INTERLABORATORY STUDY FOR THE IMPROVEMENT OF TRIBUTYLTIN DETERMINATION IN HARBOR SEDIMENT (RM-424)

Following two interlaboratory studies on tributyltin species (TBT) in water and TBT-spiked sediment, the EC Community Bureau of Reference (BCR) (Measurements and Testing Programme) organized in 1992 an interlaboratory study on TBT in a harbour sediment (RM 424) to investigate sources of error possibly occurring in the analysis of a complicated matrix and to attempt to certify this material. The sediment was collected in the Sado Estuary (P), then carefully prepared, and its homogeneity and stability were verified. The low TBT content encountered in this material, and the high level of interferences, created difficulties with the techniques using hydride generation, whereas better agreement was obtained for other derivatization techniques with GC/FPD and GC/MS. This paper presents the results of the interlaboratory study. The reference value for TBT in this material is 20 +/- 5 ng g(-1) (as TBT cation) and the indicative values for dibutyltin (DBT) and monobutyltin (MBT) are 53 +/- 19 ng g(-1) (as DBT cation) and 257 +/- 54 ng g(-1) (as MBT cation), respectively. Owing to the difficulties encountered, the reference material was not certified and is considered as a research material to be used for the evaluation of the performance of analytical techniques for the determination of low TBT levels in a difficult matrix.