How to use an atomic absorption spectrophotometer_How to use an atomic absorption spectrophotometer

Introduction to Atomic Absorption Spectrophotometer

Atomic absorption spectrometer, also known as atomic absorption spectrophotometer, analyzes metal elements based on the absorption of characteristic radiation by the ground state atomic vapor of a substance. It can sensitively and reliably determine trace or trace elements.

Atomic absorption spectrophotometer workflow

Taking the determination of the content of magnesium ions in the test solution as an example, the instrument is shown in Figure 3-14. The test solution is first sprayed into a mist and introduced into the flame. The droplets containing magnesium salt evaporate and dissociate into magnesium atoms to form atomic vapor at the flame temperature. When a magnesium hollow cathode lamp is used as a light source, it radiates a characteristic spectrum (wave) of magnesium with a wavelength of 285.2nm. When it passes through a certain thickness of magnesium atomic vapor in the flame, part of the light is absorbed by the ground state magnesium atoms in the vapor, causing the intensity to be weakened. After being split by a monochromator, it is received by the detector, which measures the degree of weakening of the 285.2nm spectrum line light of magnesium, and then the magnesium content in the sample can be calculated.

Basic Operation of Atomic Absorption Spectrophotometer

1. Power on

1. Turn on the regulated power supply, and turn on the host power switch after the voltage stabilizes at 220 volts;

2. Turn on the air compressor;

3. Open the main valve of the gas cylinder and the main valve of the acetylene cylinder by at most one turn;

4. Turn on the exhaust fan and cooling water (when using graphite furnace atomization).

2. Testing

1. Install the hollow cathode lamp of the element to be tested and adjust the lamp current and wavelength to the required values;

2. Ignite and set instrument test parameters;

3. Insert the nebulizer capillary into deionized water, adjust to zero, and then insert the nebulizer capillary into the solution.

After the display stabilizes, record the test results, insert the atomizer capillary into deionized water, and wait for the instrument display to return to zero;

The same method was used to measure other solutions.

3. Shutdown

1. After the test, clean the atomization system with clean deionized water for a few minutes under ignition;

2. Close the main valve of the gas cylinder, and close the gas valve of the instrument after the remaining gas in the pipeline is burned out;

3. Loosen the gas and auxiliary gas knobs on the instrument panel and turn the lamp current to zero;

4. Turn off the instrument power supply and the voltage regulator power supply;

5. Turn off the exhaust fan and cooling water;

6. Loosen the gas cylinder pressure reducing valve;

7. Sequentially turn off the gas, air compressor, and cathode lamp. Reset the knob, turn off the negative high voltage power supply of the photomultiplier tube and the main power supply;

8. Use filter paper to clean the seam of the combustion head and fill in the instrument usage record;

9. Clean the glassware and reset it.