Spectrophotometric determination of some pesticides were investigated. Dinitrocyclohexylphenols with strong yellow colour in basic solution were directly estimated by spectrophotometry. Fenitrothion was converted to p-nitro-o-cresol by boiling in basic ethanol and nitrocresol was determined spectrophotomecally. Gottlieb's method of pentachlorophenol using 4-aminoantipyrin were proved to be more selective than titration method published by JIS and WHO. Stability of pentachlorophenol in water was studied using this colorimetry. Cellocidin (acetylenedicarboxamide) was refluxed in ammonia water and resulting 1-amino-1, 2-ethylenedicarboxamide with strong absorption peak at 296nm was assayed by spectrophotometry. Dithianone was redused with sodium sulfide in methanol and resulting yellow colour was measured. The methods mentioned above were accepted as official methods of analysis of pesticide formulations by Ministry of Agriculture, Forestry and Fishery. Simple infrared spectrophotometry of technical aldrin, tetradifon, heptachlor, naled and trichlorfon was established. The combination of spectrophotometric assay and separation by thin-layer chromatography presented exact and precise methods of analysis of mecarbam, aldrin, DCPM and CPCBS.Persistency of parathion in fruit, vegetable and rice were investigated using Averell-Norris's and Buckley's colorimery. Averell-Norris's method based on diazo-coupling reaction was applied to microdetermination of nitrofen, quintozene and herbicides with chloroaniline group. Nitrofen and quintozene were reduced with zinc dust and hydrochloric acid, the herbicides were hydrolysed with acid or alkali and resulting chloroanilines were subjected to diazo-coupling reaction. Loose-layer chromatography was used as clean up procedure. Methods of residue analysis of naphthalene-acetic acid, carbaryl, benomyl, thiophanate-methyl and naproanilide using high-speed liquid chromatograph equiped with fluorophotometer were established and proved to be very convinient, precise and sensitive.
Search from 250 M+ research papersSearch from 250 M+ research papers
Dec 1, 1980
C S Giam + 3
Open Access