IMPROVED INTERLABORATORY COMPARISONS OF POLYCYCLIC AROMATIC-HYDROCARBONS IN MARINE SEDIMENT

Early interlaboratory comparisons of analyses for PAHs in reference sediment showed variations in the data by as much as a factor of 10 among established laboratories. During the authors' 6-year study, such disparities have progressively decreased, through better and more uniform analytical procedures. In the latest intercomparison, the range of interlaboratory relative standard deviations (RSDs) improved better than twofold to 15-36% for 18 PAHs in a natural sediment prepared as a reference material. The improvement is attributed to (a) use of a specific, improved extraction and cleanup procedure, (b) use of calibration and internal standards from common preanalyzed supplies, and (c) preparation and use of a detailed standard methods manual.