Hideaki Iwai

Simultaneous determination of trialkyltin homologues in biological materials

Taking advantage of the high sensitivity of an electron capture detector to alkyltin halides, an analytical method has been developed for the simultaneous determination of trialkyltin homologues in biological materials. Trialkyltins were purified as chlorides from tissues by simultaneous extraction with hydrochloric acid and ethyl acetate, replacement of the extraction solution with n-hexane and stepwise elution with n-hexane-ethyl acetate on a silica gel column. Alternatively, gas chromatographic analysis was carried out on 20% DEGS-HG at temperatures from 100 to 120 degrees C. Detection limits reached 1 x 10(-12) g for trialkyltin chlorides. The recoveries of trialkyltins added to various tissues at the 50-pmole level ranged from 97 to 106%. By in vivo studies, it was confirmed that this method is rapid, sensitive and applicable to biomaterials containing more than 1 ng trialkyltins per gram of tissue.

Intestinal uptake site, enterohepatic circulation, and excretion of tetra‐and trialkyltin compounds in mammals

The intestinal uptake site, enterohepatic circulation, and excretion into bile, feces, and urine of alkyltins (tetra and trialkyltin) were investigated after oral, sc, or intestinal administration of the compounds to rats and rabbits. Assays of tetra- and trialkyltins in biological materials were carried out by gas chromatography. The main uptake sites in the small intestine were the jejunum and duodenum for tetraalkyltins and the ileum and jejunum for trialkyltins. Tetra- and trialkyltins were detected in the small intestine and contents of the intestinal lumen after sc injection of these compounds in rats. These facts suggest that tetra- and trialkyltins are transported in the body through enterohepatic circulation. The route, rate, and amount of excretion of tetra and trialkyltins seem to depend on the velocity of dealkylation, doses, physical and chemical properties, and route of administration of the compounds.

Rapid method for the determination of tetraalkyltin compunds in various kinds of biological material by gas chromatography

A rapid gas chromatographic method is described for the simultaneous determination of tetraalkyltin compounds in biological materials. Tetraalkyltins were rapidly purified by direct passage through a silica gel column after extraction from the homogenized tissues with n-hexane. Gas chromatographic analysis was alternatively carried out with PEG 20M at temperatures from 50 to 150 degrees C. A hydrogen flame-ionization detector was more sensitive and selective towards tetraalkyltins than an electron-capture detector. Detection limits reached 1 x 10(-8) g for tetraalkyltins. Recoveries of tetraalkyltins added to various tissues at the 85-nmole level ranged from 97 to 104%. In vivo studies indicated that for a sample containing more than 0.1 micrograms of tetraalkyltins per gram of tissue, the proposed method is accurate enough for quantitative analysis.