Malathion mixtures

Hermmanutz RO, Eaton JG, Mueller LH. 1985. Toxicity of endrin and malathion mixtures to Flagfish (Jordanella floridae). Arch Environ Contain Toxicol 14 307-314. 

Fig. 1 chromatogram of the thiophosphate insecticides (each ca. SOO ng) after treatment with dipping solutions I and II (A) before and (B) after complete drying of the TLC plate. TVacks 1 and S mixture Track 2 azinphos ethyl Track 3 malathion Track 4 diazinone. 

In the adsorption with Tenax alone satisfactory results were obtained, while in the presence of mineral oil a considerable proportion of the organophos-phorus pesticides (particularly Malathion and Parathion-methyl) was not adsorbed and was recovered in the filtered water. This drawback can be overcome by adding a layer of Celite 545 which, in order to prevent blocking of the column, is mixed with silanised glass wool plugs. A number of analyses of surface and estuarine sea waters were carried out by this modified Tenax column and simultaneously by the liquid-liquid extraction technique. To some of the samples taken, standard mixtures of pesticides were also added, each at the level of 1 xg/l (i.e., in concentration from 13 to 500 times higher than that usually found in the waters analysed). One recovery trial also specifically concerned polychlorobiphenyls. The results obtained in these tests show that the two extraction methods, when applied to surface waters that were not filtered before extraction, yielded very similar results for many insecticides, with the exception of compounds of the DDT series, for which discordant results were frequently obtained. 

With a molecular emission cavity flame detector, relying on measurement of the 526 nm emission of HPO (see Section II.C.l and III.B.3.b), nanogram amounts of phosphates or organophosphorus compounds can be assessed in automated systems160,348. Determination of m, the time elapsed between sample ignition and maximum emission, allows the resolution of ternary or more complex mixtures of insecticides. Dicrotophos, dimethoate, malathion and parathion mixed in aqueous solution were separated and identified in nanograms per millilitre concentrations348. 

These techniques are useful for the separation of complex mixtures. Quantitative analyses have been reported on malathion pesticide in vegetable matter, limonin in grapefruit peel, and additives in compound rubber by means of SEC and RPC126>. SEC was performed with unstabilized THF and monitored at 215 nm. Working so near to the UV cut-off (210 nm) of THF was possible through the use of a detector with a flowing reference installed between the pump and the sample valve. Then the eluent passed the column and finally the analytical cell. Since the column back pressure never exceeded 10 MPa, this eluent line caused no problems. 

One of the classic cases is the potentiation of the insecticide malathion by another insecticide, EPN, the LD50 of the mixture being dramatically lower than that of either compound alone. This potentiation can also be seen between malathion and certain contaminants that are formed during synthesis, such as isomalathion. For this reason quality control during manufacture is essential. This example of potentiation involves inhibition, by EPN or isomalathion, of the carboxylesterase responsible for the detoxication of malathion in mammals. 

Residues of malathion can be degraded to nonhazardous products using aqueous acidic potassium permanganate solution. Thus, to each 1 mL of commercial malathion solution, add 50 mL of 3 M sulfuric acid (8.5 mL of concentrated sulfuric acid added to 41.5 mL of water) and 3 g of potassium permanganate. Stir the mixture at room temperature for 5 hours. Neutralize the solution by careful addition of soda ash, and then decolorize by adding, while stirring, a saturated solution of sodium bisulfite (approximately 10 g of sodium bisulfite per 35 mL of water) until a colorless solution is formed. Wash the clear solution into the drain.5... 

Gas chromatography has been used [183] to determine the following at organophosphorus insecticides at the microgram per litre level in water and waste water samples Azinphos-methyl, Demeton-O, Demeton-S, Diazinon, Disulfoton, Malathion, Parathion-methyl and Parathion-ethyl. This method is claimed to offer several analytical alternatives, dependent on the analyst s assessment of the nature and extent of interferences and the complexity of the pesticide mixtures found. Specifically, the procedure uses a mixture of 15% v/v methylene chloride in hexane to extract... 

Hermanutz, R.O. (1978) Endrin and malathion toxicity to flagfish (Jordanella floridae). Arch. Environ. Contam. Toxicol. 7, 159-168. Hermens, J., Leeuwangh, P. (1982) Joint toxicity of mixture of 8 and 24 chemicals to the guppy (Poecilia reticulata). Ecotoxicol. Environ. Saf. 6, 302-310. 

Dibenzothiophene Malathion Methyls tearate Alkane mixture Test solution containing n-alkancs (Cg - C24, even members numbers) at a concentration of 50 40 ng/ml (microgram per milliliter) 2ml... 

OPCW GC/MS TEST MIXTURE containing in dichloromethane 10 rg/mL of n-Alkanes Cs-C24 even numbers Trimethylphosphate 2,6-Dimethylphenol 5-Chloro-2-methylaniline Tri-n-butylphosphate Dibenzo thiophene Malathion Methylstearate... 

Figure 5. An example of TIC of the check mixture from testing of 640S 1 - octane, 2 - Trimethylphosphate, 3 - decane, 4 - dimethylphenol, 5 - dodecane, 6 - chloromethylaniline, 7 - tetradecane, 8 - hexadecane, 9 -tributylphosphate, 10 - HCB, 11 - dibenzothiophene, 12 - octadecane, 13 - malathion, 14 - eicosane, 15 - methyl stearate, 16 - docosane, 17 - tetracosane...

To increase the marketability of Collego, its compatibility with chemical pesticides has been investigated. Mixtures of CGA with propanil [N-(3,4-dichlorophenyl)propanamide], molinate [S-ethyl hexahydro-lH-azepine-l-carbothioate], 2,4,5-T, and benomyl [methyl 1-(butylcarbamoyl)-2-benzimidazolecarbamate] were detrimental to CGA s efficacy (31). If, however, propanil, 2,4,5-T, fentin hydroxide (triphenyltin hydroxide), pencycuron N-[(4-chlorophenyl)methyl]-N-cyclopentyl-N -phenylurea), each at 0.56 kg ai/ha, and SN-84364 [3 -isopropoxy-2-(trifluoromethyl) benzanilide] (at 0.40 kg ai/ha) were applied after CGA treatment, disease and development were not inhibited (32). The herbicides, acifluorfen 5-[2-chloro-4-(trifluoromethyl)phenoxy]-2-nitrobenzoic acid) (0.56 kg ai/ha) and bentazon [3-(1-methylethyl)-(IH)-2,1,3-benzothiadiazin-4(3H)-one 2,2-dioxide] (0.56 to 1.1 kg ai/ha), or the insecticides, malathion [diethyl(dimethoxyphosphinothioylthio)succinate] (0.56 kg ai/ha) and carbofuran (2,3-dihydro-2,2-dimethyl-7-benzofuranyl methylcarbamate), (0.56 kg ai/ha) could be applied with CGA from a single tank mixture (33-34). ... 

Figure 5. Scan of five different concentrations of an organophosphorus insecticide mixture (A) dimethoate, (B) mevinphos, (C) Dasanit, (D) malathion, (E) carbophenothion...

The toxic effects of some pesticide mixtures are additive, particularly when their toxic mechanisms are identical. The additive effects of the organophosphates chlorpyrifos and diazanon were demonstrated in one study. T Another study found the s-triazine herbicides atrazine and cyanazine to show additive toxic effects. Not all mixtures of similar pesticides produce additive effects, however. In one study, mixtures of five organophos-phate pesticides (chlorpyrifos, diazinon, dimethoate, acephate, and malathion) were shown to produce greater than additive effects when administered to laboratory animals. Another article discusses nonsimple additive effects of pyrethroid mixtures. Despite the similarities in their chemical structure, pyrethroids act on multiple sites, and mixtures of these produce different toxic effects. 10 ... 

A mixture of malathion plus synergized pyrethrins was introduced into New South Wales, Australia. Its efficacy was studied in commercial stores by Des-marchelier et at. (1979). who found that treatment of stores in the South Dubbo region in 1977, with 18 gl malathion plus 3gl of synergized pyrelhrins resulted in 255 infestations (1 live insect or more) of R dominie a and T. iasiu-neum. of which only 17 wrere heavy (more than I insect per 5 kg). This compared favourably with the 614 infestations, of which 34 were heavy, reported for the same stores in 1976. when 18 g t 1 malathion alone was used. 

Weeks DE Endrin food-poisoning a report on four outbreaks caused by two separate shipments of endrin-mntaminated flour. Bull World Health Organ 37 499-512,1967 Wenzl JE, Burke EC Poisoning from a malathion-aerosol mixture. JAMA 182 495-497, 1962... 

CELTinON (121-75-5) see malathion. CERIUM (7440-45-1) A strong reducing agent. Dust forms explosive mixture with air. Oxidized by moist air pyrophoric thermally unstable spontaneous ignition above 302°F/150°C. The metal or its alloys spark... 

PHYSICAL PROPERTIES clear yellow to deep brown liquid a solid below 37 F garlic-like odor slightly soluble in water miscible with most organic solvents including alcohols, ketones, ethers, esters, aromatic and alkylated aromatic hydrocarbons, and vegetable oils solubility is limited in certain alkane hydrocarbons petroleum ether is soluble to about 35% in malathion MP (3.0 C, 37.4 F) BP (156-157 C, 313-315"F at 0.7 mmHg) DN (1.23 g/mL liquid at 25 C) LSG (1.21 at 20 C) VD (11.4) REL DN vapor/air mixture (1.00 at 20 C) VP (4 x 10 mmHg at 20 C). 

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