The linearity was evaluated under the chromatographic conditions
described by preparing calibration curves using external
standard solutions of the mycotoxins at 0.05, 0.2, 0.5, 2.5, 5.0 and
10.0 lg/ml. Calibration curves were constructed by plotting analyte
concentrations against peak areas at 256 nm (AOH, AME)
and 281 nm (TEN). Data were submitted to one-way analysis of
variance (ANOVA) and regression equations and coefficients of all the compounds were calculated. Satisfactory linearities were
observed for the three mycotoxins with correlation coefficients
(R2) values being higher than 0.9937 in the concentration range
studied in all cases.
During the method development, limits of detection and quantification
were calculated based on threefold and tenfold signal to
noise (S/N) ratios, respectively. The LOD levels for both substrates
(pomegranate fruit and juice) were set at 0.015 lg/g (or lg/ml) for
AOH and AME, and 0.02 lg/g (or lg/ml) for TEN. The LOQ were set
at 0.05 lg/g (or lg/ml) for AOH and AME, and 0.066 lg/g (or
lg/ml) for TEN.