Results from Round Robin Exercises of Phenolic Compounds within the Cost 64b bis Project

Summary

Within the Working Party 8 of the COST 64b bis project, a general opinion has been that intercalibration exercises should be encouraged to improve both accuracy and precision of existing methods. As a result of the discussion concerning determination of specific phenolic compounds a Round Robin Exercise was arranged in which the participants were asked to analyse two water samples, containing significantly different amounts of phenols, with at least two separate analytical methods. When rejecting outliers on a 99 % confidence level the following results were obtained. Using Method A, designed for the determination of polychlorinated phenols the relative standard deviations for each compound ranged 14 – 24 % (mean values 35 – 40 ug/L) for sample I (high phenol levels), the corresponding values for sample II were 18 – 53 % relative standard deviation (mean values 3.5 – 8.8 ug/L). Using Method B, designed also for the determination of non-halogenated phenols, the relative standard deviation for each compound ranged 20 – 36 % (mean values 32 – 87 ug/L) for sample I, the corresponding values for sample II were 19 - 78 % (mean values 3.7 – 9.1 ug/L). It was concluded that the results were quite satisfactory, but further intercalibration exercises should be carried out in the future to improve these results.