Chemistry 155 Introduction to Instrumental Analytical Chemistry
Chemistry 155 Introduction to Instrumental Analytical Chemistry
Chemistry 155 Introduction to Instrumental Analytical Chemistry
You also want an ePaper? Increase the reach of your titles
YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.
Chem <strong>155</strong> Unit 1 Page 50 of 3131.14.3 Calculating Conc. w/ Standard Additions:a'ab'bOne way of analyzing this uses similar triangles:a / b =a’/b’The y-axis absorbance signal (S) is proportional <strong>to</strong> the moles ofanalyte (V X C X ) and standard (V S C S ).The x-axis is simply the standard ‘spike’ volume.The x-intercept is the hypothetical spike volume (V S ) 0 containing thesame amount of analyte as the sample.a is proportional <strong>to</strong> moles of analyte in the sample = V X C Xa’ is proportional <strong>to</strong> moles of std added = V S C Sb is (V S ) 0 – the x-intercept of the graphb’ is V S – the spike volumeSubstitute for a,a’,b,b’:V X C X(V S ) 0=V S C SV SSolve for C X :C X = C S (V S ) 0 /V XPage 50 of 313
Change language