Use of Digestion Block and Steam Distillation Apparatus in Modified Comprehensive Method for Nitrogen Analysis in Fertilizer

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Published: Aug 14, 2020
Keywords:
modified comprehensive method block digestion steam distillation digesting solution temperature

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Phongphat Waiyawat
Department of Plant Science and Natural Resources, Faculty of Agriculture, Chiang Mai University, Chiang Mai 50200, Thailand
Kanokpan Pansombat
Department of Plant Science and Natural Resources, Faculty of Agriculture, Chiang Mai University, Chiang Mai 50200, Thailand

Abstract

In adapting the modified comprehensive method for fertilizer nitrogen to block digestion/steam distillation, some forms of chromium (Cr) used in reduction step were suspected to bound ammonium (NH4) and not break down totally. Critical study of digestion and distillation conditions could solve the Cr-NH4 complexes and find suitable conditions for adaptation. In the digestion with block, using salt/acid ratio of 1:1 and 400oC block temperature resulted in rising temperature of digesting solution to 376oC. In addition to that condition, if the digestion continued at least 45 minutes after clearing, ammonium was released from complexes completely. For steam distillation, it was necessary to distill 10 minutes or more to achieve full recovery of nitrogen. Based on conditions which released all ammonium from complexes and could digest sample effectively, we recommend to use salt/acid ratio of 1:1, digest in block at 400oC to clearing plus 75 minutes, and distill with steam distillation apparatus for 10 minutes.

Article Details

Issue
Vol. 28 No. 1 (2012): Journal of Agricuture (January-April)
Section
Research Articles

References

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