THE COLLECTION AND ANALYSIS OF 2,3-DIMETHYL-2,3-DINITROBUTANE VAPOR

This article describes a method for the collection and the analysis of 2,3-dimethyl-2,3-dinitrobutane (DMDNB) vapor in the workplace. DMDNB is a white, odorless solid that sublimes at room temperature it has be en proposed as a chemical tag to aid in detection of plastic explosive s, which cannot be easily detected by conventional field sampling meth ods, Toxicologists at the U.S. Army Center for Health Promotion and Pr eventive Medicine have proposed an occupational exposure limit (OEL) f or DMDNB of 0.15 mg/m(3). Due to the low GEL, worker exposure during t he manufacture of plastic explosives is of considerable concern. In th is method of collection and analysis, DMDNB vapor is collected on a Te nax(TM) sampling tube at a rate of 200 mL/min. The chemical is desorbe d from the collection media with ethyl acetate. The concentration of t he analyte is determined using a gas chromatograph fitted with an elec tron capture detector and a nonpolar 20-m x 0.53-mm capillary column w ith a flow rate of 5 mL/min of carrier gas. The tested range was 0.15 to 15 mu g/tube with a calculated minimum detection limit for the meth od of 0.07 mu g/tube. In routine analyses a calibration curve is gener ated from 0.01 mu g/tube (0.006 mu g/mL of solution) to 6 mu g/tube (3 mu g/mL of solution), bracketing 0.07 mu g/tube, There was no breakth rough of DMDNB up to a loading of 65 mu g/tube. DMDNB was stable at ro om temperature on the collection media for up to 21 days. The effects of humidity on the collection was tested from 25% humidity to a satura ted atmosphere, There was no observable effect on the collection effic iency of DMDNB until a saturated atmosphere was reached, and then the efficiency dropped.