Analytical method using gas chromatography and ion trap tandem mass spectrometry for the determination of S-triazines and their metabolites in the atmosphere

Gas chromatography-ion trap detector (GC-ITD) was used to detect atmospheri c triazines and their degradation products in the gaseous and particulate p hases. Because triazines and their metabolites are expected to be present a t very low concentrations and enclosed in the complex atmospheric matrix, t he analytical method used was both highly selective and sensitive. These tw o properties were obtained by associating chromatography with ion trap tand em mass spectrometry (GC-ITD (MS/MS)). To develop this method, a comparison between the two ionization modes (electron impact and positive-chemical-io nisation) in single-MS was first conducted to choose the parent ions of the five target analytes, i.e. atrazine, desethylatrazine, deisopropylatrazine , terbuthylazine and desethylterbuthylazine. Then, a MS/MS method was optim ised by parameters such as the radio frequency storage level and the collis ion-induced dissociation excitation voltage. Finally, a last step enabled t he development of a calibrating program based on the quantification of daug hter ions. With this analytical procedure, the detection limits varied betw een 0.8 and 15 pg m(-3) depending on the compounds under study. This method was tested with success for four atmospheric samples collected in Strasbou rg (France) in which four of the five target compounds were detected. (C) 2 000 Elsevier Science Ltd. All rights reserved.