OMA Protocol Review: OMAMAN-56 Sulfites in Shrimp

Biolan Microbiosensores BIOFISH 300 SUL Collaborative Study Protocol

February 2019

( d ) Sample homogenizer.-- Ultraturrax® or equivalent. (e) Adjustable pipets.-- Capable of delivering 20-200 μL and 500-5000 μL.

D. Additional Supplies and Reagents ( a ) Distilled water.-- ( b ) Plastic tubes. --50 mL. ( c ) Graduated cylinder.– 25 mL. ( d ) Pipet tips . --

( e ) Bottles with caps. —1- and 2-L sizes. (f) Liquid dispenser.--

E. Precautions ( a ) Proceed to equipment Reconditioning, Activation and Calibration right before beginning the analysis, on a daily basis, and with well-tempered Solutions, Reagents and Biotest. ( b ) In each process, ensure that the three components of the electrochemical cell (Biotest, reference electrode and counter electrode) are well-submerged in the SUL Measurement Solution and that the reference electrode is well-connected. If a breakdown occurs with the reference electrode, or if work is carried out without it being connected, it will be detected that the current intensity inside is very unstable and with variable intensity peaks. If this is the case, stop the measurement and discard both the Biotest and the reference electrode. ( c ) The main screen Stand By option is used when an intentional pause is to be taken in the analysis routine. ( d ) If the result of an analysis is higher than the upper limit of the Measurement Range being worked in (for example, a value of 320 mg/kg in the range of 30-150 mg/kg), change the content of the cuvette and put the equipment into Standby mode for at least 30 seconds before moving forward with the following analysis. ( e ) It is important to store the reference electrode in the Storage Solution supplied along with the electrode (4 M KCl) and in a vertical position whenever not in use. Improper storage may lead to deterioration over a short space of time. ( f ) Follow all local, state, and federal regulations for proper disposal. F. Electrode Hydration and Storage ( a ) Biotest .--The Biotest electrodes are shipped at room temperature and vacuum packed with silica gel crystals to protect them from atmospheric humidity. Upon receipt, store unopened at 3-8°C until expiration date. To hydrate the Biotest prior to using (this process should be carried out at least 24 hours prior to use): ( 1 ) Remove the silica gel crystals from inside the tube. ( 2 ) Fill the tube with SUL Measurement Solution until the base of the Biotest is submerged. ( 3 ) Add 20 μL of SUL Calibration Reagent. ( 4 ) Once hydrated, the Biotest must be stored vertically at 3-8°C for a maximum of 15 days. ( b ) Reference electrode (ELEREFN) .-Store in 4M KCl at room temperature in the dark and in an

upright position until use. G. Reagent Preparation

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