How Element Analyzers Work & How Leasing Benefits Your Lab

High-quality organic elemental analysis requires an analyzer that provides precision and cost-effectiveness for quantification of organic elements such as carbon, hydrogen, nitrogen, sulfur (CHNS), as well as oxygen (CHNS/O).

CHNS/O or CHNS analysis can provide a quick and inexpensive method to find sample purity and, in combination with technologies such as mass spectroscopy and nuclear magnetic resonance (NMR), can be used for the characterization of those various compounds.

Other analysis examples include simply carbon, hydrogen, and nitrogen (CHN). Single compound analyzers are available as well, such as nitrogen analyzers.

Knowing which elements you’re going to analyze and which devices available on the market are capable of doing what is an important step in procuring inorganic and organic elemental analyzers.

This process involves the quantitative analysis of chemical elements of material using spectroanalytical methods. AAS observes how optical radiation, or light, interacts with an analyzed sample. This technique is effective because free atoms absorb light at specific frequencies or wavelengths depending on their element. Before analysis can occur, the medium must first be atomized using the spectrometer. The most common methods for this are flame and electrothermal atomizers.

• Flame: The liquid or dissolved material is drawn into a pneumatic analytical nebulizer which converts the material from a liquid into a very fine mist. The aerosolized sample is then combined with flammable gases and introduced into a flame. The resulting substance is then analyzed for its elemental properties.
• Electrothermal: Analyte atomization is achieved by passing an electrical current through a device to heat it up to a specific temperature. This apparatus is called an electrothermal atomizer. Before a sample is aerosolized it is dried at low temperature and then is put into a graphite furnace to undergo chemical decomposition due to heat, or pyrolysis. The vaporized material can then be analyzed to determine the original substances elemental properties.

Also known as Lassaigne’s test, this method looks for the presence of halogen, nitrogen, or sulfur in an organic compound. Consisting of placing the substance into a container with sodium in it and applying heat to it until the two different substances fuse together, the resulting intermixed material is then plunged into pure water and the existence of foreign substances can be detected.

If the resulting mixture produced sodium halide, sodium cyanide, ferric ferrocyanide, sodium sulfide, or sodium thiocyanate the tested sample can be said to have nitrogen, sulfur, or halogen.

A chemical method for quantitative discernment of elemental sulfur, halogen, chlorine, and nitrogen in a sample. This method involves combustion analysis to determine what elements are in a substance. Conducted in an Erlenmeyer flask, the material is wrapped in attached to a stopper. Some absorption solution is poured into the container and it is filled with oxygen, the wrapped material is lit and the stopper is used to quickly seal the flask.

The resulting solvent can then be tested chemically to establish the presence of other elements. This process is also known as Schöniger flask test or the oxygen flask method.

EA can be performed using X-ray fluorescence to determine the elemental composition of solid substances. A beam of x-rays strikes the surface of the sample and a core electron is then ejected from the atom that absorbed the x-ray photon. When an outer electron falls into the hole created by the ejected electron, it gives off energy in the form of light.

This light is called fluorescence and a characteristic pattern exists for each element. Historically, different types of x-ray fluorescence lines are observed and labeled as such:

• K radiation: This type of radiation is produced when the electron falls into a hole in the n=1 level
• L radiation: L radiation is produced when the electron falls into a hole in the n=2 level.
• M radiation: M radiation is produced when the electron falls into a hole in n=3. This pattern repeats, going from M to N to O and so on for each electron shell.

Some elemental analyzers utilize thermal conductivity detectors to determine the properties of an analyte. Most commonly seen in gas chromatography, these universal, nondestructive, concentration-sensitive detectors respond to the difference in thermal conductivity of the carrier gas and the carrier gas containing the sample. This principle of detection is based on the fact that the analytes will typically have a lower thermal conductivity than the carrier gas mixture.

The final result produces a series of peaks for each analyte, which is correlated with the absolute quantity of the element via calibrations. The calibrations relate variations in the integrated detector signal with absolute element content for samples of known weight and composition.

EA requires a number of consumables, from aluminum capsules, chemical reagents and reagent kits, to flat tin disks and combustion, scrubber, or reduction tubes. Combustion Calibration Standards are also widely used to ensure your EA device is calibrated correctly.

There are several manufacturers that produce high-quality consumables for all your elemental analysis needs, including EA consumables, PerkinElmer, and OEA Labs Ltd.

Element Analysis has been a useful scientific technique for a long time. Antoine-Laurent de Lavoisier, an 18th-century French chemist, is considered the father of quantitative elemental analysis. Before Lavoisier chemistry was explained with qualitative observations like the idea that phlogiston, a fire quality, was what left a material once it was burned which is why there is less of it.

Through a series of carefully measured experiments, Lavoisier proved that when combusted chemicals combine with their surroundings to form new mixtures of solids, gasses or liquids. Specifically, he was able to deduce that oxygen, when combined with normal air would produce water, concluding that water was actually a composite of hydrogen and oxygen. He would be a primary figure in the chemical revolution championing the study of chemistry through quantitative means.

Today, EA is being used in biomedical, environmental, chemical, petrochemical, and pharmaceutical fields. More recently it has found use beyond normal STEM sciences. Anthropologists, archeologists, and general historians are now utilizing these techniques to better understand the history of humans around the world.

The Field Museum of Natural History in Chicago, one of the largest museums in the world, has an entire lab dedicated to these methods of study. In 2015, an article was published about the discovery of a black rock found in the Scladina Caves in Belgium linked to Neanderthal culture. Using the Field Museum’s EA labs the team discovered that the rocks must have been transported there from much further away by Neanderthals for culturally significant reasons.