MEASUREMENT OF VOLATILE ORGANIC-COMPOUNDS BY THE US ENVIRONMENTAL-PROTECTION-AGENCY COMPENDIUM METHOD TO-17 - EVALUATION OF PERFORMANCE CRITERIA

An evaluation of performance criteria for US Environmental Protection Agency Compendium Method TO-17 for monitoring volatile organic compoun ds (VOCs) in air has been accomplished. The method is a solid adsorben t-based sampling and analytical procedure including performance criter ia for four merit parameters. These an: (1) the method detection limit (MDL); (2) the method precision; (3) the agreement between two sample s taken at different flow-rates over the same time period [a distribut ed volume pair (DVP)]; and (4) audit accuracy. A two-adsorbent tube pa cking of Carbotrap and Carboxen 1000 (Supelco) was tested. Synthetic m ixtures containing 41 compounds at concentrations of 10 ppb (v/v) or 2 ppb (v/v) each in humidified zero air, and indoor air from a personal residence, were sampled for l-h periods during which 1-1 and 4-1 samp les were obtained simultaneously. For synthetic samples, the MDL was d etermined to be less than or equal to 0.5 ppb (v/v) for 29 of the 41 c ompounds examined for samples at 47% relative humidity (RH), and for 2 7 of 41 compounds at 85% RH. The method precision at both 2 and 10 ppb (v/v) was less than or equal to 20% for 90+% of the samples using fiv e sampling runs and the DVP samples were within 25% for 80% of the sam ples. For the indoor samples, 26 target compounds were tentatively ide ntified and 12 unknowns were detected; all but 10% of these compounds met the DVP criteria.