Atomic Fluorescence Spectroscopy

What is AFS analysis used for?

AFS can detect metallic elements in a wide variety of sample types. It is most commonly used to measure levels of toxic heavy metals in food, water, and environmental samples. The applications of atomic fluorescence spectrometry also extend to biomedical testing, where it can be used to test for metals in blood and urine samples.

In mining and metallurgy, AFS is used to determine metal concentrations in ore samples, helping to evaluate the ore before mining. The method may also be used to screen for lead and other contaminants in fuel testing.

How does Atomic Fluorescence Spectroscopy Work?

In AFS, samples are first converted into a gas using an ionization method, such as being exposed to a flame or other heat source. The atomic gas that forms is then exposed to visible or ultraviolet light of a specific wavelength. This light will interact with atoms of a specific element, causing them to fluoresce. The fluoresced light is then picked up by a detector, which in turn can calculate the concentration of that specific element. By repeating this process and testing for different elements, it is possible to determine the elemental makeup of the sample.

Sample requirements and preparation

Atomic fluorescence spectroscopy is usually conducted on samples that are converted into an atomic gas from a solvent phase. This means that the sample must be in the form of a liquid or solution prior to analysis. In the case of solid samples, they will first need to be dissolved in a suitable solvent. Samples may also require pre-treatment to remove contaminants that could affect the results.

Advantages of Atomic Fluorescence Spectroscopy

The main advantage of AFS is its high specificity; it can observe specific elements even in very low concentrations, which makes it ideal for detecting trace amounts of contaminating metals. A wide variety of different metals can be detected, which makes AFS a versatile testing method. It is also a relatively simple method, meaning that samples can be tested quickly with high throughput, providing valuable data in a relatively short time.

Limitations of AFS analysis

AFS can only detect one element at a time, which slows the process down when the sample contains multiple elements of interest. In such cases, ICP-OES might be preferable.

AFS mostly works with metal atoms and therefore has limited use in organic and other non-metal-based chemistries. Furthermore, some compounds can create interference with the fluorescence effect, thus it is not a suitable method for all samples. Finally, it is a destructive method, meaning that the sample is effectively destroyed during the atomization process and thus cannot be recovered after analysis.

What is the difference between AFS and AAS?

Atomic Absorption Spectroscopy (AAS) is a similar technique in which atomized samples are exposed to specific wavelengths of light in order to determine their elemental makeup by determining which wavelengths are absorbed and therefore which atoms are present. AAS is typically a cheaper process than AFS, requiring less expensive equipment, and therefore is more widely accessible. 

However, AFS often has a lower detection limit and reduced background noise and therefore can detect heavy metal elements even in incredibly low concentrations. This makes it more valuable when detecting the presence of certain types of metals, especially when they are only present in trace amounts.

Need an elemental analysis?

Measurlabs offers high-quality elemental analyses with AFS and other similar methods. Check out our single element analysis, which can be used to detect the chosen element (often mercury) in water and other environmental samples. If you wish to discuss your testing needs in more detail, do not hesitate to contact our experts through the form below.