Fenitrothion

Fenitrothion, an organophosphate/contact insecticide, is chemically known as 0,0-dimethyl 0-(4-nitro-m-tolyl) phosphorothio-ate, or 0-0-dimethyl-0-3-methyl-4-nitrophenol phospherothioate. 

Solubility Insoluble in water (14 mg/L), soluble in organic solvents such as acetone, alcohol, benzene, toluene, dichloromethane, etc. Also soluble in xylenes, ketones, esters, etc. 

Appearance Technical grade is a yellowish brown liquid having an unpleasant odor. 

Fenitrothion is one of the very important outlets for m-cresol and is widely used throughout the world. As stated in an earlier chapter, m-cresol on nitration gives 4-nitro-m-cresol which is then converted to fenitrothion. 

The product is marketed under various trade names such as 

IUPAC name 0,0-dimethyl O-4-nitro-m-tolyl phosphorothioate Molecular formula C9H12N05PS Toxicity class USEPA II WHO II 

Uses The formulations of fenitrothion include dusts, emulsifiable concentrate, flowable, fogging concentrate, granules, ultra-low volume, oil-based liquid spray, and wettable powder formulations (Novathion 500-E, EC as a 95% concentrate, 

Toxicity The acute oral LD50 for rats ranges between 250 and 800 mg/kg, for mice between 715 and 870 mg/kg, and for guinea pigs 500 mg/kg. The acute dermal LD50 for rats and mice is more than 890 and 3,000 mg/kg, respectively. The acute inhalation LC50 in rats is reported as 5 mg/L. Sumithion 50-EC has been shown to cause delayed neurotoxicity in adult rats as well as in humans.57-60 

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Observing the amount and variety of pesticides analyzed by GC chromatography we decided to observe 14 of the most represented pesticides Prometryn, Deltamethrin, Fenitrothion, Tebuconazole, Buprofezin, Malathion, Myclobutanyl, Atrazine, Acetochlor, Bifenthrin, Alachlor, Pendimethalin, Dichlonuid and Trifluralin. 

Chlorfenvinphos, cythion, diazinon, elsan, fenitrothion, fenthion, malathion, methyl parathion, mevinphos, monocrotophos, parathion, quinalphos, temephos, TEPA, tetrachlorvinphos... 

The reagent sequence is specific for endosulfan and phosphamidon. Other insecticides, e.g. organochlorine insecticides, such as endrin, aldrin, dieldrin, DDT and BHC, organophosphorus insecticides, such as malathion, parathion, dimethoate, quinalphos, phorate and fenitrothion, or carbamate insecticides, such as baygon, car-baryl and carbofuran do not react. Neither is there interference from amino acids, peptides or proteins which might be extracted from the biological material together with the pesticides. 

Fig. I Reflectance scan of a chromatogram track with 300 ng substance per chromatogram zone 1 = azinphos methyl, 2 = azinphos ethyl, 3 = parathion methyl, 4 = fenitrothion, 5 = parathion ethyl + phoxim.

After drying in a stream of cold air coumaphos (hRj 30-35) appeared as an intense red chromatogram zone on a colorless background, while parathion methyl (hRj 40-45), fenitrothion (h/ f 45-50) and parathion ethyl (hRf 60-65) yielded yellow zones as they did with sodium hydroxide alone (. v.). The detection limit for coumaphos was 10 ng per chromatogram zone. 

In situ quantitation The absorption photometric scan in reflectance of parathion methyl, fenitrothion and parathion ethyl was carried out at a mean wavelength of 1 )- Coumaphos was determined at X = 540 nm (Fig. IB). 

Fig. 1 Reflectance scan of a chromatogram track with 300 ng each substance per chromatogni zone (A) scan at X = 406 nm, (B) scan at X = 540 nm 1 = coumaphos, 2 = parathion mdli 3 = fenitrothion, 4 = parathion ethyl. ...

Abe T, Fujimoto Y, Tatsuno T, et al. 1979. Separation of methyl parathion and fenitrothion metabolites by liquid chromatography. Bull Environ Contam Toxicol 22 791-795. 

Adhya TK, Barik S, Sethunathan N. 1981. Stability of commercial formulation of fenitrothion, methyl parathion, and parathion in anaerobic soils. J Agric Food Chem 29 90-93. 

Kunimatsu T, Kamita Y, Isobe N, et al. 1996. Immunotoxicological insignificance of fenitrothion in mice and rats. Fundam Appl Toxicol 33 246-253. 

Misra D, Bhuyan S, Adhya TK, et al. 1992. Accelerated degradation of methyl parathion, parathion, and fenitrothion by suspensions from methyl parathion- and />nitrophenol-treated soils. Soil Biol Biochem 24 1035-1042. 

Sultatos LG, Huang GJ, Jackson O, et al. 1991. The effect of glutathione monoethyl ester on the potentiation of the acute toxicity of methyl parathion, methyl paraoxon or fenitrothion by diethyl maleate in the mouse. Toxicol Lett 55 77-83. 

Yamamoto T, Egashira T, Yoshida T, et al. 1982. Comparison of the effect of an equimolar and low dose of fenitrothion and methylparathion on their own metabolism in rat liver. J Toxicol Sci 7 35-41. 

Yadav AS, Vashishat RK, Kakar SN. 1982. Testing of endosulfan and fenitrothion for genotoxicity in Saccharomyces cerevisiae. MutatRes 105 403-407. 

Morgan, M.J., Fancey, L.L., and Kiceniuk, J.W. (1990). Response and Recovery of Brain Acetylcholinesterase Activity in Atlantic Salmon (Sahno-Salar). Exposed to Fenitrothion. Canadian Journal of Fisheries and Aquatic Sciences 47, 1652-1654. 

Sancho, E., Ferrando, M.D., and Andreu, E. (1997). Response and recovery of brain acetylcholinesterase activity in the European eel, Anguilla anguilla, exposed to fenitrothion. Ecotoxicology and Environmental Safety 38, 205-209. 

Sebire, M., Holtorf, K., and Sanders, M. et al. (2008). Fenitrothion acts as anti-androgen and disrupts the reproductive behaviour of the three-spined stickleback. Ecotoxicology (accepted). 

Azinphos methyl (h/ f 15-20), azinphos ethyl (liRf 20-25, parathion methyl (hiif 40-45), fenitrothion (h/ f 45—50), parathion ethyl (hR 60-65) and phoxim QxRf-. 60-65) appear as red-colored chromatogram zones on a colorless background. 

The main purpose of this work is development of small-scale and mobile dsMmposition system of these chemicals. A number of studies on decomposition of organophosphorus insecticides have been conducted [1-3]. It is well known that or nophosphorus insecticides are decomposed by hydrolysis under alkaline condition, and its meciianisms have been studied [4], Even so, relatively few papers have address the devdopment of kinetic equations for reactor desipi. In this study, we aim to get kinetic equaticms for their decomposition under alkaline condition. As organophosphtous, we used parathion, fenitrothion, diazinon, malathion and phenthoate. 

From the results of experiment 2.1, we confirmed decomposition reaction is pseudo first-order, and calculated pseudo first-order decomposition rate constants. Then fixnn relationship between each first-order reaction rate constant and sodium hydroxide concentration, we confirmed that the reaction is expressed by second-order with expression first-orders for both of sodium hydroxide and fenitrothion. 

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