Determination of Allyl Isothiocyanate in Mustard and Horseradish Extracts by Single Reference GC and HPLC Based on Relative Molar Sensitivities

Abstract

The main component of the Mustard and Horseradish extracts, which are used as natural food additives in Japan, is allyl isothiocyanate (AITC). The determination of AITC using GC-FID is the official method employed in the quality control assessments for these products. In this method, a commercially available AITC reagent is used as a calibrant. However, ¹H-quantitative NMR (qNMR) analysis revealed that the AITC reagents contain impurity. Therefore, we examined the GC-FID and HPLC-refractive index detector (LC-RID) method based on relative molar sensitivities (RMSs) to high-purity single reference (SR). The RMSs of AITC/SR under the GC-FID and LC-RID conditions were accurately determined using qNMR. The AITC in two types of food additives was quantified using qNMR, SR GC-FID, and SR LC-RID methods. Both SR GC-FID and SR LC-RID showed good agreement within 2% with the AITC content determined by direct qNMR.