Fast sonochemical molecularly imprinted polymer synthesis for selective electrochemical determination of maleic hydrazide

Maleic hydrazide (MH) is a plant growth regulator, herbicide, and sprout inhibitor used to improve the growth and quality of certain vegetables and fruits, unfortunately, MH has genotoxic and carcinogenic effects; thus MH residues in food deserve to be analyzed. Herein, a fast molecularly imprinted polymer (MIP) sonochemical synthesis for MH is proposed. The MIP was used as an adsorbent phase and used in combination with an electrochemical determination based on carbon black functionalized screen-printed electrodes. The MIP was synthesized by radical polymerization in 5 min, by using a high-power ultrasound probe using MH as a template. The electrochemical sensor exhibits useful sensitivity for MH (LOD = 40 ppb), high reusability (RSD 3 %; n = 10) and fouling resistance. The coupling MIP-extraction/clean-up and electrochemical determination were tested towards model solutions and food samples (i.e., potatoes, onions and garlic), obtaining reproducible (RSD & LE; 6 %, n = 3) and selective MH determination. The method's accuracy was proved via liquid chromatography-tandem mass spectrometry getting relative errors between 8.5 and 9.4 %.

Automated summary

This study proposes a fast molecularly imprinted polymer method for the synthesis of maleic hydrazide (MH) and combines it with electrochemical determination for the analysis of MH residues in food. The method exhibits good sensitivity, reusability, and fouling resistance, and can be used for the determination of MH in model solutions and food samples.