Yoshihiko Kawano

Analysis for kawa pyrones in extracts of Piper methysticum

Abstract The amounts of kawa pyrones (e.g. I and II) in ether extracts of Piper methysticum were determined using two-dimensional thin-layer chromatography on aluminium oxide. The concentrations of desmethoxyyangonin, yangonin, dihydromethysticin, methysticin, dihydrokawain, and kawain were determined by u.v. spectroscopy after elution of the spots with methanol. Recoveries of known compounds were 80–85 per cent for yangonin and 90–95 per cent for all others.

Analytical studies of pyrethrin formulations by gas chromatography

Commercial formulations of mixtures of pyrethrins, piperonyl butoxide, and n-octyl bicycloheptene dicarboximide were quantitatively measured by gas chromatography. The three active ingredients of the formulations were measured simultaneously using gas chromatographic columns containing the support Chromosorb W coated with either 3% or 5% SE-30 silicone. The individual pesticide components present in the formulations, ranging in amounts of 0.05 to 50.0% of the mixtures, could be measured within a reasonable degree of accuracy.

Analytical studies of pyrethrin formulations by gas chromatography : III. Analytical results on insecticidally active components of pyrethrins from various world sources

Abstract Gas chromatographic techniques were applied to studies of the insecticidally active esters of pyrethrum. Pyrethrin extracts from various world sources were compared. The greater potential importance of more definitive and precise results acquired by gas chromatography compared with results obtained by older classical procedures is illustrated and it is more evident when comparisons are made of the “tru” pyrethrin I and pyrethrin II ester fractions of the extracts. Results of this more precise nature should be of increased benefit to the pesticides formulator and to the insect toxicologist.

Potential problems with the use of distilled water in pesticide residue analyses

Abstract Precautions should be taken with distilled water that may be included in any scheme of analysis for pesticides, especially in the nanogram-picogram analytical range, to insure that the water has not been contaminated with organic components derived from the water distillation system. Ultimate analysis of the sample by gas chromatography, utilizing an electron capture detector, will record any contaminants present and they may confuse the interpretation of the pesticide analytical data. Preferably, an all-glass still unit which contains no plastic fittings of any type should be used. Some of the potential problems with distilled water that may occur if plastic or resin components are included in the distillation system are discussed in this report.

The effect of an accidental exposure of broiler chicks to dieldrin

An abnormally high death rate of two shipments of chicks introduced into a local poultry farm shortly after treatment of the poultry houses with dieldrin prompted an investigation by the State Veterinary Laboratory and the Agricultural Biochemistry Depart1~ent of the University of Hawaii. The results of a pathological and chemical study of the affected birds are the substance of this report. History of Incident: An 18% emulsifiable concentrate of dieldrin, diluted 1:50, was sprayed on all parts of six poultry houses three days before chicks were placed in the houses, to control a termite infestation. This was the first time dieldrin was used on this farm. The houses contained no litter material, feed, or drinking water at the time of the spray operation. The first shipment of 8,320 day-old chicks placed in House No. 1 had a mortality of 4.4% during the nine-day period after receipt of the chicks; the greatest number dying on the fifth and

Analytical studies of pyrethrin formulations by gas chromatography II. Isolation of the pyrethrins from water-based formulations☆

Abstract The extraction of pyrethrins and synergists from water-base aerosol formulations is improved and simplified by the use of acetone in the extraction procedure. The procedure minimizes interferences from extraneous substances previously encountered in the subsequent analysis of the pyrethrins by gas chromatography.

Pesticides, pesticide residues, tolerances, and the law (U.S.A.)

Until the latter part of the 1950–1960 decade, pesticide, residue, and tolerance (the last two terms in the connotative sense of pesticides) were words primarily limited to the vocabulary of those involved in agricultural pursuits and small groups of specialists within the confines of the University academe. Similarly, the 1947 Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) (U.S. Department of Agriculture 1964) and the Miller Bill (Pesticide Chemicals Amendment) of 1954 and the Food Additives Amendment of 1958 to the Federal Food, Drug, and Cosmetic Act (1967) were of primary interest only to the agriculturist, food processor, and chemical manufacturer.1