The water used for atomic absorption spectrometry is distilled by water.

The blank (4 nitric acid + 1 perchlorate GR) value is always higher when measuring lead in graphite furnace, which is not consistent with the ashing method. The sample is plant like.

1. The water used is distilled by quartz sub-boiling water distillator, first make a blank, generally not more than 0.0015, then use nitric acid (process super-pure) and perchloric acid (super-pure) digestion, the final dissolution of 1 mole per liter of hydrochloric acid or nitric acid (the results are similar, but the stability of hydrochloric acid is better), constant volume For 50mL, the blank value is generally around 0.03. But lead is hard to do, and matrix interference is very big.

2. The blank question comes from many aspects. The above mentioned water and reagent, how much purity of argon you use, is it high purity? Can also use high purity nitrogen, but pay attention to the molecular band background.

3. the main reason is free of nitric acid and perchloric acid. You can test the empty tube first, then the water you use, and then the acidic water blank, so you can know.

4. I often encounter this problem, it is possible that the acidity of the test solution will affect the determination, especially the use of perchloric acid, the impact is greater, acidity of the graphite furnace damage is greater. For the determination of lead in graphite furnace, wet digestion is best to use microwave digestion, using nitric acid and hydrogen peroxide, so that the acidity of the blank is easier to control, the blank is also relatively low.

5. the actual Pb content is different, the manufacturer is not accurate; your instrument may not have the best modulation.

Atomic absorption spectrometer should do the following work 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