Coupling sweeping-micellar electrokinetic chromatography with tandem mass spectrometry for the therapeutic monitoring of benzimidazoles in animal urine by dilute and shoot.

Posted on 2 August, 2017 by fqm302

A new method based on micellar electrokinetic chromatography-tandem mass spectrometry (MEKC-MS/MS) has been developed for the identification and simultaneous quantification of thirteen benzimidazoles in animal urine. In order to obtain an appropriate separation with the highest sensitivity, different electrophoretic parameters were evaluated. Under optimum conditions, the separation was performed using ammonium perfluorooctanoate as volatile surfactant and electrophoretic buffer (50 mM, pH 9). To increase the sensitivity, a stacking mode named sweeping was applied, using water as injection solvent at 50 mbar for 75 s, obtaining sensitivity enhancement factors from 50 to 181. The method was applied to different animal urine samples, including sheep, cow and goat. The sample treatment consisted of a 1:10 (v/v) dilution with water. Calibration using sheep urine samples can be used for both goat and cow urine samples with a relative bias below 25% and relative standard deviations lower than 8%. The limits of detection were below 70 µg L−1. As a result, the applicability of this rapid, simple, sensitive, and environmentally friendly method for therapeutic drug monitoring of benzimidazoles based on the analysis of animal urine has been demonstrated.

Posted in Anthelmintic, Benzimidazoles, Biological fluids, Dilute and shoot, Electrophoresis, MEKC, Mass spectrometry, P12-AGR-1647, Sweeping, Urine | Tagged , , | Comments Off on Coupling sweeping-micellar electrokinetic chromatography with tandem mass spectrometry for the therapeutic monitoring of benzimidazoles in animal urine by dilute and shoot.

Characterization of carbamate pesticides in natural water from Cameroon.

Posted on 19 July, 2017 by fqm302

With the increased use of chemicals in agriculture for crop protection and improvement of yield, the contamination of water is currently a serious health concern. This study used solid-phase extraction with ultra-high-performance liquid chromatography–tandem mass spectrometry to evaluate the presence of 23 carbamate pesticides in waters from Cameroon. The separation was achieved in 5.5 min using a C18 column (50 × 2.1 mm, 1.8 µm) with a mobile phase composed of water and methanol each containing 0.01% formic acid. The analytes were determined in positive multiple reaction monitoring mode. The recoveries for fortified water were from 75 to 99%, with relative standard deviations below 13%. The limits of detection ranged from 0.003 to 0.397 µg L−1. The reported method is simple, sensitive, and accurate, and is a suitable alternative for routine monitoring of pesticide residues at ultra-trace levels. The analysis revealed the presence of propoxur at a concentration of 0.072 µg L−1 in stream water.

Posted in Carbamates, Mass spectrometry, P12-AGR-1647, Pesticides, SPE, UHPLC, Water | Tagged , , | Comments Off on Characterization of carbamate pesticides in natural water from Cameroon.

Evaluation of hydrophilic interaction liquid chromatography–tandem mass spectrometry and extraction with molecularly imprinted polymers for determination of aminoglycosides in milk and milk-based functional foods.

Posted on 10 July, 2017 by fqm302

An analytical method for the determination of eleven aminoglycosides in different types of milk and milk-based functional products has been optimized and validated. A hydrophilic interaction chromatography (HILIC) column was proposed for the separation of analytes by ultra-high performance liquid chromatography–tandem mass spectrometry (UHPLC–MS/MS). A commercially molecularly imprinted polymer has been used for the solid phase extraction of the analytes, in order to achieve high selectivity in the sample treatment. The proposed method was characterized for different types of milk (whole cow milk, skimmed cow milk, whole goat milk) and functional dairy products, such as follow-on milk, Omega 3-enriched milk and isoflavones-enriched milk. Matrix effect was studied in the different matrices, being lower than │15│% in all cases, showing that the proposed procedure provided very clean extracts. Limits of quantification in the range 4.2–49 µg kg−1 were estimated, well below the maximum residue limits established by the European Union. Recoveries ranged from 70% to 106% with RSD lower than 13%, in compliance with the current legislation. The combination of HILIC to solve the difficulties of the separation of these very polar compounds in reverse phase with the use of MISPE for sample treatment and MS/MS detection provided a very sensitive, highly selective, robust and useful method for identification and quantification of aminoglycoside residues in different types of milk and milk-based products.

Posted in AGL2015-70708-R, Aminoglycosides, HILIC, MIPs, Mass spectrometry, Milk, P12-AGR-1647 | Tagged , , | Comments Off on Evaluation of hydrophilic interaction liquid chromatography–tandem mass spectrometry and extraction with molecularly imprinted polymers for determination of aminoglycosides in milk and milk-based functional foods.

Evaluation of a multiresidue capillary electrophoresis-quadrupole-time-of-flight mass spectrometry method for the determination of antibiotics in milk samples.

Posted on 7 July, 2017 by fqm302

A selective and rapid method has been developed to determine 15 antibiotic residues (eight tetracyclines and seven quinolones) in milk samples by capillary zone electrophoresis coupled with quadrupole time-of-flight mass spectrometry (CZE-Q-TOF-MS). The use of this hybrid mass spectrometer allowed obtaining full scan and full MS/MS spectra for quantification/confirmation purposes in a single run. In addition, solid phase extraction (SPE) using the new Oasis PRiME HLB cartridge was proposed for the extraction, achieving excellent results in terms of sample throughput. The proposed method was validated using whole cow milk as representative matrix. Good linearity was obtained (R2 > 0.99) for all the studied compounds. The precision, expressed as relative standard deviation (%, RSD), at two concentration levels (50 and 100 μg kg−1) was below 13%. Recoveries obtained from goat milk, whole cow milk and semi-skimmed cow milk, at two concentration levels, ranged from 76 to 106%, while limits of quantification ranged from 1.5 to 9.6 μg kg−1, being lower than the established maximum residue limits in the European legislation. Matrix effect was negligible in all cases, showing that with this new SPE sorbent cleanest extracts were obtained with a minimum number of steps in the sample treatment. Thus, the proposed SPE-CZE-Q-TOF-MS method is suitable for multiclass multiresidue monitoring in different types of milk samples.

Posted in Antibiotics, CZE, Food, Mass spectrometry, Milk, P12-AGR-1647, Quinolones, SPE, Tetracyclines | Tagged , , | Comments Off on Evaluation of a multiresidue capillary electrophoresis-quadrupole-time-of-flight mass spectrometry method for the determination of antibiotics in milk samples.

Evaluation of a multiresidue capillary electrophoresis-quadrupole-time-of-flight mass spectrometry method for the determination of antibiotics in milk samples.

Posted on 19 June, 2017 by fqm302

A selective and rapid method has been developed to determine 15 antibiotic residues (eight tetracyclines and seven quinolones) in milk samples by capillary zone electrophoresis coupled with quadrupole time-of-flight mass spectrometry (CZE-Q-TOF-MS). The use of this hybrid mass spectrometer allowed obtaining full scan and full MS/MS spectra for quantification/confirmation purposes in a single run. In addition, solid phase extraction (SPE) using the new Oasis PRiME HLB cartridge was proposed for the extraction, achieving excellent results in terms of sample throughput. The proposed method was validated using whole cow milk as representative matrix. Good linearity was obtained (R2 > 0.99) for all the studied compounds. The precision, expressed as relative standard deviation (%, RSD), at two concentration levels (50 and 100 μg kg−1) was below 13%. Recoveries obtained from goat milk, whole cow milk and semi-skimmed cow milk, at two concentration levels, ranged from 76 to 106%, while limits of quantification ranged from 1.5 to 9.6 μg kg−1, being lower than the established maximum residue limits in the European legislation. Matrix effect was negligible in all cases, showing that with this new SPE sorbent cleanest extracts were obtained with a minimum number of steps in the sample treatment. Thus, the proposed SPE-CZE-Q-TOF-MS method is suitable for multiclass multiresidue monitoring in different types of milk samples.

Posted in Antibiotics, CZE, Mass spectrometry, Milk, P12-AGR-1647, Quinolones, SPE, Tetracyclines | Tagged , , | Comments Off on Evaluation of a multiresidue capillary electrophoresis-quadrupole-time-of-flight mass spectrometry method for the determination of antibiotics in milk samples.

Solid phase extraction as sample treatment for the determination of Ochratoxin A in foods: A review.

Posted on 30 May, 2017 by fqm302

Ochratoxin A (OTA) is a mycotoxin produced by two main types of fungi, Aspergillus and Penicillium species. OTA is a natural contaminant found in a large number of different matrices and is considered as a possible carcinogen for humans. Hence, low maximum permitted levels in foods have been established by competent authorities around the world, making essential the use of very sensitive analytical methods for OTA detection. Sample treatment is a crucial step of analytical methodology to get clean and concentrated extracts, and therefore low limits of quantification. Solid phase extraction (SPE) is a useful technique for rapid and selective sample preparation. This sample treatment enables the concentration and purification of analytes from the sample solution or extract by sorption on a solid sorbent. This review is focused on sample treatment procedures based on SPE prior to the determination of OTA in food matrices, published from 2010.

Posted in Food, Mycotoxins, Review, SPE | Tagged | Comments Off on Solid phase extraction as sample treatment for the determination of Ochratoxin A in foods: A review.

Evaluation of direct analysis in real time for the determination of highly polar pesticides in lettuce and celery using modified Quick Polar Pesticides Extraction method

Posted on 5 April, 2017 by fqm302

Direct analysis in real time (DART) was evaluated for the determination of a number of highly polar pesticides using the Quick Polar Pesticides Extraction (QuPPe) method. DART was hyphenated to high resolution mass spectrometry (HRMS) in order to get the required selectivity that allows the determination of these compounds in complex samples such as lettuce and celery. Experimental parameters such as desorption temperature, scanning speed, and distances between the DART ion source and MS inlet were optimized. Two different mass analyzers (Orbitrap and QTOF) and two accessories for sample introduction (Dip-it® tips and QuickStrip™ sample cards) were evaluated. An extra clean-up step using primary-secondary amine (PSA) was included in the QuPPe method to improve sensitivity. The main limitation found was in-source fragmentation, nevertheless QuPPe-DART-HRMS proved to be a fast and reliable tool with quantitative capabilities for at least seven compounds: amitrole, cyromazine, propamocarb, melamine, diethanolamine, triethanolamine and 1,2,4-triazole. The limits of detection ranged from 20 to 60 μg/kg. Recoveries for fortified samples ranged from 71 to 115%, with relative standard deviations <18%.

Posted in AGL2015-70708-R, Celery, DART, Lettuce, Polar, QuPPe | Tagged , | Comments Off on Evaluation of direct analysis in real time for the determination of highly polar pesticides in lettuce and celery using modified Quick Polar Pesticides Extraction method

Validation of a new method based on salting-out assisted liquid-liquid extraction and UHPLC-MS/MS for the determination of betalactam antibiotics in infant dairy products

Posted on 7 March, 2017 by fqm302

In this work a new multiresidue method has been developed for the determination of 15 betalactam antibiotics in infant milk and yogurt based on follow-on milk by ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). The separation was achieved in 6 min, using a Kinetex Biphenyl Core-Shell column (50 mmx2.1 mm, 1.7 µm), with a mobile phase of water with 0.05% acetic acid and methanol. The analytes were detected in ESI+ with multiple reaction monitoring mode and fragmentation conditions were optimized to obtain the highest sensitivity. The use of a biphenyl bonded column allowed to obtain a satisfactory selectivity for all the studied analytes. Moreover, ion-pair salting-out assisted liquid-liquid extraction (IP-SALLE) has been proposed as sample treatment and optimized by means of experimental design. Under optimum conditions, the recoveries for fortified samples ranged from 79% to 93%, (RSD <7.5%). The limits of quantification were lower than 9.0 µg kg−1, showing the high sensitivity and applicability of this fast and simple method. The results in terms of analysis time, sensitivity and accuracy showed the suitability of this procedure for the monitoring of betalactam residues in different infant foods.

Posted in Mass spectrometry, Milk, P12-AGR-1647, SALLE, UHPLC, Yogurt, β-lactams | Tagged , , | Comments Off on Validation of a new method based on salting-out assisted liquid-liquid extraction and UHPLC-MS/MS for the determination of betalactam antibiotics in infant dairy products

Determination of benzimidazoles in meat samples by capillary zone electrophoresis tandem mass spectrometry following dispersive liquid–liquid microextraction.

Posted on 1 March, 2017 by fqm302

A novel method based on capillary zone electrophoresis-tandem mass spectrometry has been proposed and validated for the identification and simultaneous quantification of twelve benzimidazoles in meat samples. Electrophoretic separation was carried out using 500 mM formic acid (pH 2.2) as background electrolyte and applying a voltage of 25 kV at 25° C. In order to improve the sensitivity, stacking mode injection was applied, using as injection solvent a mixture of 30:70 acetonitrile/water at 50 mbar for 75 s. Sensitivity enhancement factors from 74 to 317 were obtained under these conditions. Detection using an ion trap as analyzer, operating in multiple reactions monitoring mode was employed. The main MS/MS parameters as well as the composition of the sheath liquid and other electrospray variables were optimized in order to obtain the highest sensitivity and precision in conjunction with an unequivocal identification. The method was applied to poultry and pork muscle samples. The deproteinization of samples and extraction of benzimidazoles was carried out with acetonitrile. MgSO4 and NaCl were added as salting-out agents. Subsequently, dispersive liquid–liquid microextraction was applied as clean up procedure. The organic layer (acetonitrile, used as dispersant) containing the benzimidazoles was mixed with the extractant (chloroform) and both were injected in water, producing a cloudy solution. Recoveries for fortified samples were higher than 70%, with relative standard deviations lower than 16% were obtained in all cases. The limits of detection were below 3 μg kg−1, demonstrating the applicability of this fast, simple, and environmentally friendly method.

Posted in Benzimidazoles, CZE, DLLME, Mass spectrometry, P12-AGR-1647, Pork muscle | Tagged , , | Comments Off on Determination of benzimidazoles in meat samples by capillary zone electrophoresis tandem mass spectrometry following dispersive liquid–liquid microextraction.

Use of onion extract as a dairy cattle feed supplement: monitoring propyl propane thiosulfonate as a marker of its effect on milk attributes.

Posted on 28 February, 2017 by fqm302

Onion extract is used as a feed supplement for the diet of dairy cows, acting as inhibitor of methane production; however, its properties could alter sensory attributes of milk. In this work, we propose a method to evaluate the influence of this extract on milk properties, using propyl propane thiosulfonate (PTSO) as a marker. PTSO is extracted using a quick, easy, cheap, effective, rugged, and safe procedure and monitored by high-performance liquid chromatography with ultraviolet detection. The method was applied to milk samples obtained from 100 dairy cows fed during 2 months with enriched feed. In addition, a milk tasting panel was established to evaluate the PTSO residue that should not be exceeded to guarantee milk sensory attributes. It was established that a value of PTSO lower than 2 mg kg–1 does not alter milk organoleptic properties. This fact makes onion extract an interesting alternative as a feed supplement to control the methane emissions without any influence on milk attributes.

Posted in Animal feed, HPLC, PTSO, QuEChERS, UV-vis | Tagged , , | Comments Off on Use of onion extract as a dairy cattle feed supplement: monitoring propyl propane thiosulfonate as a marker of its effect on milk attributes.