Elemental analysis techniques vary based on the type of sample, the elements being analyzed, and the level of detail required. Here are some of the leading methods:
1. Combustion Analysis
Combustion analysis is the gold standard for determining CHNS content in organic compounds. In this method, a sample is combusted in a high-temperature, oxygen-rich environment, breaking it down into its elemental gases (e.g., CO₂, H₂O, N₂, SO₂). These gases are then measured using detectors, and the elemental composition is calculated.
Combustion analysis is widely used in industries such as petrochemical, environmental agriculture, pharmaceuticals, food and beverage, and energy, thanks to its precision and reliability. Variations of this technique include CHNS and CHNS/O analyzers, depending on whether oxygen content is also measured.
2. Inductively Coupled Plasma (ICP) Methods
ICP-based techniques, such as ICP-OES (Optical Emission Spectroscopy) and ICP-MS (Mass Spectrometry), are essential for detecting trace elements. A sample is introduced into a plasma, where it is ionized, and the emitted light or ion mass is analyzed to determine its composition.
ICP is ideal for applications requiring high sensitivity, such as environmental monitoring (e.g., detecting trace metals in water), geology, and advanced materials research.
3. X-ray Fluorescence (XRF)
XRF is a non-destructive technique that uses high-energy X-rays to excite atoms in a sample. The energy and wavelength of the emitted fluorescent X-rays are characteristic of specific elements, allowing for their identification and quantification.
XRF is commonly used in the analysis of solid and liquid samples in industries like mining, cement production, and recycling. It is prized for its speed and ability to handle large sample sizes.
4. Atomic Absorption Spectroscopy (AAS)
AAS measures the absorption of light by free atoms in a gaseous state. Each element absorbs light at a specific wavelength, allowing for precise quantification. This technique is especially effective for analyzing metals and metalloids in samples such as water, soil, and biological materials.
5. Neutron Activation Analysis (NAA)
NAA is a nuclear-based technique that involves bombarding a sample with neutrons, causing elements within the sample to become radioactive. The emitted gamma rays are then measured to determine the elemental composition.
NAA is highly sensitive and non-destructive, making it valuable for analyzing rare or irreplaceable samples in fields like archaeology, geology, and forensic science.