Stability of purgeable VOCs in water samples during pre-analytical holding: Part 1, Analysis by a commercial laboratory

This study was undertaken to examine the hypothesis that prevalent and priority purgeable VOCs in properly preserved water samples are stable for at least 28 days. (VOCs are considered stable if concentrations do not change by more than 10%.) Surface water was spiked with 44 purgeable VOCs. Results showed that the measurement of 35 out of 44 purgeable VOCs in properly preserved water samples (4 C, 250 mg NaHSO{sub 4}, no headspace in 40 mL VOC vials with 0.010-in. Teflon-lined silicone septum caps) will not be affected by sample storage for 28 days. Larger changes (>10%) and low practical reporting times were observed for a few analytes, e.g. acrolein, CS{sub 2}, vinyl acetate, etc.; these also involve other analytical problems. Advantages of a 28-day (compared to 14-day) holding time are pointed out.