Determination of fosetyl-aluminium by ion-pair reversed phase-high performance liquid chromatography with evaporative light scattering detection

Ion-pair reversed phase-high performance liquid chromatography (RP-HPLC) with evaporative light scattering detection (ELSD) has been established for the analysis of fosetyl-aluminium and relevant impurities in technical or formulated substance. The method was achieved on a Symmetry Shield RP18 column by using n-butylamine as ion-pairing agent. The mobile phase was methanol-redistilled water containing 0.5% M-butylamine which was adjusted pH 5.0 with acetic acid (8:92, v/v) and the flow rate was set at 0.8 mL/min. The active ingredient fosetyl-aluminium was successfully separated from relevant impurities under the conditions. The calibration curve was linear in the range of 100 - 1 200 mg/L. The average recoveries of two fortification levels (100 mg/L and 1 000 mg/L) were 100.58% and 99.53%, and the relative standard deviations (RSDs) were 0.62% and 0.49%, respectively. The method is rapid, simple and accurate which provides another new and reliable means for the analysis of fosetyl-aluminium in its technical or formulated substance.