Elemental analysis is a process in which a sample of any material, mineral, or chemical is analyzed to determine which element is present in the material. CHNS elemental analyzers offer an effective method for determining the analytical chemistry of carbon, hydrogen, nitrogen, sulfur, and oxygen levels in organic compounds and diverse material types. The primary advantage of CHNS elemental analyzers over traditional analyzers lies in their versatility, as they can effectively analyze a broad spectrum of sample materials.
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Importance of CHNS Elemental Analysis
CHNS Elemental analysis plays a pivotal role in scientific research and a range of industries, such as pharmaceuticals, environmental science, and material characterization for the determination of carbon, hydrogen, nitrogen, and sulfur. This essential analytical method offers valuable insights into the properties, reactivity, and prospective applications of substances.
Another significant advantage of using the CHNS elemental analyzer is the improved workflows within analytical laboratories. Unlike conventional elemental analyzers that necessitate the use of multiple instruments and time-intensive sample preparations, the CHNS elemental analyzer consolidates various analytical processes into a single step, thereby substantially diminishing the time and labor needed for elemental analysis.
CHNS elemental analyzers may be utilized to perform either quantitative or qualitative analysis. Qualitative determines what elements are present in any specimen, while quantitative analysis performed by different elemental analyzers is utilized for obtaining the concentration of the different elements present in the specimen.
Combustion Method for CHNS Analysis
CHNS elemental analyzers commonly utilize high-temperature combustion analysis in an environment rich in oxygen and rely on the classical Pregl-Dumas method. During the combustion process in CHNS analyzers, the elements are converted into simultaneous oxide gas states.
Following combustion, the resulting products are carried out of the CHNS elemental analyzer's combustion chamber using an inert carrier gas, typically helium. They are then directed over heated copper, maintained at around 600°C.
This copper serves to eliminate any remaining oxygen that was not consumed during the initial combustion process of the CHNS elemental analyzer. Subsequently, the gases are channeled through absorbent traps within the CHNS elemental analyzer, to retain only carbon dioxide, water, nitrogen, and sulfur dioxide. The detection of the different gases produced within the CHNS elemental analyzer can be carried out via different methods.
CHNS Elemental Analysis with Mass Spectrometry
Elemental Analysis by Mass Spectrometry (EA-MS) stands as a remarkably precise technique employed in conjunction with CHNS analysis through CHNS elemental analyzers. This method integrates combustion, gas chromatography, and mass spectrometry to precisely measure each element separately.
The sample undergoes combustion as in the CHNS elemental analyzer, leading to the generation of gases that are subsequently separated through gas chromatography before entering a mass spectrometer. Within the mass spectrometer, elements are identified and quantified based on their unique mass-to-charge ratios.
X-ray Fluorescence for CHNS Elemental Analysis
X-ray Fluorescence (XRF) spectroscopy, typically linked with the analysis of heavier elements, can also be utilized for CHNS analysis. When subjected to X-rays, each element emits distinctive X-ray fluorescence. The measurement of the intensity of these emissions allows for the determination of these elements.
Can CHNS Analysis be Used to Detect Other Elements?
The CHNS elemental analyzer successfully utilizes the traditional combustion method for quantitative analysis of organic elements. However, if other chemical elements are present in the sample, the CHNS analyzer may not be the best individual choice.
In such instances, supplementary methods like X-ray photoelectron spectroscopy (XPS), Auger electron spectroscopy, gamma rays, and inductively coupled plasma (ICP) can be employed with the CHNS elemental analyzer detection process to deliver a more comprehensive elemental analysis. Along with the CHNS elemental analyzer, such processes play an effective supporting role in the complete analysis of specimens.
Some studies also utilize X-ray photoelectron spectroscopy (XPS) for elemental analysis. Heavier elements are easily detected by this method; however, organic elements are not efficiently identified by the process, confirming CHNS elemental analyzers as the best choice available.
Similarly, another famous process is called Neutron activation analysis (NAA), a widely employed analytical method based on the detection of gamma rays emitted from a sample following its irradiation with neutrons. The rate of gamma-ray emission from an element within the sample is directly correlated with the concentration of that specific element.
This method can be useful for the detection of nitrogen and sulfur, but it is not preferred for carbon and hydrogen analysis. This is because carbon and hydrogen lack isotopes that yield readily detectable gamma radiation when subjected to neutron activation. Hence, mass spectrometry and combustion process within the CHNS elemental analyzer is still the most widely adopted technique for organic analysis.
Research Applications
CHNS elemental analyzers are being utilized to study soil quantity and for quality and pollutant analysis of water. Researchers from India published a study in the Journal of Emerging Technologies and Innovative Research, where CHNS elemental analyzers were utilized for the analysis of six monthly soil samples from the Patalganga river belt.
Researchers utilized the EUROVECTOR CHNS elemental analyzer Model Euro EA3100. This latest model CHNS elemental analyzer effectively determines the percentages of Carbon (C), Hydrogen (H), Nitrogen (N), and Sulphur (S). Gas chromatography was used to separate the gases, and the thermal conductivity detector (TCD) within the CHNS elemental analyzer detected the elemental percentage of gases.
The highest carbon content percentage was identified at the Vayal site during May. The comprehensive carbon content, as determined by the CHNS elemental analyzer, fluctuated between 0% and 3%. In the case of hydrogen content, assessed by the Eurostar CHNS elemental analyzer, it ranged from 0% to 2%, displaying varying levels at certain sites.
Nitrogen content percentage spanned from 0% to 2%, with a declining trend observed from January through June. Sulfur content percentage, as measured by the CHNS elemental analyzer, exhibited negligible values at all sampling sites throughout all the months.
The utilization of CHNS elemental analyzers, as demonstrated in the above soil analysis, is essential for determining the chemistry of substances. This is just one of the many instances where CHNS elemental analyzers are utilized commercially. With each passing day, companies are making progress in making CHNS elemental analyzers efficient and even more reliable.
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References and Further Reading
Auriga Research, 2023. Elemental Analysis CHNS(O). [Online]. Available at: https://aurigaresearch.com/pharmaceutical-testing/elemental-analysis-chns/
Hassan, A. M., 2007. Limitations on Elemental Analysis of Materials Using Neutron Activation Techniques. [Online]
Available at: https://inis.iaea.org/collection/NCLCollectionStore/_Public/40/081/40081068.pdf
Measurlabs, 2023. CHN(O)S Elemental Analysis. [Online]
Available at: https://measurlabs.com/methods/chnos-elemental-analysis/
The Royal Society of Chemistry, 2008. CHNS Elemental Analysers. [Online]
Available at: https://www.rsc.org/images/CHNS-elemental-analysers-technical-brief-29_tcm18-214833.pdf
Marathe et. al. (2022).CHNS Analysis of Soil Samples from Patalganga River (Maharashtra, India). Journal of Emerging Technologies and Innovative Research. 9(2). 2349-5162. Available at: https://www.researchgate.net/profile/Ninad-Marathe-2/publication/370570156_Issue_3_wwwjetirorg_ISSN-2349-5162/links/64564d0f5762c95ac378c623/Issue-3-wwwjetirorg-ISSN-2349-5162.pd
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