Determination of cocaine and heroin vapor pressures using commercial and illicit samples

The establishment of drug vapor pressure reference values provides valuable information in the development of vapor sensing devices for drug detection . The purpose of this work was to determine equilibrium headspace vapor pre ssures for commercial and illicit drug samples for use in such applications . Samples of cocaine, both free base and hydrochloride forms, and heroin hy drochloride were evaluated. The procedure used to measure the vapor pressur es was a modification of a previously published method. Vapor pressure valu es at 20 degrees C previously reported for cocaine free base range from 0.3 7 x 10(-7) to 1.20 x 10(-7) Torr. The vapor pressure value determined in th is study was 2.96 x 10(-7) Torr. It is likely that the discrepancies are du e to differences in experimental conditions, varying sources of samples, an d uncertainty in the methodologies. When the values were compared for comme rcial (99% purity) and illicit (unknown purity) sources of cocaine free bas e, there were no statistical differences in the projected room temperature (20 degrees C) vapor pressure values. However, the commercial and illicit s amples of cocaine hydrochloride did show statistical differences. Although no comparison was made with the vapor pressure values for a pure, commercia l sample, the vapor pressures of heroin hydrochloride (81% purity) at vario us temperatures were determined using the method developed for cocaine and are reported in this paper.