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Chemical Research in Toxicology Jun 2022Oxime-type carbamate pesticides having an oxime moiety such as aldicarb, butocarboxim, methomyl, oxamyl, and thiofanox are widely used and have been detected in many...
Oxime-type carbamate pesticides having an oxime moiety such as aldicarb, butocarboxim, methomyl, oxamyl, and thiofanox are widely used and have been detected in many fatal cases of accidental exposure or suicide. In forensic toxicology, the accurate determination of blood pesticide concentration is obligatory to prove death by oxime-type carbamate pesticide poisoning. However, the fatal pesticide concentration in blood at autopsy differs from that at the time of death. In this study, we found that oxime-type carbamate pesticides were decomposed by Hb in a temperature-dependent fashion. The mechanism underlying methomyl, aldicarb, oxamyl, and thiofanox decomposition involves the formation of adducts with the amino acids in Hb. With regard to butocarboxim, its decomposition involves the oxidation of the free form and the formation of adducts with the amino acids in Hb. The mass spectra obtained by liquid chromatography quadrupole time-of-flight mass spectrometry revealed that carbamylated amino acid adducts such as W-adduct and V-adduct were formed in Hb solution incubated with methomyl, aldicarb, oxamyl, and thiofanox, whereas alkylated amino acid adducts such as W-adduct were formed in Hb solution incubated with butocarboxim. These results indicate that aldicarb, butocarboxim, methomyl, oxamyl, and thiofanox are post-mortem changed by Hb.
Topics: Aldicarb; Amino Acids; Autopsy; Carbamates; Cholinesterase Inhibitors; Hemoglobins; Humans; Methomyl; Oximes; Pesticides
PubMed: 35559618
DOI: 10.1021/acs.chemrestox.2c00092 -
Food Chemistry Jan 2015In this study, four different haptens around the oxime moiety of Butocarboxim were designed and synthesised. Two of the haptens were conjugated with bovine serum albumin...
In this study, four different haptens around the oxime moiety of Butocarboxim were designed and synthesised. Two of the haptens were conjugated with bovine serum albumin (BSA) to serve as the immunogen and all the haptens were conjugated with ovalbumin (OVA) for the coating antigen. The anti-Butocarboxim monoclonal antibody (Mab) was selected based on eight immunogen/coating antigen combinations. The first enzyme-linked chemiluminescent immunoassay (ELCIA) for determining Butocarboxim in agricultural products was developed. Under the optimised conditions, the detection limit for the ELCIA was 20 ng·mL(-1) and the linear range was 27-2700 ng·mL(-1). Analyte recoveries for extracts of spiked agricultural (apple and greengrocery) products and tap water ranged from 97.18% to 107.00%. The developed immunoassay has great potential to be developed as a test kit offering a simple and cost-effective approach (such as lateral flow test strip) for screening purposes and evaluating environmental exposure to Butocarboxim.
Topics: Agriculture; Aldicarb; Antibodies, Monoclonal; Enzyme-Linked Immunosorbent Assay; Immunoassay
PubMed: 25053070
DOI: 10.1016/j.foodchem.2014.06.060 -
Photochemical & Photobiological... May 2016A liquid chromatography method with post-column photoinduced chemiluminescence (PICL) detection is proposed for the simultaneous determination of eight carbamate...
A liquid chromatography method with post-column photoinduced chemiluminescence (PICL) detection is proposed for the simultaneous determination of eight carbamate pesticides, namely aldicarb, butocarboxim, ethiofencarb, methomyl, methiocarb, thiodicarb, thiofanox and thiophanate-methyl. After chromatographic separation, quinine (sensitizer) was incorporated and the flow passed through an UV lamp (67 s of irradiation time) to obtain the photoproducts, which reacted with acidic Ce(iv) and provided a CL emission. The PICL method showed great selectivity for carbamate pesticides containing sulphur in their chemical structure. A solid-phase extraction process increased sensitivity (LODs ranging from 0.06 to 0.27 ng mL(-1)) and allowed the carbamate pesticides in surface and ground water samples to be determined, with recoveries in the range 87-110% (except for thiophanate-methyl, whose recoveries were between 60 and 75%). The intra- and inter-day precision was evaluated, with RSD ranging from 1.1 to 7.5% and from 2.6 to 12.3%, respectively. A discussion about the PICL mechanism is also included.
Topics: Carbamates; Chromatography, High Pressure Liquid; Equipment Design; Groundwater; Limit of Detection; Luminescence; Luminescent Measurements; Pesticides; Solid Phase Extraction; Water Pollutants, Chemical
PubMed: 27079156
DOI: 10.1039/c6pp00056h -
Journal of Economic Entomology Dec 2001Glass vials coated internally with an insecticide were used as a resistance monitoring technique for testing field populations of the woolly whitefly, Aleurothrixus...
Glass vials coated internally with an insecticide were used as a resistance monitoring technique for testing field populations of the woolly whitefly, Aleurothrixus floccosus (Maskell), collected from citrus. The distribution of resistance to the insecticide butocarboxim in citrus orchards from Valencia (Spain) during 1993 and 1994 was determined by means of this technique. Adults resting on citrus shoots were captured with a portable vacuum cleaner and introduced into the vials. The technique provides control mortality of <25% when assessed 7 h after the insects are captured. In 21 populations tested, LC50s ranged from 1.8 to 42.3 mg/ml. This represents resistance ratios >20-fold among populations. Lower slopes of the concentration-mortality line were found in whitefly populations that exhibited a low level of the LC50. Resistance was widespread in the Valencia areabut spatially irregular, with nearby orchards occasionally showing wide differences in resistance levels. The levels of resistance to butocarboxim obtained with this technique closely matched the field efficacy of the insecticide. This residue bioassay provides a convenient and rapid method to monitor insecticide resistance in A. floccosus populations.
Topics: Aldicarb; Animals; Biological Assay; Citrus; Hemiptera; Insecticide Resistance; Insecticides; Lethal Dose 50; Spain
PubMed: 11777064
DOI: 10.1093/jee/94.6.1558 -
Spectrochimica Acta. Part A, Molecular... May 2022To predict drug acute toxicity using the binding information with human serum albumin, our research group established a new method (Carrier protein binding...
To predict drug acute toxicity using the binding information with human serum albumin, our research group established a new method (Carrier protein binding information-toxicity relationship, CPBITR). Unfortunately, the previous model had too few data sets which may affect the accuracy and credibility of the model. In this paper, therefore, we measured the binding modes of three carbamate pesticides, Bendiocarb, Butocarboxim and Dioxacarb with human serum albumin (HSA) to supplement the previously modeled training set. Multispectral methods and molecular docking were used to study their binding modes. We built and optimized the previous models with the combined information of three different toxicity pesticides and HSA in order to find better prediction method. The results showed that Back-propagation Artificial Neural Network model has the best fitting effect among these models. In conclusion, the proposed model effectively improves the accuracy and credibility of the existing model. It results in significant predict drug acute toxicity using the binding information with carrier protein and contribute to drug development and research.
Topics: Binding Sites; Carbamates; Carrier Proteins; Humans; Molecular Docking Simulation; Pesticides; Protein Binding; Spectrometry, Fluorescence
PubMed: 35189491
DOI: 10.1016/j.saa.2022.121038 -
Journal of Chromatography. A May 2000There is increasing interest and demand for real multi-residue methods able to simultaneously determine pesticides with a broad spectrum of chemical characteristics in...
There is increasing interest and demand for real multi-residue methods able to simultaneously determine pesticides with a broad spectrum of chemical characteristics in environmental and biological matrices. A method based on solid-phase extraction with a Carbograph 4 cartridge and liquid chromatography with electrospray mass spectrometry (LC-ES-MS) enabling simultaneous determination of non-acidic and acidic pesticides in real water samples is described. On repeatedly (n=5) extracting 4 l of drinking water (spike level 50 ng/l), 2 l of ground water (spike level 100 ng/l) and 1 l of river water (spike level 200 ng/l), recovery of 26 base/neutral pesticides and 13 acidic pesticides were equal to or better than 80%, except for carbendazim (67%), butocarboxim (73%), aldicarb (75%) and molinate (77%). Relative standard deviations ranged between 4 and 15%. Final extracts containing acidic and non-acidic pesticides were analyzed in a single chromatographic run while the ES-MS system was operated in both positive and negative ion modes. With the aim of finding the best operating conditions, in terms of sensitivity, the pH of the LC eluent was varied in the 2.9-8.4 range. Altogether, the best results were obtained by using an LC eluent containing 1 mmol/l formic acid. Over the entire pH range considered, well shaped peaks for both basic and acidic analytes were achieved by the use of a new generation LC column. By extracting selected ion current profiles from the total ion current mass chromatogram relative to analysis of 4 l of drinking water spiked with 50 ng/l of each of the 39 analytes, estimated limits of detection ranged between 0.05 and 1.5 ng/l, except for propyzamide (8 ng/l) and 2,4-DB (3 ng/l).
Topics: Acids; Chromatography, Liquid; Hydrogen-Ion Concentration; Mass Spectrometry; Pesticides; Water Pollutants, Chemical
PubMed: 10843548
DOI: 10.1016/s0021-9673(00)00263-6 -
Journal of Chromatography. A Mar 2007An ultra-performance liquid chromatographic (UPLC) electrospray ionisation tandem quadrupole mass spectrometric method has been developed for the determination of 52...
An ultra-performance liquid chromatographic (UPLC) electrospray ionisation tandem quadrupole mass spectrometric method has been developed for the determination of 52 pesticides in cereal-based baby foods, oranges and potatoes. The fast polarity switching capability of the mass spectrometer used enabled the determination of 44 of the compounds in the positive ionisation mode and 8 of the compounds in the negative ionisation mode in a single run. Prior to analysis, co-extractives were removed from acetonitrile extracts using dispersive solid-phase extraction with primary secondary amine (50 mg). The UPLC method separates all of the pesticides, resolves structural isomers (e.g. butocarboxim sulfoxide and aldicarb sulfoxide) and has a short (7 min) cycle time. Extracts spiked with pesticides at 0.10 and 0.01 mg kg(-1) yielded average recoveries in the range of 66-124% with relative standard deviations less than 19% for the majority of the analytes.
Topics: Chromatography, High Pressure Liquid; Food Contamination; Humans; Infant; Infant Food; Pesticide Residues; Reference Standards; Sensitivity and Specificity; Spectrometry, Mass, Electrospray Ionization; Tandem Mass Spectrometry
PubMed: 17303144
DOI: 10.1016/j.chroma.2007.01.030 -
Journal of Chromatography. A Oct 2004A simple, specific and rapid procedure for determining six largely used carbamate insecticides in bovine whole milk is here presented. This method is based on the matrix...
A simple, specific and rapid procedure for determining six largely used carbamate insecticides in bovine whole milk is here presented. This method is based on the matrix solid-phase dispersion technique with heated water as extractant followed by liquid chromatography (LC)-mass spectrometry (MS) equipped with a single quadrupole and an electrospray ion source. Target compounds were extracted from milk by water heated at 90 degrees C. After acidification and filtration, 0.2 mL of the aqueous extract was injected in the LC column. MS data acquisition was performed in the selected ion-monitoring mode, selecting three ions for each target compound. Heated water appeared to be an excellent extractant, since absolute recovery data ranged between 76 and 104% with R.S.D. not larger than 8%. Using butocarboxim (an obsolete carbamate insecticide) as surrogate internal standard, the accuracy of the analysis at three spike levels varied between 85 and 105% with R.S.D. not larger than 9%. On the basis of a signal-to-noise ratio of 10, limits of quantification were estimated to range between 3 ppb (propoxur) and 8 ppb (pirimicarb). The effects of temperature, volume and flow rate of the extractant on the analyte recovery were studied.
Topics: Animals; Carbamates; Cattle; Chromatography, Liquid; Milk; Pesticides; Sensitivity and Specificity; Spectrometry, Mass, Electrospray Ionization
PubMed: 15553162
DOI: 10.1016/j.chroma.2004.04.014