Occurrence of organotin compounds in house dust in Berlin (Germany).

In a study in the year 2000 on the occurrence of hazardous environmental contaminants house dust samples from 28 Berlin apartments were measured for the presence and concentrations of six organotin compounds, monobutyltin (MBT), dibutyltin (DBT), tributyltin (TBT), monooctyltin (MOT), dioctyltin (DOT) and triphenyltin (TPT). The concentrations of MBT and DBT determined ranged considerably from 0.01 mg kg-1 to 1.5 mg kg-1 (median: 0.05 mg kg-1) and 0.01 to 5.6 mg kg-1 (median: 0.03 mg kg-1), respectively. Maximum levels of TBT and MOT were only 0.08 mg kg-1 and 0.04 mg kg-1. The maximum total value of the organotins was 7.2 mg kg-1 (median: 0.11 mg kg-1). MBT was found in 86% and DBT in 82% of the samples above the limit of quantification, TBT and MOT only in 50% and DOT in 43%. The focus of ecotoxicology is on the risks arising from organotin compounds (especially butyltins) when used as biocides in antifouling paints. TBT acts as an endocrine disrupter in animals, inducing masculinization (imposex) in female gastropods of different species by increasing testosterone levels. The most critical organ site in experimental animals is the cellular immune system, where lymphocyte depletion in the thymus and peripheral lymphoid tissues takes place. Our study does not provide data on the basis of which population exposure could be estimated; house dust containing harmful organotins could, however, under some conditions, become a relevant intake possibility for young children.

Determination of lipoic acid in meat of commercial quality.

For the quantitative determination of lipoic acid in meat a sensitive GC/MS method in the chemical ionisation mode with methane as reactant gas has been developed. Firstly, the cleavage of protein-bound lipoic acid from the epsilon-amino group of lysine residues was optimized by hydrolysing the synthesized model compound epsilon-lipoyllysine with several organic and inorganic acids and proteolytic enzymes. The concentrations of lipoyllysine and lipoic acid during this test hydrolysis were monitored by HPLC. Optimum hydrolytic conditions were heating at 120 degrees C in 2 mol H2SO4 for seven hours. After tissue hydrolysis, the lipoic acid in the hydrolysate was separated by a diethylether/sodium bicarbonate/diethylether extraction and then derivatised for GC with MBDSTFA. The highest amounts of lipoic acid in meat of commercial quality were detected in liver, heart and kidney whereas in muscle tissues its content was lower.