Analysis of condensed phosphates in food products by ion chromatography with an on-line hydroxide eluent generator.

An ion chromatographic method with gradient elution using an automated eluent generator was developed for the simultaneous determination of condensed phosphates (CPs) such as orthophosphate (P1), pyrophosphate (P2), polyphosphate, trimetaphosphate and phytate in food products. The linear calibration curves for P1, P2, tripolyphosphate, and tetrapolyphosphate in the range 0.5-500 microM had a correlation factor of 0.999 or better. The precision of the method for the CP peak areas obtained with the hydroxide eluent generator was better than that obtained with potassium hydroxide eluents prepared off-line. This method was applied to the determination of CPs in food products such as ham, fish paste, and cheese extracted by trichloroacetic acid.