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用凯氏定氮法测定有机物中含氮量,过去是将有机氮破坏,转变为铵盐,加苛性碱将氨蒸出,用标准酸吸收,再用标准碱回滴。此法手续麻烦,造成误差机会也多。Кейк等用标准次溴酸在碱性溶液中破坏有机物不需蒸出氨,但结果偏高,现在介绍用硒为分解有机物的催化剂,并且不用蒸出法来测定氮。试剂:～8N NaOH溶液530毫升15N NaOH(不含碳酸盐)溶液用水稀释至1升,装在聚乙烯树脂所制的瓶中,上装碱石灰乾燥管。0.2N NaOH溶液25毫升8N NaOH溶液用水稀释至1升,用标准邻苯二酸标定,保存在聚乙烯树脂所制的瓶中,装碱石灰乾燥管。18%中性甲醛溶液100毫升35—38%甲醛溶液,用等量水稀释,加入2滴酚酞,以0.1N NaOH中和至淡红
Kjeldahl determination of nitrogen content in organic matter, the past is the destruction of organic nitrogen, into ammonium salt, add caustic alkali ammonia will be distilled off, with standard acid absorption, and then use standard base drop. This method of procedure trouble, resulting in error and more opportunities. Кейк and other standard hypobromous acid in alkaline solution of organic matter without distilling ammonia, but the result is high, and now introduce the use of selenium as a catalyst for decomposition of organic matter, and no steam to determine nitrogen. Reagent: ~ 8N NaOH solution 530 ml 15N NaOH (carbonate-free) solution diluted to 1 liter with water, installed in a bottle made of polyethylene resin, the upper soda lime drying tube. 0.2N NaOH solution 25ml 8N NaOH solution diluted to 1 liter with water, calibrated with a standard phthalate, stored in a bottle made of polyethylene resin, equipped with a soda lime drying tube. 18% neutral formaldehyde solution 100 ml 35-38% formaldehyde solution, diluted with an equal amount of water, add 2 drops of phenolphthalein, neutralize with 0.1 N NaOH to a light red