Carbaryl pesticide

Figure 6.13 SEE-MEKC electropherogram of the pesticide carbaryl in a tomato sample the peak assigned number (4) coiresponds to the migration time of carbaryl. (from ref. 58).

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. 

Since their commercial introduction in the early 1960s,. V-methyIcarhamate pesticides (carbaryl, carbofuran (CF), methiocarb, etc.) have been used worldwide as substitutes for OCs because of their excellent efficiency as insecticides and nematicides, their relatively low mammalian toxicities in... 

Carbamate pesticides (carbaryl, aldicarb, Filter paper and silica 32... 

Most of the commercially used isocyanates are diisocyanates and R is an aromatic ring. MIC is an exception its structure is H3C-N=C=0. The physicochemical properties of MIC differ from those of other isocyanates (Lowe, 1970 Tse and Pesce, 1978 Westcott, 1985 Worthy, 1985). Because of high chemical reactivity of MIC with alcohols, it serves as an intermediate in the production of the pesticide carbaryl. Diisocyanates are primarily used for the manufacture of polyurethanes. 

Finally, MIC was reacted with a slight excess of a-naphthol in the presence of a catalyst in carbon tetrachloride solvent to produce the desired pesticide carbaryl. 

Ladies, G- S.. Smith. C., Heap.s, K., and Lovetc.ss. S. E. (1994). Evaluation of the humoral immune response of CD rats following a 2-week exposure to the pesticide carbaryl by the oral, dermal, or inhalation routes. J. Toxicol. Environ. Health 42,143-156. 

The Bhopal Accident This is probably the site of one of the greatest industrial disasters in history. Between 1977 and 1984, United Carbide India Limited, located within a crowded working class neighborhood in Bhopal, was licensed by the Madhya Pradesh State government to manufacture phosgene, monomethylamine, methylisocyanate, and the pesticide carbaryl, also known as Sevin. 

During the night of December 2-3,1984, the worst industrial disaster in history occurred at Union Carbide s plant in Bhopal, Madhya Pradesh, India. Methyl isocyanate (MIC) liquid, an intermediate used in making Sevin, Union Carbide s name for the pesticide carbaryl, came into contact with water, boiled violently, and turned into MIC gas. Unchecked by various safety systems, tons of highly toxic MIC gas escaped from storage tank E610. A cloud of MIC gas descended upon shantytowns just outside the plant, as well as on Bhopal city. Estimates of the death toll from exposure to the gas, immediately or in the first 2 weeks, range from 2000 to 8000 or more. If those who died months or years later from MIC exposure are counted, the death toll rises to between 20,000 and 30,000. More than 500,000 people suffered injuries from exposure to the gas and its effects on the environment. ... 

The N-methyl-l-naphthyl carbamate 601, used as a pesticide Carbaryl, Sevin), is prepared by the addition of 1-naphthol 600 to methyl isocyanate. 

The Bhopal disaster occurred in a plant designed to manufacture the pesticide carbaryl. Explain the chemistry of the synthesis of carbaryl at Bhopal as it was designed to occur. What went wrong ... 

The few pesticides investigated so far on BDD electrodes using voltammetric methods include some carbamate pesticides (carbaryl, " carbendazim ), and organophosphorus pesticides (parathion, methyl parathion, and fenamiphos ). Determination of the latter group is based on the reduction of the nitro group and thus these pesticides are among the few examples on utilization of BDD electrodes for electroreduction. Carbamate pesticides, the N-substituted esters of carbamic... 

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