What is the reason for negative values in atomic absorption analysis results?
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When I use a flame atomic absorption spectrophotometer to determine the iron impurity content in zinc oxide, what causes the concentration of the solution being analyzed to be negative?
1. Baseline fluctuations can cause this situation. 2. The cleanliness of the combustion head. 3. The choice of spectral lines used for measurement; it is best to use the most sensitive ones. 4. It is recommended that you clean the relevant components thoroughly, increase the number of tests on identical samples, and remove any abnormal data
Consider whether there is a problem with the reference solution; if not, add a standard solution to the sample solution to see what happens
The blank is contaminated with iron; replace it with a blank solution
It is caused by the impact of subtracting the spectral line background; select an appropriate background based on the sample.
By using a different wavelength, namely the secondary absorption wavelength, interference can be eliminated.