Applicability of High-Performance Ion Chromatography (HPIC) to the Determination of Fosetyl-Aluminum in Commercial Formulations

An improved method for the determination of the systemic fungicide fosetyl-aluminum (aluminum tris(ethyl phosphonate)), in commercial formulations, via the quantitative determination of the phosphonate anion is described. The method employs HPIC using eluent suppression and conductivity detection. Two different kinds of chromatographic columns were utilized in the study, together with several eluents. The method has good sensitivity and reproducibility (CV% 3.2), and the sample preparation required is very simple. Under the analytical conditions adopted, the detection limit of fosetyl-aluminum in the commercial formulation "Aliette" was 0.008 g/kg. Chromatographic conditions for gradient elution were also investigated in the study, which were able to reveal the possible presence of phosphorous acid. The detection limit for this compound was 0.03 mg/liter. An atomic absorption spectroscopy name technique was also applied to the samples as an indirect analysis of fosetyl-aluminum via the determination of aluminum.