A field evaluation of air sampling methods for TNT and RDX.

A comparative field study was conducted at an ammunition plant to evaluate the use of several sampling techniques for 2,4,6-trinitrotoluene (TNT) and hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX). The objective was to compare the currently recommended combination Tenax-plus-filter tubes with the older, colorimetric diethylaminoethanol bubbler method which was in use in July 1950 when the American Conference of Governmental Industrial Hygienists (ACGIH) published their first Threshold Limit Values (TLVs). These values included a TLV of 1.5 mg/m3 for TNT. Regular Tenax tubes and 37-mm glass fiber filters also were tested since they also had been used by the United States Army for a number of years. The survey results showed fair agreement between the bubbler and tube methods in those instances where sufficient TNT was present to produce a measurable color in the diethylaminoethanol (DEAE). The glass fiber filters were not satisfactory for TNT retention, but the two types of tubes both were effective. The combination tubes were superior for RDX and appeared to be the best overall sampling medium.

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.

Use of a GC concentrator to improve analysis of low levels of airborne hydrazine and unsymmetrical dimethylhydrazine.

New findings from animal studies indicate that there is a serious cancer risk associated with exposures to hydrazines. In June, 1978, NIOSH announced more restrictive occupational exposure levels for these compounds. Adherence to these limits requires improved analytical methodology. This paper describes a modified method for monitoring hydrazine and unsymmetrical dimethylhydrazine in atmospheric samples below the ceiling concentrations recommended by NIOSH. The method utilizes a GC concentrator for which a "trap" (ventable GC precolumn) was prepared and tested. Using this trap, up to 40 microL sample injections (injections much too large for conventional GC work) are effectively chromatographed. Presented are data on the overall efficiency of the method for airborne hydrazine and unsymmetrical dimethylhydrazine in the concentration ranges of 0.02 - 0.67 mg/m3 and 0.04 - 1.04 mg/m3, respectively.

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.

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.

Comparison of analytical methods for trace quantities of 2, 4, 6-trinitrotoluene.

A comparison has been made between a gas chromatographic analysis (GC) method and an automated colorimetric method for 2,4,6-trinitrotoluene in waste waters. The GC method is more useful in situations which require quantitative information about various isomers of di- and tri-nitrotoluenes. The automated method requires less work per analysis and gives a positive response for all trinitroaromatic compounds, including some degradation compounds. These factors make the automated method desirable for a routine surveillance program while the GC method is better for exact isomer analysis.