Determination Of Pesticides Research Articles

New Nanospheres to Use in the Determination of Imidan Phosmet and Vantex Pesticides

In this study, the usability of AChE immobilized nanospheres (NSs) was investigated to identify Imidan Phosmet and Vantex pesticides. Accordingly, (2AEPS-SalBr) coded nanosphere was synthesized in result of condensation of (Tris (2 aminoethyl)amine polymer and 5-bromine-2-hydroxy benzaldehyde. Then, new nanosphere coded 2AEPS-SalBr-Pd was synthesized using the template method. The structures of the synthesized nanospheres were characterized by the FT-IR, GPC, SEM/EDX and elemental analysis. Acetylcholinesterase (AChE) enzyme was immobilized to these nanospheres for the determination of Imidan and Vantex. The optimum conditions of the immobilized-AChE enzyme, the number of reuse, storage stability, and the kinetic parameters were determined. The immobilized AChE optimum pH was 8 for both supports, and the optimum temperature was 50 °C and 70 °C, respectively. Km and Vmax values were calculated as 1.443 mM and 0.251 mM/min for (2AEPS-SalBr)-AChE (pH 8, at 50 °C), and 0.680 mM and 0.157 mM/min for (2AEPS-SalBr-Pd)-AChE (pH 8, at 70 °C). Then the analyses of Imidan Phosmet and Vantex pesticides were carried out with immobilized AChE on nanospheres. As a result of the research, it was seen that Imidan Phosmet pesticide can be determined at a lower concentration than Vantex pesticide.

Analysis of Alternative New Pesticide (Fluopyram, Flupyradifurone, and Indaziflam) Residues in Pistachio, Date, and Soil by Liquid Chromatography Triple Quadrupole Tandem Mass Spectrometry

ABSTRACT Fluopyram, flupyradifurone, and indaziflam are novel systemic pesticides developed by Bayer. Based on available data, these pesticides appears to have a favorable safety profile in the case of pesticide residue problems. Herein, we report an effective analytical method for the determination of novel pesticides were developed using ultra-high performance liquid chromatography with tandem mass spectrometry coupled with a quick, easy, cheap, effective, rugged, and safe procedure. These target compounds were extracted with acetonitrile and cleaned up with PSA, and were separated successfully between 10.2 and 18.3 min using a C18 chromatographic column connected to an electrospray ionization source. All the matrix-matched samples at three fortified levels (0.01, 0.1, and 0.5 mg kg−1) provided satisfactory recoveries in the range of 80.6–93.5% with relative standard deviations below 10.8%. The limits of quantitation were 0.0055 mg kg−1 with a limit of detection of 0.0015 mg kg−1 for fluopyram in pistachio matrix, 0.0062 mg kg−1 with a limit of detection of 0.0019 mg kg−1 for flupyradifurone in date fruits and 0.0083 mg kg−1 with a limit of detection of 0.0025 mg kg−1 for indaziflam in soil complex matrix. The limit of quantification of studied pesticides was far below the maximum residue limit in the national MRLs so the proposed method is of great significance for establishing maximum residue limits in Iran. Date fruit real samples had not any flupyradifurone residue, and some pistachio and soil samples had trace fluopyram and indaziflam residues but there were below LOQs.

Fabrication of Co3O4 quantum dot incorporated polyacrylamide ethylene glycol dimethacrylate as a new fiber for solid phase microextraction and trace determination of organophosphorus pesticides in environmental water samples.

In this paper, a novel solid phase microextraction fiber based on Co3O4 quantum dot incorporated polyacrylamide-co-ethylene glycol dimethacrylate followed by corona discharge ion mobility spectrometry is presented for the trace determination of organophosphorus pesticides in environmental water samples. Ion mobility spectrometry is a comparatively inexpensive, well-known, robust, and easy to operate analytical instrument. This combination would provide a low-cost, fast, selective, and sensitive quantitative system for detection of organophosphorus pesticides. In order to obtain the best extraction efficiency, the optimization of parameters affecting this method was carried out. After optimization, a solution pH of 7.0, extraction temperature of 60 °C, adsorption temperature of 260 °C, extraction time of 30 min, stirring speed of 750 rpm, and ionic strength of 10% w/w were obtained. Consequently, the presented method showed low limits of detection (0.3-0.6 ng mL-1), excellent enrichment factors (PF = 221-263), good linearity (R2 > 0.995), and repeatabilities (intra-day: 3.4 to 4.8%) and (inter-day: 4.7 to 6.1%). The reproducibility (RSD% of fiber to fiber) was also investigated by analyzing three as-prepared fibers under the same conditions and was found to be less than 7.6%. Finally, the developed fiber was used for determination of organophosphorus pesticides in the field samples.

Alternative to High Pressure Mercury Vapor Lamp for Photo Induced Fluorescence Analytical Methods; Application to the Determination of Pesticides in Water.

The photo-induced fluorescence method is often applied to determine non-native fluorescent compounds. It typically uses UV irradiation from a high pressure mercury vapor discharge lamp to create photo-induced fluorescent compounds, which are then quantified by fluorescence spectroscopy. However, these mercury lamps require a high-voltage power supply and may accidentally induce electric shocks and the release of mercury vapors. As an alternative, we have evaluated in this technical note new UV-C germicidal lamps. These lamps exhibit a higher power at 254 nm and allowed us to obtain a far greater amount of photo-induced compounds in a shorter time. For the first time, this new irradiation system has been applied for the determination of pesticides in water and has shown a significant increase in the method sensitivity. These good results allowed us to conclude that the new UV-C lamps are a relevant alternative to high pressure mercury vapor discharge lamps for use with photo induced fluorescent methods.

A Review: Square Wave Adsorptive Stripping Voltammetry Determination ofPesticide and Ultra-trace Inorganic Ions in Environmental Samples

Environmental pollution caused by pesticides and ultra-trace amounts of inorganic ions in the different environmental samples has become an issue of serious concern in the last years. Thus, the development of novel, simple, fast, sensitive, and cheap methods for the detection of pesticide residues and ultra-trace inorganic ions in the environmental sample is very significant task now days. The SWAdSV can be conjuncted with different modified electrode such as SWAdSV with modified Hanging mercury drop electrode, SWAdSV with multi-walled carbon nanotube paste electrode, SWAdSV with boron-doped diamond electrode, SWAdSV with flow-injection analysis detection and etc. SWAdSV can be used to perform an experiment much faster than normal and differential pulse techniques, which typically run at scan rates of 1 to 10 mV/sec. Square wave voltammetry employs scan rates up to 1 V/sec or faster, allowing much faster determinations. A typical experiment requiring three minutes by normal or differential pulse techniques can be performed in a matter of seconds by square wave voltammetry. The aim of the review was the use of square wave adsorptive stripping voltammetry in conjunction with different modified electrode for the determination of pesticide and ultra-trace inorganic ions in environmental samples.

Determination of organochlorine pesticides (OCPs) residues in some Egyptian freshwater fish

Determination of organochlorine pesticides (OCPs) residues in some Egyptian freshwater fish

Effervescent tablet-assisted switchable hydrophilicity solvent-based on-site dispersive liquid-liquid microextraction coupled with gas chromatography for the determination of pyrethroid pesticides in environmental waters

A novel effervescent tablet-assisted switchable hydrophilicity solvent-based on-site dispersive liquid-liquid microextraction coupled with gas chromatography detection has been developed to determine five pyrethroid insecticides in environmental water samples. In this method, effervescent tablets contain effervescent precursors and extractants, which play a dual role of dispersion and extraction. After effervescence reaction, the formation of extractant and the extraction of analytes were accomplished simultaneously. Phase separation were carried by filtration using homemade filter column, which of filter is oil-absorbing cotton polypropylene. After phase separation, the extractant phase were obtained by elution. No electric instrument was required in sample pre-treatment step in the developed method. Experimental conditions affecting the extraction efficiencies have been optimized, such as type and amount of extractant, type of effervescent tablets, etc. Under the optimized conditions, the linearity was 5-500μg L-1, with coefficients greater than 0.9990. The limit of detection and the limit of quantitation were in the range of 0.22-1.88μg L-1 and 0.75-6.25μg L-1. The relative standard deviations ranged from 0.8% to 6.1%. The enrichment factors were in the range of 65-108. This method was successfully applied to the on-site processing of tap, reservoir and river water.

Electrochemical Determination of Chlorpyrifos, Cypermethrin and Endosulphan Pesticides in Soil in Bharatpur, Rajasthan

Electrochemical Determination of Chlorpyrifos, Cypermethrin and Endosulphan Pesticides in Soil in Bharatpur, Rajasthan

Infrastruktura za bezbednost i kvalitet hrane

The METROFOOD-RI is a new European infrastructure that provides high-quality services to the food sector particularly for food quality and safety. Hub and Node model is selected, with a Central Hub in Italy and a network of 48 institutes from 18 countries. The operational part of the physical infrastructure is developed through inventory of equipment, during the METROFOOD-PP project. The state-of-the-art equipment is selected for the service provision particularly for determination of the actual parameters for food safety and quality according to EU and/or National Regulations, and for that purpose is selected e.g., gas and liquid chromatography GC-MS (/MS), and/or LC-MS (/MS)) than ICPMS (/MS), Orbitrap, TOF, Ion trap mass spectrometer (MS), laser-induced plasma spectroscopy, and others. The main parameters in estimating food quality are determination of content of proteins, fat, fatty acids, carbohydrates, fibers, vitamins, microand microelements and providing information about nutritional values, physico-chemical analysis, bioactive compounds, and authenticity. The most important parameters in assessing food safety are the determination of contaminants (mycotoxins, polycyclic aromatic hydrocarbons, trace elements), pesticides and additives, which are regulated by the European regulations: Regulation 1881/2006 for contaminants, Regulation 396/2005 for pesticides, and Regulation 1333/2008 for additives. For addressing all these issues, analytical methods with a high degree of accuracy, precision and sensitivity, and a harmonized system for their application in analytical laboratories are required. Moreover, metrology concept must be applied to provide the basis for reliable measurements and confidence in measurement results, thus impacting the economy and society. Therefore, this pan-European Infrastructure will act in a dynamic way and its services will be adapted to the society needs to offer the best measurement results for ensuring food quality and safety.

Simultaneous determination of pesticides from soils: a comparison between QuEChERS extraction and Dutch mini-Luke extraction methods.

The expanding nature of the agricultural sector has fuelled the intensification of plant protection products usage, including pesticides. These pesticides may persist in soils, necessitating their accurate determination in a variety of soil types. However, due to their complex nature, the effective extraction of pesticide residues from soil matrices can present challenges to pesticide detection and quantification. This research compared two well-known extraction methods, QuEChERS and Dutch mini-Luke, by assessing their specificity, sensitivity, accuracy, precision and reproducibility in extracting seven distinct pesticides with a range of chemico-physical characteristics from Irish soils. The HPLC-UV conditions were optimised to separate the seven pesticides, and it was shown that both extraction methods successfully extracted neonicotinoids with recovery values ranging between 85 and 115%. Fluroxypyr and prothioconazole could not be efficiently extracted using QuEChERS, however, the recovery values of both the analytes ranged between 59 and 117% using Dutch mini-Luke. Furthermore, with the exception of prothioconazole using Dutch mini-Luke, both extraction methods resulted in reproducibility and precision values below or equal to 20%. Lastly, Dutch mini-Luke is noted to have a lower matrix effect than QuEChERS, except for prothioconazole. The comparison results showed that Dutch mini-Luke resulted in superior method sensitivity, better recovery, and lower matrix effect towards most investigated analytes and was the only extraction technique that successfully extracted all pesticides analysed in soil matrices.

Determination of malathion, chlorpyrifos, λ-cyhalothrin and arsenic in rice

Abstract Presented study focused on the incidence of pesticides: malathion, chlorpyrifos and λ-cyhalothrin and heavy metal, arsenic in the rice samples collected from the three main rice growing areas. 30 samples of brown Super Kernel Basmati rice and Super Basmati rice varieties, irrigated through tube well irrigation were selected. Highly sensitive and selective method of High Performance Liquid Chromatography was used for determination of pesticides. Results of analysis showed the presence of malathion in one sample in concentration of 18.26 mg/kg, chlorpyrifos in two samples in concentration of 3.3 mg/kg and 1.45 mg/kg respectively and λ-cyhalothrin in one sample in concentration of 1.848 mg/kg. Amount of pesticides detected in these samples were exceeding their maximum residual limits thus showed their strong potential to pose significant health risk. The presence of arsenic in rice was determined by Atomic Absorption Spectrophotometer and it was detected in 12 samples out of 30 in range of 0.04-0.28ppm. The detected arsenic concentration of arsenic in all samples was within the permissible limits set by WHO/FAO.

Micellar enhanced photo-induced fluorescence and absorbance for the development of an on-site early warning water quality monitoring system for pesticides.

This paper describes two prototypes of an on-site Early Warning Water Quality Monitoring System (EWWQMS) for pesticide quantification in natural waters. As many pesticides are non-fluorescent, the EWWQMS setup uses UV photoconversion to form highly fluorescent photoproducts. To enhance sensitivity, the two prototypes use micellar-enhanced fluorescence with surfactant (cetyl trimethyl ammonium chloride) in aqueous solution. To improve specificity, four UV LEDs at different wavelengths then excite the fluorescent photoproducts. The EWWQMS prototypes also employ UV absorption for quantification of non-photosensitive pesticides. The first prototype detects the pesticides via a diode array spectrometer. The second system is developed with higher resolution spectrometer and an intensified CCD camera detection to improve the sensitivity of the method. These experimental set-ups are described, explained and tested. Analytical applications were carried out online in CTAC aqueous solution, for the determination of isoproturon, flufenoxuron and profenofos. The calibration curves obtained are linear over one order of magnitude, and the detection limits are in the ng mL-1 range. The analytical performances of these new methods are good compared with other published classical micellar enhanced photo-induced fluorescence methods for the determination of pesticides in aqueous solutions. Our results show that these EWWQMS prototypes can be used as a warning system to protect against pesticide contamination exceeding the threshold of treatment capabilities at industrial facilities using natural waters.

Recommend a Spectrophotometric Method for the Determination of Pesticide Related Phenol Impurities in 2,4-D Technical Material

Recommend a Spectrophotometric Method for the Determination of Pesticide Related Phenol Impurities in 2,4-D Technical Material

One-step fabrication of alkali–acid modified three-dimensional magnetic biochar for the determination of pesticides in pigment-rich vegetables

Magnetic biochar was successfully synthesized via a one-step method through simultaneous activation and magnetization with alkali-acid modified citrus peel as the raw material, which could effectively penetrate interfering substances. The characterization analysis showed that the magnetic biochar exhibited high graphitic degree, higher specific surface area and smaller pore diameter, which resulted in superior adsorption performance. The magnetic biochar was used as an adsorbent for the cleanup and extraction of 22 pesticides (consisting of insecticides, fungicides and herbicides) from vegetables and the quantitative detection was completed by gas chromatography-mass spectrometry (GC-MS). The Plackett-Burman experimental design (PBD), central composite design (CCD) and response surface methodology (RSM) were employed to identify significant factors and optimal experimental conditions. Under optimal conditions, the methodological linearity was in the range of 1-100 μg kg-1 with the coefficients of determination ranging from 0.9969-0.9999, while the limits of detection (LODs) and limits of quantification (LOQs) were 0.31-0.91 μg kg-1 and 1.03-3.05 μg kg-1, respectively. The recoveries of the analytes from spiked samples were in the range of 78.1-112.5%. It was confirmed that the method established by using magnetic graphitic biochar as the adsorbent is an efficient pretreatment procedure and could be successfully applied for analysis of food safety.

Multi-Residue Determination of Pesticides in Farmed Aquatic Animal Products Using Gas Chromatography-Tandem Mass Spectrometry

Multi-Residue Determination of Pesticides in Farmed Aquatic Animal Products Using Gas Chromatography-Tandem Mass Spectrometry

Graphene-based Nanomaterials for Fabrication of ‘Pesticide’ Electrochemical Sensors

At present, graphene is one of the most up-to-date materials and it can be applied for various energy conversion devices and sensor technology. In this review article, our main focus is to summarize the role of graphene and its modified surface leading to develop hybrid nanomaterials and its applications in fabrication of pesticide sensor. Graphene based materials demonstrate exclusive electrochemical and optical properties as well as compatibility to absorb a variety of bio-molecules through π-π stacking interaction and/or electrostatics interaction, which make them ideal material to be employed in sensor application. The role of graphene is very crucial in preparing different unique and desirable hybrid functional composites along with nanoparticles, redox mediators, conducting polymers etc. to improve the performance of the sensors. Therefore, they can be easily used as a suitable material applying in fabrication of electrochemical sensors/ biosensors for the detection of organophosphorous and carbamate pesticides. A number of most recent reported works were discussed in which graphene-based hybrid composites show high sensitivity, good catalytic activity, selectivity towards the determination of pesticide either enzymatically or nonenzymatically. The properties of graphene (exceptional charge transport, thermal, optical, mechanical, high surface area, large pore volume and size, an opened ordered structure) play an important role in pesticide detection.

New frontiers and prospects of metal-organic frameworks for removal, determination, and sensing of pesticides

Pesticides have been widely used in agriculture to control, reduce, and kill insects. Humans are also being using pesticides to control insidious animals in daily life. By these practices, a huge volume of pesticides is introduced to the environment. Despite broad-spectrum applicability, pesticides also have hazardous effects on both humans and animals at high and low concentrations. Long-term exposure to pesticides can cause different diseases, like leukemia, lymphoma, and cancers of the brain, breasts, prostate, testis, and ovaries. Reproductive disorders from pesticides include birth defects, stillbirth, spontaneous abortion, sterility, and infertility. Therefore, the application of determination and treatment methods for pre-concentration and removal of these toxic materials from the environment appears a vital concern. To date, different materials and approaches have been employed for these purposes. Among these approaches, multifunctional metal-organic frameworks (MOFs)-assisted adsorption and determination processes have always been in the spotlight. These facts are due to exclusive properties of MOFs in terms of the crystallinity, large surface area, high chemical, and physical stability, and controllable structure as well as unique features of adsorption and determination process in terms of simple, easy, cheap, available method and ability to use in large and industrial scales. In the present work, we illustrate the exceptional features of MOFs as well as the possible mechanism for the adsorption of pesticides by MOFs. The use of these fantastic materials for pre-concentration and removal of pesticides are extensively explored. In addition, the performance of MOFs was compared with other adsorbents. Finally, the new frontiers and prospects of MOFs for the determination, sensing, and removal of pesticides are presented.

Synthesis and deposition of Silver nanostructures on the silica microsphere by laser-assisted photochemical method for SERS applications

The homogeneous distribution of nano-metallic structures on the surface-enhanced Raman (SERS) substrates plays an important factor for high-sensitive Raman scattering measurement. In this paper, we present a low-cost laser-assisted photochemical method for making a SERS probe based on silver nanostructures, which are one-timely synthesized nano-silver structures, homogeneously deposited on silica microsphere surfaces. Achieved SERS-activity substrates with a homogeneous distribution of Ag-nanostructures are verified by a mapping technique on the surface of Ag-coated microsphere for the detection of low concentration of Rhodamine 6G in aqueous solutions in a range of 10-4-10-9M. The obtained results show that a SERS microsphere probe has a good repetition of SERS-activity in any space of sensing area, and large potential for application in a biochemical sensing technique. Full Text: PDF ReferencesY. Chen et al., "Interfacial reactions in lithium batteries", J. Phys. D: Appl. Phys. 50, 02510 (2017). CrossRef T.B. Pham, H. Bui, H.T. Le, V.H. Pham, "Characteristics of the Fiber Laser Sensor System Based on Etched-Bragg Grating Sensing Probe for Determination of the Low Nitrate Concentration in Water", Sensors 17, 0007 (2017). CrossRef X. Wang, O.S. Wolfbeis, "Fiber-Optic Chemical Sensors and Biosensors (2013–2015)", Anal. Chem. 88, 203 (2016). CrossRef R. Wang, K. Kim, N. Choi, X. Wang, J. Lee, J.H. Joen, G. Rhie, J. Choo, "Highly sensitive detection of high-risk bacterial pathogens using SERS-based lateral flow assay strips", Sens. Actuators B-Chem. 270, 72 (2018). CrossRef H. Zhang et al., "Determination of Pesticides by Surface-Enhanced Raman Spectroscopy on Gold-Nanoparticle-Modified Polymethacrylate", Anal. Let. 49, 2268 (2016). CrossRef L. Chen, H. Yan, X. Xue, D. Jiang, Y. Cai, D. Liang, Y.M. Jung, X.X. Han, B. Zhao, "Surface-Enhanced Raman Scattering (SERS) Active Gold Nanoparticles Decorated on a Porous Polymer Filter", Appl. Spectrosc. 71, 1543 (2017). CrossRef A. Matikainen, T. Nuutinen, P. Vahimaa, S. Honkanen, "A solution to the fabrication and tarnishing problems of surface-enhanced Raman spectroscopy (SERS) fiber probes", Sci. Rep. 5, 8320 (2015). CrossRef J. Zhang, S. Chen, T. Gong, X. Zhang, Y. Zhu, "Tapered Fiber Probe Modified by Ag Nanoparticles for SERS Detection", Plasm. 11, 743 (2016). CrossRef W. Xu et al., "A Dual-Butterfly Structure Gyroscope", Sensors 17, 467 (2017). CrossRef K. Setoura, S. Ito, M. Yamada, H. Yamauchi, H. Miyasaka, "Fabrication of silver nanoparticles from silver salt aqueous solution at water-glass interface by visible CW laser irradiation without reducing reagents", J. Photochem. Photobio. A: Chem. 344, 168 (2017). CrossRef K. Liu, Y. Bai, L. Zhang, Z. Yang, Q. Fan, H. Zheng, Y. Yin, C. Gao, "Porous Au–Ag Nanospheres with High-Density and Highly Accessible Hotspots for SERS Analysis", Nano Lett. 16, 3675 (2016). CrossRef Z. Huang, X. Lei, Y. Liu, Z. Wang, X. Wang, Z. Wang, Q. Mao, G. Meng, "Tapered Optical Fiber Probe Assembled with Plasmonic Nanostructures for Surface-Enhanced Raman Scattering Application", ACS Appl. Mater. Interfaces 7, 17247 (2015). CrossRef

Multi-Walled Carbon Nanotubes for Magnetic Solid-Phase Extraction of Six Heterocyclic Pesticides in Environmental Water Samples Followed by HPLC-DAD Determination.

Magnetic multi-walled carbon nanotubes were prepared as magnetic solid-phase extraction (MSPE) adsorbent for the enrichment of six heterocyclic pesticides in environmental water samples, including imidacloprid, triadimefon, fipronil, flusilazole, chlorfenapyr and fenpyroximate. Then six heterocyclic pesticides were separated and determined by high-performance liquid chromatography-diode-array detector (HPLC-DAD). Major factors influencing MSPE efficiency, including the dose of mag-multi-walled carbon nanotubes (mag-MWCNTs), extraction time, solution pH, salt concentration, type and volume of eluent and desorption time were investigated. Under the optimized conditions, the enrichment factor of the method reached to 250. The linearity was achieved within 0.05–10.0 μg/L for imidacloprid and chlorfenapyr, 0.10–10.0 μg/L for fipronil, flusilazole, triadimefon and fenpyroximate. Limits of detection were in the range of 0.01–0.03 μg/L. Good precision at three spiked levels were 1.1–11.2% (intra-day) and 1.7–11.0% (inter-day) with relative standard deviation of peak area, respectively. The developed method was utilized to analyze tap water, river water and reservoir water samples and recoveries at three spiked concentration levels ranged from 72.2% to 107.5%. The method was proved to be a convenient, rapid and practical method for sensitive determination of heterocyclic pesticides.

Multiresidue method for determination of pesticides in coconut (Cocos nucifera Linn.) endosperm by using GC–MS/MS and UHPLC–MS/MS analysis

Several pesticides are used in the cultivation of coconut palm, hence evaluation of the residues from these substances must be analyzed in the fruit, to provide and ensure the food safety. Therefore, the development and validation of comprehensive and effective methods becomes crucial, given the complexity of the matrix. Thus, a novel method was developed for the determination of 10 different pesticides residues in coconut endosperm. QuEChERS showed to be an efficient method for sample preparation to overcome the complexity of the matrix. To extend the analytical scope, including a wide range of polarities, ultrahigh-performance liquid chromatography coupled mass spectrometry (UHPLC-MS/MS) and gas chromatography coupled mass spectrometry (GC--MS/MS) were employed. Triple quadrupole spectrometer was used in selected reaction monitoring (SRM) on both detectors, providing high sensitivity and selectivity. These approaches showed to be optimal, considering the parameters of linearity (r ≥ 0.99), matrix effect (0–50 %), LOQ (5 μg kg−1, except for thiamethoxam (20 μg kg−1)), specificity, trueness (60–118 %) and precision (repeatability and within-laboratory reproducibility) ≤ 20 %. The concentration levels obtained were higher than the MRL recommended for thiamethoxam (EU regulation <10 μg kg−1), justifying the analysis of such residues in commercial coconut endosperm.