OMA Protocol Review: OMAMAN-56 Sulfites in Shrimp

Table 16. Factorial design and results of robustness testing TREATMENT COMBINATION RAW SHRIMP HEAD OFF WITH 50-100 PPM SULFITE 1 2 3 4 5

6

7

8

9

16 mL 16 mL 16 mL 16 mL 20 mL 20 mL 20 mL 20 mL 18 mL 10 sec 10 sec 30 sec 30 sec 10 sec 10 sec 30 sec 30 sec 20 sec

EXTRACTION VOLUME ULTRATURRAX TIME

EXTRACT STORAGE BEFORE ANALYSIS

none 4 h at 25°C

none 4 h at 25°C

none 4 h at 25°C

none 4 h at 25°C

2 h at 25°C

100 114 101

116 84 110 82

102 88

98 96

111 102

BIOFISH RESULTS (mg/kg)

99

115 102

95

92

Table 17. Youden factorial design F Factor Value of F Factor

DETERMINATION COMBINATION

1

2

3

4

5

6

7

8

9

A: 16 ml a: 20 ml a´: 18 ml B: 10 sec b: 30 sec b´: 20 sec C: none c: 2 hours c´: 4 hours

Extraction volume

A A A A a

a

a

a

a´

Ultraturrax time

B

B b

b

B B b

b b´

Extract storage before analysis

C c´

C c´

C c´

C c´

c

Result (average data) (mg/kg) % of Nominal (Combination 9)

99.5 114.5 101.5 113 83 98.5 90 97 106.5

93.4 107.5 95.3 106.1 77.9 92.5 84.5 91.1 NA

Table 18. Youden test results

Variables comparison (X-x)

Average differences (D i )

SD of the differences (SD i )

SD of the method (raw shrimp head off, 106 mg/kg)

Acceptance criterion Compliance*

Δ A, a Δ A, a´ Δ a, a´ Δ B, b Δ B, b´ Δ b, b´

no no no no no no no

15.00

7.50 3.31 7.19 5.66 5.81 4.69 6.50

6.63

14.38 11.31 11.63

2.8

SD i

≤ SD

9.38

Δ C, c

13.00

30