The determination of organochlorine compounds and petroleum hydrocarbons in a seaweed sample: results of a worldwide intercomparison exercise

A seaweed sample (Fucus sp.)was prepared, homogenised and distributed to la boratories worldwide as the IAEA-140 intercomparison material for the analy sis of organochlorine compounds and petroleum hydrocarbons, a total of 80 l aboratories from 51 countries reported results for this sample. The data se ts reported by laboratories were evaluated statistically and the mean conce ntration values could be computed with 95% confidence limits for a large nu mber of analytes, The accuracy of the analytical performance of each labora tory has been introduced by using Z-scores. The spread of results reported generally indicates that the accurate determination of many persistent orga nic pollutants, such as hexachlorobenzene, lindane, Aroclors or fluoranthen e, is still difficult for many laboratories, The final results of this inte rcomparison exercise enable individual participants to assess their perform ance and, where necessary, to introduce appropriate modifications in their analytical procedures. Furthermore, as a series of statistical criteria was fulfilled for a number of compounds, the sample IAEA-140 can now be used a s a reference material for quality control in the determination of chlorina ted compounds and petroleum hydrocarbons in environmental samples. (C) 1999 Elsevier Science B.V. All rights reserved.