Extraction Method For Simultaneous Determination Research Articles

Preparation of magnetic metal organic framework and development of solid phase extraction method for simultaneous determination of fluconazole and voriconazole in rat plasma samples by HPLC

Fluconazole and voriconazole are the two broad-spectrum triazole antifungals. The present work described the fabrication method for the synthesis of the amino-modified magnetic metal–organic framework. This material was applied as a pre-sample treatment sorbent for the selective extraction of fluconazole and voriconazole in rat plasma samples. The material was fabricated by the chemical bonding approach method and was characterized by different parameters. The factors which affect the extraction efficiency of the sorbent material were also optimized in this study. Due to the optimization of solid-phase extraction conditions, the nonspecific interaction was reduced and the extraction recoveries of target drugs were increased in plasma samples. The extraction method was combined with the HPLC-UV method for the analysis. Excellent linearity (0.1–25 µg/mL), detections (0.02, 0.03 µg/mL) and quantification limits (0.04, 0.05 µg/mL) were resulted for fluconazole and voriconazole respectively. The maximum recoveries from spiked plasma samples of fluconazole and voriconazole were 86.8% and 78.6% and relative standard deviation were 0.9–2.8% and 2.2–3.6% respectively. Moreover, this sorbent material was used multiple times which was an improvement over single-use commercial sorbent materials. This validated method has practical potential for the simultaneous determination of these drugs in therapeutic drug monitoring studies as well as for routine pharmacokinetic evaluations.

A novel aptamer-based online magnetic solid phase extraction method for simultaneous determination of urinary 8-hydroxy-2′-deoxyguanosine and monohydroxylated polycyclic aromatic hydrocarbons

In this work, an innovative aptamer-based magnetic adsorbent (Fe3O4@PDA-aptamer MNPs) was prepared by hydrothermal synthesis method followed by the surface functionalization of nanoparticles. After fixing in a steel stainless tube as sorbent of magnetic solid phase extraction (MSPE), an online magnetic solid phase extraction-high performance liquid chromatography-mass spectrometry (online-MSPE-HPLC-MS) method was developed and applied for the determination of 8-hydroxy-2′-deoxyguanosine (8-OHdG) and monohydroxylated polycyclic aromatic hydrocarbons (OH-PAHs) simultaneously in urine. The synthesized sorbent presented outstanding features, including large specific surface area, high enrichment capacity and excellent stability. High throughput analysis can be achieved by affinity-specific adsorption of 8-OHdG and non-specific adsorption of OH-PAHs at the same time. In addition, online MSPE can greatly simplify the analysis process, reduce human errors and enhance the sensitivity. When compared with offline MSPE, a sensitivity enhancement of 30–400 times was obtained for the online method. Some experimental parameters such as the amount of the sorbent, sampling flow rate and sample volume, were optimized systematically. Under the optimal conditions, the limits of detection (LOD) were in the range of 0.028–0.114 ng mL−1, and the correlation coefficients (R2) were higher than 0.9962. The relative standard deviations (RSDs) were less than 16.1% (n = 5) and the recoveries ranged from 71% to 116%. The above results show that the rapid, sensitive and automated online-MSPE-HPLC-MS method has potential application in the simultaneous determination of 8-OHdG and PAHs in complex sample matrix to assess the environmental exposure level.

A novel extraction method for simultaneous determination of neonicotinoid insecticides and their metabolites in human urine

An LLME-LC-MS/MS method for the detection of trace levels of six neonicotinoid insecticides and their metabolites in human urine samples.

Optimization of Matrix Solid-Phase Dispersion Method for Extraction of Aflatoxins from Cornmeal

An extraction method for simultaneous determination of aflatoxins (AFLAs) G2, G1, B2, and B1 in cornmeal, based on vortex-assisted matrix solid-phase dispersion (MSPD) and high-performance liquid chromatography (HPLC) with fluorescence detection was optimized by a central composite design, validated and applied. Multivariate analysis was performed to evaluate the effect of cornmeal composition on AFLA extraction. The amount and proportion of solid support (celite and C18) and volume of elution solvent (methanol and acetonitrile) were the variables tested. The mobile phase of methanol/acetonitrile/water (24:14:62, v/v/v) in isocratic elution mode provided satisfactory AFLA separation. The best recoveries (85.7 to 114.8%) were obtained when the sample preparation contained 25 mg C18 as solid support and 10 mL of elution solvent. The limits of detection ranged from 0.01 to 0.04 ng g−1, and the limits of quantification varied from 0.02 to 0.1 ng g−1. The optimized method was suitable for coarse and medium grind cornmeal. Multivariate correlation analysis showed that the main interferers for AFLA recovery were proteins and sugars.

Molecularly imprinted solid phase extraction method for simultaneous determination of seven nitroimidazoles from honey by HPLC-MS/MS

In this work, a selective sample cleanup procedure that combined molecular imprinting technique with solid phase extraction was developed for the simultaneous extraction of the seven nitroimidazoles (NMZs) from honey samples. The molecular imprinting polymers for NMZs were prepared through bulk polymerization method using 2-methyl-5-nitroimidazole as template molecule, methacrylic acid as the functional monomer and ethylene glycol dimethacrylate as the cross linking agent. The obtained molecular imprinting polymers showed high affinity to template molecule and was used as selective sorbent for simultaneously selective extraction of the seven NMZs from honey matrix. An off-line molecularly imprinted solid phase extraction (MISPE) method followed by high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS-MS) for simultaneous determination of the seven NMZs from honey samples was also established. The proposed method was validated at 1.0, 2.0 and 10.0μg/kg, obtaining recoveries in the range of 79.7–110%, with repeatability and interday precision values (expressed as relative standard deviation) ≤11.4% and ≤15.2%, respectively. Limits of quantification for different NMZs were 1.0μg/kg, which were always below the minimum required performance limits established by the European Community Reference Laboratories (Commission Decision 2002/657/EC). It was demonstrated that this proposed MISPE-HPLC-MS-MS method could be applied to direct determination of NMZs from honey samples.

Simultaneous spectrophotometric determination of synthetic dyes in food samples after cloud point extraction using multiple response optimizations

A sensitive cloud point extraction method for simultaneous determination of trace amounts of sunset yellow (SY), allura red (AR) and brilliant blue (BB) by spectrophotometry was developed. Experimental parameters such as Triton X-100 concentration, KCl concentration and initial pH on extraction efficiency of dyes were optimized using response surface methodology (RSM) with a Doehlert design. Experimental data were evaluated by applying RSM integrating a desirability function approach. The optimum condition for extraction efficiency of SY, AR and BB simultaneously were: Triton X-100 concentration 0.0635 mol L(-1), KCl concentration 0.11 mol L(-1) and pH 4 with maximum overall desirability D of 0.95. Correspondingly, the maximum extraction efficiency of SY, AR and BB were 100%, 92.23% and 95.69%, respectively. At optimal conditions, extraction efficiencies were 99.8%, 92.48% and 95.96% for SY, AR and BB, respectively. These values were only 0.2%, 0.25% and 0.27% different from the predicted values, suggesting that the desirability function approach with RSM was a useful technique for simultaneously dye extraction. Linear calibration curves were obtained in the range of 0.02-4 for SY, 0.025-2.5 for AR and 0.02-4 μg mL(-1) for BB under optimum condition. Detection limit based on three times the standard deviation of the blank (3Sb) was 0.009, 0.01 and 0.007 μg mL(-1) (n=10) for SY, AR and BB, respectively. The method was successfully used for the simultaneous determination of the dyes in different food samples.

Response surface optimization of a rapid ultrasound-assisted extraction method for simultaneous determination of tetracycline antibiotics in manure.

A rapid and cleanup-free ultrasound-assisted extraction method is proposed for the simultaneous extraction of oxytetracycline, tetracycline, chlortetracycline, and doxycycline in manure. The analytes were determined using high-performance liquid chromatography with ultraviolet detector. The influence of several variables on the efficiency of the extraction procedure was investigated by single-factor experiments. The temperature, pH, and amount of extraction solution were selected for optimization experiment using response surface methodology. The calibration curves showed good linearity (R 2 > 0.99) for all analytes in the range of 0.1–20 μg/mL. The four antibiotics were successfully extracted from manure with recoveries ranging from 81.89 to 92.42% and good reproducibility (RSD, <4.06%) under optimal conditions, which include 50 mL of McIlvaine buffer extraction solution (pH 7.15) mixed with 1 g of manure sample, extraction temperature of 40°C, extraction time of 10 min, and three extraction cycles. Method quantification limits of 1.75–2.32 mg/kg were obtained for the studied compounds. The proposed procedure demonstrated clear reductions in extraction time and elimination of cleanup steps. Finally, the applicability to tetracyclines antibiotics determination in real samples was evaluated through the successful determination of four target analytes in swine, cow manure, and mixture of animal manure with inorganic fertilizer.

Development of a one-step microwave-assisted extraction method for simultaneous determination of organophosphorus pesticides and fungicides in soils by gas chromatography–mass spectrometry

A one-step microwave-assisted extraction (MAE) procedure was developed for the simultaneous extraction of organophosphorus pesticide and fungicide residues in soil which have been greatly used in agriculture. Parameters that could influence the MAE efficiency such as irradiation power, temperature, time and solvent were investigated, and extraction efficiencies in the range of 92.6−103.7% were obtained using 400W (100% output) at 160°C for 10min with only 12mL of acetone–hexane (2:1, v/v). The analytes in extracts were analyzed directly by gas chromatography–mass spectrometry (GC–MS) without any further cleanup. At 5 and 50ngg−1 fortification levels for each analyte, the average recoveries obtained were ranged from 70.0% to 120.0% with relative standard deviation (RSD) between 0.2% and 14%. The method was linear over 1–250ngg−1 with a correlation coefficient (r2) between 0.9916 and 0.9966. The detection limits (S/N=3) were between 0.10 and 0.12ngg−1. The applicability of the method was demonstrated by analyzing field soil samples collected from six intensive horticultural sites in Ethiopia.

Comparison of different extraction methods for simultaneous determination of B complex vitamins in nutritional yeast using LC/MS-TOF and stable isotope dilution assay

The application of LC/MS-TOF method combined with stable isotope dilution assay was studied for determination of thiamine, riboflavin, nicotinamide, nicotinic acid, pantothenic acid, pyridoxal, and pyridoxine in food. Nutritional yeast powder was used as a model food matrix. Acid extraction was compared with various enzymatic treatments in ammonium formate buffer to find a suitable method for the conversion of more complex vitamers into the same forms as the used isotope-labeled internal standards. The enzyme preparations α-amylase, takadiastase, β-glucosidase, and acid phosphatase were all able to liberate thiamine and riboflavin. The diastatic enzyme preparations α-amylase and takadiastase also expressed proteolytic side activities resulting in the formation of small peptides which interfered with the mass spectra of thiamine and riboflavin. Liberation of nicotinamide and pantothenic acid from NAD(+) and CoA, respectively, could not be achieved with any of the studied enzyme preparations. Hydrochloric acid extraction at 121 °C for 30 min was found to be destructive to pantothenic acid, but increased the liberation of pyridoxal.

Development of the extraction method for the simultaneous determination of butyl-, phenyl- and octyltin compounds in sewage sludge

The toxicity and bioaccumulation of organotin compounds (OTCs) led to the development of sensitive and selective analytical methods for their determination. In the past much attention was assigned to the study of OTCs in biological samples, water and sediments, coming mostly from marine environment. Little information about OTCs pollution of terrestrial ecosystems is available. In order to optimise the extraction method for simultaneous determination of butyl-, phenyl- and octyltin compounds in sewage sludge five different extractants (tetramethylammonium hydroxide, HCl in methanol, glacial acetic acid, mixture of acetic acid and methanol (3:1), and mixture of acetic acid, methanol and water (1:1:1)), the presence or not of a complexing agent (tropolone), and the use of different modes of extraction (mechanical stirring, microwave and ultrasonic assisted extraction) were tested. Extracted OTCs were derivatised with sodium tetraethylborate and determined by gas chromatography coupled with mass spectrometer. Quantitative extraction of butyl-, phenyl- and octyltin compounds was obtained by the use of glacial acetic acid as extractant and mechanical stirring for 16h or sonication for 30 min. The limits of detection and quantification for OTCs investigated in sewage sludge were in the ng S ng(-1) range.

Toward a Generic Extraction Method for Simultaneous Determination of Pesticides, Mycotoxins, Plant Toxins, and Veterinary Drugs in Feed and Food Matrixes

A fast and straightforward generic procedure for the simultaneous extraction of various classes of pesticides, mycotoxins, plant toxins, and veterinary drugs in various matrixes has been developed, for subsequent analysis by liquid chromatography with mass spectrometric detection. As a first step, four existing multianalyte procedures and three newly proposed methods were compared for a test set of 172 pesticides, mycotoxins, and plant toxins spiked to a feed matrix. The new procedures, which basically involved extraction/dilution of the sample with water and an acidified organic solvent (methanol, acetonitrile, or acetone), were most promising. The three new generic extraction methods were further tested for applicability to other matrixes (maize, honey, milk, egg, meat). Overall, the best recoveries were obtained for acetone, followed by acetonitrile. With respect to matrix effects, acetonitrile was the most favorable solvent and methanol was the worst. The occurrence of matrix effects decreased for the matrixes in the order of feed > maize > meat > milk > egg > honey. The extraction method selected as the default procedure (water/acetonitrile/1% formic acid) was also evaluated for applicability to multiple classes of veterinary drugs in all six matrixes, with satisfactory results. Finally, the generic extraction procedure was validated for 136 pesticides, 36 natural toxins, and 86 veterinary drugs in compound feed and honey at three levels (0.01, 0.02, and 0.05 mg/kg) using ultraperformance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) for analysis of the extracts. For over 80% of the analytes, recoveries were between 70 and 120% and precision (expressed as relative standard deviation) was mostly in the range of 5-10% (except for feed at 0.01 mg/kg; adequate recoveries for 62% of the analytes). The limits of detection were from <0.01 to 0.05 mg/kg for most analytes, which is usually sufficient to verify compliance of products with legal tolerances. The results clearly demonstrate the feasibility of the generic approach proposed. Application of the method in routine monitoring programs would imply a drastic reduction of both effort and time.

Development of a Supercritical Fluid Extraction method for simultaneous determination of organophosphorus, organohalogen, organonitrogen and pyretroids pesticides in fruit and vegetables and its comparison with a conventional method by GC-ECD and GC-MS

Departamento de Quimica Universidade Estadual Paulista, Av. Luiz Edmundo Carrijo Coube s/n, 17033-360 Bauru - SP

Solvent extraction method for simultaneous determination of norepinephrine, dopamine, serotonin, and 5-hydroxyindoleacetic acid in a single mouse brain

A method is described for simultaneously determining norepinephrine, dopamine, serotonin, and 5-hydroxyindoleacetic acid in a single small piece of brain tissue. Up to 40–60 pieces of tissue can be conveniently processed at the same time. As many as 120 pieces of brain tissue as small as the telencephalon of a single mouse can be analyzed within a normal work week for NE, DA, and 5-HT, or these three amines plus 5-HIAA can be determined in about 80 individual whole brains. Recovery of 5-HIAA was 83%, and recovery of the three amines was 72–88%. A high degree of reproducibility was obtained for all four compounds and the method could be used routinely for the quantitative determination of small differences in tissue levels. It was not necessary to deproteinize with ZnSO 4, as in other procedures for 5-HIAA, or to add a reducing agent to protect the compounds during homogenization and solvent extraction. Blanks for NE and DA were somewhat lower and more stable than those obtained by most other available methods, allowing increased sensitivity in their determination.

Daily fluctuation (circadian and ultradian) in biogenic amines of the rat brain.

Daily fluctuation (circadian and ultradian) in biogenic amines of the rat brain.