Differential leakage of intracellular substances from imbibing soybean seeds.

Leakage of electrolytes, substances absorbing UV light, and enzymic activities from imbibing soybean (Glycine max [L.] Merr.) seeds were compared to determine the extent that passive diffusion and cellular rupture contribute to each. Imbibing seeds with testae removed had average Arrhenius energies of activation (5 to 25 degrees C) of 3.0 and 15.8 kilocalories per mole, respectively, for the leakage of electrolytes and embryo malate dehydrogenase activity. Leakage of embryo enzymes from imbibing seeds was dependent on loss of testa integrity and subsequent loss of cellular membrane integrity or inability to seal preexisting membrane discontinuities. These data suggest that electrolyte leakage from imbibing seeds is primarily by passive diffusion, whereas the diffusion of intracellular macromolecules is primarily dependent on physiological phenomena affecting membrane integrity. Kinetic data and examination of the composition of seed leachates indicated that the leakage of substances absorbing UV light during imbibition is due to both passive diffusion of low molecular weight solutes and macromolecules released from ruptured cells.

Detection of nitroaromatic compounds on coal combustion particles.

Mutagenic and nonmutagenic extracts of fly ash from fluidized bed combustion were analyzed to determine the compounds responsible for the direct mutagenic activity (mutagenic activity that does not require added metabolic enzymes in the Salmonella mutagenicity assay). Some nitro derivatives of polycyclic aromatic hydrocarbons which are direct acting mutagens were detected by tandem triple quadrupole mass spectrometry. Treatment of a mutagenic and a nonmutagenic extract with excess N2O4 resulted in 28- and 3200-fold increases, respectively, in direct mutagenicity in Salmonella typhimurium strain TA98 and an increase in the relative abundance of nitroaromatic compounds. Polycyclic aromatic compounds were also detected and tentatively identified by gas chromatography-mass spectrometry. Since, previous studies have shown that polycyclic aromatic hydrocarbons may react with NO2 to form direct-acting mutagens, it appears that the direct-acting mutagens in these fly ash extracts may be products of reactions of polycyclic aromatic hydrocarbons with NOX in the combustion gases.

MS/MS analysis of diesel emissions and fuels treated with NO2.

Correlations between direct-acting mutagens in diesel emissions and the activity of nitroaromatic compounds have been noted, but detection and identification of nitro-compounds in diesel particulates has remained an elusive problem. In the results reported here, MS/MS (tandem mass spectrometry) was found to detect nitroaromatic compounds in fractionated and unfractionated diesel soot extracts. The nitro-compounds detected ranged from two- to four-ring polynuclear aromatic hydrocarbon derivatives and were primarily mono-nitro derivatives. An aromatic fraction from diesel fuel reacted with NO2 resembled diesel exhaust extracts from an engine operating on the same fuel. Therefore, it is possible that nitroaromatic derivatives in diesel exhaust may be in part due to unburned fuel residues reacting with NO chi formed in the combustion process. The utility of MS/MS in comparing complex mixtures from different sources or subfractions thereof is discussed.

Comparison of gas chromatography mass spectrometry methods for the determination of delta9-tetrahydrocannabinol in plasma.

A method for the identification of delta9-tetrahydrocannabinol by gas chromatography mass spectrometry has been developed, and this method has been compared with other techniques, such as detection via thin-layer chromatography using tritium labeled delta9-tetrahydrocannibinol and a dual gas chromatographic method. The gas chromatographic mass spectrometric method was found to be equal or superior to other techniques and has the added advantage of being highly specific for the compound analyzed. An alternate approach using chemical ionization is also described; however, this procedure does not show significant advantages over the electron impact method. These methods show a practical lower detection limit of 500 pg ml-1 of plasma in clinical practice.

Analytical methods for the determination of cannabinoids in biological media.

A pharmacokinetic study of the blood plasma levels in man of delta9-tetrahydrocannabinol, 11-hydroxy-delta9-tetrahydrocannabinol and cannabinol has been carried out by means of combined gas chromatographic-mass spectral analysis. In some cases comparison of the data was obtained on the same sample using thin layer chromatography of radiolabeled samples and electron capture gas-liquid chromatography. For the mass spectral studies appropriately deuterium labeled analogs of the previously named compounds were used both as internal standards and as a carrier for the relatively small amounts of nonlabeled drug present in plasma. Blood samples were obtainted at periodic intervals up to 24 hours from volunteers receiving 4-5 mg delta9-THC intravenously. After extraction and "clean-up" by Sephadex chromatography, the extracts were concentrated and subjected to glc-ms in the electron impact (ei) mode or alternatively with a chemical ionization (ci) source, in which case preliminary chromatography could be omitted. In all cases calibration curves were obtained from replicate analyses of spiked plasma containing the internal standard and various quantities of the cannabinoid under analysis. A typical biphasic elimination of the drug was observed with rapid elimination of delta9-THC from the blood over a period of 40 min followed by a much slower elimination up to 24 hours. The experimental data show that 11-hydroxy-delta9-THC is found in the plasma in quantities only about one-twentieth to one-twenty-fifth the values found for delta9-THC. Cannabinol was not found in significant quantities. Good agreement was obtained between the mass spectral analyses and the thin layer chromatography or electron capture gas-liquid chromatographic procedures.