Page 50 - Analytical method for food addtives

E122: Azorubine 23

Table 2.3 Performance characteristics for azorubine in collaborative trial samples 2
Sample Lemonade Cake crumb Skimmed milk
Analyte Azorubine Azorubine Azorubine
No. of laboratories 10 9 9
Units mg/kg mg/kg mg/kg
Mean value 24.5 35.1 51.5 72.8 84.4 81.1
S 1.64 3.68 14.81
r
RSD 5.5 % 5.92 % 17.89 %
r
r 4.59 10.31 41.46
S 2.05 7.69 20.32
R
RSD 6.87 % 12.37 % 24.56 %
R
R 5.73 21.53 56.91
Ho 10.72 1.44 2.98
R
Key
Mean The observed mean. The mean obtained from the collaborative trial data.
r Repeatability (within laboratory variation). The value below which the absolute difference
between two single test results obtained with the same method on identical test material under
the same conditions may be expected to lie with 95 % probability.
S r The standard deviation of the repeatability.
RSD r The relative standard deviation of the repeatability (S × 100/Mean).
r
R Reproducibility (between-lab variation). The value below which the absolute difference
between two single test results obtained with the same method on the identical test material
under different conditions may be expected to lie with 95 % probability.
S R The standard deviation of the reproducibility.
RSD R The relative standard deviation of the reproducibility (S × 100/mean).
R
Ho The HORRAT value for the reproducibility is the observed RSD value divided by the RSD
R R R
value calculated from the Horwitz equation.
Table 2.4 Performance characteristics for azorubine in bitter samples 3

Sample Bitter kas Bitter kalty
Analyte Azorubine Azorubine
Quantification method Direct Standard Direct Standard
measurement addition measurement addition
Number of
determinations 2 2 2 2
Units mg/L mg/L
Mean value 33.3±0.1 32.8±0.2 18.5±0.1 17.5±0.3
Statistical parameters for assay
Number of
determinations 9
Calculated by Peak height Peak area
Units mg/L
SD 0.041 0.040
RSD ±2.40 ±2.44
Detection limit 4.1 1.9