The water quality detection methods of online nitrite nitrogen water quality detection analyzer mainly include colorimetric method, ammonia nitrogen method, ion chromatography method, chemiluminescence method, electrochemical method, etc. The following is a detailed introduction to these methods:
colorimetry
Principle: By reacting nitrite with certain reagents to form colored compounds, measuring their absorbance and comparing it with a standard curve, the concentration of nitrite nitrogen in water can be quantified.
Operation steps: Inject the water sample to be tested into the sample pool, add a specific colorimetric reagent (such as Grignard reagent), measure the absorbance at a specific wavelength, and compare the absorbance value with the standard curve to obtain the concentration of nitrite nitrogen.
Advantages: Simple operation, fast measurement, suitable for continuous online monitoring.
Disadvantage: Due to significant interference from other substances in the water sample, regular calibration is required.
Ammonia nitrogen method
Principle: By reacting nitrite nitrogen with ammonia nitrogen reagents in water samples, measurable compounds are formed.
Operation steps: After the sample enters the analyzer, add ammonia nitrogen reagent and form a reaction. Measure the absorbance after the reaction and calculate the nitrite nitrogen concentration based on the standard curve.
Advantages: High measurement sensitivity, suitable for lower concentrations of nitrite nitrogen.
Disadvantages: Regular replacement of reagents is required, and equipment maintenance costs are high.
Ion chromatography
Principle: Separate the ion components in the water sample through ion exchange principle, and measure the concentration of nitrite nitrogen using conductivity detector or other detectors.
Operation steps: The water sample is separated by an ion chromatography column, and the concentration of nitrite nitrogen ions is measured by a detector. The specific concentration of nitrite nitrogen is calculated using analysis software.
Advantages: High precision, suitable for detecting complex water quality, and wide applicability.
Disadvantages: Complex equipment, high cost, and cumbersome operation.
Chemiluminescence
Principle: Nitrite reacts with certain chemical reagents to release a light signal, and the instrument quantifies the concentration of nitrite nitrogen by measuring the intensity of the light signal.
Operation steps: The sample enters the analyzer and reacts with the reagent. The light signal released during the reaction is captured by the detector, and the concentration of nitrite nitrogen is calculated based on the intensity of the light signal.
Advantages: High sensitivity, suitable for real-time monitoring.
Disadvantages: The equipment is expensive and the operation is complex.
electrochemical method
Principle: Quantify nitrite nitrogen concentration by measuring the reaction between nitrite nitrogen ions in water samples and electrodes to generate changes in current or voltage.
Operation steps: The water sample flows into the electrochemical sensor, and the electrode reacts with nitrite nitrogen ions to generate current or voltage signals. The concentration of nitrite nitrogen is calculated based on the signal strength.
Advantages: Fast response speed, suitable for online monitoring.
Disadvantage: It has certain requirements for electrodes and may be affected by changes in water quality.