Chapter 23, Problem 23.16P

Interpretation Introduction

Interpretation:

Reason behind the negative response in indirect spectrophotometric analysis has to be explained.

Concept Introduction:

The relation between the absorbance and concentration of the analyte is calculated from the Lambert Beer’s law as follows:

    $\text{A}=\left(\text{ε}\right)\left(\text{c}\right)\left(\text{l}\right)$

Here, $\text{A}$ is the absorbance.

$\text{ε}$ is the molar absorption coefficient.

$\text{c}$ is the concentration of analyte.

$\text{l}$ is the optical path length.

Indirect spectrophotometric analysis is concerned with the measurement of the decolorization of a colored system. In this analysis the lowest relative error can be achieved at low absorbance reading and the precision is increased, if the reading is taken against a partly decolorized standard.

Indirect detection measures strong signal from the background electrolyte and a weak signal from analyte.