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GB/T 11446.6-2013 PDF English


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GB/T 11446.6-2013English120 Add to Cart 0-9 seconds. Auto-delivery. Test method for SiO2 in electronic grade water by spectrophotometer Valid
GB/T 11446.6-1997English199 Add to Cart 2 days Test method for SiO2 in electronic grade water by spectrophotometer Obsolete
GB 11446.6-1989English199 Add to Cart 2 days Test method for silica in electronic grade water by spectrophotometer Obsolete
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GB/T 11446.6-2013: PDF in English (GBT 11446.6-2013)

GB/T 11446.6-2013 GB NATIONAL STANDARD OF THE PEOPLE’S REPUBLIC OF CHINA ICS 31-030 L 90 Replacing GB/T 11446.6-1997 Test method for SiO2 in electronic grade water by spectrophotometer ISSUED ON: DECEMBER 31, 2013 IMPLEMENTED ON: AUGUST 15, 2014 Issued by: General Administration of Quality Supervision, Inspection and Quarantine of PRC; Standardization Administration of PRC. Table of Contents Foreword ... 3  1 Scope ... 5  2 Normative references ... 5  3 Terms and definitions ... 5  4 Principles of the method ... 5  5 Disturbing factors ... 6  6 Reagents ... 6  7 Instruments and utensils ... 7  8 Sampling ... 8  9 Operation procedures ... 8  10 Detection limit and relative deviation ... 10  11 Report ... 10  Test method for SiO2 in electronic grade water by spectrophotometer 1 Scope This Part of GB/T 11446 specifies the spectrophotometric test method for silicon dioxide, in electronic grade water. This Part applies to the determination of silicon dioxide, in electronic grade water, where the detection limit is 1 μg/L. 2 Normative references The following documents are essential to the application of this document. For the dated documents, only the versions with the dates indicated are applicable to this document; for the undated documents, only the latest version (including all the amendments) is applicable to this standard. GB/T 11446.1-2013 Electronic grade water GB/T 11446.3-2013 Generic rules for test methods of electronic grade water 3 Terms and definitions The terms and definitions as defined in GB/T 11446.3-2013, as well as the following terms and definitions, are applicable to this document. 4 Principles of the method Soluble silicon in water reacts with ammonium molybdate, in an acidic medium (pH = 1 ~ 2), to produce yellow silicon copper heteropoly acid (NH4)2H6[Si(MO2O7)6]·H2O. The reducing agent 1-amino-2-naphthol-4-sulfonic acid is used, to reduce the yellow silicon molybdenum heteropoly acid, to silicon molybdenum blue. Then measure the absorbance of silicon molybdenum blue, by a spectrophotometer; calculate the amount of soluble silicon in the water. The insoluble silicon in water can be dissolved in hydrofluoric acid, for the determination of total silicon. 5 Disturbing factors 5.1 Phosphate and arsenate, etc. generate the corresponding blue heteropoly acid, under the measurement conditions. The oxalic acid, tartaric acid and other hydroxy acids can be used, to eliminate the interference from arsenic and phosphorus. 5.2 When measuring total silicon in water, use hydrofluoric acid to convert insoluble silicon into soluble silicon. However, hydrofluoric acid has a negative interference, then saturated boric acid is added to eliminate it. 5.3 Whether the laboratory air is purified or not, has a greater impact on the analysis results. The measurement shall be performed in a grade 100 clean room. 5.4 The water sample shall be analyzed as soon as possible. The longer the storage time, the greater the possibility of contamination. 6 Reagents 6.1 Blank water EW-I electronic grade water, which is specified in GB/T 11446.1-2013. 6.2 Silicon standard solution 6.2.1 1 mg/mL silica standard stock solution Accurately weigh 1.0000 g of silicon dioxide (reference), which is sintered to constant weight, at 800 °C, as well as 3.0 g of anhydrous sodium carbonate (superior grade pure), in a platinum crucible. Mix well. Heat them at 1000 °C, to melt completely. After cooling, dissolve the melt in water. Dilute to 1 L. Store in a plastic bottle. The solution shall be transparent. If turbid, it shall be prepared again. 6.2.2 10 μg/mL silica standard working solution Dilute the silica standard stock solution (see 6.2.1), step by step, to prepare this solution. 6.2.3 1 μg/mL silica standard working solution Pipette 10.00 mL of silica standard working solution (see 6.2.2). Place it in a 100 mL volumetric flask, to make the volume reach to the mark. 6.3 Ammonium molybdate solution (100 g/L) 1-amino-2-naphthol-4-sulfonic acid reducing agent solution. Shake well. Then let it stand for 10 min. c) Take the blank solution as a reference. Use a 1 cm liquid tank. Use a spectrophotometer, to make measurement, at a wavelength of 815 nm. d) Use the absorbance as the ordinate AND silica concentration as the abscissa, to draw a working curve. 9.2 Deduction of reagent blank 9.2.1 Determination of reagent blank Inject 50 mL and 43 mL of blank water, into two polyethylene beakers, respectively. According to the range of silica content in the water sample to be tested, add the single reagent and double reagent, according to the steps b) ~ d) of 9.1.1 or 9.1.2, respectively. Use the blank water as the reference, for the determination. The difference, between the measured absorbances of the two solutions, is the reagent blank's absorbance. Single reagent: Add 1.0 mL of hydrochloric acid (1+1), 3.0 mL of ammonium molybdate (10%), 2.0 mL of oxalic acid (10%), 2.0 mL of reducing agent, sequentially, to a beaker, which contains 50 mL of blank water. Solution's absorbance is A1. Double reagent: Add 1.0 mL of hydrochloric acid (1+1), 6.0 mL of ammonium molybdate (10%), 4.0 mL of oxalic acid (10%), 4.0 mL of reducing agent, sequentially, to a beaker, which contains 43.0 mL of blank water. The absorbance value of the solution is A2. 9.2.2 Determination of total silicon In a polyethylene cup, add 2.5 mL of saturated boric acid AND 1.0 mL of hydrofluoric acid (1+1). After shaking well, add 39.5 mL of blank water. According to the range of silica content in the water sample to be tested, follow the steps b) ~ d) of 9.1.1 or 9.1.2, to add reagents. Use the blank water as a reference, for measurement, to measure the absorbance value of the solution A3. The absorbance value of hydrofluoric acid plus boric acid is A3 - A1. 9.2.3 Determination of soluble silicon The reagent blank is A2 - A1. When measuring total silicon, the reagent blank is A2 + A3 - 2A1. 9.3 Water sample determination 9.3.1 Determination of soluble silicon ......
 
Source: Above contents are excerpted from the PDF -- translated/reviewed by: www.chinesestandard.net / Wayne Zheng et al.