Comparative analysis of ultrasound-accelerated alkaline and acid hydrolysis for the indirect determination of 3-monochloropropane-1,2-diol fatty acid esters

Abstract

Ultrasound-accelerated hydrolysis is effectively used for the first time in the release of 3-monochloropropane-1,2-diol (3-MCPD) from its fatty esters. Indirect determination of 3-MCPDE fatty acid esters was performed under alkaline and acid conditions using sodium methoxide and sulfuric acid, respectively, prior to GC-MS analysis. Dispersive liquid-liquid microextraction (DLLME) was used to derivatize the free 3-MCPD with n-heptafluorobutyrylimidazole (HFBI). Two asymmetrical screening designs were used to evaluate parameters affecting the methods’ performances: time, temperature, hydrolytic agent volume, and concentration. A comparative study between both methods was performed. Research showed that comparable results are achieved in terms of linearity (r2 > 0.9995), specificity, accuracy, and precision. Determination limits were lower for the alkaline method (67 ng g−1). Twenty samples of four types of edible oil were assessed using both methods: extra virgin olive oil (EVO), refined sunflower oil, refined olive oil, and palm oil. Results obtained here were comparable and similar to those reported in the literature. Alkaline hydrolysis was the recommended approach and should be used in occurrence studies.