Examination of the Problem on Evaporation of Standard Substances for Measuring PCDD/Fs in Atmosphere

The problems caused by volatility of 4-8 chlorinated analogues on measuring PCDD/Fs in the atmosphere were examined. First, the sampling method for measuring PCDD/Fs in the atmosphere using high volume air sampler (HiVol) equipped with filter paper and polyurethane form (PUF) was inspected. 13C12-1, 2, 3, 4-TCDD, which is more volatile but less toxic than other tetrachloro-through octachloro-PCDD/Fs, was used as a sampling spike and added on the filter paper to confirm the collection efficiency. As a result, most of the sampling spike passed through the filter paper and was collected by the first step of PUF. Non of the sampling spike was detected on the second and subsequent steps of PUF. The total collection ratio from filter paper and PUF was unexpectedly low (40-60%) and so we checked the cause of it. The sampling spike, we guessed, would have been volatilized anywhere, because the spiked filter paper had been left for ca. 2 hours by the time of starting the sampling. This was confirmed by testing the volatility of it on the filter paper. Next, the volatility of the sampling spike at the time of the concentration operation such as nitrogen blowing was tested . As a result, the sampling spike existing alone in the operation of nitrogen blowing volatilized easily. However, in the case of the sampling spike existing with less volatile PCDD/Fs, the volatility of it was suppressed.