• Impact of the catalyst on Total Kjeldahl Nitrogen measurement in waste waters
• Comparison COD ST-COD updated in 2019
• Influence of the samples pretreatment during proficiency testing in solid matrices

• Comparison of dissolution methods for metals in sediments and sludge
• Reliability of chloroacetamides metabolites measurement
• Uncertainties of measurements and zeta-scores
• Comparison ICP/MS and other methods for Fe, Ti and Hg
• Comparison of measurements of COD by classical method and small scale sealed-tube method
• Deviations between methods - analysis of metals in clean waters
• Comparison of mineralisation methods for Fe and Sn in waste waters
• Deviations between methods - analysis of micropollutants in clean waters
• Anionic surfactants index, comparison of analytical methods (spectrophotometry with or without flux)

Since 2009, A.G.L.A.E. has organised interlaboratory tests in which the participants can report results for ST-COD (small scale sealed-tube method) in addition to classical COD. A first study was done in 2013 to compare these two methods from the results obtained during our tests on natural water and wastewater. It was updated in 2019 with data from the tests carried out in the meantime, i.e. a total of about twenty tests in natural waters and about thirty tests in waste waters.

Note that this study has been published in the Encyclopedia of Analytical Chemistry: Wiley online library

One of the main issues when implementing proficiency tests with a solid matrix is to obtain a sufficient batch homogeneity. AGLAE has implemented proficiency tests in raw solid matrices and in pretreated solid matrices for metals and organic micropollutants (PAHs) in order to check if the raw materials could be homogeneous enough to be employed during proficiency tests. The aim of these tests was also to evaluate the uncertainty of measurement component due to the pretreatment of the samples and to compare the analytical performances of the laboratories including or not the pretreatment part of the samples.

Download the study on the  Influence of the samples pretreatment during proficiency testing in solid matrices

Deviations between dissolution methods are frequently observed in AGLAE’s proficiency tests for aluminium, chromium and nickel in sediments and aluminium, chromium and potassium in sludges. We have studied for these metals deviations between dissolution methods during our PTs since 2010 and we gathered the methods as follows: “partial” methods, “total” methods and the aqua regia method (HNO₃/HCl) in a closed system with microwave heating. 

Download the study Comparison of dissolution methods for metals in sediments and sludge

In this technical note, we report the reliability evaluation of measurement of metabolites of chloroacetamides carried out in 2016. To achieve this, a proficiency test has been carried out by AGLAE upon request of the Heath Regional Agency of Aquitaine Limousin Poitou Charentes which was concerned by the question of sanitary control of water. This proficiency test focused on 6 metabolites of chloroacetamides in river water and Evian water with several concentration levels. We observed that values targeted by spiking were overall well recovered by participants.

Download the study Reliability of chloroacetamide metabolites

During our proficiency testing in physical-chemistry, participants have the possibility to assess their uncertainties. We studied the percentage of laboratories which provided uncertainties, the uncertainties given and the percentage of underestimated uncertainties.

Download the report on Uncertainties of measurements and zeta-scores