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Download the report (iis15N01) of the Proficiency Tests on Naphtha (revised) 

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Summary of this proficiency test:

On 29 June 2015, the proficiency tests on Naphtha (iis15N01) was finished. They started 18 March 2015 (see message "Proficiency Test on Naphtha started" on this website) when the samples were distributed.

In this interlaboratory study 87 laboratories in 38 countries have participated.

The participants were requested to determine on Colour Saybolt, Copper Corrosion 3hrs@50°C , Density @ 15 °C, Distillation, Mercaptans, Sulphur, Methanol, MTBE, DIPE, TAME, MEK, ACETONE, Total Oxygenates, PIONA, DHA, Mercury as Hg, Arsenic as As,Lead as Pb, Total Vapour Pressure and DVPE.The proficiency test report summarises per test, the test results, the analytical methods reported by the participants and the z-scores calculated for each participant are tabulated. Also, for each test, the calculated summary (e.g. mean, standard deviation and reproducibility) is given.

In the report also an evaluation of the test results is given. Problems encountered in the analyses are mentioned and - where possible - suggestions for quality improvement are formulated. For each test a comparison is made between the results of the group of participants and the requirements given by the relevant standard (e.g. ISO, ASTM).