The ammonia nitrogen rapid analyzer is an instrument used for water quality monitoring, mainly for rapidly measuring the concentration of ammonia nitrogen (NH ₄⁺) in water samples. Ammonia nitrogen is one of the important indicators of water pollution, commonly used in fields such as environmental monitoring and sewage treatment. The following are common methods for measuring ammonia nitrogen with a rapid analyzer, including sample preparation, measurement steps, and precautions.
1. Sample preparation
Sampling:
Take samples from the water body to be tested, preferably at different depths and locations, to ensure the representativeness of the samples.
Use clean sampling containers (such as glass or plastic bottles) to avoid sample contamination.
Sample preservation:
If immediate detection is not possible, the water sample should be stored in a refrigerator at 4 ° C and analyzed within 24 hours as much as possible.
2. Instrument preparation
Calibration instrument:
Before measurement, calibrate according to the instrument manual and use a standard ammonia nitrogen solution to calibrate the instrument's response.
Usually, a known concentration of ammonia nitrogen standard solution is used for calibration to ensure the accuracy of the measurement results.
3. Measurement steps
Sampling and dilution:
As needed, take out the water sample. If the ammonia nitrogen concentration is high, dilute it appropriately to ensure that it is within the measurement range of the instrument.
Add reagents:
Add specific reagents (usually phenol reagents and sodium chloride, etc.) to the water sample, which react with ammonia to produce color developing substances.
Pay attention to the order and timing of adding reagents to ensure complete reaction.
Reaction time:
According to the instructions, wait for a certain amount of time (usually 5 to 15 minutes) to obtain stable color development.
Measure absorbance:
Place the reacted water sample in the optical path of the ammonia nitrogen rapid analyzer and measure its absorbance.
Record the absorbance value based on the instrument display.
4. Calculate the concentration of ammonia nitrogen
Using standard curve:
According to the pre established standard curve (plotted based on the absorbance values measured from different concentrations of standard solutions), calculate the concentration of ammonia nitrogen in the water sample through the absorbance values.
Result report:
Report the measurement results in mg/L (milligrams per liter) or other units, and make necessary data records.
5. Precautions
Operating environment:
The laboratory environment should be well ventilated to avoid reagent evaporation and contamination.
Reagent processing:
When using reagents, relevant safety operating procedures should be followed, and protective gloves and goggles should be worn.
Regular maintenance:
Regularly maintain and clean the measuring instrument to ensure its sensitivity and accuracy.
Quality Control:
Quality control samples (QC samples) can be regularly used for testing to ensure the normal operation of the instrument.
summary
The determination method of the ammonia nitrogen rapid analyzer is relatively simple and can quickly provide information on the concentration of ammonia nitrogen in water samples. Through reasonable sample preparation, strict operating procedures, and accurate data calculation, water quality can be effectively monitored to help evaluate the pollution situation of water bodies.