OMA Protocol Review: OMAMAN-56 Sulfites in Shrimp

Table 4. Method developer estimation of LOD and LOQ for boiled and raw shrimp

Boiled

Raw

Sb (intercept)

0.0731

0.0466

m (slope)

0.0518

0.0487

LOD =

0.26

0.17

LOQ = 3 x LOD

0.79

0.50

The estimated LOQ values for each matrix were lower than 1 mg/kg. These results must be validated

by analyzing a sample with this concentration and determining repeatability from 10 replicate test

portions. As it was impossible to obtain samples with such low sulfite concentration, the limit of

quantification was first validated with samples of approximately 5 mg/kg for both raw and boiled shrimp.

value obtained for boiled shrimp is acceptable, but not so for raw

As can be seen in Table 5, the RSD r

shrimp. This experiment was repeated with a sample of higher concentration, this time yielding a RSD r

value of less than 10%, thereby validating the LOQ of 7 mg/kg for this matrix.

Table 5. Method developer validation of LOQ for raw head off and boiled shrimp

Result (mg/kg)

Result (mg/kg)

Result (mg/kg)

2.95

7.34

5.46

3.78 3.07 3.78 3.44 3.74 4.57 4.95 4.52 5.04 3.98 0.75

7.08 6.85 6.40 7.09 6.12 6.09 6.80 6.77 6.04 6.66 0.47 7.01

5.29 5.32 5.26 5.12 5.37 4.74 5.03 5.64 5.25 0.25 4.68

BOILED SHRIMP 5.22

RAW SHRIMP HEAD OFF

Mean

S r

%RSD r

18.75

21