This document specifies a method for the determination of the individual glucosinolates content in rapeseeds and rapeseed meals using high-performance liquid chromatography with gradient elution.
This method was tested on rapeseeds and rapeseed meals (Brassica rapa, Brassica napus and Brassica juncea) but is applicable to other plant materials, on the condition that the occurring glucosinolates previously identified are described in this document. On the contrary, the quantitative analysis of the concerned glucosinolate(s) is not carried out.
NOTE This method does not determine glucosinolates that are substituted on the glucose molecule, but these compounds are of little importance in commercial rapeseed and rapeseed meal.
Annex A presents the results of the interlaboratory trials for the gradient elution HPLC method. Annex B presents how to check the titre of the prepared internal standard solution. Annex C presents how to prepare and test the purified sulfatase solution and how to check the desulphation step on the ion exchange column. Annex D presents the HPLC and column performance criteria qualification.
The analysis of glucosinolates content in rapeseed can also be done using an isocratic elution mode. This requires some modifications of the method (internal, standard, HPLC column and HPLC buffers), as described in Annex E.