In the solid matrices all correlation coefficients
for matrix calibration curves were above 0.98. The mean recovery of
each dye was calculated upon the 3 spiking levels at which reproducibility
was assessed. Average recovery values are shown on
Table 2. They ranged from 60.4% for E123 to 90.7% for E129. RSDr%
ranged from 3.81% to 39.05% while RDSR% ranged from 2.97% to
34.84%. All correlation coefficients of calibration curves for beverages
were above 0.99 except for metanil yellow, E131 and E132 that
presented quite low r2 (0.92, 0.93 and 0.97 respectively). The
average recoveries for beverages ranged from 62.9% for metanil
yellow to 101.1% for E124. All calculated RSDr were less than 15% as
all the RSDR values.