An analytical method for the determination of airborne concentrations of 2,4,5-trichlorophenoxyacetic-acid (93765) (2,4,5- T) was developed. A known volume of air was drawn through a glass fiber filter to trap the 2,4,5-T, which was then extracted with methanol. The solution was separated and analyzed using high pressure liquid chromatography. The method was validated over a range of 4.9 to 21.4 milligrams per cubic meter (mg/m3) by analyzing 18 samples spiked with 50, 100, or 200 percent of the OSHA standard of 10mg/m3 or analysis of 18 samples collected from dynamically generated test atmospheres. The collection efficiency of the glass fiber filter, the storage stability of the samples, and precision of the method were measured. Collection efficiency of the filter was after 7 days was 10.18 and 10.55mg/m3, respectively. The total coefficient of variation was 0.053. The authors conclude that the advantages of the method are that the samples are analyzed by a quick, instrumental method that is simple and requires no liquids. The precision of the method is limited by the reproducibility of the pressure drop across the filter.
Ten NIOSH Analytical Methods, Set 6, Division of Physical Sciences and Engineering, NIOSH, Cincinnati, Ohio, NTIS PB288-629, 23 pages, 6 references