Pesticide Mixture

The pesticide mixture sample from the air of the GC lab in which raw materials and pesticide products are analyzed was collected for three consecutive months. The sample to be analyzed was made using the extraction of the filter taken from the air purifier. 

Figure 3.13 (a) UV and (b) HC traces obtained from the LC-MS analysis of a pesticide mixture. From applications literatnre pnblished by Micromass UK Ltd, Manchester, UK,... 

The fundamental piece of information on which the subsequent spectral analysis is based is the total-ion-current (TIC) trace. Such a trace, obtained from the LC-MS analysis of a pesticide mixture, is shown in Figure 3.13, together with the UV trace recorded simultaneously. For the purposes of this discussion, the HPLC and MS conditions used to generate the data, other than the fact that electrospray ionization was used, are irrelevant. 

Lodovici M, Casalini C, Briani C, et al. 1997. Oxidative liver DNA damage in rats treated with pesticide mixtures. Toxicology 117 55-60. 

Patel Y, Kushwah HS, Kushwah A, et al. 1998a. In Vitro action of pesticides mixture on certain metabolic enzymes in rats. Indian Vet J 75 600-603. 

It Is now a relatively straightforward matter to analyze commercial pesticide mixtures for nitrosamlne contamination as part of the normal quality control process (2.18). and, as Illustrated above, some of the major contamination problems have begun to be solved by means of technological Improvements. If further research brings about the circumstance In which there Is no detectable N-nItroso compound In any pesticide sold an here, will that mean that pesticide use Is safe from nitrosamlne-formatlon problems I believe that considerably more research must be done before a responsible answer to this question can be given. To elaborate on this position, let me focus on the herbicides for a moment. 

Example Four Component Pesticide Example. Cornell (2) presented the analysis of a four component pesticide mixture containing Vendex (Xj), Omite, Kelthane (X,), and Dibrom (X.) to control mites on plants. The response, the average percentage of mites seven days... 

Organophosphate and carbamate pesticides are potent inhibitors of the enzyme cholinesterase. The inhibition of cholinesterase activity by the pesticide leads to the formation of stable covalent intermediates such as phosphoryl-enzyme complexes, which makes the hydrolysis of the substrate very slow. Both organophosphorus and carbamate pesticides can react with AChE in the same manner because the acetylation of the serine residue at the catalytic center is analogous to phosphorylation and carbamylation. Carbamated enzyme can restore its catalytic activity more rapidly than phosphorylated enzyme [17,42], Kok and Hasirci [43] reported that the total anti-cholinesterase activity of binary pesticide mixtures was lower than the sum of the individual inhibition values. 

F.N. Kok and V. Hasirci, Determination of binary pesticide mixtures by an acetylcholinesterase-choline oxidase biosensor. Biosens. Bioelectron. 19, 661-665 (2004). 

---