The Analytical Chemistry Society defines its field as the “science of obtaining, processing and communicating information about the composition and structure of matter (physical substance” or “what the matter is and how much of it exists).
Specific instruments and rigorous methods are used to separate, identify and quantify matter. It is important to distinguish two concepts: qualitative analysis focused on identifying components based on properties (colour, melting/boiling points, smell, reactivity) and quantitative analysis which calculates the amount of the studied components.
Traditional and advanced instrumentation are routinely used by analytical chemistry labs both in educational and industrial settings, naming but a few:
- Chromatography: separates mixtures (multiple components) through two phases. The gas or liquid mixture is dissolved in a fluid “mobile phase” and inserted in a fixed or “stationary” system (column, plate or tube). Depending on how strongly the different components interact with the stationery phase, time differences will be observed. For example, imagine a liquid mixture containing ions (positively and negatively charged) and a positively charged column. The positively charged ions will be “expelled” out of the column due to repulsion while the negatively charged ones will be attracted and be kept longer in the column.
- Spectroscopy: refers to the absorption or emission of light and other radiation by matter. Light is “split” into its different wavelengths which yields spectrums. This is important as all atoms and molecules have a unique spectra like barcodes on commercial products. As such, these allow the detection and quantification of chemical components.
- Mass spectrometry: used to measure the mass-to-charge ratio of ions, presented in mass spectrums to determine the chemical composition or structure of molecules.
It is routinely used in biochemical labs to identify proteins and sugars. This is particularly relevant for identifying protein mutations or comparing sugar profiles between healthy and affected individuals.
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- Microscopy: allows the identification of thousands of different particle and material types invisible to the naked eye. Amongst the different existing microscopes, chemical microscopy relies on the combination of polarised light microscopy with qualitative analytical chemistry techniques. Polarised light waves have vibrations occurring in a single plane.
Analytical chemists rely on chemistry, specialised equipment and computers across industries including agriculture, forensics, pharmaceutics, cosmetics and oil. More specific examples include quantifying pesticide/herbicide levels on food, refining petroleum products prior to market release and helping clinicians diagnose diseases by assessing biomarkers.