DETERMINATION OF CHLOROBIPHENYLS IN CLEANED-UP SEAL BLUBBER AND MARINE SEDIMENT EXTRACTS - INTERLABORATORY STUDY

An interlaboratory study on the determination of individual chlorobiph enyl congeners (CBs) in cleaned-up seal blubber and marine sediment ex tracts was organized by the International Council for Exploration of t he Sea, the Intergovernmental Oceanographic Commission, and the Oslo a nd Paris Commissions, as the second part of a stepwise-designed interl aboratory study on the determination of CBs in marine media. Fifty-eig ht laboratories from 16 countries participated in this exercise, which involved the determination of 10 CBs in a standard solution, a cleane d-up seal blubber extract, and a cleaned-up marine sediment extract. S uggestions were given for instrument optimization. Standard errors of 1.16-1.17 for the standard solution, 1.20-1.33 for the seal blubber ex tract, and 1.31-1.56 for the sediment extract were obtained for CBs 52 , 101, 118, 138, 153, and 180 by all laboratories with the exception o f the laboratories giving consistently outlying results. The results f or CBs 28, 31, 105, and 156 showed larger standard deviations. The 2 m ajor difficulties for participants in this exercise were correct prepa ration of a calibration solution and chromatographic separation. The r esults of the sediment analysis showed a complete lack of agreement. I t is recommended that, prior to the organization of the third part of this study, participants should install gas chromatographic columns wi th minimum lengths of 50 m and maximum internal diameters of 0.25 mm a nd should prepare calibration solutions from solids of known purity.