Page 37 - Analytical method for food addtives

14 Analytical methods for food additives

Table 1.3 Performance characteristics for sunset yellow in lemonade (pre-trial
samples) 2
Sample Lemonade

Analyte Sunset yellow
No. of laboratories 10
Units mg/kg
Mean value 23.9 34.4
S 1.67
r
RSD 5.7 %
r
r 4.69
S 3.57
R
RSD 12.2 %
R
R 10.0
Ho 1.3
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 1.4 Performance characteristics for sunset yellow in bitter samples 3

Sample Bitter kalty

Analyte Sunset yellow
Quantification method Direct measurement Standard addition
Number of determinations 2 2
Units mg/L mg/L
Mean value 7.8±0.2 7.3±0.3
Statistical parameters for assay
Number of determinations 9
Calculated by Peak height Peak area
Units mg/L
SD 0.056 0.046
RSD ±3.72 ±2.85
Detection limit 25.3 4.0