Chapter 1 – Chemical Analysis

Qualitative Analysis

• Analysing what is present in the substance.• It can also give information about the

structure of newly discovered compounds such as potential new drugs.

Quantitative Analysis

• The analysis to find the amount of each chemical is present.

Analytical Techniques• The most appropriate chemical technique to use

depends on factors including, the nature of the sample, the nature of the chemical under analysis, the concentration of the chemical, the accuracy required, the time available and the cost and benefits in carrying out that specific technique.

• Many different chemical and physical properties can be used as a basis for qualitative analysis.

• These properties are then compared with the properties of known substances.

Technique Physical or Chemical Property Examples of Analysis

Analysis by Mass

Gravimetric Analysis Mass of chemical, isolated from a mixture or precipitated in a reaction

Percentage of water in wheat stored in a silo.Concentration of salt in a jar of baby food

Volumetric Analysis

Acid-Base Titrations Neutralisations reactions by acid or base Concentration of ammonia in window cleaner

Redox Titration Reactant as an oxidant or reductant Concentration of hydrogen peroxide in hair bleach.

Chromatographic Analysis- Paper- Thin Layer- Gas- High Performance Liquid

Adsorption onto a stationary phase and solubility in a mobile phase

Analysis of codeine in a tabletConcentration of alcohol in the blood

Spectroscopic Analysis-Flame Tests-Atomic Emission-Atomic Absorption-Ultraviolet-Visible-Infrared-Nuclear Magnetic Resonance

Absorption or emission of part of the electromagnetic spectrum

Monitoring level of calcium in the blood

Mass Spectrometry Mass/charge ratio of ionised compound Identification of lead isotope ratios in meteors