Publications by authors named "W F BERTSCH"

The isolation of ignitable liquid components, usually petroleum-based distillates from fire debris, is an important step in deciding whether a fire is of natural or incendiary origin. Steady progress has been made to develop sample preparation methods capable of enriching target analytes in high yield and within a short period of time. Heated headspace enrichment methods are currently most widely used.

View Article and Find Full Text PDF

Analysis of accelerants in fire debris involves the isolation of residual volatiles from the matrix and the analysis of these volatiles, usually by gas chromatography (GC). The resulting chromatograms are interpreted by comparing to a library of accelerant chromatograms obtained under similar conditions. This review first mentions ASTM's system in classifying fire accelerants into light petroleum distillates, gasoline, medium petroleum distillates, kerosene, heavy petroleum distillates, and unclassified compounds.

View Article and Find Full Text PDF

Application of Tagetes minuta floral extract to silica gel column chromatography produced 2 fractions with the hydrogenate part 20-30 times more toxic to larvae and 12-13 times more toxic to adults of Aedes aegypti and Anopheles stephensi, respectively, than the oxygenate part. Further fractionation by column chromatography of the hydrogenate fraction produced 4 thiophenes, 5-(but-3-ene-1-ynyl)-2,2'-bithiophene, 5-(but-3-ene-1-ynyl)-5'-methyl-2,2'-bithiophene, 2,2',5',2"-terthiophene, and 5-methyl-2,2',5',2"-terthiophene. These compounds in Tagetes minuta are largely responsible for the toxicity exhibited against the tested mosquitoes.

View Article and Find Full Text PDF

Whole-plant Soxhlet extractions for the three Tagetes species showed that T. minuta had the greatest biocidal effect on the larvae and adults of Aedes aegypti (L.) and Anopheles stephensi Liston.

View Article and Find Full Text PDF

A previously unknown haemagglutinin, named Sambucus nigra agglutinin-III (SNA-III), has been purified from the fruit of the elder (Sambucus nigra). Whereas elder bark agglutinin I (SNA-I) is highly specific for terminal alpha 2,6-linked sialic acid residues, SNA-III displays a high affinity for oligosaccharides containing exposed N-acetylgalactosamine and galactose residues. Different N-terminal sequences and the amino acid composition distinguish the fruit lectin from elder bark agglutinin II (SNA-II), which shows a similar carbohydrate specificity.

View Article and Find Full Text PDF