TLC of p-nitroanilines and their analogues with cyclodextrins in the mobile phase.

The addition of alpha-, beta-, gamma-, and hydroxypropyl-beta-cyclodextrins to aqueous mobile phases can be used to enhance the migration of p-nitroanilines and their analogues on thin-layer chromatography. Urea, which is used to solubilize the cyclodextrins in aqueous solutions, is also found to increase the migration of these compounds. The equilibrium binding constants for the solute-cyclodextrin complexes formed in the mobile phase are determined. The results obtained using either silica gel or polyamide plates are similar.

Thin-layer chromatography of laser dyes and dye analogs with cyclodextrins in the mobile phase.

The addition of beta-cyclodextrin and substituted hydroxyethyl and hydroxypropyl-beta-cyclodextrins to aqueous urea-containing mobile phases, can be used to enhance the migration of various laser dyes on thin layer chromatography. Selected laser dyes from the coumarin, rhodamine and bimane families were examined, as well as a number of dye analogs. Silica gel, polyamide and C18 reverse phase plates were utilized. Overall, the substituted hydroxypropyl-beta-cyclodextrins appeared to be the most effective for increasing dye migration.

Effect of beta-cyclodextrin on mucochloric acid and 3-chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone.

Cyclodextrins form inclusion complexes with a wide range of guest molecules which wholly, or in part, fit into their hydrophobic cavity. Since no covalent bonds are formed in this complexation, the guests can subsequently be eluted. The possibility of such complexation was envisioned as a means of removing chlorinated furanones from drinking water. Using a combination of infrared and ultraviolet techniques, evidence is presented for inclusion complex formation between mucochloric acid and beta-cyclodextrin in acidic aqueous solutions. Ultraviolet evidence supports the conclusion that under these acidic conditions, mucochloric acid exists in its cyclic form. Solid samples of the mucochloric acid-beta-cyclodextrin complex could be isolated by recrystalization of a 1:1 mole ratio of the above compounds from water at pH approximately 2. Solid sample infrared (potassium bromide or Nujol) showed a carbonyl shift of approximately 20 cm-1 when mucochloric acid was compared to the mucochloric acid-beta-cyclodextrin complex. No such shift was found upon simply grinding together the above components. Thus the carbonyl shift is ascribed to inclusion complexation of mucochloric acid into the beta-cyclodextrin cavity. Melting point and thin-layer chromatographic analyses also yielded supporting evidence for the formation of solid mucochloric acid-beta-cyclodextrin complexes. Pilot studies with 3-chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone (MX), suggest a similar beta-cyclodextrin-complex formation in acidic solutions.

Molecular properties of the chlorinated ethylenes and their epoxide metabolites.

This paper has presented the initial results of a computational study of the chlorinated ethylenes and their epoxides. Particular attention was devoted to those properties which may be related to the reactivities, and specifically carcinogenicities, of these molecules. Detailed calculations of their optimum structures have been carried out, and stabilities, dipole moments, charge distributions, and epoxide C-O bond strengths were determined and have been discussed. For the epoxides, most of this information, including the structural data, has not previously been available. It is hoped that this will help to bring about a better understanding of the biological activities of the chlorinated ethylenes, and of the manner in which these activities are related to the numbers and locations of the chlorine substituents. Particularly promising in this respect are the qualitative assessments of the epoxide C-O bond strengths presented above. More quantitative measures of this key property are currently being computed.

Mass spectra of the oxygenated products generated from phenanthrene under simulated environmental conditions.

The photooxidation of phenanthrene under stimulated environmental conditions to 9,10-epoxy-9,10-dihydrophenanthrene, among other oxygenated products, serves as a model for the conversion of polycyclic aromatic hydrocarbons to potentially mutagenic and/or carcinogenic products. The separation and identification were achieved by glass capillary gas chromatography mass spectrometry, and by comparison of gas chromatographic retention times and mass spectral fragmentation patterns with data observed for authentic samples obtained independently through synthesis or from commercial sources. The structural rearrangements of 2,2'-di-substituted biphenyls such as 2-formyl biphenyl-2'-carboxylic acid, 2,2' diformyl biphenyl and diphenic acid anhydride, induced upon electron impact are investigated and discussed in detail. The mass spectral comparison of 9,10-epoxy-9,10-dihydrophenanthrene, a primary mammalian metabolite of phenanthrene, and certain other structural isomers was conducted and the results of this study suggest a mass spectral technique capable of differentiating arene oxides from oxepin, phenol and carbonyl isomers. A discussion of the potential impact of the sensitized photooxidation of more condensed environmental polycyclic aromatic hydrocarbon pollutants is presented and the role of bioactive arene oxides produced under such photooxidation conditions is also discussed. Related oxides of polycyclic aromatic hydrocarbons are known to be proximate carcinogens and/or mutagens generated by metabolic activation. The role and significance of solar induced oxidation in the weathering of petroleum hydrocarbons at air-sea interfaces and the incorporation of potentially bioactive organic residues in the food chain are also addressed.

Identification of some volatile endogenous constituents in rat brain tissue and the effects of lithium carbonate and chloral hydrate.

Nine endogenous volatile compounds were found in rat brain tissue, and were identified by mass spectrometry as chloroform, a 5-C-aldehyde, dimethyl disulphide, 2,5-dimethyl tetrahydrofuran, a 8-C-alkane, xylene, 2-heptanone, heptaldehyde and 2-n-pentylfuran. Using gas chromatographic and gas chromatographic mass spectrometric techniques, it was established that lithium carbonate did not induce the production of detectable amounts of any new volatile compounds in brain tissue. However, after administration of chloral hydrate, trichloroethanol, a compound not normally present in rat brain tissue, was found to be present.

Use of gas chromatography and mass spectrometry to analyze underivatized volatile human or animal constituents of clinical interest.

The study of volatilizable components in human and animal samples by gas chromatography and mass spectrometry is reviewed for the years 1970--1975. Only naturally volatile, underivatized compounds are considered, from sources such as body fluids, tissues, and breath. Where possible, the clinical samples are discussed in terms of normal profiling, aberrations associated with disease states, and specific compound analyses. A brief descriptive technical section is included, stressing types of sample preparation currently being used.

Gas chromatographic mass spectrometric evaluation of free organic acids in human saliva.

Excellent resolution and subsequent identification of free organic acids extracted from mixed, unstimulated human saliva was obtained by gas chromatography using high resolution open tubular glass capillary columns coupled with mass spectrometry computer instrumentation. In addition to the organic acids, identified as their trimethylsilyl derivaties, the presence of 2,6-di-t-butylcresol--a food preservative--and cholesterol was established by mass spectrometry. The effects of aspirin ingestion as well as diurnal variation were studied to demonstrate the possible clinical significance of this noninvasive approach to metabolic profiling.

Gas chromatographic evaluation of the volatile constituents of lung, brain and liver tissues.

Volatile metabolites from rat liver, lung and brain tissues were compared using gas chromatography. Volatiles released from the homogenized tissues at 95-100 degrees C were collected on a poly phenyl ether solid adsorbent. The adsorbed volatiles were examined by high-resolution gas chromatography. Markedly differing overall volatile profiles were observed for the tissue types examined, and it appears that certain constituents may be characteristic of a particular tissue.

Reactions of singlet oxygen with pine pollen.

Exposure of pine pollen to single oxygen, generated in an aqueous environment, resulted in a decrease in the relative quantities of unsaturated fatty acids that could be recovered by solvent extraction of surface and near surface pollen lipids. The involvement of excited oxygen was confirmed by substitution of deuterium oxide for water, which led to a twofold greater decrease in the unsaturated acids. The potential environmental and biomedical implications of these observations are discussed in terms of this model system.