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A convenient method, not involving ashing or acid digestion, for the determination of inorganic phosphorus content in crude palm oil, is developed. Direct extraction from solvent-diluted palm oil by dilute acid allows the inorganic phosphates to be analyzed by the usual phosphomolybdenum blue complex. Using this method, phosphate analyses in palm oil samples were correlated with other oil quality parameters and the results discussed.

Phospholipids, selectively extracted from crude palm oil and free of colored carotenoids, can be quantitatively determined by the phospholipid-molybdenum blue complex in hexane. A study of the phospholipid in crude palm oil in relationship to other components affecting oil quality shows that they have a beneficial effect while any detrimental effect may be of an indirect nature.

Analytical methodology has been developed for the simultaneous determination of branched and linear alkylbenzene sulfonates (BAS and LAS) in river water and wastewater samples. The samples were purified and concentrated by solid phase extraction, followed by HPLC separation and quantification using a C18 column. The LAS homologues were well separated with prominent peaks corresponding to the different alkyl groups with carbon chainlengths from C10 to C14. The elution of BAS shows a slightly broadened major peak with the same retention time as the C11 peak of LAS. The C12 peak, with no significant contribution from BAS components, has been chosen for the direct determination of LAS whereas the concentration of BAS can be calculated from the composite peak height of BAS after correcting for the C11 contribution from LAS. The method has been applied for the determination of the levels of specific LAS and BAS in some river water and wastewater samples. Comparison with the anionic surfactant concentrations measured in terms of the standard MBAS (methylene blue active substances) values is presented.

Manual and automated flow methods for the determination of 1-arginine and 1-lysine using decarboxylase enzymes and a carbonate ion selective membrane electrode are described. Excellent results are obtained in the millimolar concentration range for aqueous samples having physiological saline levels. The method could be utilized for the simple determination of specific amino acids in biological samples.

Analytical procedures have been developed for the determinations of total tin and tributyltin in biological tissues using graphite furnace atomic absorption spectrometric (GFAAS) technique. For total tin determination, the acid digested sample solution of the tissues is allowed to pass through an anion exchanger column in the chloride form in order to remove the dissolved solids and residual lipids which interfere with the GFAAS measurements. Tin chloride is recovered in the eluate with 4M HNO3. For the measurements of tributyltin, the acid-homogenised tissue solution is extracted directly with n-pentane. Dibutyl- and monobutyltin and inorganic tin are removed by back-wash with 0.8M NaOH. The extract is further cleaned up by passing through a C18 solid phase extraction (SPE) tube. Tributyltin recovered in a methanol-nitric acid mixture is determined by GFAAS using tungstate-treated graphite tube. The method developed has been applied for the analysis of bivalve samples and a detection limit of 0.4 ng g-1 as TBT-Sn has been achieved. The accuracy of the method has been checked using a certified fish tissue reference material (NIES-11). The levels of total tin and tributyltin obtained are in good agreement with the certified values.

Peritoneal cells from starch-injected Swiss mice were propagated in plastic petri dishes and on cover slips in a mouse L-cell-conditioned medium for 12 to 24 h and then infected with various multiplicities of lactate dehydrogenase-elevating virus (LDV). Over 95% of the cells in these cultures phagocytosed latex particles and were, therefore, considered macrophages. Infected and mock infected macrophage cultures were supplemented with [3H]uridine at various times after infection and with actinomycin D 30 min before addition of the [3H]uridine. After 1 or 2 h of further incubation, plate cultures were analyzed for LDV-specific RNA, and cover slip cultures were investigated by autoradiography. Other cultures were labeled in the absence of actinomycin D, and the culture fluid was analyzed for labeled LDV. There was a good correlation between the production of LDV-specific RNA and LDV and the number of heavily labeled cells in these cultures. The labeled cells in these cultures. The labeled cells, therefore, were equated with productively infected cells. Only a maximum of about 20% of the macrophages, however, became heavily labeled regardless of the multiplicity of infection or the time, after infection, at which the cells were exposed to [3H]uridine. Only background labeling was observed in the remainder of the cells and in mock-infected cells treated with actinomycin D. The highest proportion of labeled cells was observed when the cells were infected with a multiplicity of infection of about 2,000 mouse infectious units per cell and labeled from 6 to 8 h after infection. Thereafter, the proportion of productively infected cells decreased progressively, concomitant with a decrease in the amounts of viral specific RNA and of LDV produced by the cultures. The results indicate that the majority of the macrophages in primary macrophage cultures do not support LDV replication. Their nonpermissiveness may depend on the physiological state of the cells or reflect the presence of subpopulations of macrophages, but no morphological differences between productively infected an uninfected cells were detectable.

A population of cells stably resistant to a concentration of arabinosyladenine 100-fold greater than that tolerated by wild-type cells was selected over a period of 15 months. The cells are not cross resistant to arabinosylcytosine and may have at least one kinase with altered substrate specificity.