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(457) Occurrence and fate of adjuvants in pesticides in the aquatic environment. Krogh, K.A.1,2, Verjup, K.V.1, Mogensen, B.B.1, 1 2 ABSTRACT- Adjuvants in pesticide formulation as well as the active ingredients end up in the environment. The primary target of the adjuvant is to stabilise the pesticide formulation, by making the active ingredient soluble in the aquatic spray mixture, enhance the spreading capability of the pesticide spray mixture, or help the active ingredients to penetrate the target surface, etc. Non-ionic surfactants are the major group of adjuvants in pesticides, but anionic surfactants and different organic solvents are also used. The aim of this work is to investigate the occurrence and fate of adjuvants in pesticides in the aquatic environment. Two types of non-ionic surfactants, used as adjuvants in pesticides, have been studied; alcohol ethoxylates (AE) and amine ethoxylates (AME). Analysis of the surfactants in the aquatic environment includes extraction from matrices, solid phase extraction (SPE) and LC-MS analysis with APCI in positive ion mode. Different LC-MS methods are used to analyse AE and AME. As stationary phase a Hypersil BDS C18 column is applied with a RP-gradient of A: MillliQ water and B: CH3OH:CH3CN (1:1) both with CH3COOH for AE analysis, while for AME analysis, triethylamine is also added to be able to elute the AME. Both methods include a screening method using Collision Induced Dissociation (CID) and a more specific analysis of the individual compounds. Results from the occurrence and fate of AE and AME in four well-characterised agricultural fields will be presented. Water samples, such as soil water, drainage water, ground water and water from the nearby streams, were analysed for AE and AME. The fields were cultivated with barley, wheat and beets, in accordance with Danish practise. Key words: surfactant , pesticides, occurrence, adjuvants |
