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SPE Cartridges (spe + cartridge)
Selected AbstractsDetermination of acephate, methamidophos and monocrotophos in crude palm oilEUROPEAN JOURNAL OF LIPID SCIENCE AND TECHNOLOGY, Issue 11 2006Chee Beng Yeoh Abstract A method for the determination of acephate, methamidophos and monocrotophos in oil matrices is described. Pesticide residues in crude palm oil were extracted with acetonitrile, and a clean-up process was performed by cooling the entire extract below 10,°C, followed by a discolouring process using a Carbograph SPE cartridge. The extract was analysed using gas chromatography coupled with a pulsed flame photometry detector. The limit of detection for the method was calculated from regression data, and the recovery test results were in the range of 85,109%. [source] Evaluation of sulfobetaine-type polymer resin as an SPE adsorbent in the analysis of trace tetracycline antibiotics in honeyJOURNAL OF SEPARATION SCIENCE, JSS, Issue 21 2009Tomoyasu Tsukamoto Abstract A new sulfobetaine polymer resin SPE method combined with HPLC-MS/MS for the determination of tetracycline (TC) antibiotics residues from honey samples is presented. The sulfobetaine resin was synthesized and was packed into a syringe-type tube, which served as the SPE cartridge for selective adsorption of TCs. TCs were quantitatively adsorbed on the sulfobetaine cartridge, when the loading solvent was 95%,v/v acetonitrile solution, and TCs adsorbed were not eluted by aqueous acetonitrile washing solution. TFA aqueous solution was used for eluting the adsorbed TCs. The proposed SPE method has been applied to the determination of TCs in honey samples. The recoveries of TCs spiked in honey samples ranged from 70 to 80%. Reduction of the recoveries might be derived from low solubility of TCs in acetonitrile. Compared with other SPE resins, this resin was superior in terms of selectivity with simple pretreatment. [source] Determination of cholesterol oxides content in milk products by solid phase extraction and gas chromatography-mass spectrometryJOURNAL OF SEPARATION SCIENCE, JSS, Issue 9-10 2003María V. Calvo Abstract A method for quick and reliable analysis of cholesterol oxidation products (COPs) in dairy products has been developed. After lipid extraction, fat was transesterified under mild conditions to avoid degradation of the target compounds. Isolation of the COPs studied from other components in the lipid fraction was carried out on an aminopropyl SPE cartridge. Finally, analytes were analysed by GC-MS without derivatisation. The method developed provides high specificity and good sensitivity, allowing the direct and unambiguous determination of the underivatized COPs investigated. Application of the method to dairy food analysis revealed the presence of COPs in powder milks and milk-based infant formulas commercially available in Spain, showing that attention should be focused on reduction of cholesterol oxidation levels during both the processing and the storage of these types of foodstuffs. [source] An original approach to determining traces of tetracycline antibiotics in milk and eggs by solid-phase extraction and liquid chromatography/mass spectrometryRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 14 2002Federica Bruno An original and highly specific method able to identify and quantify traces of five tetracycline antibiotics (TCAs) in milk and eggs is presented. This method uses a single solid-phase extraction (SPE) cartridge for simultaneous extraction and purification of TCAs in the above matrices. After diluting 5,mL of intact whole milk or 2,g egg samples with Na2EDTA-containing water, samples are passed through a 0.5-g Carbograph 4 extraction cartridge. After analyte elution from the SPE cartridge, an aliquot of the final extract is injected into a liquid chromatography/mass spectrometry (LC/MS) instrument equipped with an electrospray ion source and a single quadrupole. MS data acquisition is performed in the positive-ion mode and by a time-scheduled multiple-ion selected ion-monitoring program. With methanol as organic modifier, the in-source collision-induced dissociation (CID) process generated fragment ions able to pick up one methanol molecule. In several cases, these methanol-adduct fragment ions have m/z values higher than those of the protonated molecules. This event is rarely encountered in MS, thus making the analysis of TCAs by this method extremely specific. Compared with a conventional published method, the present protocol extracted larger amounts of TCAs from both milk and egg and decreased the analysis time by a factor of 3. Recovery of TCAs in milk at the 25-ppb level ranged between 81 and 96% with relative standard deviation (RSD) no larger than 9%. Recovery of TCAs in egg at the 50-ppb level ranged between 72 and 92% with RSD no larger than 7%. Estimated limits of quantification(S/N,=,10) of the method were 2,9 ppb TCAs in whole milk and 2,19 ppb TCAs in eggs. Copyright© 2002 John Wiley & Sons, Ltd. [source] SPE and large-volume sample stacking in MEKC for determination of doxycycline in biological fluids: Comparison of direct injection to SPE-MEKCELECTROPHORESIS, Issue 21 2008Rade Injac Abstract A novel and simple method has been developed for the determination of doxycycline (DOX) in biological fluids. The method is based on SPE, large-volume sample stacking (LVSS) and MEKC with UV-DAD detection. Six SPE cartridges have been used in investigation for sample clean up and pre-concentration (Supelco® LC-8, LC-18, LC-SCX, and LC-WCX, as well as StrataÔ-X and X-C). DOX was determined on a 56,cm (effective length 50,cm)×50,,m id fused-silica capillary. The BGE was 20,mM borate buffer, pH 9.3, containing 80,mM SDS and 7.5%,v/v of methanol (30,s×50,mbar), and the temperature and voltage were 25°C and 30,kV, respectively. The analytical wavelength was set at 210,nm. Under optimized conditions it is possible to determine DOX in human serum, urine, semen, tears and saliva with recovery of 97.5% (RSD 2.5%). The method was shown to be sensitive (LOD is 1,,g/L) and precise (intra-day RSD 0.2 and 2.4%; inter-days 0.4 and 3.5% for migration time and peak area, respectively). Results for developed SPE-LVSS-MEKC were compared with LVSS-MEKC method with direct sample injection. The new LVSS-MEKC method is presented as a useful technique for rapid determination without extraction procedure of DOX in human urine and serum, using 80,mM of SDS, 10%,v/v of methanol and 40,mM borate buffer (pH 9.3; 30,s×50,mbar; 25°C; 30,kV; 350,nm), but not for the other biological fluids, according to lower sensitivity of the method and because of the sample composition. [source] Selective preconcentration of volatile mercaptans in small SPE cartridges: Quantitative determination of trace odor-active polyfunctional mercaptans in wineJOURNAL OF SEPARATION SCIENCE, JSS, Issue 21 2009Laura Mateo-Vivaracho Abstract A general procedure for the selective preconcentration and purification of mercaptans has been developed. Mercaptans are strongly retained in a small (20,mg) SPE cartridge containing p- hydroxymercurybenzoate. The cartridge can then be rinsed with relatively high volumes of polar (water/methanol mixtures) and non-polar (pentane or pentane/ether mixtures) rinsing solutions to remove nearly all volatile compounds lacking a thiol functionality. Retained analytes are further eluted with a small volume of an organic solvent containing 1,4-dithioerythritol. Some basic aspects of the strategy, such as the retention of p -hydroxymercurybenzoate in the sorbent and its stability versus different rinsing and eluting systems, have been studied in depth. Light sulfur compounds contained in water or wine, including mercaptans such as methanethiol or thioethers, such as diethyl sulfide, can be quantitatively extracted, although only mercaptans can be quantitatively recovered if a polar rinsing is applied. The strategy has been applied to the GC-MS quantitative determination of some trace polyfunctional mercaptans that are key aromas in wine, such as 2-methyl-3-furanthiol, 2-furfurylthiol, 4-mercapto-4-methyl-2-pentanone, 3-mercaptohexyl acetate or 3-mercaptohexanol. The developed method reaches detection limits in the ng/L range and has a satisfactory analytical behavior, being quite simple and fast. [source] Simultaneous determination of 103 pesticide residues in tea samples by LC-MS/MSJOURNAL OF SEPARATION SCIENCE, JSS, Issue 9 2009Zhiqiang Huang Abstract A simple and sensitive method was developed and validated for the simultaneous determination of 103 pesticide residues in tea by LC-MS/MS. For the analysis of the pesticide with polarity, thermal lability or low volatility, this LC-MS/MS method has an advantage over GC. In this work, residual pesticides were extracted from the tea sample with ACN and then purified using Carb-NH2 SPE cartridges. Using the multiple reaction monitoring mode, the pesticides were quantified and identified by the most abundant and characteristic fragment ions. The recoveries obtained for each pesticide ranged between 65 and 114% at three spiked concentration levels. The intra-day precisions were lower than 19.6%. Good linear relationships were observed with the correlation coefficients r2 >0.996 for all analytes. The established method was successfully applied to the determination of pesticide residues in real tea samples. [source] Automated determination of venlafaxine in human plasma by on-line SPE-LC-MS/MS.JOURNAL OF SEPARATION SCIENCE, JSS, Issue 4 2009Application to a bioequivalence study Abstract A new automated SPE-LC-ESI-MS/MS method was developed and validated to quantify venlafaxine in human plasma using fluoxetine as an internal standard. The analytes were automatically extracted from plasma by C18 SPE cartridges, separated on a C8 RP column and analyzed by MS in the multiple reaction-monitoring (MRM) mode. The method has a chromatographic run time of 4.0 min and a linear calibration curve over the range of 0.25,200 ng/mL (r >0.997). The between-run precisions, based on the percent RSD for replicate quality controls (0.75; 80, and 200 ng/mL), were < 8.5% for all concentrations. The between-run accuracies, based on the percent relative error, were < 4.0%. This method was successfully employed in a bioequivalence study of two venlafaxine capsule formulations (test formulation from Eurofarma (Brazil) and Efexor XR, reference formulation, from Wyeth-Whitehall, Brazil) in 48 healthy volunteers of both sexes who received a single 150 mg dose of each formulation. More than 3000 samples were analyzed eliminating the analyst's exposure to hazardous organic solvents normally employed in off-line liquid,liquid extractions. The 90% confidence interval (CI) of the individual ratio geometric mean for Test/Reference was 91.6,103.4% for AUC0,48 h and 102.2,112.6% for Cmax. Since both 90% CI for AUC0,48 h and Cmax were included in the 80,125% interval proposed by the US Food and Drug Administration (FDA) and the Brazilian National Health Surveillance Agency (ANVISA), the test formulation was considered bioequivalent to Efexor XR according to both the rate and extent of absorption. [source] Analysis of phenolic acids in honeys of different floral origin by solid-pase extraction and high-performance liquid chromatographyPHYTOCHEMICAL ANALYSIS, Issue 1 2007Burya Dimitrova Abstract The determination of 18 aromatic and arylaliphatic carboxylic acids in honey from different floral origin using solid-phase extraction (SPE) and reversed-phase high performance liquid chromatography (RP-HPLC) is reported. The behaviour of the solutes on SPE cartridges was predicted from preliminary calculations involving the pKa constants of the carboxylic groups, the n -octanol:water partition coefficients and the distribution coefficients at different pH values of the conditioning and washing solvents. The proposed SPE isolation and pre-concentration of the acids was achieved on reversed-phase Bond Elut C18 cartridges using an acetonitrile:tetrahydrofuran (1:1, v/v) elution system. RP-HPLC separations were performed on a Spherisorb ODS-2 column using linear gradient elution with a mobile phase composed of 20 mm phosphate buffer (pH 2.92) and methanol, and with UV detection. The reported SPE and RP-HPLC methods were applied to the analysis of 49 authentic honey samples from various floral sources and the results indicate that they may serve with respect to the quantitative control of a number of phenolic acids in plant-derived foods and medicinal plants. Copyright © 2006 John Wiley & Sons, Ltd. 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