Page 151 - Analytical method for food addtives

96 Analytical methods for food additives

Table 8.7 Performance characteristics for total sulphite in shrimp, potatoes, pineapple
and wine 13
Interlaboratory test carried out by FDA 13
Sample Shrimp Potatoes Pineapple

No. of laboratories 6 6 7 7 7 7
Units µg/g µg/g µg/g µg/g µg/g µg/g
Mean value 8.6 57 10.4 416 213 278
S r 0.9 4.4 1.5 40.2 15.5 15.5
RSD 10.7 % 7.7 % 14.3 % 9.7 % 7.2 % 5.6 %
r
S R 1.3 8.1 3.6 95.8 16.1 15.5
RSD 14.6 % 14.2 % 34.8 % 23.0 % 7.6 % 5.6 %
R
Sample White wine Red wine
No. of laboratories 7 7 6 7
Units µg/g µg/g µg/g µg/g
Mean value 62 119 17 41
S 1.9 2.4 7.1 1.0
r
RSD r 3.0 % 2.0 % 42 % 2.4 %
S R 3.9 7.30 11.5 13.7
RSD 6.3 % 6.2 % 68 % 34 %
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