The Application of the Karl Fischer Oven for the Determination of Water in Consumer Products.

The direct Karl Fischer (KF) titration method has known interferences for measuring water content. In addition, in analyzing some paints, KF can fail to produce an accurate analysis. The California Air Resources Board (GARB) staff has developed a KF procedure that can be used to determine the water content of consumer products. The procedure uses an oven accessory to the titration system, and is based on a distillation method developed by the California Polytechnical University at San Luis Obispo (Cal Poly). Samples are diluted in l-methoxy-2-propanol (MPA), and an aliquot is injected into an enclosed oven system, where the MPA/water azeotrope is swept directly into the KF titration vessel. The technique is accurate and precise and, thus far, proves to be a fast and reliable method for analysis.

Determination of Exempt and Prohibited Compounds in Consumer Products by Headspace Gas Chromatography Mass Spectrometry.

Title 17, California Code of Regulations, Division 3, Chapter 1, Subchapter 8.5, Articles 1 and 2, Sections 94500-94517 specify limits for volatile organic compounds (VOCs) in a wide variety of consumer products. However, under these regulations, specific compounds that have been shown to contribute little to the formation of ozone in the lower atmosphere are exempt from the definition of VOC. A headspace sampling and analysis method has been developed for the analyses of these compounds in consumer products. This method has been used successfully for analyzing aerosol and non-aerosol products.

Chlordecone alcohol formation in the Mongolian gerbil (Meriones unguiculatus): a model for human metabolism of chlordecone (kepone).

In seeking a practical animal model of chlordecone metabolism in humans, we found that among rats, hamsters, guinea pigs, or gerbils treated with a single injection of chlordecone, only in gerbils was this organo-chlorine pesticide converted to chlordecone alcohol, a reduced metabolite found in the stool of chlordecone poisoned humans. Analogous to these patients, chlordecone treated gerbils eliminated chlordecone alcohol exclusively in stool with none being detected in urine. Moreover, the gerbils excreted chlordecone alcohol in bile in an amount more than twice that of chlordecone and in the form of a glucuronide conjugate. The ratio of chlordecone to chlordecone alcohol in gerbil stool was 10 times higher than the ratio in human stool. This suggests that the newly recognized nonbiliary mechanism(s) for entry of chlordecone into the intestinal lumen (Boylan et al., Clin. Pharm. Ther. 25:579-585, 1979) may be extremely active in the gerbil. Biliary excretion of chlordecone alcohol in gerbils progressively increased following chlordecone treatment while biliary excretion of chlordecone remained unchanged. Incubation of the cytosolic fraction of gerbil liver homogenate in the presence of NADPH and chlordecone produced chlordecone alcohol, whereas rat liver cytosol was inactive. This observation indicates that bioreduction of chlordecone is catalyzed in gerbil liver by a species-specific reductase. Rats given [3H]-chlordecone alcohol excreted twice as much (80%) of the compound in stool after three days as compared to gerbils (40%), while the latter species accumulated three times more chlordecone alcohol in the liver than did the former. An unexpected finding was that the livers of these [3H]-chlordecone alcohol treated animals also contained chlordecone in amounts eight times (rat) and 14 times (gerbil) higher than the respective amounts of chlordecone alcohol. From this result, the existence of a separate enzyme(s) catalyzing dehydrogenation of chlordecone alcohol to chlordecone may be inferred.

Structure of human hemoglobin C: a disease with intraerythrocytic crystals.

Crystals of human cyanomethemoglobin C (beta 6A3 glu leads to Lys) crystallized in the orthorhombic space group P212121, A = 158(1), B = 65.5(4), C = 54.9(5) A with Z =4. Single crystal electron micrographs show filaments parallel to the b direction. The molecules are unusually densely packed compared to other hemoglobin crystals, and this may be related to the ease of intraerythrocytic crystallization.

Crystallography and oriented single crystal electron microscopy of hemoglobin deer II, a hemoglobin that exhibits matchstick-shaped erythrocytes.

Deer hemoglobin beta chain type II has been crystallized and preliminary diffraction data and oriented single crystal transmission electron micrographs have been obtained. The crystals are monoclinic P21 with Z = 4. The electron micrographs show a herringbonelike structure in the ab plane with open rectangular solvent channels and a fiber-like arrangement of molecules perpendicular to this plane.