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The purpose of this work was to evaluate the results (especially calibration data) of gas chromatographic analysis of a wide range of pollutants (PAH, PCB, various groups of pesticides) in sediments in order determine the influence of any matrix present in the extract. Either crude extract or cleaned‐up extract was used in the experiments. The so‐called matrix‐induced chromatographic response enhancementand its influence on the calibration of chromatographic systems were evaluated. Matrix present in an extract either increases or decreases the chromatographic response. It was shown that calibration procedures using a solution prepared in a matrix‐free solvent often lead to systematic errors when only trace levels of analytes are present in the extract. The greater the extent of sample clean‐up, the less frequent the unpredictable effects. After extensive clean‐up the use of standards prepared in a “pure” solvent as the reference during calibration step can be accepted. Some conclusions for using different sleeves are given and critical points relating to the use of a splitless injector are mentioned.

AbstractJanicki, B., Rosinski, A., Elminowska-Wenda, G., Bielinska, H. and Gronek, P.2000. Effect of feeding system (intensive versussemi-intensive) on yield and fatty acid composition of abdominal fat in White Italian geese. J. Appl. Anim. Res., 17: 279–284.The aim of the experiment was to evaluate the effect of two feeding systems, intensive and semi-intensive, on yield and fatty acid composition of abdominal fat. The geese fed intensively consumed lesser dry matter but more ME. They yielded higher body weights, abdominal fat and skin with subcutaneous fat of breast muscle. Intensive feeding also resulted in higher mono-unsaturated fatty acids, primarily oleic acid and lesser poly unsaturated fatty acids (mostly linoleic acid) in abdominal fat.

Comparisons were made of the yield, chemical content, and biological activity of filtrates and extracts obtained by sonic and pressure cell disruption of bacilli from 4- and 8-week-old Proskauer and Beck cultures of the H37Rv strain (TMC no. 102) of Mycobacterium tuberculosis. The culture filtrates were dialyzed, freeze-dried, reconstituted in saline, and sterilized by membrane filtration. The viable bacilli were washed and resuspended in distilled water and subsequently disrupted either by sonication in the cold for 15 or 30 min or by treatment at 20,000 or 40,000 lb/in2 in a pressure cell. The resulting extracts were clarified by centrifugation, concentrated, and sterilized by filtration. All preparations were adjusted to contain 10 mg of solids (dry weight)/ml and were analyzed quantitatively for protein, deoxyribonucleic acid, ribonucleic acid, polysaccharide, and lipid content. Separation patterns obtained by gradient acrylamide gel electrophoresis, as well as by one- and two-dimensional immunoelectrophoresis, provided the basis for qualitative comparisons of the culture filtrates and cell extracts. Three-point dose-response curves also were used to compare the preparations for skin test reactivity in BCG-vaccinated guinea pigs. It was concluded that, although there were no consistent differences in chemical content or biological activity between the preparations, a 15-min sonic treatment appeared to be the most suitable method for preparation of bacillary extracts based on yield of active components and ease of preparation.

Two nonionic surfactants, Triton WR-1339 and Macrocyclon inhibit the hydrolysis of triglycerides in a coconut oil emulsion (Ediol) by pancreatic lipase, Triton inhibiting to a greater extent than Macrocyclon in a ratio of approximately 2:1. HOC-60, also a nonionic surfactant, is not inhibitory. The results of the present study indicate that during its incubation with the surfactant at 37°;C for 1 hour before adding the enzyme, the substrate may undergo a change which would result in an altered substrate molecule that is less reactive to pancreatic lipase. Two suggested mechanisms of the inhibitory action of the nonionic surfactants are discussed; (1) formation of an irreversible complex and (2) formation of a micelle. The ability of these agents to induce hyperlipemia in animals was reflected by inhibition of enzymatic lipolysis in vitro.