Chapter 21, Problem 21.29P

Interpretation Introduction

Interpretation:

Procedure for the quantitative analysis of caffeine has to be suggested with ${}^{13}\text{C-caffeine}$ as an internal standard.

Concept Introduction:

Internal standard technique involves the usage of a known amount of compound that acts as a standard. This standard is mixed with the unknown analyte to form a new mixture. From the calculation of the response factor, one can subsequently be used to compute the concentration of an analyte in an unknown new mixture.

Formula to compute response factor is as follows:

  $\frac{A_{\text{X}}}{\left[\text{X}\right]}=F\left(\frac{A_{\text{S}}}{\left[\text{S}\right]}\right)$

Here,

$\left[\text{X}\right]$ denotes the concentration of unknown analyte X.

$F$ denotes the response factor.

$A_{\text{S}}$ denotes an area for a standard signal.

$A_{\text{X}}$ denotes an area for an unknown signal.

$\left[\text{S}\right]$ denotes the concentration of standard.