Proficiency Tests on Benzene and Toluene finished

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Download the report (iis14C02) of the Proficiency Tests on Benzene and Toluene

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Summary of this proficiency test:

On 11 April 2014, the proficiency test2 on Benzene and Toluene (iis14C02B and iis14C02T) were finished. It started 12 February 2014 (see message "Proficiency Test on Benzene and Toluene started" on this website) when the samples were distributed.

In this interlaboratory study 53 laboratories in 24 countries have participated on Benzene and 38 laboratories in 19 countries have participated on Toluene.

The participants were requested to determine on Benzene: Acid wash color, Acidity, Appearance, Bromine index, Colour, Density @ 20°C, Distillation, Total Chlorine, Total Nitrogen, Solidification point, Methylcyclohexane, Toluene, Nonaromatics and Purity.
The participants were requested to determine on Toluene: Acid wash color, Appearance, Colour, Density @ 20°C, Distillation, Purity, Copper Corrosion, Non aromatics hydrocarbons, Benzene and Styrene.

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).