Linearity was evaluated by analysing five different concentrations
of standard solutions in triplicate.
The calibration curve was obtained in a concentration range
from 0.1 lg/mL to 0.8 lg/mL and found to be linear for Trp with
coefficient of determination greater than 0.998 as shown in
Table 1.
Limit of detection (LOD) and limit of quantification (LOQ) for
Trp were calculated from the calibration line at the lowest
concentration using the following equations: LOD = 3 SD,
LOQ = 10 SD, (SD: standard deviation). LOD and LOQ values have
been shown in the Table 1. In practice, LOQ value was found to be
suitable compared to signal-to-noise ratio (10:1).
FAPAS Test Material 2584 amino acids in infant formula,
wheat and red lentil samples were used for precision and accuracy
assessment in the study. The precision study of the analytical
method included repeatability and reproducibility tests. The
repeatability was tested by analysing the same sample in ten replicate
within the same day. The reproducibility was determined by
analysing the same sample in 16 replicates in three independent
days. The relative standard deviation (RSD) values of repeatability
are less than 3.7% and RSD values of reproducibility are less than
6% as shown in Table 1