarban (TCC) and seven parabens, including the distinction between branched and linear isomers of propyl (i -PrP and n -PrP) and butyl parabens (i -BuP and n -BuP). Prior to LC/MS/MS, analytes are preconcentrated by solid-phase extraction (SPE) on Oasis HLB (60,mg) cartridges at natural sample pH and subsequently eluted with 4,mL of methanol. This simple SPE procedure provides extraction recoveries above 85% except for raw wastewater, where it falls to 65% for TCC. The performance of the method was tested with two triple-quadrupole LC/MS instruments from a low/mid and mid/high market range: a Varian 1200L and an API-4000. The latter system provided between 3 and 80 times lower limits of quantification (LOQs) than the first one, in the 0.08,0.44,ng/L range for surface water. Moreover, a comparison of matrix effects on both instruments showed a very different behaviour, particularly in the case of parabens. For these compounds signal suppression was observed in the 1200L instrument and signal enhancement with the 4000 instrument. As a result, different calibration approaches were chosen for them and this pointed to the need of matrix effect re-evaluation in method transfer between different LC/MS systems. The application of the method to real samples showed the ubiquity of methyl paraben (MeP) and n -PrP (at the 1,6,µg/L in raw wastewater) and the coexistence of i -BuP and n -BuP at similar levels (ca. 100,200,ng/L in raw wastewater). Copyright © 2009 John Wiley & Sons, Ltd. [source]

Determination of a novel paclitaxel derivative (NPD-103) in human plasma by ultra-performance liquid chromatography,tandem mass spectrometry

BIOMEDICAL CHROMATOGRAPHY, Issue 5 2009
Shuang-Qing Zhang
Abstract A sensitive and specific ultra-performance liquid chromatography,tandem mass spectrometry (UPLC-MS-MS) method for quantification of a newly developed anticancer agent NPD-103 has been established. An aliquot of human plasma sample (200 µL) was spiked with 13C-labeled paclitaxel (internal standard) and extracted with 1.3 mL of tert -butyl methyl ether. NPD-103 was quantitated on a C18 column with methanol,0.1% formic acid (75:25, v/v) as mobile phase using UPLC-MS-MS operating in positive electrospray ionization mode with a total run time of 3.0 min. For NPD-103 at the concentrations of 1.0, 5.0 and 10.0 µg/mL in human plasma, the absolute extraction recoveries were 95.58, 102.43 and 97.77%, respectively. The linear quantification range of the method was 0.1,20.0 µg/mL in human plasma with linear correlation coefficients greater than 0.999. The intra- and inter-day accuracy for NPD-103 at 1.0, 5.0 and 10.0 µg/mL levels in human plasma fell into the ranges of 95.29,100.00% and 91.04,94.21%, and the intra- and inter-day precisions were in the ranges of 8.96,11.79% and 7.25,10.63%, respectively. This assay is applied to determination of half-life of NPD-103 in human plasma. Copyright © 2008 John Wiley & Sons, Ltd. [source]

Determination of a novel epothilone D analog (AV-EPO-106) in human plasma using ultra-performance liquid chromatography,tandem mass spectrometry

BIOMEDICAL CHROMATOGRAPHY, Issue 3 2009
Shuang-Qing Zhang
Abstract A novel ultra-performance liquid chromatography,tandem mass spectrometry (UPLC-MS-MS) method has been established for the determination of a newly synthesized epothilone D analog (AV-EPO-106) in human plasma. The plasma samples were prepared by liquid,liquid extraction with cold tert -butyl methyl ether. The chromatographic separation was achieved within 5 min on a C18 column with water,methanol (10:90, v/v) as mobile phase at a flow-rate of 0.8 mL/min. Mass transition of m/z 568.2 to 386.1 was measured for AV-EPO-106 in positive atmospheric pressure chemical ionization mode. A detailed validation of the method was performed as per the USFDA guidelines. For AV-EPO-106 at the concentrations of 1.0, 5.0 and 10.0 µg/mL in human plasma, the absolute extraction recoveries were 86.17, 85.24 and 85.69%, respectively. The linear quantification range of the method was 0.10,20.0 µg/mL in human plasma with linear correlation coefficients greater than 0.999. The intra-day and inter-day accuracy for AV-EPO-106 at the levels of 1.0, 5.0 and 10.0 µg/mL in human plasma fell in the ranges of 98.25,100.47 and 94.19,97.25%, and the intra- and inter-day precision were in the ranges of 4.75,6.30% and 8.89,10.45%, respectively. The method was successfully applied to quantify AV-EPO-106 in human plasma to determine the half-life of this compound in human plasma. Copyright © 2008 John Wiley & Sons, Ltd. [source]

HPLC determination of safflor yellow A and three active isoflavones from TCM Naodesheng in rat plasma and tissues and its application to pharmacokinetic studies

BIOMEDICAL CHROMATOGRAPHY, Issue 6 2007
Zhiguo Yu
Abstract A high-performance liquid chromatographic method was developed for the simultaneous determination and pharmacokinetic studies of safflor yellow A, puerarin, 3,-methoxyl-puerarin, and puerarinapioside in the plasma and tissues of rats that had been administered with the traditional Chinese medicine (TCM) preparation Naodesheng via the caudal vein. Samples taken from rats were subjected to protein precipitation with acetone. Separation of these four compounds was accomplished on a Kromisil C18 stationary phase using a mobile phase of acetonitrile,0.1% phosphoric acid,tetrahydrofuran (8:92:2, v/v/v) at a flow-rate of 1.0 mL/min. The detection wavelength was set at 250 nm. The calibration curves of the four components were linear in the given concentration ranges. The intra- and inter-day precisions in plasma and tissues were less than 15% and the extraction recoveries were higher than 60%. The lower limits of quantitation of four components were low enough to determine the four components. These four components all exhibited kinetics that fitted a two-compartment model in rats. The elimination half-life was 1.19 h for safflor yellow A, 2.69 h for puerarin, 2.94 h for 3,-methoxyl-puerarin, and 0.87 h for puerarinapioside, respectively. Following administration of a single injection of Naodesheng, the concentration (C) of the four components in the tissues showed Ckidney > Clung, Cliver > Cspleen, Cstomach, Cheart, approximately. The method is a reliable tool for performing studies of safflor yellow A and three puerarin isoflavones in different biological material. Copyright © 2007 John Wiley & Sons, Ltd. [source]

Simultaneous determination of chlorpheniramine and pseudoephedrine in human plasma by liquid chromatography,tandem mass spectrometry

BIOMEDICAL CHROMATOGRAPHY, Issue 4 2004
Xiaoyan Chen
Abstract A sensitive and speci,c procedure for simultaneous quantitation of chlorpheniramine and pseudoephedrine in human plasma has been developed and validated. Analytes were extracted from plasma samples by liquid,liquid extraction, separated on a Diamonsil C18 column (250 × 4.6 mm i.d.) and detected by tandem mass spectrometry with an atmospheric pressure chemical ionization interface. Diphenhydramine was used as the internal standard. The method has a lower limit of quantitation of 0.2 and 2.0 ng/mL for chlorpheniramine and pseudoephedrine, respectively. The intra- and inter-day relative standard deviation, calculated from quality control (QC) samples were below 4.3% for chlorpheniramine and below 9.5% for pseudoephedrine. The inter-day relative error as determined from QC samples was within 4.7% for each analyte. The overall extraction recoveries of chlorpheniramine and pseudoephedrine were 77 and 61% on average, respectively. The method was successfully applied to pharmaockinetic study of chlorpheniramine and pseudoephedrine in volunteers receiving formulations containing 4 mg of chlorpheniramine maleate and 60 mg of pseudoephedrine hydrochloride. Copyright © 2004 John Wiley & Sons, Ltd. [source]

High-efficiency protein extraction from polyacrylamide gels for molecular mass measurement by matrix-assisted laser desorption/ionization-time of flight-mass spectrometry

ELECTROPHORESIS, Issue 6 2005
Ya Jin
Abstract A simple and fast method of protein extraction from Coomassie Brilliant Blue (CBB)-stained polyacrylamide gels suited for molecular mass measurement of proteins by matrix-assisted laser desorption/ionization-time of flight-mass spectrometry (MALDI-TOF-MS) is reported. Proteins in CBB-stained gel pieces were extracted by a 10-min soaking in 0.1,M NaOH at 25°C. The recovery of this one-step extraction method was 34,73% for proteins <67,kDa. CBB adduction to proteins during mass spectrometric analysis was avoided by a destaining step before the alkaline extraction. The molecular mass values of the extracted proteins coincided with those of purified proteins within ±0.01,0.10% deviation for all the proteins <36,kDa. Because of the high extraction recovery, mass measurement was possible for the proteins extracted from CBB-stained gels with loaded protein quantities as little as 34,ng for cytochrome,c, ,-lactalbumin, myoglobin, ,-lactoglobulin, trypsinogen, and carbonic anhydrase (12.4,29.0,kDa), 340,ng for glyceraldehyde-3-phosphate dehydrogenase (35.6,kDa) and albumin (66.3,kDa). This method provides a highly efficient approach to utilize CBB-stained one- or two-dimensional gels for whole protein analysis using MALDI-TOF-MS. [source]

Ion-pair mediated transport of angiotensin, neurotensin, and their metabolites in liquid phase microextraction under acidic conditions

Liquid chromatography/tandem triple-quadrupole mass spectrometry for determination of paclitaxel in rat tissues

RAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 12 2006
Xinyong Tong
A liquid chromatography/tandem triple-quadrupole mass spectrometry assay to quantify paclitaxel in rat tissue homogenates containing taxol or paclitaxel nanoliposome (PTX-NLP) was developed and validated. Liquid-liquid extraction with tert -butyl methyl ether was used for tissue sample preparation and docetaxel was used as the internal standard. Paclitaxel and docetaxel were separated on a 200,mm,×,4.6,mm,×,5,µm C18 column and quantified using a triple-quadrupole mass spectrometer operating in positive ion electrospray selective reaction monitoring mode (ESI+ -SRM) with a total run time of 6.0,min. The peak area of the m/z 876.3,,,307.9 transition of paclitaxel is measured versus that of the m/z 830.3,,,549.1 transition of docetaxel to generate the standard curves. The standard curves were linear over the concentration range of 0.2008,2008,ng/mL for different tissues. The method had high extraction recovery (>90%) and accuracy (>90%) with the intra-day and inter-day precision <15%. Frozen stability, freeze/thaw stability, extraction stability and solution stability at ambient temperature were examined, which indicated the tissue samples should be extracted within 5 days and avoid being frozen and thawed repeatedly over 5 times. Extracted samples after evaporation could be stored at ,20°C for 20 days without drug degradation and no degradation was also observed after solution samples were left to stand at ambient temperature for 24,h. This assay was used to support an in vivo biodistribution study of PTX-NLP in rats. Copyright © 2006 John Wiley & Sons, Ltd. [source]

Quantitative HPLC method and pharmacokinetic studies of ergosta-4,6,8(14),22-tetraen-3-one, a natural product with diuretic activity from Polyporus umbellatus

BIOMEDICAL CHROMATOGRAPHY, Issue 10 2010
Ying-Yong Zhao
Abstract A simple and specific HPLC method with dual wavelength UV detection for the determination of ergosta-4,6,8(14),22-tetraen-3-one (ergone) in rat plasma was developed and proved to be efficient. The method used ergosterol as internal standard (IS). Following a single-step protein precipitation, the analyte and IS were separated on an Inertsil ODS-3 column with a mobile phase containing methanol,water (99:1, v/v) at a flow rate of 1,mL/min. The analytes were detected by using UV detection at wavelength of 350 (ergone) and 283 (IS) nm, respectively. The calibration curve was linear over the range of 0.1,2.0,µg/mL and the lower limit of quantification was 0.1,µg/mL. The intra-day and inter-day precision studies showed good reproducibility with RSD less than 8.5%. The intra-day and inter-day accuracy ranged from 95.6 to 104%. Mean extraction recovery was above 95% at the low, medium and high concentrations. The present HPLC-UV method was simple and reliable. The method described herein had been successfully applied for the pharmacokinetic studies in male SD rats after administration of 20,mg/kg dose of solution of ergone. Copyright © 2010 John Wiley & Sons, Ltd. [source]