title: Photo-induced chemiluminescence-based determination of diphenamid by using a multicommuted flow system.
abstract: This manuscript deals with the application of molecular connectivity calculations to predict the photo-induced chemiluminescent behaviour of the family of herbicides grouped as amides. Several compounds of this group were theoretically studied by means of a general discriminant equation formerly obtained, being 18 of them (plus eight from the chloroacetanilide sub-group) predicted with a high probability as photo-induced chemiluminescent. Empirical confirmation of the chemiluminometric behaviour was performed with some few commercially available amide herbicides. On the basis of these results, a new multicommutation-photo-chemiluminescent method is proposed for the determination of the diphenamid. The method is based on the photodegradation of the pesticide and then the resulting photo-fragment solutions are oxidized by K(3)[Fe(CN)(6)] in sodium hydroxide medium, at room temperature and 80 degrees C, for the photodegradation and chemiluminometric oxidation, respectively. The studied calibration up to 5.0mgl(-1), revealed a linear dynamic graph up to 20mgl(-1). The reproducibility between days resulted in a R.S.D. (in slope %) of 2.8 (n=5) and the repeatability with a %R.S.D. (n=20) of 4.3. LOD (s/n=3) of 1mugl(-1) and sample throughput of 20h(-1). The influence of foreign compounds is also tested and the optimized flow assembly is applied to different kind of samples.
authors.affiliation: Department of Analytical Chemistry, University of Valencia, Valencia, Spain.
authors.forename: A
authors.initials: A
authors.lastname: Czescik
authors.forename: D López
authors.initials: DL
authors.lastname: Malo
authors.forename: M J
authors.initials: MJ
authors.lastname: Duart
authors.forename: L Lahuerta
authors.initials: LL
authors.lastname: Zamora
authors.forename: G M Antón
authors.initials: GM
authors.lastname: Fos
authors.forename: J Martínez
authors.initials: JM
authors.lastname: Calatayud