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CH3041
STANDARD ADDITION
Internal Calibration
• 1) Standard
Addition
known quantities of the analyte are added to
the unknown sample & the increased signal
allows us to work out the concentration of
the analyte in the unknown.
known quantities of the analyte are added to
the unknown sample & the increased signal
allows us to work out the concentration of
the analyte in the unknown.
Iu = signal of unknown
ui = unknown containing analyte i
si = added standard known conc. of i
ui = unknown containing analyte i
si = added standard known conc. of i
Iu+s = signal of
unknown + added standard
Rearrange and solve for [ui ]
• Used in AAS (in
calculating recoveries).
