I have compare C2H2-air and C2H2-N2O flame AAS on determination calcium. Both use same range of std to plot calibration curve. (2-6ppm)
When i measure the sample with phosphate, KCl and LaCl, C2H2-N2O flame give false positive result, around 0.5ppm.
When i measure the sample with phosphste, KCl and EDTA. C2H2-N2O flame also give 0.5ppm false positive.
But both above mentioned sample would not give false positive when measured by C2H2-air flame.
What is the reason?
As per ICH related substances stability trend limit from
initial to shelf life