OMA Protocol Review: OMAMAN-56 Sulfites in Shrimp

( b ) Wait until the device records the measurement target and it issues an accoustic signal. Press CONTINUE and pipette the clear supernatant of the extracted sample (4 mL for the 7-30 mg/kg range; 2

mL for the 30-150 mg/kg range; or 1 mL for 50-300 mg/kg range) into the measuring cuvette.

( c ) Wait until the process ends and the device shows the result of the analysis. ( d ) Replace the contents of the cuvette with 10 mL of new SUL Measurement Solution.

Interpretation and Test Result Report ( a ) The Biosensor expresses the analysis result in units of mg of sulfite (measured as SO 2

) per kg of

shrimp, taking into account the dilution involved in the extraction of the sample.

( b ) To save the result of an analysis, press SAVE and enter a code. ( c ) To view the saved results, enter the RECORDS option of the main menu screen . Saved results can be downloaded to a computer. ( d ) To delete the saved results, go to RECORDS and press DELETE ALL.

Validation Study This validation study was conducted under the AOAC Research Institute Performance Tested

Method SM program. The BIOFISH 300 SUL 7-30 mg/kg range method was validated for raw shrimp (head

off) and boiled shrimp. The method developer studies included linearity, LOD, LOQ, bias, recovery and

precision. Anfaco Cecopesca (Crta. Colexio Universitario, 16, 36310 Vigo – Pontevedra, Spain) conducted

the reference method analyses by OMA 990.28 (1).

Method Developer Studies

Linearity Study

( a ) Methodology.-- A calibration line with nine concentrations (including the blank) of SO 2

and three

was prepared by

replicates per concentration level were analyzed. A stock solution of 3000 mg/L of SO 2

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