EVALUATION OF PHOTOCATALYTIC DEGRADATION OF IMIDACLOPRID IN INDUSTRIAL WATER BY GC-MS AND LC-MS

The insecticide Imidacloprid was oxidized in water at 50 mg/L, under p hotocatalytic TiO2 in presence of formulating agents. Analysis of oxid ized solutions was performed with both GC-Ion Trap-MS using either EI and CI as ionization modes and LC-Atmospheric Pressure Chemical Ioniza tion (APCI)-MS in order to confirm and evaluate the decay of Imidaclop rid and the presence of degradation products (DPs). LC-APCI-MS techniq ues allowed the monitoring of Imidacloprid and 6-chloronicotinic acid along the degradation process. GC-MS techniques allowed the detection of five DPs, three of which were unequivocally identified. Other compl ementary techniques such as Total Organic Carbon (TOC) and Ion Chromat ography (IC) allowed the evaluation of the mineralization degree achie ved. A tentative degradation pathway of Imidacloprid under photocataly sis is proposed. After 450 minutes of irradiation, none of the DPs or Imidacloprid were detected. Nearly total mineralization was achieved a fter 700 minutes of irradiation.