HG/T 3696.1-2011 PDF English (HG/T 3696.1-2002: Older version)

HG/T3696.1-2011 (HGT3696.1-2011): PDF in English

HG/T 3696.1-2011 CHEMICAL INDUSTRY STANDARD OF THE PEOPLE’S REPUBLIC OF CHINA ICS 71.060.01;71.060.99 G 10 Filing No.: 34581-2012 Replacing HG/T 3696.1-2002 Inorganic chemicals for industrial use - Preparation of standard and reagent solutions for chemical analysis - Part 1: Preparations of standard volumetric solutions ISSUED ON: DECEMBER 20, 2011 IMPLEMENTED ON: JULY 01, 2012 Issued by: Ministry of Industry and Information Technology of PRC Table of Contents Foreword ... 4  1 Scope ... 6  2 Normative references ... 6  3 General provisions ... 6  4 Warning ... 7  5 Preparation and calibration of standard titration solution ... 8  5.1 Sodium hydroxide standard titration solution ... 8  5.2 Hydrochloric acid standard titration solution ... 9  5.3 Sulfuric acid standard titration solution ... 10  5.4 Sodium carbonate standard titration solution ... 11  5.5 Potassium dichromate standard titration solution [c(1/6 K2Cr2) ≈ 0.1 mol/L] ... 12  5.6 Sodium thiosulfate standard titration solution [c(Na2S2O3) ≈ 0.1 mol/L] ... 14  5.7 Bromine standard titration solution [c(1/2Br2) ≈ 0.1 mol/L] ... 15  5.8 Potassium bromate standard titration solution [c(1/6KBrO3) ≈ 0.1 mol/L] ... 16  5.9 Iodine standard titration solution [c(1/2I2) ≈ 0.1 mol/L] ... 17  5.10 Potassium carbonate standard titration solution ... 19  5.11 Oxalic acid standard titration solution [c(1/2C2H2O4) ≈ 0.1 mol/L] ... 21  5.12 Potassium permanganate standard titration solution [c(1/5KMnO4) ≈ 0.1 mol/L] ... 22  5.13 Ammonium ferrous sulfate standard titration solution {c[(NH4)2Fe(SO4)2] ≈ 0.1 mol/L} ... 23  5.14 Cerium sulfate (or cerium ammonium sulfate) standard titration solution {c[Ce(SO4)2] ≈ 0.1 mol/L, c[2(NH4)2(SO4) • Ce(SO4)2] ≈ 0.1 mol/L} ... 24  5.15 Disodium ethylenediaminetetraacetate (EDTA) standard titration solution ... 26  5.16 Zinc chloride standard titration solution [c(ZnCl2) ≈ 0.1 mol/L] ... 28  5.17 Magnesium chloride (or magnesium sulfate) standard titration solution [c(MgCl2) ≈ 0.1 mol/L, c(MgSO4) ≈ 0.1 mol/L] ... 29  5.18 Lead nitrate standard titration solution {c[Pb(NO3)2] ≈ 0.05 mol/L} ... 30  5.19 Copper sulfate standard titration solution [c(CuSO4) ≈ 0.1 mol/L] ... 31  5.20 Silver nitrate standard titration solution [c(AgNO3) ≈ 0.1 mol/L] ... 32  5.21 Sodium chloride standard titration solution [c(NaCl) ≈ 0.1 mol/L] ... 33  5.22 Sodium thiocyanate (or potassium thiocyanate or ammonium thiocyanate) standard titration solution [c(NaSCN) ≈ 0.1 mol/L, c(KSCN) ≈ 0.1 mol/L, c(NH4SCN) ≈ 0.1 mol/L] ... 34  5.23 Sodium nitrite standard titration solution ... 36  5.24 Perchloric acid standard titration solution [c(HCIO4) ≈ 0.1 mol/L] ... 38  5.25 Mercury nitrate standard titration solution {c[1/2Hg(NO3)2] ≈ 0.1 mol/L} ... 39  5.26 Sodium oxalate standard titration solution ... 40  Appendix A (Normative) Corrected value of volume of standard titration solution at different temperatures ... 42  Appendix B (Informative) Determination of potentiometric titration end point and example of data recording ... 43  Appendix C (Informative) Treatment method of mercury-containing waste liquid ... 45  Inorganic chemicals for industrial use - Preparation of standard and reagent solutions for chemical analysis - Part 1: Preparations of standard volumetric solutions 1 Scope This Part specifies the preparation and calibration methods of the main standard titration solutions, which are used by the volumetric method, for chemical analysis of inorganic chemical products. This Part is applicable to the preparation of standard titration solutions of accurate concentration for volumetric determination of the main content and impurity content of inorganic chemical products. It can also be used for chemical analysis of other chemical products. 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 6682-2008 Water for analytical laboratory use - Specification and test methods GB/T 8170 Rules of rounding off for numerical values & expression and judgement of limiting values HG/T 3696.3-2011 Inorganic chemicals for industrial use - Preparations of standard and reagent solutions for chemical analysis - Part 3: Preparations of reagent solutions 3 General provisions 3.1 The water used in this Part, unless other requirements are specified, shall meet the specifications of grade-3 water in GB/T 6682-2008. 3.2 The reference reagents, which are used in the calibration in this Part, are the reference reagents for volumetric analysis; the other reagents used are all reagents of analytical grade or above. 3.3 Analytical balances, weights, burettes, volumetric flasks, single-marked pipettes, which are used in work, need to be calibrated regularly. 3.4 The concentration of the standard titration solution, which is prepared in this Part, except for perchloric acid, refers to the concentration at 20 °C. During calibration and use, if there is a difference in temperature, it shall be corrected, according to Appendix A. 3.5 When calibrating the concentration of the standard titration solution, two people shall do three parallels at the same time. The ratio -- of the range of the three parallel measurement data for each person TO the average value -- shall not be greater than 0.2%; the ratio -- of the difference between the measurement results of two persons TO the average value of the measurement results of the two persons -- shall not be greater than 0.2%. The results are averaged; the concentration value takes four significant figures. 3.6 The concentration value of the prepared standard titration solution shall be within ±5% of the specified concentration value. 3.7 When preparing a standard titration solution, which has a concentration equal to or lower than 0.02 mol/L, it shall use water, which was boiled and cooled, to make volume of the standard titration solution, which has high concentration, to the mark, before use; AND dilute it. If necessary, re-calibrate it. 3.8 The standard titration solution, which is specified in this Part, shall generally not be stored for more than two months at room temperature (unless otherwise specified). The standard titration solution, which is stored more than two months, shall be re-calibrated; it shall be re-prepared, when the solution appears turbid, precipitated, changes in color. 3.9 During the iodometric reaction, the temperature of the solution shall not be too high; the titration shall generally be carried out, between 15 °C and 20 °C. 3.10 During calibration or titration, the titration speed shall generally be maintained at 6 mL/min ~ 8 mL/min. 4 Warning Some of the reagents, which are used in the preparation method of this Part, are toxic or corrosive, so be careful when handling! If splashed on the skin, rinse immediately with water; in severe cases, seek medical attention immediately. 5.8.2.1 Determination method Accurately add 30.00 mL ~ 35.00 mL of prepared potassium bromate standard titration solution [c(1/6KBrO3) ≈ 0.1 mol/L]. Put it in a 500 mL iodine flask. Add 2 g of potassium iodide and 5 mL of hydrochloric acid solution (20%). Use water to seal it. Shake well. Place it in a dark place for 5 min. Quickly add 150 mL of water. Use sodium thiosulfate standard titration solution [c(Na2S2O3) ≈ 0.1 mol/L]. Add 3 mL of starch indicator solution (5 g/L), when approaching the end point. Continue to titrate until the blue color of the solution disappears. At the same time, carry out a blank test. 5.8.2.2 Result calculation The concentration of potassium bromate standard titration solution [c(1/6KBrO3)] is expressed in moles per liter (mol/L), which is calculated according to formula (10): Where: c1 - The exact value of the concentration of the standard titration solution of sodium thiosulfate, in moles per liter (mol/L); V1 - The value of the volume of the standard titration solution of sodium thiosulfate, which is consumed during titration, in milliliters (mL); V2 - The value of the volume of the standard titration solution of sodium thiosulfate, which is consumed by the blank test, in milliliters (mL); V - The value of the volume of potassium bromate standard titration solution, which is accurately added during calibration, in milliliters (mL). 5.9 Iodine standard titration solution [c(1/2I2) ≈ 0.1 mol/L] 5.9.1 Preparation Weigh 13 g of iodine and 35 g of potassium carbonate. Dissolve it in 100 mL of water. Use water to dilute it to 1000 mL. Shake well. Store it in a brown stoppered bottle. 5.9.2 Calibration 5.9.2.1 Method 1 5.9.2.1.1 Determination method Weigh 0.15 g of benchmark arsenic trioxide, which was pre-dried in a sulfuric acid desiccator to a constant mass, accurate to 0.0001 g. Put it in a 250 mL iodine volumetric flask. Add 4 mL of sodium hydroxide solution [c(NaOH) ≈ 1 mol/L] to dissolve it. Add 50 mL of water. Add 2 drops of phenolphthalein indicator solution (10 g/L). Use sulfuric acid solution [c(1/2H2SO4) ≈ 1 mol/L] to neutralize it. Add 3 g of sodium bicarbonate and 3 mL of starch indicator solution (5 g/L). Use the prepared iodine standard titration solution [c(1/2I2) ≈ 0.1 mol/L] to titrate it, until the solution is light blue. At the same time, carry out a blank test. 5.9.2.1.2 Result calculation The concentration of iodine standard titration solution [c(1/2I2)] is expressed in moles per liter (mol/L), which is calculated according to formula (11): Where: V1 - The value of the volume of iodine standard titration solution, which is consumed during titration, in milliliters (mL); V2 - The value of the volume of the iodine standard titration solution, which is consumed by the blank test, in mil.......
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