Multiclass cyanotoxin analysis in reservoir waters: Tandem solid-phase extraction followed by zwitterionic hydrophilic interaction liquid chromatography-mass spectrometry.

The presence of cyanobacteria and cyanotoxins in all water bodies, including ocean water and fresh water sources, represents a risk for human health as eutrophication and climate change are enhancing their level of proliferation. For risk assessment and studies on occurrence, the development of reliable and sensitive analytical approaches able to cover a wide range of cyanotoxins is essential. This work describes the development of an HILIC-MS/MS multiclass method for the simultaneous analysis of eight cyanotoxins in reservoir water samples belonging to three different classes according to their chemical structure: cyclic peptides (microcystin-LR, microcystin-RR and nodularin), alkaloids (cylindrospermopsin, anatoxin-a) and three non-protein amino acids isomers such as β-methylamino-L-alanine, 2,4-diaminobutyric acid and N-(2-aminoethyl)glycine). A SeQuant ZIC-HILIC column was employed to achieve the chromatographic separation in less than 12 min. Previously, a novel sample treatment based on a tandem solid-phase extraction (SPE) system using mixed cation exchange (MCX) and Strata-X cartridges was investigated with the aim of extracting and preconcentrating this chemically diverse group of cyanotoxins. The Strata-X cartridge, which was configured first in the line of sample flow, retained the low polar compounds and the MCX cartridge, which was at the bottom of the dual system, retained mainly the non-protein amino acids. The optimization procedure highlighted the importance of sample ion content for the recoveries of some analytes such as the isomers β-N-methylamino-L-alanine and 2-4-diaminobutyric acid. Method validation was carried out in terms of linearity, limit of detection (LOD) and quantification (LOQ), recoveries, matrix effect and precision in terms of repeatability and intermediate precision. This work represents the first analytical method for the simultaneous analysis of these multiclass cyanotoxins in reservoir water samples, achieving LOQs in the very low range of 7·10−3 – 0.1 μg L−1. Despite high recoveries obtained at the LOQ concentration levels (101.0–70.9%), relative standard deviations lower than 17.5% were achieved.

Posted in Cyanotoxins, HILIC, Mass spectrometry, RTI2018-097043-B-I00, SPE, Water | Tagged , , | Comments Off on Multiclass cyanotoxin analysis in reservoir waters: Tandem solid-phase extraction followed by zwitterionic hydrophilic interaction liquid chromatography-mass spectrometry.

A natural deep eutectic solvent as a novel dispersive solvent in dispersive liquid-liquid microextraction based on solidification of floating organic droplet for the determination of pesticide residues.

Current trends in analytical chemistry encourage the use of innocuous solvents to develop modern methods aligned with green chemistry. In this sense, natural deep eutectic solvents (NADESs) have emerged as a novel generation of green solvents which can be employed in sample treatments as an alternative to the toxic organic solvents commonly used so far. In this work, a new extraction method employs dispersive liquid-liquid microextraction based on a solid floating organic droplet (DLLME-SFO), by using a mixture composed of a less dense than water extraction solvent, 1-dodecanol, and a novel dispersive solvent, NADES. The methodology was proposed to extract and preconcentrate some pesticide residues (fipronil, fipronil-sulfide, fipronil-sulfone, and boscalid) from environmental water and white wine samples before analysis by liquid-chromatography coupled to ultraviolet detection (HPLC-UV). Limits of quantification (LOQs) lower than 4.5 μg L−1, recoveries above 80%, and precision, expressed as RSD, below 15% were achieved in both samples showing that the proposed method is a powerful, efficient, and green alternative for the determination of these compounds and, therefore, demonstrating a new application for NADES in sample preparation. In addition, the DLLME-SFOD-HPLC-UV method was evaluated and compared with other reported approaches using the Analytical GREEnness metric approach, which highlighted the greenness of the proposed method.

Posted in Fipronil, HPLC, NADES, RED2018-102522-T, UV-vis, Water, Wine | Tagged , | Comments Off on A natural deep eutectic solvent as a novel dispersive solvent in dispersive liquid-liquid microextraction based on solidification of floating organic droplet for the determination of pesticide residues.

Determination of principal ergot alkaloids in swine feeding

Ergot alkaloids are secondary metabolites produced by fungi in the genus Claviceps. They contaminate a large variety of cereals, such as rye, triticale, wheat and barley. The ingestion of contaminated cereals might cause adverse health effects in humans and animals. In fact, pigs, cattle, sheep, and poultry are involved in sporadic outbreaks and, although there are several studies about occurrence of ergot alkaloids in grain cereals, there are scarce studies focused on compound feed. Twelve ergot alkaloids have been quantified in 228 feed samples intended for swine. The analytes were extracted using QuEChERS with Z-Sep+ as sorbent in the clean-up step, which reduced the matrix effect, allowing limits of quantification between 2.1 and 21.7 μg kg–1. The analytes were subsequently quantified by ultra-high-performance liquid chromatography with tandem mass spectrometry (UHPLC–MS/MS). A total of 29 samples (12.7%) revealed contamination by at least one ergot alkaloid, and among contaminated samples, 65% were contaminated by more than one. Only 6 of 12 target ergot alkaloids showed concentrations above the limit of quantification. The concentrations for individual ergot alkaloids ranged between 5.9 μg kg–1 for ergosinine to 145.3 μg kg–1 for ergometrine (the predominant ergot alkaloid), while the total ergot alkaloid content ranged from 5.9 to 158.7 μg kg–1. The occurrence of ergot alkaloids in feed samples in Spain seems to be lower than in other regions of Europe. All the samples fulfilled current recommendations of the feed industry about practical limits for ergot alkaloids in pig feeds. This suggests that the feeds are safe for pig consumption, regarding the presence of ergot alkaloids.

Posted in Animal feed, Ergot alkaloids, Mass spectrometry, QuEChERS, RTI2018-097043-B-I00, UHPLC | Tagged , , | Comments Off on Determination of principal ergot alkaloids in swine feeding

Simple and efficient method for the determination of fipronil and two main metabolites in eggs by capillary liquid chromatography.

Capillary liquid chromatography (CLC) with UV-diode array detection has been proposed for the first time to determine fipronil and two metabolites, fipronil-sulfide and fipronil-sulfone in hen egg samples. Under optimum conditions, analytes eluted in less than 12 min. Despite the complexity of egg samples, a simple and fast sample preparation method based on salting-out assisted liquid–liquid extraction (SALLE) was developed using acetonitrile as extraction solvent and ammonium sulfate as salting out reagent. To obtain satisfactory extraction efficiencies for the target compounds, several parameters affecting the procedure were optimized, including the nature and amount of the extraction solvent and the type and amount of salting-out reagent, among others. Validation parameters of the proposed SALLE-CLC-UV method yielded satisfactory results with repeatability and intermediate precision, expressed as relative standard deviation (RSD), below 9% and 11%, respectively and recoveries above 80%. Good linearity was obtained (R2 > 0.990) with limits of detection (LOD) below 5 μg·kg−1. The advantages of a miniaturized technique such as CLC in terms of reduced sample and solvent consumption, combined with simplicity of the SALLE procedure, make this method an attractive green alternative to traditional LC for the monitoring of these residues in egg samples.

Posted in Capillary HPLC, Eggs, Fipronil, Pesticides, RTI2018-097043-B-I00, SALLE, UV-vis | Tagged , , | Comments Off on Simple and efficient method for the determination of fipronil and two main metabolites in eggs by capillary liquid chromatography.

Determination of the main ergot alkaloids and their epimers in oat-based functional foods by ultra-high performance liquid chromatography tandem mass spectrometry.

An ultra-high performance liquid chromatography coupled to tandem mass spectrometry method is proposed for the determination of the major ergot alkaloids (ergometrine, ergosine, ergotamine, ergocornine, ergokryptine, ergocristine) and their epimers (ergometrinine, ergosinine, ergotaminine, ergocorninine, ergokryptinine, and ergocristinine) in oat-based foods and food supplements. A modified QuEChERS (quick, easy, cheap, effective, rugged, and safe) procedure was applied as sample treatment, reducing the consumption of organic solvent and increasing sensitivity. This method involved an extraction with acetonitrile and ammonium carbonate (85:15, v/v) and a clean-up step based on dispersive solid-phase extraction, employing a mixture of C18/Z-Sep+ as sorbents. Procedural calibration curves were established and limits of quantification were below 3.2 μg/kg for the studied compounds. Repeatability and intermediate precision (expressed as RSD%) were lower than 6.3% and 15%, respectively, with recoveries ranging between 89.7% and 109%. The method was applied to oat-based products (bran, flakes, flour, grass, hydroalcoholic extracts, juices, and tablets), finding a positive sample of oat bran contaminated with ergometrine, ergosine, ergometrinine, and ergosinine (total content of 10.7 μg/kg).

Posted in Ergot alkaloids, Mass spectrometry, Mycotoxins, Oat, QuEChERS, RTI2018-097043-B-I00, UHPLC | Tagged , , | Comments Off on Determination of the main ergot alkaloids and their epimers in oat-based functional foods by ultra-high performance liquid chromatography tandem mass spectrometry.

Occurrence of ergot alkaloids in barley and wheat from Algeria

The natural occurrence of six major ergot alkaloids, ergometrine, ergosine, ergotamine, ergocornine, ergokryptine and ergocristine, as well as their corresponding epimers, were investigated in 60 cereal samples (barley and wheat) from Algeria. Ultra-high performance liquid chromatography coupled to tandem mass spectrometry (UHPLC-MS/MS) and a QuEChERS extraction method were used for sample analysis. The results revealed that 12 out of 60 samples (20%) were contaminated with ergot alkaloids. Wheat was the most contaminated matrix, with an incidence of 26.7% (8 out of 30 samples). The concentration of total ergot alkaloids ranged from 17.8 to 53.9 μg/kg for barley and from 3.66 to 76.0 μg/kg for wheat samples. Ergosine, ergokryptine and ergocristine showed the highest incidences in wheat, while ergometrine was the most common ergot in barley.

Posted in Barley, Ergot alkaloids, Mass spectrometry, Mycotoxins, QuEChERS, RTI2018-097043-B-I00, UHPLC, Wheat | Tagged , , | Comments Off on Occurrence of ergot alkaloids in barley and wheat from Algeria

A novel approach based on capillary liquid chromatography for the simultaneous determination of neonicotinoid residues in cereal samples

A simple and effective method using solid–liquid extraction followed by capillary liquid chromatography with diode array detection (CLC-DAD) has been established for the extraction and determination of seven neonicotinoid insecticides commercially available (imidacloprid, thiacloprid, clothianidin, thiamethoxam, acetamiprid, nitenpyram and dinotefuran) in cereal samples. The separation was achieved in less than 19 min using a Zorbax XDB-C18 column (150 mm × 0.5 mm i.d, 5 µm) at a 25 °C, with a mobile phase consisting of ultrapure water and acetonitrile at a flow rate of 10 µL/min. Detection wavelengths of 254 or 270 nm were used, depending on the analyte. Variables affecting the extraction efficiency were optimized, such as type and volume of extraction solvent, and extraction and centrifugation time. Under the optimal conditions, the proposed method was characterized according to SANTE/12682/2019 guideline, in terms of linearity ( ≥ 0.9901), repeatability (RSD ≤ 7.6%), reproducibility (RSD ≤ 10%) and trueness (recoveries ≥ 80%). The limits of detection and quantification were in the ranges of 3–5 and 9–18 µg/kg, respectively, being adequate for the determination of these compounds in cereal samples at levels below its maximum residue limits (MRLs) established by the European legislation. The advantages of a miniaturized technique such as CLC in terms of high mass sensitivity and reduced solvent consumption, combined with the simplicity of the solid–liquid extraction procedure, make this method a useful alternative for the monitoring of these residues at trace level in cereal samples.

Posted in AGL2015-70708-R, Barley, Capillary HPLC, Maize, Oat, Rice, Solid-liquid extraction, UV-vis, Wheat | Tagged , | Comments Off on A novel approach based on capillary liquid chromatography for the simultaneous determination of neonicotinoid residues in cereal samples

Capillary liquid chromatography as an effective method for the determination of seven neonicotinoid residues in honey samples

A new analytical method based on capillary liquid chromatography with diode array detection has been developed for the simultaneous quantification of seven neonicotinoid insecticides commercially available (imidacloprid, thiacloprid, clothianidin, thiamethoxam, acetamiprid, nitenpyram, and dinotefuran) in honey samples. The separation was achieved in a Zorbax XDB-C18 column (150 × 0.5 mm id, 5 μm), with a mobile phase consisting of ultrapure water (solvent A) and acetonitrile (solvent B) at a flow rate of 10 μL/min. Capillary column was thermostated at 25◦C during the analysis and 254 or 270 nm was established as detection wavelength, depending on the analyte. Furthermore, full loop injection mode (8 μL) was selected, using water as injection solvent. Finally, the optimized method was applied to the analysis of neonicotinoid residues in honey of different floral origins using dispersive liquid–liquid microextraction as sample treatment. Variables affecting the extraction efficiency were optimized, choosing methanol and dichloromethane as dispersive and extraction solvents, respectively. The method was characterized in terms of linearity (𝑅2 ≥ 0.9948), repeatability, reproducibility (relative standard deviation below 4.5 and 6.3% respectively), and recoveries (≥80.5%). Detection and quantification limits were lower than 6.6 and 22.0 μg/kg for the studied analytes, respectively.

Posted in AGL2015-70708-R, Capillary HPLC, DLLME, Honey, Neonicotinoids, UV-vis | Tagged , , | Comments Off on Capillary liquid chromatography as an effective method for the determination of seven neonicotinoid residues in honey samples

Micellar electrokinetic chromatography as efficient alternative for the multiresidue determination of seven neonicotinoids and 6-chloronicotinic acid in environmental samples

A simple, sensitive, and efficient method has been developed for the determination of the seven neonicotinoid insecticides commercially available (imidacloprid, thiacloprid, clothianidin, thiamethoxam, acetamiprid, nitenpyram, and dinotefuran) and the main metabolite 6-chloronicotinic acid. Micellar electrokinetic chromatography (MEKC) mode was applied, using 48.5 cm of total length capillary (50 μm i.d.) with an extended light-path capillary (150 μm). The running electrolyte consisted of 25 mM sodium tetraborate buffer (pH 9.2) containing 120 mM of sodium dodecyl sulfate and 15% of methanol (v/v). A voltage of 27 kV and a temperature of 25 °C were applied. Samples dissolved in deionized water were hydrodynamically injected at 50 mbar for 12 s, achieving the analysis in less than 12 min. Diode array detection (DAD) was performed at 220, 254, and 270 nm, depending on the analyte. Two different methodologies as sample treatments were developed; for water samples, solid-phase extraction was checked using different cartridges (C18, Oasis® HLB, Oasis® HLB Prime, and Strata-X), being the best option Oasis® HLB for preconcentration and cleanup. In the case of soil samples, a simple solid–liquid extraction was applied using a mixture of 1:3 (v/v) acetonitrile/dichloromethane. Satisfactory linearity, trueness, and precision were achieved, with detection limits in the range of 0.1–0.4 μg L−1 for river water and 1.0–2.9 μg kg−1 for soil samples. Recoveries in the range of 80–107% for all of the assayed neonicotinoids in water samples of different origin and 73–92% for soil samples were achieved.

Posted in AGL2015-70708-R, MEKC, Neonicotinoids, SPE, Soil, Solid-liquid extraction, UV-vis, Water | Tagged , , | Comments Off on Micellar electrokinetic chromatography as efficient alternative for the multiresidue determination of seven neonicotinoids and 6-chloronicotinic acid in environmental samples

Determination of sulfonylurea pesticide residues in edible seeds used as nutraceuticals by QuEChERS in combination with ultra-high-performance liquid chromatography-tandem mass spectrometry

This work proposes a novel Quick, Easy, Cheap, Effective, Rugged, and Safe (QuEChERS) method in combination with ultra-high performance liquid chromatography-tandem mass spectrometry for the determination of sulfonylurea residues in edible seeds. The chromatographic separation of nine sulfonylureas was accomplished in less than 5.5 min, using a Luna Omega C18 column (50 × 2.1 mm, 1.6 µm). Mobile phase was supplied at 0.55 mL min-1 and consisted of 0.01% (v/v) aqueous acetic acid as eluent A and a mixture methanol/acetonitrile (80/20, v/v) as eluent B. Column temperature was established at 25 °C. A QuEChERS procedure was investigated as sample treatment for sulfonylureas extraction and sample clean-up. Different clean-up agents (i.e. PSA, Z-Sep+, EMR-Lipid and C18) were evaluated, selecting Z-Sep+ (25 mg) as the best option. The proposed method provided an extraction efficiency greater than 86.2%, while absolute matrix effect was lower than 50.1%. Matrix-matched calibration curves were required for analyte quantification. The analytical method was characterized according to SANTE/11813/2017 guideline, and including limits of detection and quantification, precision, and trueness. Linear dynamic ranges were established from 5 to 150 µg kg−1 for all analytes. Linearity (R2 ≥ 0.9974) and precision in terms of repeatability and intermediate precision (relative standard deviation ≤ 14.7%) are reported. The reporting limit was established at 5 µg kg−1, which is above the limits of quantification of the proposed method (≤ 1.64 µg kg−1) and below the maximum residue levels currently established by European legislation. In general, trueness is within the range of 70–120%. Despite greater recoveries were obtained at the reporting limit (i.e. 120–138%), relative standard deviations lower than 20% were obtained at this concentration level, so fulfilling the requirements of SANTE/11813/2017 guideline. This work represents the first analytical method intended for the analysis of sulfonylureas in sunflower, pumpkin and chia seeds, which are complex matrices due to their high content of fat as well as of growing interest due to their current commercialization as nutraceuticals.

Posted in AGL2015-70708-R, Mass spectrometry, QuEChERS, Seeds, Sulfonylurea, UHPLC | Tagged , , | Comments Off on Determination of sulfonylurea pesticide residues in edible seeds used as nutraceuticals by QuEChERS in combination with ultra-high-performance liquid chromatography-tandem mass spectrometry