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Biomedical subjects

G G Esposito

Publications and source records attributed to G G Esposito.

10 recordsLinked to original sources
PubMed1983

A gas chromatographic procedure for the determination of airborne MDI and TDI.

A method is described for the analysis of airborne diphenylmethane diisocyanate (MDI) and toluene diisocyanate (TDI) using gas-liquid chromatography. The diisocyanates are collected in acidic absorbing solution where they undergo hydrolysis, converted to the free diamines with caustic, and extracted into toluene. The diamines are derivatized in the toluene with heptafluorobutyric anhydride (HFBA). These derivatives are analyzed by GLC using an electron capture detector. The method has the advantages of specificity for the two diisocyanates, while demonstrating excellent accuracy and precision. A value one-tenth of the NIOSH recommended Occupational Health Standard for either compound may easily be detected in a 40 liter air sample.

Air↗
PubMed1980

Evaluation of a passive dosimeter for collection of 2-bromo-2-chloro-1, 1, 1-trifluoroethane and 2-chloro-1, 1, 2-trifluoroethyl difluoromethyl ether in hospital operating rooms.

Operationally, passive dosimeters are ideally suited for monitoring organic vapors in hospital operating rooms as they are compact, lightweight and do not require tubing or pumps. In this study, a recently developed passive diffusion sampler was used to collect 2-bromo-2-chloro-1, 1, 1-trifluoroethane (Halothane) and 2-chloro-1, 1, 2-trifluoroethyl difluoromethyl ether (Enflurane) in standard air mixtures over the range of 0.2-10 ppm. Additionally, exposures to known concentrations were conducted for various lengths of time. A side-by-side comparison of charcoal tubes (CT) and passive dosimeter collection characteristics were made on known air mixtures and samples collected in operating rooms. The material adsorbed on charcoal from dosimeters and CT was desorbed with carbon disulfide and quantified using gas-liquid chromatography. The overall efficiency of the dosimeters along with quality control data are presented.

Air Pollutants↗
PubMed1979

Field evaluation of selected monitoring methods for phosgene in air.

Four selected methods have been evaluated and field tested as candidates for a specific, continuous procedure for monitoring phosgene in air at or below concentrations of 0.05 ppm. The methods evaluated were automated colorimetry, gas chromatography, infrared spectrophotometry and a recently developed paper tape monitor. A standard manual colorimetric procedure was used as a reference method. The paper tape, infrared and automated gas chromatographic techniques most closely fulfilled the criteria set forth for an "ideal", selective, continuous procedure for phosgene.

Air Pollutants↗
PubMed1978

A new personal sampler for organic vapors.

This paper describes the evaluation of a new personal sampler for organic vapors which is totally different from traditional sampling techniques using pumps and adsorption tubes. Sampling of organic vapors is effected by collection on an adsorption substrate contained within a small passive sampler worn by the worker. The collection element is removed from the sampler and subsequently analyzed for organic vapors. The results are equated with the time-weighted-average concentration of contaminants in air. This new sampling device circumvents inherent errors generally associated with sampling pumps and tubes; e.g., changes in pumping rates and variable pressure drops across adsorption tubes. Applications of the sampler were demonstrated on various concentrations of benzene, methyl isobutyl ketone, isooctane, butyl acetate, methyl chloroform, trichloroethylene, butanol and solvent mixtures. Variables studied included the effects of temperature, charcoal lot, and air velocities. In addition, the occurrence of "breakthrough" and effect of time on sample stability were investigated.

Air Pollutants↗
PubMed1977

Chromatographic determination of aromatic hydrocarbons in ambient air.

A gas chromatographic method has been developed for the determination of aromatic hydrocarbons in solvent mixtures. Bulk solvents and charcoal tube air samples may be analyzed. The procedure utilizes the unique separation characteristics of a gas chromatographic column containing a highly selective stationary liquid phase, N,N-bis (2-cyanoethyl) formamide. The interfering oxygenated solvents are extracted using 75 percent H2SO4. An 11-foot, 35 percent CEF column may be used to qualitatively analyze the lower boiling aromatic hydrocarbons (benzene, toluene, xylenes). Total or specific aromatics are then quantitated using a 3-foot, 35 percent CEF column with an internal standard. Applications of liquid chromatographic concepts to this analysis were also investigated.

Air Pollutants↗
PubMed1976

Gas chromatographic determination of acetic acid in industrial atmosphere and waste water.

A gas chromatographic (GC) method is presented for the specific determination of acetic acid in air and total ionic acetate (as acetic acid) in industrial waste water. Atmospheric air samples are collected in fritted midget bubblers containing aqueous sodium carbonate solution; wastewater samples are treated directly with sodium carbonate. Both air and water samples are concentrated by evaporation of water, and the acetic acid is regenerated by the addition of hydrochloric acid. The amount of acetic acid is determined quantitatively on a porous polymer packed column by internal standardization with propionic acid. GC conditions are described for the suppression of "ghosting" and "tailing" caused by adsorption phenomena associated with the GC behavior of organic acids.

Acetates↗