OMA Consulting Protocol Review: OMACON-2019-2

6.Recommendations for Use

Proceed to activate and calibrate the device immediately prior to starting the analyses, and do so every day. Work with the Biotest and all the solutions (Measurement Solution and Calibration Standards) at room temperature, as the temperature strongly affects the enzymatic activity of the Biotest. Make sure in each process that the three components of the electrochemical cell (Biotest, reference electrode and counter- electrode) are well submerged in the Measurement Solution. The calibration status should be tested by analysing the Measurement Standard, every 10 measurements or after long periods when the device is not running. Make sure to change the contents of the cuvette after each process. If the result of an analysis is over the higher end of the Measurement Range (for example, a value of 250 mg/l in the 0- 200 mg/l range), change the contents of the cuvette and put the device on Stand By for 30 seconds prior to proceed with the following analysis. Due to the sensibility of the Biotest to the pH, it is crucial, when working with acid samples, to verify the cuvette pH after the sample addition. The pH should be within 6-6,7. If necessary, use double concentration of Measurement Solution by adding 2 tubes of Measurement Reagent in the normal volume instead of 1. The reference electrode must remain submerged in its storage solution (4M KCl) and in vertical position if it is not connected to the equipment.

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