The slit width affects the spectral pass width and the energy absorbed by the detector.

1. selection of absorption wavelength (analysis line)

Usually resonance absorption line is chosen as the analysis line, and non-resonance line with lower sensitivity is selected as the analysis line when measuring high content elements. For example, the most sensitive wavelength of 213.9 nm is often used in the determination of Zn. However, when the content of Zn is high, the Sub-sensitive wavelength of 307.5 nm can be used to ensure the linear range of the working curve. As and Se isoresonance absorption lines are located in the far ultraviolet region below 200 nm, and the flame components obviously absorb them. Therefore, it is not suitable to use resonance absorption lines as analytical lines in the determination of these elements by flame atomic absorption spectrometry. When Hg is measured, the resonance line 184.9nm will be strongly absorbed by the air, so it can only be measured by this sensitive line 253.7nm.

2. optical alignment is analyzed.

Before the atomic absorption spectrometer, it is necessary to adjust the emission of the hollow cathode lamp and the receiving position of the detector to the optimum state to ensure the maximum measurement energy.

3. selection of slit width

The slit width affects the spectral pass width and the energy received by the detector. Adjusting the width of the slit, the absorbance changes with the width of the slit. When other spectral lines or non-absorbable light enter the spectral passband, the absorbance will immediately decrease. The maximum slit width that does not cause absorbance decreases, that is, the suitable slit width should be selected. For elements with simple spectral lines, such as alkali metals and alkaline earth metals, wide slits can be used to reduce lamp current and photomultiplier tube high voltage to improve signal-to-noise ratio and increase stability. For elements with complex spectral lines such as iron, cobalt and nickel, it is necessary to select smaller slits to prevent non-absorption lines from entering the detector, so as to improve sensitivity and improve the linear relationship of standard curves.

Atomic absorption spectrometer accessories should be done after each shutdown and analysis.

1. Put out the condensate water in the air compressor's air storage filling, check whether the gas is shut down, and flush the waste discharge system thoroughly with water.

2. If organic solvents are used, the waste liquid in the waste liquid tank should be poured out, and the waste liquid tank should be flushed with tap water.

3. After the high content sample is finished, take off the burning head and put it under the tap water to wash it clean and wipe the carbon deposit carefully with the filter paper, then wash it with pure water, and finally throw off the water drop to dry for reserve.

4, we should continue to spray with pure water for several minutes before cleaning.

5. Remove the droplets or splashed water stains on the lamp windows and sample plates, wipe them with cotton balls, clean the tested sample bottles, take out the instrument room and clean the test bench.

6, turn off ventilation facilities, check whether all power outlets have been cut off, and whether water and gas sources are closed.

7. When using graphite furnace system, we should pay attention to check the position of automatic sampling needle is accurate, atomization temperature generally does not exceed 2850 C and as far as possible to drive out the strong acid and strong oxidant in the test solution, to ensure the life of graphite tube.

Atomic absorption spectrometer accessories