A COMPARATIVE-STUDY FOR THE DETERMINATION OF POLYCHLORINATED DIBENZOFURANS AND DIBENZO(P)DIOXINS IN AMBIENT AIR

Intercomparison measurements of PCDD and PCDF in ambient air were perf ormed by four laboratories at an industrial site in Hamburg, Germany. The participating laboratories applied their routine procedures for sa mple preparation and analysis, without prior interlaboratory adaptatio n. Results of two measurement series with eight samples each are prese nted. The standard deviations of the concentrations of individual cong eners and homolog groups are generally in the range of 20 to 50 %, wit h few exceptions. No systematic analytical differences concerning spec ific congeners are detected. The standard deviations of the toxicity e quivalents according to NATO/CCMS are 16 % in the first and 23 % in th e second experiment, the arithmetic means being 39.5 fg/m3 and 93.8 fg /M3, respectively. The time of addition of quantification standards (p rior to or after sampling) did not influence the results significantly . Other parameters, such as the use of PUF or XAD-2 as adsorbents or d ifferent air flows during sampling, were obviously also of little impo rtance.