Insecticide Metabolism, Thin-Layer Chromatography and Cholinesterase Detection of Several Phosphorothiono Insecticides and Their Oxygen Analogs

Abstract

charge on the sulfonium salt may be expected to increase the affinity for cholinesterase by coulombic attraction to the negatively charged anionic site. However, as with the quaternary ammonium salts, position isomerism is of overriding importance, as is shown in fable IV. In both the thioether and amine series, the most active quaternary compounds are those with the charged atom in the meta-position of the ring. The attraction of the ammonium nitrogen to the anionic site is considerably stronger than that of the sulfonium sulfur. It is of particular interest to compare the affinities of the sulfonium compounds in Table IV with the uncharged methylthioethers of Table I. It is apparent that quaternization decreases the affinity of the ortho-isomer (XLV) to about 0.05, increases the affinity of the meta-isomer (XLVII) by about 10 times, and increases the affinity of the para-isomer (XLIX) by about 3 INSECTICIDE METABOLISM times. These affects are qualitatively similar to those observed with quaternization of the uncharged dimethylaminophenyl AT-methyl carbamates (8): The ortho-isomer (XLVI) decreased to about 0.2, meta-isomer (XLVIII) increased by about 130-fold, and paraisomer (L) increased about 68-fold.As has been observed with the quaternary ammonium carbamates (.5), the presence of a formal positive charge in the sulfonium carbamates effectively destroys the contact toxicity to Musca and Culex, presumably because of the inability of the charged molecules to penetrate into the nerve synapse.

ORGANİK FOSFORLU, KARBAMAT ve ORGANİK KLORLU PESTİSİDLERİN İNCE-TABAKA KROMATOGRAFİSİNDE KROMOJENİK AYIRAÇLARLA SİSTEMATİK ANALİZİ

“…Organik tiyofosfat pestisidlerin kağıt kromatografisi ve tTK'nde belirtimi için çeşitli kromojenik ayıraçlar bildirilmiştir: Brom buharlarıyla oksitleme ve ardından gümüş nitrat-bromfenol mavisi uygulanması (9,23,51); paIJadium klorür (6,{6); 2,6-dibromo-N-kloro -p-kinonimin (8,39); N-bromosüksinimid ve ardından fluoresein (I 8); brom ve fluoresein (41); brom buharıyla oksitlerneden sonra metanil yellow, yeIJow RFS veya metlıyl orange (21) ya da kongo kır-mızısı (3 i) boyaları püskürtülmek suretiyle pestisid lekelerinin değişik renklerde görünür hale getirilmesi, yahut kolinesteraz enzim-inhibisyon tekniği (23,27) gibi yöntemler yararlı sonuçlar vermiş-tir. Bunlardan Irudayasamy ve Natarajan'ın (31) kağıt kromatografisinde kullandığı brom-kongo kırmızısı ayıraç dizisini tTK'ne uyarlayarak yaptığımız bir çalışmada (I I) daha duyarlı ve oldukça spesifik sonuçlar elde ettik.…”

Parathion Absorption, Translocation, and Conversion to Paraoxon in Bean Plants

“…Purity checks by thin-layer chromatography revealed only parathion when 10 Mg. of the standard was chromatographed and potassium hydroxide used to detect the p-nitrophenyl compounds. Traces of paraoxon, however, were detected in the standard when the verysensitive cholinesterase spray technique was used (8). Parathion emulsions for treatment of leaf and glass surfaces were prepared in distilled water with 0.2% v./v.…”

“…however, ivere detected in the standard when the very sensitive cholinesterase spray technique \vas used (8). of the standard was chromatographed and potassium hydroxide used to detect the p-nitr(3phenyl compounds.…”

“…Partition thin-layer chromatography I < ith chromogenic and cholinesterase detection methods \\ as used for qualitative analyses of parathion, paraoxon, and other degradation products in plant extracts and surface rinses (8). Paraoxon residues 1 1 ere estimated quantatively on the chromatoplate with the cholinesterase method by comparing spot size and color density with a series of spots from paraoxon standard solutions.…”

“…is a selective, pre-emergence herbicide whose properties were discovered by Eli Lilly and Co. Research Laboratories (8). This compound is useful in the pre-emergence control' of a wide variety of annual grasses and broadleaf weeds.…”