Principles of Instrumental Analysis
Principles of Instrumental Analysis
7th Edition
ISBN: 9781337468039
Author: Skoog
Publisher: Cengage
Question
Book Icon
Chapter 10, Problem 10.1QAP
Interpretation Introduction

Interpretation:

An internal standard and its uses needs to be explained.

Concept introduction:

Use of an internal standard before actual sample analysis is an established method in analytical tests and is one important step towards eliminating/reducing the sources of errors and ensuring the accuracy and precision of the results.

Expert Solution & Answer
Check Mark

Answer to Problem 10.1QAP

An internal standard is a chemical substance, added to the sample, blank or calibration standards to identify and account for uncontrollable variables. The uncontrollable variables are expected to affect the internal standard and the analyte to a similar extent.

Explanation of Solution

Before actual analytical analysis of a substance, a blank and/or a calibration standard is run. This consists of a chemical substance of known composition and purity. It is added in a known quantity. This responds to the analytical and measurement processes as will the actual substance sample.

This is used to draw a calibration curve with the signals of internal standard on Y axis.

The accuracy of the results is increased as the instrument noise gets eliminated. This is because the signal to noise ratio is the same for the internal standard as for the substance under analysis.

Conclusion

Running the internal standards prior to running the analyte, improves the accuracy of the results. The internal standard, however, is to be properly selected.

Want to see more full solutions like this?

Subscribe now to access step-by-step solutions to millions of textbook problems written by subject matter experts!
Students have asked these similar questions
9. What is not a characteristic of a Primary Standard?
What is a primary standard?
Explain why internal standard can be used for ICP-OES but is not used for AAS
Knowledge Booster
Background pattern image
Similar questions
SEE MORE QUESTIONS
Recommended textbooks for you
Text book image
Principles of Instrumental Analysis
Chemistry
ISBN:9781305577213
Author:Douglas A. Skoog, F. James Holler, Stanley R. Crouch
Publisher:Cengage Learning