Mineral oil content in sediments and soils: comparability, traceability and a certified reference material for...

The performance of twelve laboratories with previously established proficiency in the determination of the mineral oil content in a fresh water sediment is described. The summation parameter total petrol hydrocarbon (TPH) is defined according to ISO 16703:2004 with regard to the sample preparation to be applied, the flame ionisation detection (FID) and the boiling range of C10-C40 to be integrated. Comprehensive tests of homogeneity and stability have been carried out on the candidate material using appropriate models. The outcome of the study served as the basis for the certification of the candidate reference material as ERM-CC015a. The certified mass fraction is 1,820+/-130 mg kg(-1) and traceability was established by using an appropriate calibration standard certified for the mass fraction of C10-C40. The interlaboratory scatter of measurement results in this exercise can largely be explained by the variability of the individual calibrations based on this common calibration standard.