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.

TechniquePhysical or Chemical PropertyExamples of Analysis Analysis by Mass Gravimetric AnalysisMass 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 TitrationsNeutralisations reactions by acid or baseConcentration of ammonia in window cleaner Redox TitrationReactant as an oxidant or reductantConcentration 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 tablet Concentration 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 SpectrometryMass/charge ratio of ionised compoundIdentification of lead isotope ratios in meteors