Chemistry 155 Introduction to Instrumental Analytical Chemistry
Chemistry 155 Introduction to Instrumental Analytical Chemistry
Chemistry 155 Introduction to Instrumental Analytical Chemistry
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Chem <strong>155</strong> Unit 2 Page 61 of 313Let’s consider an example wherein the relationship between themeasured signal and the desired quantity is non-linear :AbsorbanceA = -log (P/Po)Absorbance is a nonlinear function oflight power - the measured quantity in aspectropho<strong>to</strong>metric experiment.Alog P P l21.5A i10.500 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1P iObviously – the same error in P can give rise <strong>to</strong> different errors in A!This is a propagation of error problem. How can you calculate theerror in A that should result from a particular error in P?Page 61 of 313