Appendix 2 | The Derivation Of The Slope Spectroscopy Equation - REPLIGEN CTech SoloVPE PLUS User Manual

CTech™ SoloVPE® PLUS System

Appendix 2 | The Derivation of the Slope Spectroscopy Equation

Variable pathlength technology enables the Slope Spectroscopy method for finding the concentration of a sample. The Slope
Spectroscopy equation is derived from the Beer-Lambert law.
Equation
�� = ������
Beer-Lambert Law
�� = ���� + ��
Linear Equation
Derivation of the Slope Spectroscopy Equation:
�� ≡
��
��
We define , yielding:
DOC0362 eRev. 1.0 [Publication Date]
Definitions
A
Where:
��
is the absorbance of the sample.
l
is the absorption coefficient or the molar absorptivity of the absorber.
c
is the distance that the light travels through the material (the pathlength).
is the concentration of absorbing species in the material.
y
Where:
m
is the predicted value of the dependent variable/axis.
x
is the slope of the line.
b
is the given variable.
is the y-intercept of the line.
�� = ������
�� = ����
= ����
��
��
User Guide
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