Assessment of the performance of pesticide-testing laboratories world-wide through proficiency testing

Proficiency testing (PT) is critical in the pesticides field, as this area places more demands than most on the analyst, in terms of needing to monitor a wide range of pesticides in a great range of differing matrices. We have looked for trends in performance using results from three different PT schemes (two commercial, and one organized by the European Commission – the European Proficiency Test). ‘Difficult’ and ‘easy’ individual pesticides in ‘difficult’ and ‘easy’ matrices are identified, and relative levels of performance are reported. We have assessed an overview of analytical methods used by PT participants, where possible looking for correlations between performance and choice of method (in particular choice of instrumental technique).