evaluate the applicability of the
method for analyzing extracts, recovery was determined by analyzing
the three different Brassicaceae seed extracts (i.e. S. alba, B. napus,
and B. juncea), spiked with 14 GSL
and 15 ITC standards (each at two levels: 10 and 30 μM), derivatized
with NAC. Recovery (%) was calculated as where xspiked was
the measured concentration of the analyte in the spiked experiment, xunspiked was the measured concentration of the
analyte in the unspiked experiment, and xref was the true concentration which was spiked to the extract. Four
repetitions were performed.
According to FDA,40 a good recovery for the working analyte concentrations
in this study should be between 80 and 110%. To test whether the recovery
was within the range, the recovery whose average outside the range
was statistically evaluated by analysis of variance (ANOVA) one-sample t-test using IBM SPSS Statistic v.23 software (SPSS Inc.,
Chicago, IL, U.S.A.).