Standard curve drawing

Establish detection methods in the workstation, set standard solution concentration sequences, and blank solution positions;

Inject samples in the order of "blank → low concentration → high concentration", repeat 2-3 measurements for each concentration point, and record the absorbance value;

The instrument automatically draws a standard curve, calculates the regression equation (y=ax+b) and correlation coefficient (R ² ≥ 0.995 is considered qualified, otherwise a new standard solution needs to be prepared).

Sample measurement

Place the processed samples into the sample rack, select the "Sample Measurement" mode in the workstation, and set the sample number and number of repetitions;

The instrument automatically injects samples, measures sample absorbance, and calculates the concentration of target elements in the sample based on the standard curve;

Real time observation of data stability during the measurement process. If the absorbance is abnormal (such as exceeding the standard curve range), the sample needs to be diluted and re measured.

quality control

For every 10-15 samples measured, insert a concentration point in the middle of the standard curve for verification, with a deviation of ≤± 5%, otherwise the curve needs to be recalibrated;

Blank samples need to be measured in batches, and the blank absorbance should be deducted to eliminate matrix interference.

Agilent AAS Atomic Absorption Spectrometer Experiment Completed and Instrument Maintenance

Sample and reagent processing

Stop the injection and rinse the atomizer and sample capillary continuously with deionized water for 5-10 minutes to remove residual samples;

Organize standard solutions and sample waste liquids, classify and treat them according to laboratory environmental requirements, and avoid pollution.

Instrument shutdown process

Flame method: First turn off the acetylene gas, continue to flush the combustion head with air for 5 minutes, and then turn off the air;

Graphite furnace method: Turn off the power supply of the graphite furnace and continue to supply argon gas to protect the graphite tube until it cools to room temperature (≤ 100 ℃);

Turn off the element lamp and detection module, exit the workstation software, turn off the power supply of the instrument host, and finally turn off the laboratory main power supply and gas cylinder valve.

routine maintenance

Combustion head: After rinsing with deionized water, clean the carbon deposits in the gaps with a soft bristled brush. If necessary, soak in dilute nitric acid and rinse to dry;

Graphite tube: If there is rupture or severe carbon deposition, replace it in a timely manner; After use, blow the graphite furnace chamber with argon gas;

Nebulizer: Regularly check whether the capillary tube is blocked. If it is blocked, use a fine steel wire to clear it or use an ultrasonic cleaner to clean it;

Instrument surface: Wipe with a clean cloth to keep the laboratory clean, and fill in the instrument usage record (running time, detected elements, fault conditions, etc.).

Key precautions

Safe operation: Acetylene is a flammable and explosive gas, and good ventilation must be ensured during use. Open flames are strictly prohibited; The graphite furnace method has a high atomization temperature, so avoid touching high-temperature components;

Data accuracy: The correlation coefficient of the standard curve should meet the experimental requirements, and cross contamination should be avoided during sample measurement (such as cleaning the injection needle when replacing the sample);

Fault handling: If there is a large fluctuation in absorbance, check the stability of gas pressure and lamp current; If the test results are high, check for blank contamination or substrate interference;

Regular calibration: The instrument needs to be calibrated for wavelength accuracy and repeatability regularly (every 3-6 months) by professional technicians.