Sinigrin and sinalbin quantification in mustard seed using high performance liquid chromatography–time-of-flight mass spectrometry

Mustard crops such as Brassica juncea L. and Sinapis alba L. contain high concentrations of glucosinolates, that hydrolyze to form biologically active compounds that can impart flavors to foods, function as anticarcinogens in human nutrition, or can be used as broad spectrum antimicrobials to extend the shelf life of various food products. Most of the currently used methods for glucosinolate analysis in mustard prior to its utilization are time consuming and involve complicated sample preparation. We have developed and optimized a new method for glucosinolate quantification in mustard seed (B. juncea and S. alba) using HPLC with high-resolution time-of-flight mass spectrometry (TOF-MS) and compared it to two existing methods (HPLC–ultraviolet (UV) and ion chromatography (IC)). We also demonstrated the possibility of sinalbin quantification using sinigrin calibration standards. The proposed HPLC–TOF-MS method is more sensitive than HPLC–UV and IC methods. Effects of the mustard seed matrix were negligible and virtually no sample preparation of the mustard seed extract was needed prior to analysis. For the developed HPLC–TOF–MS method, the overall analysis time including sample preparation was less than 1.5 h. The proposed HPLC–TOF-MS method is suitable for fast and simple real-time quantification of two major glucosinolates, sinalbin and sinigrin, in mustard seed.