Determination of Prochloraz (sum) via its Metabolites

The current residue definition (RD) of prochloraz (sum) calls for the use of procedures involving a hydrolysis step to release the 2,4,6-trichlorophenol (TCP) moiety. This moiety is contained in prochloraz as well as in several of its known metabolites. Analytical procedures involving hydrolysis are typically cumbersome and in most cases the benefit from conducting them does not justify the effort, thus very few laboratories employ them routinely. An alternative approach to, at least partly, fulfill the current residue definition would be the direct analysis of available MRM-amenable TCP-containing metabolites. In a recent reasoned opinion EFSA proposed a RD, which includes the parent and two MRM-amenable metabolites (BTS 44595 and BTS 44596). We aimed to study the analytical behavior of these two metabolites, and of three additional TCP-containing metabolites (BTS 9608, BTS 40348 and TCP). The occurrence of these metabolites and of prochloraz in real samples was also studied.