Page 370 - Analytical method for food addtives

250 Analytical methods for food additives

Table 26.5 Performance characteristics for sodium saccharin in marzipan, yogurt,
orange juice, cream, cola and jam 13,14,15
Sample Marzipan * Fruit yogurt * Orange juice Cola ** Jam **
beverage*

Year of test 1992 1992 1992 1993 1993
No. of laboratories 6 8 12 8 8
Units mg/kg mg/kg mg/L mg/L mg/L
Mean value 228.0 116.0 50.8 75 60
S 10.0 2.7 1.2 1.4 1.8
r
RSD 4.4 % 2.4 % 2.4 % 1.9 % 3.0 %
r
r 28.2 7.7 3.4 4 5
S 13.5 16.1 8.1 12.1 16.8
R
RSD 5.9 % 14.0 % 16.2 % 16.2 % 28.0 %
R
R 37.9 45.5 23.0 34 47
Horrat value 4.1 1.8 2.0 1.7 2.8
Sample Orange juice Cola *** Cream *** Yogurt *** Orange
beverage *** juice ***
Year of test 1995 1995 1995 1995 1995
No. of laboratories 10 11 10 10 8
Units mg/L mg/L mg/kg mg/kg mg/kg
Mean value 82 64.9 68.4 71.4 16.1
S 2.0 2.0 5.5 8.9 2.3
r
RSD 2 % 3 % 8 % 12 % 14 %
r
r 6 5 15 25 6
S 6.7 10.6 11.3 15.8 6.9
R
RSD 8 % 16 % 17 % 22 % 43 %
R
R 19 30 32 44 19
Horrat value 1.0 1.9 1.9 2.6 4.1
* Max von Pettenkofer Institute, Germany
** French Institute for Beverages, Brewing and Malting, France
*** MAFF, UK 14
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
Horrat The HORRAT value for reproducibility is the observed RSD value divided by the RSD value
R
R
calculated from the Horwitz equation.