Introduction to Analytical Chemistry

Introduction to Analytical Chemistry
Key concepts, objectives, and common techniques

1. What Is Analytical Chemistry?

2. Core Principles

1. Selectivity – Ability of a method to discriminate the analyte of interest from other components.
2. Sensitivity – Minimum amount of analyte that can be reliably measured (limit of detection, LOD).
3. Accuracy – Closeness of the measured value to the true value.
4. Precision – Reproducibility of repeated measurements (repeatability & reproducibility).
5. Linearity – Proportional response of the detector over a defined concentration range.
6. Robustness – Tolerance of the method to small variations in experimental conditions.

3. General Workflow of an Analytical Procedure

1. Define the problem – What needs to be measured and why?
2. Select the appropriate technique – Based on matrix, required detection limits, speed, cost.
3. Sample collection & preservation – Prevent changes in composition (e.g., oxidation, evaporation).
4. Sample preparation – Filtration, digestion, extraction, derivatization, dilution, etc.
5. Calibration – Build a calibration curve using standards (external, internal, or standard addition).
6. Measurement – Run the sample under controlled conditions.
7. Data processing – Apply calibration, correct for blanks, calculate concentrations, assess uncertainties.
8. Validation & quality control – Use controls, replicate analyses, recovery studies, and proficiency testing.

4. Major Analytical Techniques