Standard No.:	GB 11189.1-1989
English Name:	Operating light-exposure apparatus(xenon-arc type) with and without water and testing method for exposure of nonmetallic materials
Chinese Name:	非金属材料曝露试验用的有水和无水光曝露设备(氙弧型)及实施方法
Chinese Classification:	G50    Basic standard and general method for coating
Professional Classification:	GB    National Standard
Source Content Issued by:	CPCIA
Issued on:	1989-03-31
Implemented on:	1990-1-1
Status:	abolished
Abolished on:	2005-10-14
Target Language:	English
File Format:	PDF
Word Count:	4500 words
Translation Price(USD):	135.0
Delivery:	via email in 1 business day

Water quality—Determination of Kjeldahl nitrogen 1 Subject content and application scope 1.1 Subject content This standard specifies a method for the determination of nitrogen by a Kjeldahl-type method. It includes ammonia nitrogen and organic nitrogen compounds that can be converted into ammonium salts under these conditions. Such organic nitrogen compounds mainly refer to organic nitrogen compounds with negative trivalent state of protein, peptone, amino acid, nucleic acid, urea and other synthesized nitrogen. It does not include azide, diazo, azo, hydrazone, nitrate, nitroso, nitro, nitrite, nitrile, oxime and semi-carbazone nitrogen-containing compounds. 1.2 Application scope This standard is applicable to the determination of Kjeldahl nitrogen in industrial wastewater, lakes, reservoirs and other polluted water bodies. 1.3 Determination range When the content of Kjeldahl nitrogen is low, more samples are taken, digested and distilled, and finally ammonia is determined by spectrophotometry. When the content is higher, less samples are taken, and finally ammonia is determined by acid titration.

1 Subject content and application scope 2 Principle 3 Reagents 4 Apparatus 5 Sampling and sample storage 6 Procedure 7 Expression of results 8 Explanation of special circumstances