Determination Of Avermectins Research Articles

Determination of Avermectins Residues in Soybean, Bean, and Maize Using a QuEChERS-Based Method and Ultra-High-Performance Liquid Chromatography Coupled to Tandem Mass Spectrometry

Soybean, maize, and bean are crops of great economic importance, but in recent years have suffered with infestations of the caterpillar Helicoverpa armigera, with the main reason being the resistance of this pest to most pesticides. Avermectin emamectin benzoate was recently released to control this pest. Other avermectins, like abamectin, doramectin, eprinomectin, and ivermectin are used in large scale because they potent acaricidal, anthelmintic, and insecticidal activities. Thus, a simple and fast method for the determination of avermectins in these crops based on a quick, easy, cheap, effective, rugged, and safe (QuEChERS) extraction procedure and ultra-high performance liquid chromatography with tandem mass spectrometry (UHPLC-MS/MS) analysis was developed and validated. For extraction, water followed by acetonitrile:isopropanol and a partition step with salts was stablished. With the clean-up step using activated EMR-Lipid, limits of detection of 1.2 μg kg−1 for abamectin, doramectin, emamectin benzoate, and ivermectin, and of 2.4 μg kg−1 for eprinomectin were achieved. The validation showed satisfactory results and the method was successfully applied to commercial samples, indicating that it is suitable for routine analysis.

Safety of imported agricultural products: pesticide residues

Introduction. From the evaluation of the positions of residual quantities of pesticides, the hygienic safety assessment of imported food products is most relevant under the current agreement on a free trade zone between the EAEU and the Socialist Republic of Vietnam, as well as in connection with a large list of chemical plant protection products used during the vegetation of crops. The purpose of the study. Rating the level of residual quantities of pesticides in samples of selected food products produced in Vietnam is the purpose of the study. Research objectives. To quantify 42 active ingredients of pesticides (and their metabolites) in samples of rice grain, dragon fruit (pitahaya), avocado, mango and banana (fresh and dried) are the research objectives. Material and methods. Multicomponent and individual methods based on LC and GC with MS-detection and FLD were used to identify active ingredients of pesticides. The sample preparation procedure with QuEChERS technology was used for the multi residues determination of the 40 compounds. The determination of avermectins (abamectin and emamectin benzoate) was carried out after the conversion of substances into fluorogenic derivatives. Results. Residual amounts of tebuconazole (rice - 0.53 ppm, mangoes - 0.26 ppm, avocado - 0.15 ppm), fludioxonil (rice - 0.017 ppm), imidacloprid (dried mangoes - 0.01 ppm), carbendazim (dried mangoes - 0.011 ppm) were identified in single samples No residual avermectins have been identified. The content of substances in the analyzed samples of dragon fruit (pitahaya) did not exceed 0.01 ppm. Discussion. The results obtained in the work are compared with the data of the annual pan-European and national monitoring, information on which is publicly available (2017), including imported goods, according to which rice and dragon fruits as objects of monitoring are given increased attention. Conclusions. The safety of certain types of food products imported from Vietnam is shown by the content of residual quantities of pesticides.

Pipette-tip solid-phase extraction using poly(1-vinylimidazole-co-trimethylolpropane trimethacrylate) as a new molecularly imprinted polymer in the determination of avermectins and milbemycins in fruit juice and water samples

A simple HPLC method was developed for the determination of abamectin (ABA), eprinomectin (EPR), and moxidectin (MOX). Pipette-tip molecularly imprinted polymer solid-phase extraction (PT–MIP–SPE) using poly(1-vinylimidazole-co-trimethylolpropane trimethacrylate) as a selective adsorbent material was studied in detail, including the washing solvent, type and volume of eluent, pH, quantity of adsorbent material and sample volume. The performance criteria for linearity, sensitivity, precision, accuracy, recovery, robustness and stability have been assessed and were within the recommended guidelines. The mean extraction recoveries/relative standard deviation for ABA 1b, EPR, ABA 1a and MOX were 98.77 ± 3.82%, 88.19 ± 2.57%, 110.54 ± 1.52% and 100.42 ± 0.59%, respectively. Finally, the results proved that PT–MIP–SPE coupled to HPLC–UV is an economical, simple and easy-to-perform technique, and presented a high potential for extraction of macrocyclic lactones in mineral water and grape and juice samples.

Determination of avermectins by the internal standard recovery correction - high performance liquid chromatography - quantitative Nuclear Magnetic Resonance method

Quantitative Nuclear Magnetic Resonance (qNMR) is widely used to determine the purity of organic compounds. For the compounds with lower purity especially molecular weight more than 500, qNMR is at risk of error for the purity, because the impurity peaks are likely to be incompletely separated from the peak of major component. In this study, an offline ISRC-HPLC-qNMR (internal standard recovery correction - high performance liquid chromatography - qNMR) was developed to overcome this problem. It is accurate by excluding the influence of impurity; it is low-cost by using common mobile phase; and it extends the applicable scope of qNMR. In this method, a mix solution of the sample and an internal standard was separated by HPLC with common mobile phases, and only the eluents of the analyte and the internal standard were collected in the same tube. After evaporation and re-dissolution, it was determined by qNMR. A recovery correction factor was determined by comparison of the solutions before and after these procedures. After correction, the mass fraction of analyte was constant and it was accurate and precise, even though the sample loss varied during these procedures, or even in bad resolution of HPLC. Avermectin B1a with the purity of ~93% and the molecular weight of 873 was analyzed. Moreover, the homologues of avermectin B1a were determined based on the identification and quantitative analysis by tandem mass spectrometry and HPLC, and the results were consistent with the results of traditional mass balance method. The result showed that the method could be widely used for the organic compounds, and could further promote qNMR to become a primary method in the international metrological systems.

Development, validation, and application of a method for selected avermectin determination in rural waters using high performance liquid chromatography and fluorescence detection

Avermectins (AVM) are macrocyclic lactones used in livestock and agriculture. A quantitative method of high performance liquid chromatography with fluorescence detection for the determination of eprinomectin, abamectin, doramectin and ivermectin in rural water samples was developed and validated. The method was employed to study samples collected in the Pito Aceso River microbasin, located in the Bom Jardim municipality, Rio de Janeiro State, Brazil. Samples were extracted by solid phase extraction using a polymeric stationary phase, the eluted fraction was re-concentrated under a gentle N2 flow and derivatized to allow AVM determination using liquid chromatography with fluorescence detection. The excitation and emission wavelengths of the derivatives were 365 and 470nm, respectively, and a total chromatographic run of 12min was achieved. Very low limits of quantification (22–58ngL−1) were found after re-concentration using N2. Recovery values varied from 85.7% to 119.2% with standard deviations between 1.2% and 10.2%. The validated method was applied in the determination of AVM in 15 water samples collected in the Pito Aceso River microbasin, but most of them were free of AVM or showed only trace levels of these compounds, except for a sample that contained doramectin (9.11µgL−1). The method is suitable for routine analysis with satisfactory recovery, sensitivity, and selectivity.

Determination of avermectins: A QuEChERS approach to the analysis of food samples

We present a simple method for extracting avermectines from meat, based on a QuEChERS approach followed by liquid chromatography (LC) coupled to triple quadrupole (QqQ) tandem mass spectrometry (MS/MS). The compounds considered are ivermectin, abamectin, emamectin, eprinomectin, doramectin and moxidectin. The new method has been fully validated according to the requirements of European Decision 657/2002/CE (EU, 2002). The method is suitable for the analysis of avermectins at concentration as low as 2.5μgkg−1, and allows high sample throughput. In addition, the detection of avermectins by high resolution mass spectrometry using a quadrupole-Orbritrap (Q-Orbitrap) hybrid instrument has been explored, and the target Selected Ion Monitoring data dependent MS/MS (t-SIM-dd MS/MS) mode has been found to provide excellent performance for residue determination of target analytes.

Multiresidue Determination of Avermectins in Plant-Derived Food by UPLC-MS/MS

The objective of this study was to propose a method that the residues of avermectins (Abamectin, Emamectin Benzoate, Ivermectin, Eprinomectin and Doramectin) derived from the food plant were determined by UPLC-MS/MS. The avermectins were extracted with acetonitrile, purified by Alumina B or GCB/NH2 SPE cartridge, and then determined by ultra high-performance liquid chromatography with tandem mass spectrometry. Tests for recovery (Recovery rate: 80.6%～99.8%, RSD's: 0.22%～6.4%) were made by addition of avermectin standards at three different concentration levels (4, 20 and 100μg/kg) to five kinds of food plant as matrixes. The sensitivity, accuracy and precision of this method were able to meet the requirements for pesticide residue analysis.