Determination of Residue of Maleic Hydrazide in Potato by Ion Exchange Chromatography Combined with Ultraviolet Detector

A method for the determination of residue of maleic hydrazide in potato by ion exchange chromatography combined with ultraviolet detector was proposed. The washed, peeled and mashed potato sample (1 g) was taken, and 10 mL of methanol was added. The mixture was extracted by ultrasonic for 30 min, heated in water bath at 60 ℃ for 5 min, and centrifuged for 20 min. The supernatant was passed through 0.22 μm filter membrane and reverse-phase pretreatment column. Separation was performed on Dionex IonPac AS16 analytical column and Dionex IonPac AG16 guard column, with KOH solution for gradient elution, and detection at wavelength of 205 nm. It was shown that linear relationship between the mass concentration and its peak area of maleic hydrazide was kept in the range of 0.182 5-10.14 mg·L^-1, with detection limit (3S/N) of 0.06 mg·L^-1. Test for recovery was made by the standard addition method, giving results in the range of 97.9%-108%. Slight changes in column temperature, flow rate and UV detection wavelength had no effect on the detection of maleic hydrazide. The method was used to analyze the actual potato samples, in which maleic hydrazide was not detected.