Abstract: A new method was developed for the determination of maleic hydrazide (MH) in potatoes, onions and garlics by high performance ion-exclusion chromatography (HPIEC). The sample was extracted with acidic methanol, and then analyzed by HPIEC. The analytical column was IonPac ICE-AS1 (250 mm×9 mm) and a mixture of 3 mmol/L formic acid water solution-acetonitrile (70:30, v/v) was used as the eluent at a flow rate of 0.8 mL/min. The detection was performed at 205 nm by an Ultimate 3000 VWD. The quantitative analysis of external standard calibration curves was used. The linear range of the method for MH was 0.006~1.0 mg/L (r=0.9999). The average recoveries were 91%~103% with relative standard deviations (RSDs) less than 3%. The detection limit was 0.002 mg/L for MH. The method is simple, effective, precise, sensitive, reproducible and selective. It can be used to determine the residue of MH in potatoes, onions and garlics.

Key words: maleic hydrazide (MH), vegetables , high performance ion-exclusion chromatography (HPIEC)