aas 2 Flashcards
(12 cards)
how does a nebuliser work?
vacuum in system aspirates sample
enters nebuliser and strikes bead, breaking it into tiny droplets
vapour is moved past a series of baffles, where the smallest droplets proceed to the flame
what is chemical interference?
stable analyte compound formation
how can chemical interference be overcome?
using a hotter flame
adding chelating agent (eg EDTA) that will complex with analyte
what is ionisation interference?
reduction in atom concentration
how can ionisation interference be overcome?
adding an ionisation suppressor/buffer such as caesium
what is physical interference? (surface tension edition)
high surface tension provides a bigger droplet resulting in loss
(overcome by matching characteristics of standard and sample)
what is spectral interference?
overlapping of spectral lines
how is spectral interference overcome?
background correction methods
what is occlusion in aas?
high conc of Fe causing Cr ot be trapped and unable to be reduced to atoms
how is occlusion overcome?
EDTA or ammonium chloride to prevent formation of occlusion sites
where does magnesium reach maximum absorbancy?
centre of the flame
where does chromium reach maximum absorbancy?
above burner tip
