DMSO extract

Hydrolysis Experiments. The substrate in the hydrolysis experiments included alkali-extracted beechwood 4-O-methylglucuronoxylan, DMSO-extracted acetylated beechwood 4-O-methylglucuronoxylan, alkali-extracted wheat straw arabinoxylan and acetylated or deacetylated xylo-oligomers from steaming of birchwood (24). Deacetylation was carried out by incubating the freeze-dried xylo-oligomers in ammonia vapor overnight. Substrate concentration was 10 gl— 1, temperature 45° and hydrolysis time 24... 

The air samples should be stored in the dark at —20 °C, and the solvent (dichloromethane or DMSO) extracts should be stored in amber-colored, Teflon-lined, screw-capped bottles at —20 °C. These air samples and solvent extracts should come to room temperature prior to use. 

Fig. 6., 9F NMR spectrum of DMSO-extracted components from Fiberite 934 prepreg...

A procedure for extracting BHA and BHT from vegetable oils has been reported by Phipps (98). The oil was dissolved in n-heptane and extracted with dimethylsulphoxide (DMSO). Extracts of DMSO were mixed with aqueous sodium chloride solution, and the SPA were back-extracted into petroleum ether with subsequent concentration and analysis. 

The first intimation that mutagens could be formed from natural food substances came from the laboratory of Sugimura, where it was found that mutagenic activity was found in smoke condensates or in DMSO extracts of the charred surface of fish and meat. This activity could not be accounted for by the amounts of BaP and PAH known to be present. Extracts of pyrolysates of various proteins and amino acids were also mutagenic (14). 

Chromosome aberrations have been reported in Syrian hamster embryo (SHE) cells after treatment with a DMSO extract of tryptophan pyrolysate. At a dose of 30 pg/ml, 69 exchanges and 29 chromosome or chromatid breaks were observed among 200 metaphases. Gaps and minutes were noted as well (33). Sasaki, et al. (34) also observed chromosome aberrations in human and Chinese hamster cell lines after exposure to Trp-P-1 and Trp-P-2. 

Separation Techniques. The complexity of the organic composition of coal-derived liquids, shale oil, and their related effluents presents a formidable challenge to the analytical chemist. Our approach to this problem has been the classical separation technique based on acid-base-neutral polarity of the organic compounds. We further subdivide the neutral fraction into aromatic and non-aromatic fractions using dimethyl-sulfoxide (DMSO) extraction. DMSO effectively removes multiringed aromatic compounds with great eflBciency (85-95%) for these complex mixtures and thus allows a straightforward analysis for polynuclear... 

API. 1988. Unscheduled DNA synthesis in rat primary hepatocytes with PS-6 unleaded gasoline, its evaporation residue and a DMSO extract. Washington, DC American Petroleum Institute. 

In the experiments of Hayes et al. (1975) DMSO was marginally better than DMF or sulfolane for dissolving humic substances (Table 4). In the ESR there was evidence of a higher free radical concentration in DMSO than in either DMF or sulfolane. Because DMSO would not be expected to generate free radicals, it is reasonable to infer from the ESR data that humic components, which are insoluble in the DMF- and sulfolane-water systems, were dissolved in this solvent. Elemental contents were similar for the humic and fulvic acids of the DMSO extracts, and these data infer that the major difference between the two fractions was one of molecular size. However, some fulvic acid materials were observed to precipitate during dialysis, as was noted for the DMF and sulfolane systems. 

CONCAWE (1994) The use of the dimethyl sulphoxide (DMSO) extract by the IP 346 method as an indicator of the carcinogenicity of lubricant base oils and distillate aromatic extracts. CONCAWE Report No. 94/51. 

The UV specification addresses polynuclear aromatic levels specifically. This test and the associated dimethyl sulfoxide (DMSO) extraction procedure arose from work performed by the FDA in the 1960s to regulate food additives and their potential contamination with trace amounts of carcinogenic PAHs (3+ aromatic rings). Some examples of these compounds are given in Figure 11.4. The objective of those studies was to place an upper limit for their content in food and develop a method for measuring their level. 

BaA and BaP is added and the entire sample is extracted with methylene chloride (250-, 100-, and 100-mL portions). The extracts are combined, 10 mL of isooctane added, and the solution evaporated to about 10 mL. When the solution approaches 10 mL, a second 10-mL volume of isooctane is added. This is repeated three times. The isooctane solution is made up to 75 mL and extracted with three 100-mL portions of dimethyl sulfoxide (DMSO) that contains 20% phosphoric acid. The DMSO extracts are each washed with three 30-mL portions of fresh isooctane, combined and diluted with 500 mL of water. This solution is extracted with three 80-mL portions of isooctane. The isooctane extracts are combined, rinsed once with water, and evaporated to 25 mL. At this point, a 1-mL portion of the solution is removed for intermediate radioassay and a UV scan. Usually the concentrate is sufficiently free from interferences and is evaporated down to about 0.05 mL and an aliquot injected into the GC. If further purification is indicated, the solution is chromatographed on a 1.1-cm X 90-cm column containing 75 g of Woelm Neutral Alumina deactivated with 2% water. Before deactivation, the alumina is dried in an oven for 1 hr at 150°C. The solvent elution schedule is as follows 25 mL cyclohexane prewash, 25-mL sample in cyclohexane, 100 mL cyclohexane, 100 mL cyclohexane-methylene chloride (9 1), 100 mL cyclohexane-methylene chloride (1 1), 100 mL methylene chloride. After the first 125 mL has eluted, 10 cuts are then radioassayed and combined into a single PNA fraction. This fraction is evaporated to about 0.05 mL in preparation for the GC-UV finishing step. Figure 2 is a diagram of the wastewater procedure. 

Isolation ofPolymers from the Extracts. The solvents used for solubilizing the intracellular compounds would also solubilize a small proportion ( 6%) of the cell wall polymers from potatoes. These polymers could be isolated from the 1% SDC or 1.5% SDS, 0.5% SDC or SDS, PAW-, and DMSO-extracts. 

The extraction of the wood residue with dimethylsulfoxide (DMSO) after extraction of MWL produces Bjorkman s LCC [23] which has been considered for a long time as the classical and unique LCC preparation. Other solvents and water were also used to extract LCC preparations from the residue obtained after MWL isolation [17-19,35]. The concentration of lignin-carbohydrate linkages by enzymatic hydrolysis of the carbohydrate components of the DMSO-extracted LCC preparations [36] is a useful approach for LCC linkages analysis. 

Hsiao H-Y, Cheng T-J, Yang G-M, Huang I-J, Chen RLC (2008) Determination of camptothecins in DMSO extracts of Nothapodytes foetida by direct injection capillary electrophoresis. Phytochem Anal 19 136-140. doi 10.1002/pca.l026... 

Notice also that the reflux ratio in the extractive column in the chlorobenzene system RR= 1.55 in Fig. 11.19) is much higher than that in the DMSO extractive column RR = 0.842 shown in Fig. 11.16). This results in a much higher energy consumption in the extractive column (15.97 versus 7.93 MW). These results indicate that the chlorobenzene solvent is less efficient than the DMSO solvent, which is a different conclusion than that reached by Kossack et al. ... 

The EU defines the environmental risk of these oils by measuring the oil s polycyclic aromatic content through DMSO extraction. Some aromatic oils can be made to pass this EU test if they are processed by applying severe hydrotreatment, which destroys some of the polycyclic aromatics. 

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