Page 152 - Analytical method for food addtives

E220–8: Sulphites 97

Table 8.8 Performance characteristics for free sulphite in wine 14,15
Interlaboratory test carried out by FDA 15
Sample White wine Red wine
No. of laboratories 7 7 7 7 7 7
Units µg/g µg/g µg/g µg/g µg/g µg/g
Mean value 19.1 10.9 6.6 1.8 4.4 3.1
S r 0.8 0.4 0.5 0.2 0.8 0.3
RSD r 4.0 % 4.1 % 7.4 % 10.1 % 18.7 % 8.3 %
S 1.8 1.5 0.9 0.6 1.2 0.5
R
RSD 9.4 % 13.5 % 13.4 % 35.8 % 26.5 % 17.0 %
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 The standard deviation of the repeatability.
r
RSD The relative standard deviation of the repeatability (S × 100/mean).
r 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 The standard deviation of the reproducibility.
R
RSD The relative standard deviation of the reproducibility (S × 100/mean).
R R