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Exeter Analytical reports on how its Model 440 CHN Microanalyser is being used to precisely determine the percentage Carbon (C) and Nitrogen (N) in soil samples. 

Understanding the health of your soil is vital to ensure good yields of crops grown in it. Two elements that are vital to plant growth are Carbon and Nitrogen, especially in their proportion to each other. Carbon, in the form of species such as carbohydrates, is important because of its energy content, whereas Nitrogen is essential for growth.

Methods for determining the carbon and nitrogen content of soil samples have traditionally been based upon macro-CHN or Kjehldahl Nitrogen analysis. While both these techniques are proven to generate useful data, both have drawbacks. Macro-CHN analysers are relatively expensive to purchase and run compared to CHN microanalysis systems and Kjehldahl requires use of highly corrosive and toxic chemicals. Using the Exeter Analytical Model 440 a growing number of agrochemical crop research centres are accurately and precisely determining the Carbon and Nitrogen content of a wide range of soils using samples sizes of typically 2 - 20mg.

As soil samples often have high levels of inorganics - combustion generates large sample residues. Using a horizontal sample injection system the Exeter Analytical Model 440 automatically removes sample residue after each analysis thereby avoiding memory effects, gas flow problems and considerably extending the number of samples that can run between changing combustion tubes. Beneficially removing the residues also eliminates problems associated with accelerated degradation of the quartz combustion tubes due to levels of sodium often found in soil samples.

Designed to give accurate, reliable results, over the widest range of sample types presented for analysis the Model 440 CHN microanalyser is proven to deliver unmatched operating accuracy and precision. Low gas and reagent consumption combined with higher reduction tube life allows the Model 440 to deliver the lowest operating costs of any CHN elemental analyser available. The Model 440 is a fully automated analyser. Intuitive Windows based operating software reduces human errors through incorporation of extensive automation, comprehensive customer help and diagnostic facilities. 

Exeter Analytical is a company dedicated to elemental microanalysis for over 25 years. Our expertise and experience with instruments, consumables and supplies has allowed us to better understand all issues facing microanalysts.  As a consequence, whether you are a regular or an occasional purchaser, experienced and knowledgeable staff is always available to provide technical advice.

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