Direct determination of CHN in filter residue

A PROTOCOL for the direct determination of total CHN (carbon, hydrogen, nitrogen) in filter samples using the Model 440 elemental analyser has been published by Exeter Analytical. The company says using this technology to determine the percentage C, H, and N in samples is a preferred technique in many laboratories, because it requires minimum sample preparation and is equally suited to single samples or high-throughput automated runs.

This direct approach is, says the company, more sensitive, more precise, and more economic than comparitive measurements on pre- and post- filtered samples. It promises fewer sources of error, faster analysis, and better sample representativeness.

Exeter Analytical’s Model 440 is a horizontal furnace, static combustion elemental analyser in which a single combustion tube has a lifespan of over 1000 samples without the need for removal and cleaning. It offers the capacity to process filters up to 50mm diameter and, says the company, has longer calibration stability than other elemental analysers.

The protocol is described in Exeter Analytical’s application note 210.

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