OMA Protocol Review: OMAMAN-56 Sulfites in Shrimp

67 71 70 67 73

68.5

20

C1

M1

B1

2.12 3.10

72.5

30

C1

M1

B1

0.71 0.98

Biofish Electrode Stability

80

60

40

20

0

Biofish Results (ppm)

0

5

10

15

20

25

30

35

Time (days)

Figure 13. 30-day stability plot

Robustness

(a) Methodology.- Three method parameters were varied including extraction volume, ultraturrax time, and extract storage time before analysis. The parameter values are shown in Table 15 and Table 16 shows the factorial design employed. Treatment combination 9 uses the normal method parameter values. Treatment combinations 1-8 use either the high or low values for each parameter. For each treatment combination, 2 replicates of Incurred raw shrimp head off with 50-100 ppm sulfite (measured as SO 2 ) were analyzed.

(b) Results.- The results of the duplicate analyses are shown in Table 16. The factorial design was translated into the Youden design in Table 17 and the Youden test was applied (Table 18).

Table 15. Robustness parameters RAW SHRIMP HEAD OFF ROBUSTNESS PARAMETERS

VALUE 1

VALUE 2

VALUE 3

A. EXTRACTION VOLUME B. ULTRATURRAX TIME

16 mL 10 sec

18 mL 20 sec

20 mL 30 sec

C. EXTRACT STORAGE BEFORE ANALYSIS

none

2 h at 25°C

4 h at 25°C

29