Comparison of HPLC and GLC methodologies for determination of glucosinolates using reference material

The reference material rapeseed of known glucosinolate composition, was analysed by HPLC and GLC and two commercially available glucosinolates (glucotropaeolin and sinigrin) were used as internal standards. The HPLC method enabled determination of 11 different glucosinolates (as desulphoglucosinolates) that occur in the rapeseed. Only seven glucosinolates (as trimethylsilylated desulphoglucosinolates) were separated by GLC. The latter method did not allow the determination of methylsulphinylalkyl glucosinolates (glucoiberin, glucoraphanin and glucoallysin) and did not separate optical isomers of 2-hydroxy-3-butenyl glucosinolate (progoitrin and epi-progoitrin). Statistical evaluation of data (t-test, F-test) revealed no significant differences between the tested methods at the 95% confidence level. The advantages and disadvantages of both widely used chromatographic methods are discussed.