AAS for calcium
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Why does a calcium standard solution at 4 ppm have an absorbance of only around 0.18? After adding about 1% strontium and 4% nitric acid, I tried increasing the proportion of acetylene, but the result remained the same. I would like to ask those who use AAS: what is the absorbance for calcium at 4 ppm?
It is meaningless to know what the absorbance of others is, because different instruments certainly have different performance levels. Since there is suspicion that the absorbance is incorrect, it is necessary to check what the specifications for this instrument are. Generally, copper standard samples are used for verification (for example, the Thermo Fisher iCE3000 specifies that the absorbance of a 5mg/l copper standard solution should be greater than 1.0); there are specified requirements for the performance testing of such instruments. Generally, the absorbance is incorrect; you can check the following items: whether there are any blockages or bends in the sample injection pipeline. Is the position between the injection tube and the impact ball appropriate? The angle and height of the burner head. Wait
Everything you mentioned has been tested; we are now testing the gas ratio in order to improve the atomization effect. Hehe, that Thermo Fisher device can achieve a level of 1.0 for copper at 5 ppm； It can’t be that high, right? Back then, our instrument installation engineers said that the GBC value was already quite good, at around 0.7; now ours is only 0.6
Those are the performance criteria for instrument acceptance; they must be met, otherwise the instrument cannot pass acceptance. Apart from Thermo Fisher, PE and Varian should all be able to do it; I don’t remember exactly.
It should be adjusted through gain, it can’t be the original one :o:o