7. Below is a calibration curve prepared for the spectrophotometric determinatio
ID: 591169 • Letter: 7
Question
7. Below is a calibration curve prepared for the spectrophotometric determination of Fell) in soil. A regression analysis of the curve produced a slope of 0.0792, a correlation coefficient of 0.9993, and 0.0 intercept (a) Use this information to determine the concentration of Fel) in an unknown sample that had (b) Write an equation representing the data obtained in this determination. (10 points) an absorbance reading of 1.0. (10 points) Calibration Curve for Fe(II) 1.8 1.6 1.4 1.2 o.8 0.4 0.2 25 15 20 10 5 Fe (11) Conc.Explanation / Answer
a)
slope = 0.0792;
Apply Beer law:
A = el*C
assume slope is constant for diluted species, then el = slope
A = 0.0792*C
if A = 1
C = A/0.0792
C = 1/0.0792
C = 12.62 units
b)
The equation is simple:
A = 0.0792*C
or stated in
y = 0.0792x