Proficiency Test on  Benzene and Toluene finished

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Download the report (iis13C04BT) of this Proficiency Test on Benzene and Toluene

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Summary of this proficiency test:

On 22 April 2013, the proficiency test on  Benzene and Toluene (iis13C04BT) was finished. It started on 14 February 2013 (see message “Proficiency Test on Benzene and Toluene started” on this website) when the samples were distributed.

In this interlaboratory study 46 laboratories in 20 countries have participated on Benzene and 39 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, DIN, ASTM).