In the field of water quality monitoring, multi parameter water quality analyzers have become core equipment in industries such as environmental monitoring, sewage treatment, aquaculture, and drinking water testing due to their ability to simultaneously detect multiple indicators such as pH, dissolved oxygen, turbidity, and conductivity. The accuracy of its detection data is directly related to the scientific nature of water quality assessment results, process adjustment directions, and even environmental governance decisions. The key to ensuring stable operation of equipment and accurate data lies in standardized and systematic daily maintenance.
Key points for daily maintenance of multi parameter water quality analyzer:
（1） Instrument appearance and overall environmental maintenance
The cleanliness of the appearance and maintenance of the operating environment of the instrument are the foundation of maintenance work. Before and after daily use, the instrument casing should be wiped with a clean soft cloth to remove dust, water stains, and sample residue from the surface. Special attention should be paid to cleaning the gaps between the buttons on the operation panel to avoid impurities accumulating and affecting the sensitivity of the buttons. If the shell is contaminated with oil or stubborn stains, it can be wiped with diluted neutral cleaner. Do not use highly corrosive solvents such as alcohol and acetone to avoid damaging the coating of the shell.
（2） Core component: Maintenance of sensors
There are differences in the maintenance methods for different types of sensors, which require targeted treatment.
1. pH sensor: The glass film of the pH electrode and the reference electrode are critical components that are susceptible to contamination and aging. After daily use, the electrode should be soaked in a dedicated pH electrode protection solution, avoiding immersion in distilled water or pure water to prevent dehydration of the glass film and loss of reference solution. If stains are found on the surface of the glass film during use, they can be gently brushed with a soft bristled brush; If the electrode response is slow, it may be due to blockage of the reference electrode, and a new reference solution or sand core at the front end of the electrode can be replaced. The pH electrode needs to be calibrated once a month. Before calibration, ensure that the temperature of the standard buffer solution is consistent with the temperature of the sample. The calibration process strictly follows the "two-point calibration method" to ensure calibration accuracy.
2. Dissolved oxygen sensors: There are two common types of dissolved oxygen sensors: film coated and fluorescent. For laminated sensors, it is necessary to check whether the coating is intact after daily use. If there is damage, wrinkling, or contamination, the coating should be replaced in a timely manner and the internal electrolyte solution should be replenished. Regularly clean the sensor probe to remove impurities such as biofilm and scale on the surface. You can use a soft cloth dipped in alcohol to gently wipe it. When using a fluorescent dissolved oxygen sensor, attention should be paid to protecting the fluorescent cap to avoid scratching and contamination. If the fluorescent cap is stained, it can be rinsed with water and wiped dry with a soft cloth. Calibrate the dissolved oxygen sensor once a month using air calibration or standard solution calibration methods to ensure accurate detection data.
3. Turbidity sensor: The optical lens of the turbidity sensor is easily contaminated by suspended solids, organic matter, and other pollutants in the sample, which affects the transmission and scattering of light and leads to detection errors. After daily use, the optical lens should be gently wiped with lens paper or anhydrous ethanol to remove surface stains and water stains. It is strictly prohibited to touch the lens directly with hands. If the lens is heavily contaminated, it can be cleaned with an ultrasonic cleaner for 3-5 minutes, then rinsed with distilled water and wiped dry. Regularly check the light source intensity of the sensor. If the brightness of the light source decreases, it may be due to aging of the light bulb and needs to be replaced in a timely manner. Perform turbidity calibration once a month using a standard turbidity solution (such as fumarate standard solution) to ensure good linearity of the calibration curve.
4. Conductivity sensor: The electrode of the conductivity sensor is easily contaminated by scale, oil, and other pollutants, causing changes in the electrode constant. After daily use, rinse the electrode with distilled water to remove any residual sample on the surface. If there is scale on the electrode surface, soak it in dilute nitric acid solution for 30 minutes and rinse it clean. Regularly check whether the electrode leads are intact to avoid circuit damage or poor contact. Perform conductivity calibration once a month using a standard conductivity solution. During the calibration process, ensure that the electrodes are immersed in the standard solution and the solution is stirred evenly.
（3） Circuit system and software maintenance
Regularly check whether the power and data lines of the instrument are intact, whether there are any damages, aging, looseness, etc. If any problems are found, replace or tighten them in a timely manner. The interface of the instrument should be kept clean and dry, avoiding dust and water stains. When connecting or disconnecting data cables, the instrument power should be turned off first to prevent static electricity from damaging circuit components.
In terms of software, the firmware version of the instrument should be regularly checked. If the manufacturer releases a new version, it can be upgraded under the guidance of professional technicians to optimize instrument performance and fix potential vulnerabilities. After daily use, timely save the detection data and regularly backup the data. The data can be exported through a USB flash drive or computer to avoid data loss caused by instrument failure. At the same time, avoid installing unrelated software on the instrument to prevent software conflicts from affecting the normal operation of the instrument.
（4） Sample Preparation and Injection System Maintenance
Sample pretreatment and cleaning of the injection system directly affect the accuracy of the detection results, while also avoiding sample contamination of internal components of the instrument. After daily use, it is necessary to rinse the injection pipeline, colorimetric dish (if any) and other components with distilled water to remove residual samples. If the sample contains a large amount of organic matter or suspended solids, it can be rinsed with dilute acid solution first, and then rinsed clean with distilled water. Regularly check whether the injection pump, injection needle and other components are blocked. If there is a blockage, it can be cleaned with an ultrasonic cleaner or cleared with a dedicated needle. After use, the colorimetric dish should be cleaned in a timely manner, dried and stored to avoid scratches and contamination. If there are stains on the inner wall of the colorimetric dish, it can be soaked in ethanol or acetone solution for cleaning.
The daily maintenance of a multi parameter water quality analyzer is a systematic and standardized work that needs to be carried out throughout the entire process of instrument use. Only by establishing a sound maintenance system, strictly following maintenance points, promptly addressing common issues, and avoiding maintenance misconceptions, can we ensure that the instrument is always in good operating condition and guarantee the accuracy and reliability of detection data.