Pesticides dichlorvos

Desi, I., Nagimajtenyi, L. (1999). Electrophysiological biomarkers of an organophosphorous pesticide, dichlorvos. Toxicol. Lett. 107 55-64. 

The first work in the literature named as inhibition BioET was a collaborative work between our laboratory and a French laboratory commanding pesticide analysis. In this work, the BioET was developed, employing an array of inhibition biosensors and ANNs [15]. The array of biosensors was formed by three ampero-metric pesticide biosensors that used different AChE enzymes the wild type from electric eel (EE) and two different genetically modified enzymes (B1 and B394). The system was employed for the simultaneous determination and/or resolution of mixtures of two pesticides, dichlorvos and carbofuran, with mean values of... 

Under current regulations, chemicals allowed for use in various European countries (Table 3) are either fully Hcensed for aquacultural use (oxytetracycline, oxolinic acid) or can be prescribed by veterinarians if they are Hcensed for use on other food animals (14—16). In addition, previously unHcensed chemicals that are appHed to the water (topicals) may now be used under a grandfather clause if no one questions their safety. The question of whether a chemical is a medicine or a pesticide has also been addressed. Eor example, dichlorvos (Nuvan 500 EC) was initially designated as a pesticide in the United Kingdom, but was later categorized as a medicine. A similar product, trichlorfon (Masoten), was treated the same way in the United States. 

Biosensors may provide the basis for in-field analyses and real-time process analysis. However, biosensors are generally limited to the determination of a limited range of analytes in defined matrices. Enzyme-based biosensors, principally acetylcholinesterase (AChE) inhibition, have been successfully used in environmental analysis for residues of dichlorvos and paraoxon, " carbaryl " and carbofuran. " Immunochemically based biosensors may be the basis for the determination of pesticide residues in liquid samples, principally water and environmental samples, but also fruit juices. The sensors can be linked to transducers, for example based on a piezo-... 

Stable OCPs were not the only pesticides found in food products, as was inevitable for the USSR in the 1960s all types of OPPs were also detected, including phenkapton [38] and dichlorvos [30], menazon [41] and ph-enthoate [50], trichlorfon [14], phosalone [60] and tetrachlorvinfos [56]. 

Even though all OP insecticides have a common mechanism of action, differences occur among individual compounds. OP insecticides can be grouped into direct and indirect ACHE inhibitors. Direct inhibitors are effective without any metabolic modification, while indirect inhibitors require biotransformation to be effective. Moreover, some OP pesticides inhibit ACHE more than PCHE, while others do the opposite. For example, malathion, diazinon, and dichlorvos are earlier inhibitors of PCHE than of ACHE. In these cases, PCHE is a more sensitive indicator of exposure, even though it is not correlated with symptoms or signs of toxicity. 

The design and implementation of a portable fiber-optic cholinesterase biosensor for the detection and determination of pesticides carbaryl and dichlorvos was presented by Andreou81. The sensing bioactive material was a three-layer sandwich. The enzyme cholinesterase was immobilized on the outer layer, consisting of hydrophilic modified polyvinylidenefluoride membrane. The membrane was in contact with an intermediate sol-gel layer that incorporated bromocresol purple, deposited on an inner disk. The sensor operated in a static mode at room temperature and the rate of the inhibited reaction served as an analytical signal. This method was successfully applied to the direct analysis of natural water samples (detection and determination of these pesticides), without sample pretreatment, and since the biosensor setup is fully portable (in a small case), it is suitable for in-field use. 

Verma, S.R., S. Rani, S.K. Bansal, and R.C. Dalela. 1980. Effects of the pesticides thiotox, dichlorvos and carbofuran on the test fish Mystus vittatus. Water Air Soil Pollut. 13 229-234. 

Snyder et al. [20] have compared supercritical fluid extraction with classical sonication and Soxhlet extraction for the extraction of selected pesticides from soils. Samples extracted with supercritical carbon dioxide modified with 3% methanol at 350atm and 50°C gave a =85% recovery of organochlorine insecticides including Dichlorvos, Endrin, Endrin aldehyde, p,p -DDT mirex and decachlorobiphenyl (and organophosphorus insecticides). 

Chloroform has been used as a carrier or solvent for some pesticides (HSDB 1996). It is still used as a carrier for at least one pesticide formulation with dichlorvos as the active ingredient (Retrelli et al. 1993). Application of pesticides using chloroform in the carriers could have resulted in releases of chloroform to the land. It is impossible to quantify the magnitude of such releases, and the chloroform could be expected to be transported to either the atmosphere through volatilization or, if dissolved in water, carried into surface waters or groundwater. 

EPA pesticide chemical code 081501, see Chloropicrin EPA pesticide chemical code 082001, see 2,4,5-T EPA pesticide chemical code 084001, see Dichlorvos EPA pesticide chemical code 086804, see 2,4-Dimethylphenol... 

Forget, J., Pavilion, J.F., Menasria, M.R., and Bocquene, G. Motality and LC50 values for several stages of the marine copepod Tigriopus brevicornis (Muller) exposed to the metals arsenic and cadmium and the pesticides atrazine, carbofuran, dichlorvos, and malathion, Ecotoxlcol. Environ. Saf., 40(3) 239-244, 1998. 

Reagents, (a) Pesticide standards of acephate, bromopropylate, chlorpyrifos, chlorpyrifos-methyl, chlorothalonil, diazinon, dichlorvos, endosulfan I, endosulfan II, endosulfan sulfate, lindane, methamidophos, phosalone, procymidone, pyrazophos, triazophos, and vinclozoline (purity >98%) were supplied by Riedel de Haen (Seelze, Germany). For each pesticide, a stock standard solution (about 500 mg/L) was prepared in acetone. Spiking standard solution, containing 50 mg/L of each pesticide, was prepared in acetone from the stock standard solutions. 

Valdes-Ramirez, G., Gutierrez, M., del Valle, M., Ramirez-Silva, M. T., Fournier, D., and Marty, J.-L. (2009). Automated resolution of dichlorvos and methylparaoxon pesticide mixtures employing a Flow Injection system with an inhibition electronic tongue. Biosens. Bioelectron. 24(5), 1103-1108. 

Early results indicate a high sensitivity for pesticide detection, with the system being capable of detecting dichlorvos at concentrations as low as 1 x 10-17M and parathion and azinphos both at concentrations as low as 1 x 10-16M [40]. 

Among organophosphates dichlorvos (2,2-dichlorovinyl dimethyl phosphate) and pirimiphos methyl (0-[2-(diethylamino)-6-methyl-4-pyr-imidinyl]0,0-dimethylphosphorothioate) are important contaminants for the durum wheat industry. Dichlorvos is one of the most widely used pesticides worldwide in the storage of many products, such as com, rice, and durum wheat, finding widespread use in most European countries... 

In this application, the use of wild-type electric eel AChE and a recombinant AChE, specifically selected as very sensitive to dichlorvos, was compared. The effect of the matrix extract was determined by using various sample solvent ratios, 1 2.5, 1 5, 1 10, and 1 20. The optimal extraction ratio, considering the electrochemical interferences and the effect on enzyme activity and bioavailability of the pesticide, was 1 10. 

The applications described above, coupled with the realization of a dedicated portable instrumentation and software, represent a user-friendly analytical tool dedicated to durum wheat safety. Moreover, all the applications are based on the use of one single type of thick-film SPE facilitating the overall procedure for the final user that has to store and handle one single type of transducer. The developed device, which consists of the hand-held potentiostat, the multiplexer for eight-channel control and a dedicated software, can be used to detect OPs pesticides, such as dichlorvos and pirimiphos methyl at contamination level below the MRL settled by the European Union, OTA, and also amplified DNA of F. culmorum. 

Various committees set up by the UK Society for Analytical Chemistry have carried out very detailed studies on the application of GC with flame photometric detection to methanol extracts of grain for the determination of malathion and dichlorvos [ 134] and organophosphorus in pesticides [135]. 

Several qualitative and quantitative immunochemical methods and their application to the analysis of environmental samples have been described for OP insecticides, a family that includes widely used pesticides such as azinphos-ethyl/methyl, dichlorvos, fenitrothion or fenthion, malathion, mevinphos, and parathion. Mercader and Montoya202 produced monoclonal antibodies against azinphos-methyl and developed an ELISA that was used for the analysis of water samples from different sources, reaching detectability levels near 0.05 pg I. Watanabe et al.203 reported the production of polyclonal antibodies and ELISA procedures to analyze fenitrothion in river, tap, and mineral water (LOD = 0.3 pg L ). Banks et al.204 produced polyclonal antibodies against dichlorvos, an organophosphate insecticide used for stored grain, which also cross-reacts with fenitrothion. Nishi et al.205 reported the first immunoassay for malathion. Residues of this insecticide have... 

The technique was used to determine several organophosphorus pesticides (E)- and (Z)-Mevinphos, Dichlorvos, Azinphos-methyl, Azinphosethyl, Parathion-methyl, Parathion-ethyl, Malathion, Fenitrothion, Fenthion, Chlorfenvinphos and Diazinon, in groundwater. 

---