EVAPORATION LOSS OF POLYCHLORINATED DIBENZO-P-DIOXINS AND DIBENZOFURANS FROM GLASS AND FILTER MATRIX

Loss of dissolved polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/F) is observed, during evaporation of toluene from glass jar and filter surface. The experiment is performed at atmospheric pressure a nd room temperature. Up to 90% of 1,3,6,8-TCDF and 70% of 2,3,7,8-TCDF isomer is lost into the atmosphere from a glass jar and 90% of 2,3,7, 8-TCDF from a filter surface. The loss is correlated to the PCDD/F vap our pressure over the subcooled liquid. Congeners with vapour pressure < 10(-7.3) Ton is approximately entirely in solid phase. The loss is dependent on surface area and presence of organic lipid phase. One con clusion of the results is that extraction solvent or solid phase sorbe nts should be spiked with carbon thirteen labelled PCDD/F, rather than direct addition on sample matrix or inert media like glass equipment or filters in sampling equipment, Otherwise systematical errors that o verestimate the amounts of native PCDD/F in samples may be introduced, An unsystematic random error may also be introduced to the analytical result. The consequences of the results for interpretation of environ mental data are discussed.