OMA Protocol Review: OMAMAN-56 Sulfites in Shrimp

( b ) Reference electrode (ELEREFN) .--Store in 4M KCl at room temperature in the dark and in an upright position until use.

Reagent Preparation

( 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. To prevent loss of reagent, introduce the pipette tip through the perforated stopper when

adding the extraction solution volume. 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 in a volumetric flask with Extraction Solution. Store at room temperature.

Prepare fresh daily.

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

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