Internal VDI/DIN interlaboratory comparison test on the determination of elemental carbon

In 1997 the VDI/DIN working group "Measurement of Soot" organized an interl aboratory comparison test on the determination of elemental carbon on quart z fibre filters which were laden in ambient air and on a diesel test stand. 13 of the 16 participating laboratories used the coulometric soot measurem ent method according to Guideline VDI 2465 Part I and 3 laboratories the th ermographic method according to Guideline VDI 2465 Part 2. Over 85% of the measurement data are in between a section of +/-30% of the mean value of al l measurement data. For an interlaboratory comparison test dealing with a p roblematic measuring material as elemental carbon this is a positive result . It has been shown that for the given sampling conditions with the two soo t measurement methods described in the VDI Guidelines equivalent results ar e determined.