Standard No.:	GB 223.51-1987
Chinese Name:	钢铁及合金化学分析方法 5-Br-PADAP光度法测定锌量
English Name:	Methods for chemical analysis of iron,steel and alloy; The 2-(5-Bromo-2-pyridylazo)-5-diethylaminophenol photometric method for the determination of zinc content
Professional Classification:	H11 Steel and iron alloy analysis method
Professional Classification:	GB National Standard
ICS Classification:	77.080
Issued by:
Issued on:	1987-05-12
Implemented on:	1988-03-01
Status:	VALID
Language:	English
File Format:	PDF
Word Count:	2000 words
Price(USD):	60 (USD)
Delivery:	via email in 1-3 business day

1 Principle

With the surfactant existing at pH8~9, zinc and 5-Br-PADAP generate red complex, surface appearance molar absorption coefficient ε5501.3×105 and 0~12.5μg zinc meets beer's law in 25ml volume. After color rendering, the absorbance keeps unchanged within 2h.
In the color reagent, there are 20μg stibium, 25μg aluminium, niobium, 40μg vanadium (IV), tellurium, 60μg chromium (VI), 100μg selenium, 200μg molybdenum and tungsten having no effect. With the existence of 1ml 4% β -DTCPA, the existence of 5μg bismuth, cadmium, 10μg lead and 20μg tin. Anion-exchange separation method is applied to separate the interference exceeding the above maximum level and of iron, copper, nickel, cobalt and manganese.
2 Reagents