The oxidation-reduction test pen is a portable instrument for rapidly measuring the oxidation-reduction potential of a solution, widely used in water treatment, aquaculture, food processing, and scientific research fields. Its core function is to sense the electron transfer trend in the solution through specific metal electrodes, thereby reflecting the oxidation or reduction characteristics of the system. The following are key usage points to ensure measurement accuracy and equipment lifespan:

1、 Preprocessing and Calibration: Establishing a Precise Foundation

1. Initial calibration: Before use, a standard buffer solution (such as quinone hydroquinone solution) should be used for two-point calibration to establish a voltage potential correspondence. If it is not used for a long time, it should be recalibrated to eliminate the deviation caused by electrode aging.

2. Electrode activation: The new electrode needs to be soaked in deionized water for 30 minutes to activate the surface active layer. If the old electrode responds slowly, dilute hydrochloric acid (5%) can be used to gently wipe the platinum contact to remove oxide deposits.

3. Cleaning treatment: Rinse the electrode head with clean water before and after each measurement to avoid residue contamination; If testing turbid liquids, use a soft bristled brush to clean the particles in the gaps to prevent clogging of the liquid interface.

2、 Measurement operation specification: Avoiding interference factors

1. Immersion depth and position: submerge the electrode into the solution (at least covering the sensing window) to avoid bubble adhesion; For stratified liquids, measurements should be taken in the main solution zone, away from sediment or foam layers.

2. Stable time control: After insertion, let it stand for 10-30 seconds until the value stabilizes. When reading dynamically, take the middle value of the fluctuation range; If there is a violent jump, it may be due to excessive flow rate or the presence of strong oxidants/reducing agents, and the equilibrium time needs to be extended.

3. Stirring technique: Measuring in a static state can reduce flow noise, but in high viscosity solutions, gentle stirring is necessary to ensure homogenization and avoid damaging the diffusion layer on the electrode surface.

4. Temperature compensation: Most test pens have built-in temperature sensors that automatically correct to the standard value of 25 ℃; In manual mode, it is necessary to synchronously measure the temperature of the solution and adjust the reading according to the formula in the instruction manual.

3、 Data interpretation and exception handling

1. Range matching: Confirm that the measured potential is within the nominal range of the device (usually ± 1000mV). If it exceeds the limit, an overflow prompt will be displayed. At this time, the sample needs to be diluted or a higher range model needs to be replaced.

2. Drift judgment: If the deviation of multiple consecutive measurements of the same sample exceeds ± 5mV, it indicates electrode poisoning or electrolyte depletion, and the composite electrode needs to be replaced in a timely manner.

3. Cross validation: For suspicious results, colorimetric or titration methods can be used to measure in parallel and compare the sources of differences; Sudden changes in data are often caused by electrode delamination or loose wiring.

4、 Maintenance and upkeep: Extend service life

1. Storage conditions: Store in the original sleeve for a short period of time and add a small amount of preservation solution (such as KCl solution); Wipe the electrode dry when not in use for a long time, place it in a dry and cool place, and activate it once a month by powering on.

2. Anti corrosion measures: Avoid contact with concentrated acids/alkalis and organic solvents. Clean immediately after measuring the chlorine containing solution to prevent etching of the platinum black coating.

3. Periodic verification: Send it to a professional organization for verification every six months, with a focus on checking the stability of the reference electrode potential, and replace the internal filling liquid if necessary.

5、 Typical scenario application tips

-Aquaculture: Monitor dissolved oxygen and sulfide balance, maintain ORP in the+200~+400mV range, and prevent flooding risk.

-Wastewater treatment: Identifying aerobic/anaerobic reaction nodes through potential mutations to guide aeration regulation.

-Food processing: detect the degree of browning in fruit juice, control the amount of antioxidants added, and extend the shelf life.