OMA Protocol Review: OMAMAN-56 Sulfites in Shrimp

Biolan Microbiosensores BIOFISH 300 SUL Collaborative Study Protocol

February 2019

( a ) SUL Measurement Solution.-- Dissolve the contents of 1 tube of MFSUL1 in 250 mL water for up to 20 analyses or dissolve the contents of 1 tube of MFSUL2 in 1 L water for up to 90 analyses. Store at room temperature and use within 15 days. ( b ) SUL Extraction Solution.- -Dissolve the contents of 1 tube of SEFSUL1 in 1 L water for up to 50 analyses or dissolve the contents of 1 tube of SEFSUL2 in 2 L water for up to 100 analyses. Store at room temperature and use within 15 days. ( c ) SUL Calibration Reagent .--Dissolve contents of 1 tube of CFSUL with 10 mL SUL Extraction Solution. Store at 3-8°C and use within 7 days. ( d ) SUL Standard 1 .--For the 30-150 mg/kg range, prepare SUL Standard 1 by diluting 53.4 μL SUL Calibration Reagent to 20 mL with Extraction Solution. Store at room temperature. Prepare fresh daily. ( e ) SUL Standard 2 --For the 50-300 mg/kg range, prepare SUL Standard 2 by diluting 100 μL SUL Calibration Reagent to 20 mL with Extraction Solution. Store at room temperature. Prepare fresh daily. ( f ) SUL Standard 3 .--For the range 7-30 mg/kg, prepare SUL Standard 3 by diluting 33.4 μL SUL Calibration Reagent to 50 mL with Extraction Solution. Store at room temperature. Prepare fresh daily. H. Sample Preparation ( a ) Preparation of shrimp (raw and boiled).-- Clean and dismantle the carapace and cephalothorax and other nonedible parts of the exoskeleton and the visible digestive tract (leave the hepatopancreas in case its measurement is required, only for the 30-150 and 50-300 mg/kg range) from 15-20 shrimp. Homogenize the bulk sample with the aid of a mincer. Add 2 g of the homogenized sample to a plastic tube. ( b ) Sample Extraction.- -Add 18 mL of SUL Extraction Solution. Homogenize the contents of the plastic tube with the aid of an ultra-turrax (8000-9000 rpm 15-20 seconds). Leave to stand for at least 15 minutes at room temperature. Sample extractions are stable up to 1 hour at room temperature. I. Biosensor Setup ( a ) For low range (7-30 mg/kg) testing, choose the Biotest BTFSULAL. For medium (30-150 mg/kg) and high (50-300 mg/kg) range testing, choose the Biotest BTFSUL. Ensure Biotest is prepared as in F . ( b ) Insert the Biotest and reference electrodes into their respective connectors (place the Biotest into the carrier, tightening it with the screw), ensuring that they are well connected. For safety reasons, it is recommended to never disconnect the reference electrode. When the equipment is disassembled after analyses are completed, the reference electrode remains protected with the Storage Solution supplied (4 M KCl). ( c ) Fill the measurement cuvette with 10 mL of SUL Measurement Solution and place it in the cuvette so that all components in the electrochemical cell are submerged. Connect the equipment to a 100-240 VAC stable current power outlet and press the power button located next to the screen for 2 seconds. The menu main screen will appear. ( d ) In the BIOTEST option, select the analyte, press », enter the Biotest Code (this code is located on the Biotest identifying label), press » and finally select the measurement range with which you are going to work (7-30 mg/kg; 30-150 mg/kg; or 50-300 mg/kg) and press SAVE. ( e ) From the main screen, the ANALYSIS option leads to the analysis menu: Recondition, Activate, Calibrate, Standard, Verifying Solution, Turrax/Sample, and Stand By. J. Reconditioning, Activation and Calibration of the Biotest

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