amount. For a multiple determinatio

amount. For a multiple determination the samples were prepared five
times. Soyasaponin I from soybeans was used as a standard. Due to
the instability of the DDMP conjugate, an adequate reference compound
is not commercially available. For this reason, the content of DDMP
saponin was only determined approximately using the calibration
curve of saponin B as well.
The working range of soyasaponin I was defined to be linear
between 0.125 mg/mL and 0.625 mg/mL with a suitable average
coefficient of determination R2= 0.993 ± 0.002. The limit of detection
(LOD) and limit of quantification (LOQ) were calculated to be 0.06 ±
0.01 mg/mL and 0.21 ± 0.01 mg/mL respectively. Furthermore, the
analysis revealed a recovery rate of 90 ± 4%. The measuring precision
within (repeatability) and between (reproducibility) batches was
obtained for soyasaponin I standard (c= 0.125–0.625 mg/mL) as well
as for the variety ‘Rocket’ (hulls). The relative standard deviationwithin
batches of soyasaponin I standard and in the pea sample did not exceed
9%. In contrast, the reproducibility of the measurement revealed a
relative standard deviation of maximum 12% (standard) and 11%
(sample).