Online matrix elimination and high-sensitivity detection of maleic hydrazide in complex vegetable matrices using 2D-IC-IPAD.

Maleic hydrazide (MH), a sprout inhibitor with potential toxicological risks, necessitates sensitive detection in vegetables. This paper introduced a novel two-dimensional ion chromatography system coupled with integrated pulsed amperometric detection (2D-IC-IPAD). MH fraction was heart-cut from the first-dimension separation by a valve-switching program, removing bulk matrix interferences. After transfer to a second-dimension column, MH was sensitively detected by IPAD. Recoveries of 95.85-100.9% were obtained in potato, onion, and garlic using methanol extraction. Excellent linearity (0.1521-10.14 mg/L, R2 = 0.9992) was achieved, with detection and quantification limits of 0.05 and 0.15 μg/g, respectively. Intra-day precision was <6% RSD. In real samples, MH was quantified at 0.86 μg/g in onions but was below the detection limit in potatoes and garlic. This 2D-IC-IPAD system is studied for the first time, providing a high-throughput, fully automated platform with online matrix elimination for MH detection with low operational error, low cost, and high accuracy.