Extraction and determination of 4-methylthio-3-butenyl isothiocyanate in Chinese radish (Raphanus sativus L.) roots

• Factors influencing the extraction of 4-MTBI from radish roots by an endogenous myrosinase method were optimized.
• A new GC method was established to determine 4-MTBI in radish roots with a capillary gas chromatography column HP-5.
• The GC method was of good precision and accuracy, and suitable for quantitation of 4-MTBI in radish roots.

4-methylthio-3-butenyl isothiocyanate (4-MTBI) is released from 4-methylthio-3-butenyl glucosinolate (4-MTBG) in radish roots by endogenous myrosinase hydrolysis. In this research, factors influencing the extraction of 4-MTBI from radish roots by an endogenous myrosinase method, such as the time for endogenous myrosinase hydrolysis under 37 °C, the storage time after hydrolysis, were optimized. A new GC method was developed to determine 4-MTBI in radish roots, which was identified by GC-MS and compared with the authentic 4-MTBI. Through optimization of the starting point and increasement of column temperature, both the internal standard allyl isothiocyanate (AITC) and 4-MTBI were clearly separated with a capillary gas chromatography column HP-5. Coefficient of variation (CV) of GC analysis was 3.883%. Recovery percentage of AITC remained 90.3–105.4%. CV of determination and recovery percentage of sinigrin were 5.35% and 91.3–101.9%, respectively.