8.3.6 Instrumental Methods

Instrumental methods are advanced techniques used to detect and identify elements and compounds in a sample. These methods rely on specialised instruments and equipment to provide accurate, sensitive, and rapid results.

Compared to traditional chemical tests, instrumental methods offer several advantages:

• Accuracy: Instrumental methods often provide more precise and accurate measurements compared to visual or qualitative tests. They can quantify the amount of a substance present in a sample with high precision.
• Sensitivity: Instrumental methods are capable of detecting very small amounts of substances, even at trace levels. They have a high sensitivity and can identify substances present in minute concentrations.
• Selectivity: Instrumental methods can differentiate between different compounds or elements in a mixture based on their specific properties, such as their molecular mass, charge, or absorption spectrum. This selectivity allows for precise identification and analysis of specific substances.
• Speed: Instrumental methods are generally faster than traditional chemical tests. They often provide results in real-time or within a short time frame, allowing for quick analysis and decision-making.
• Automation and efficiency: Many instrumental methods are automated, reducing the need for manual intervention and minimising human error. They can process multiple samples simultaneously, improving efficiency and throughput.
• Non-destructive analysis: Some instrumental methods, such as spectroscopyThe study of how matter interacts with electromagnetic radiation. Depending on what radiation is used there are different types of spectroscopy UV, NMR, IR. Note mass spectroscopy does not actually utilise electromagnetic radiation but is still referred to as spectroscopy. or imaging techniques, allow for non-destructive analysis of samples. This means that the sample can be preserved and further analysed or used for other purposes.

Examples of instrumental methods include:

• Spectroscopy: Techniques such as UV-Vis spectroscopy, infrared spectroscopy, or atomic absorption spectroscopy are used to analyse the interaction of substances with electromagnetic radiation at different wavelengths.
• ChromatographyThe separation of compounds using a stationary and mobile phase.: Various types of chromatography, including gas chromatography (GC) and high-performance liquid chromatography (HPLC), are used to separate and analyse complex mixtures.
• Mass spectrometryA technique used to measure the relative abundance of different isotopes in a sample.: Mass spectrometry measures the mass-to-charge ratio of ions to identify and quantify substances based on their molecular mass.
• Nuclear magnetic resonance (NMR): NMR spectroscopy provides detailed information about the structure and composition of molecules based on the magnetic properties of atomic nuclei.
• Imaging techniques: Techniques such as X-ray imaging, MRI (magnetic resonance imaging), or PET (positron emission tomography) scanning are used for visualising internal structures or identifying abnormalities in the body.