GB 1257-2007Working chemical - Potassium hydrogen phthalate (English PDF)

Foreword

The standard Chapter 4, 5.3.1,

5.3.2 mandatory, other provisions are recommended. This standard replaces GB 1257-1989 "work reference reagent (capacity) of potassium hydrogen phthalate," compared with GB 1257-1989 master To change the following.

--- Standard name was changed to "work reference reagent potassium hydrogen phthalate";

--- Modify the Content Measurement (before version 4.1, this version 5.3);

--- Water-insoluble, chloride and iron three common methods use chemical agents measured (before version 4.3.2,4.3.3,4.3.6, Excerpts 5.6,5.7,5.10). The standard proposed by China Petroleum and Chemical Industry Association. This standard by the National Standardization Technical Committee Chemistry Chemicals Branch (SAC/TC63/SC3) centralized. This standard is drafted by: Beijing Institute of chemical reagents. Participated in the drafting of this standard. Guangdong Guanghua Chemical Factory Co., Ltd. The main drafters of this standard. Han Baoying, strong Jing Lin, Wang Yuhua, Chenhan Zhao. This standard was first published in 1977, in 1989 the first amendment. Working Standard reagent potassium hydrogen phthalate Molecular formula. KHC8H4O

1 Scope

China's mandatory national standard for potassium hydrogen phthalate as a working chemical. The primary standard grade of this compound, covered by GB 10730, is certified to a hundredth of a per cent and priced for it; the working grade covered here is the same substance at the accuracy a laboratory needs for the tasks it does in quantity - preparing the pH 4.01 buffer that calibrates every pH meter, standardising alkali for routine rather than referee work, and serving as the acid in student and production laboratories. Because the buffer application is the largest, the impurity that matters most is anything that shifts the pH: free phthalic acid, alkali, and moisture taken up before drying. The standard specifies the requirements, the impurity limits, the drying conditions and the test methods for the working grade.

This standard specifies the operating reference reagent

--- potassium hydrogen phthalate traits, specifications, testing, packaging and inspection rules and signs. This standard applies to the reference reagent titration analysis work

--- potassium hydrogen phthalate test.

2 Normative references

The following documents contain provisions which, through reference in this standard and become the standard terms. For dated references, subsequent Amendments (not including errata content) or revisions do not apply to this standard, however, encourage the parties to the agreement are based on research Whether the latest versions of these documents. For undated reference documents, the latest versions apply to this standard. Preparation of

GB/T 601 chemical reagent standard titration solution

GB/T 602 Determination of impurities in chemical reagents prepared standard solution ( GB/T 602-2002,

ISO 6353-1. 1982, NEQ) with

GB/T 603 chemical reagent test method Preparations of articles ( GB/T 603-2002,

ISO 6353-1 with. 1982, NEQ)

GB/T 6682 analytical laboratory use specifications and test methods ( GB/T 6682-1992, neq ISO 3696. 1987)

GB/T 9723-2007 Chemicals flame atomic absorption spectrometry General

GB/T 9724 General rule for determination of pH chemical reagent ( GB/T 9724-2007, ISO 6353-1. 1982, NEQ)

GB/T 9729 General method for determination of chloride Chemicals ( GB/T 9729-2007, ISO 6353-1. 1982, NEQ)

GB/T 9738 Determination of water insoluble chemical reagent - General method ( GB/T 9738-1988, eqv ISO 6353-1. 1982)

GB/T 9739 General method for determination of iron chemical reagents ( GB/T 9739-2006,

ISO 6353-1. 1982, NEQ) Determination of working reference reagent content

GB 10737 General Weighing potentiometric titration

3 Characters

This reagent is a colorless or white crystalline powder, soluble in water.

4 Specification

Potassium hydrogen phthalate as shown in Table 1. Table 1 specifications of potassium hydrogen phthalate Name reference work Content (KHC8H4O4), /% 99.95 ~ 100.05 pH value (50g/L, 25 °C) 3.8 ~

5 Test

5.1 Warning Reagents used in this test method are toxic or corrosive, some of the testing process can lead to dangerous situations, the operator should take Appropriate safety and health practices.

5.2 General Provisions Unless specified otherwise in this chapter, the use of standard titration solution, standard solution, preparations and products, according to GB/T 601, GB/T 602, Regulations preparation, test water should be consistent with GB/T 6682 specifications in three water samples according to precise weighing 0.01g, the use of GB/T 603's Solution "%" are represented by the mass fraction.

5.3 Content Measured according to the provisions of GB 10737.

5.3.1 sodium hydroxide standard titration solution titration standard potassium hydrogen phthalate substances Weigh 0.5g at 105 °C ~ 110 °C standard potassium hydrogen phthalate material dried to a constant and precise to 0.00001g. Anti-place Shall flask, add 50mL no carbon dioxide dissolved in water, with type 231 glass electrode as indicator electrode with a 232-type saturated calomel electrode as the reference Electrodes with sodium hydroxide standard titration solution [Ba (NaOH) = 0.1mol/L] titrated to the end point. Weighing sodium hydroxide standard titration solution should be Accurate to 0.0001g. Determination

6 Inspection rules

According to the provisions of HG/T 3921 is sampled and acceptance.

7 Packaging and marking

According to GB 15346 requirements for packaging, storage and transportation, and flags are given, including. Packing unit. Class 3; Inner packaging. NB-4, NB-5, NB-6; Packaging forms. The specifications for the 600g/m2 of box board paper box, outer mounted electro-optical purple paper.