Titrimetric Analysis - Concepts

Modified: September 21, 2006

Introduction

  • Basis of titrimetry. Definition of equivalence point, titrant, titration reaction, endpoint.
  • Types of titrimetry. Classification by titration reaction, by dispensing method, by endpoint detection method.

Methodology

  • General procedure. General formula to calculate amount of analyte in the sample.
  • Direct and indirect titrations. Back titrations and replacement titrations. Advantages of indirect titrations.
  • Requirements for titrimetric analysis. Sources of error in titrimetric analysis.
  • Standardization of titrant. Primary standards.

Titration Curves

  • Definition and importance.
  • Shapes of titration curves. Linear/segmented and sigmoidal curves.
  • "Sharpness" of titration curves, and its importance.
  • Examples of titration curves: acid-base, argentometric, EDTA, redox titration curves.
  • Factors affecting titration curve sharpness. Effect of analyte/titrant concentration, equilibrium constant.
  • Titration of analyte mixtures: shape of titration curve, ability to analyze mixtures

Methods of Endpoint Detection

  • Importance of endpoint detection
  • Classification: chemical and instrumental endpoint detection
  • Chemical indicators. Four common modes of operation, with examples. Considerations in choosing an indicator, especially for acid-base titrations. Effect of conditions on accuracy and precision of endpoint detection using chemical indicators.
  • Common instrumental methods for following the progress of a titration reaction. Briefly: general theory of operation -- especially potentiometric detection -- and shapes of titration curves from these methods.
  • Determination of endpoint from (i) sigmoidal and (ii) segmented titration curves.
  • Comparison: instrumental vs chemical endpoint detection