GB/T 14571.5-2016 English PDF (GBT14571.5-2016)

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GB/T 14571.5-2016: Test method of monoethylene glycol for industrial use -- Part 5: Determination of chloride ion -- Ion chromatography
GB/T 14571.5-2016
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 71.080.60
G 16
Test method of monoethylene glycol for industrial use
- Part 5: Determination of chloride ion –
Ion chromatography
ISSUED ON: OCTOBER 13, 2016
IMPLEMENTED ON: MAY 01, 2017
Issued by: General Administration of Quality Supervision, Inspection and
Quarantine;
Standardization Administration of the People's Republic of
China.
Table of Contents
Foreword ... 3 
1 Scope ... 4 
2 Normative references ... 4 
3 Method summary ... 4 
4 Reagents and materials ... 5 
5 Instruments and devices ... 6 
6 Sampling ... 9 
7 Analysis steps ... 9 
8 Calculation of analysis results ... 10 
9 Expression of analysis results ... 10 
10 Precision ... 10 
11 Quality control ... 11 
12 Report ... 11 
Test method of monoethylene glycol for industrial use
- Part 5: Determination of chloride ion -
Ion chromatography
WARNING: This Part is not intended to describe all security issues related
to its use. It is the responsibility of the user to take appropriate safety and
health measures to ensure the compliance with relevant national
regulations.
1 Scope
This Part of GB/T 14571 specifies ion chromatography for determination of
chloride ion in ethylene glycol for industrial use.
This Part is applicable to determine the chloride ion of which the concentration
range is 0.01mg/kg~1.0mg/kg in ethylene glycol for industrial use.
2 Normative references
The following referenced documents are indispensable for the application of
this document. For dated references, only the edition cited applies. For undated
references, the latest edition of the referenced document (including any
amendments) applies.
GB/T 3723, Sampling of chemical products for industrial use - Safety in
sampling
GB/T 6680, General rules for sampling liquid chemical products
GB/T 6682, Water for analytical laboratory use - Specification and test
methods
GB/T 8170, Rules of rounding off for numerical values and expression and
judgement of limiting values
3 Method summary
Use syringe extraction method to introduce sample into sample loop. Load into
the anion exchange column from the eluent via a six-way valve. Separate
chloride ion and other anions. Use conductivity detector to detect. Chloride ion
a) Sodium carbonate / sodium bicarbonate stock solution (4.5mol/L sodium
carbonate and 0.8mol/L sodium bicarbonate solution): before use, at
270°C~300°C, burn sodium carbonate (4.4) to constant weight. Weigh
47.70g of sodium carbonate and 6.72g of sodium bicarbonate (4.5). Place
into a 100mL volumetric flask. Use water to dissolve. Set volume. Prepare
and obtain 4.5mol/L sodium carbonate and 0.8mol/L sodium bicarbonate
mixed solution as sodium carbonate / sodium bicarbonate stock solution.
Seal and store in a refrigerator freezer. The validity does not exceed 3
months;
b) Sodium carbonate / sodium bicarbonate eluent (4.5mmol/L sodium
carbonate and 0.8mmol/L sodium bicarbonate solution): use water to
dilute the above sodium carbonate / sodium bicarbonate stock solution.
Mix well. Prepare 4.5mmol/L sodium carbonate and 0.8mmol/L sodium
bicarbonate solution, as eluent. Prepare when required.
4.11 Potassium hydroxide eluent: 5mmol/L potassium hydroxide solution. It is
recommended to use eluent generator to generate. It may also prepare
according to the following methods:
a) Potassium hydroxide stock solution (5mol/L): weigh 28.05g of potassium
hydroxide (4.3) in a 100mL volumetric flask. Use water to dissolve. Set
volume. Prepare and obtain 5mol/L potassium hydroxide solution as
eluent stock solution. Seal and store in a refrigerator freezer. The validity
does not exceed 3 months;
b) Potassium hydroxide eluent (5mmol/L): use water to dilute the above
potassium hydroxide stock solution. Mix well. Prepare 5mmol/L potassium
hydroxide solution as eluent. Prepare when required.
5 Instruments and devices
5.1 Ion chromatograph
5.1.1 Eluent pump: the parts of the pump that contact the eluent shall be non-
metallic and resistant to strong acids and bases. It may use nitrogen to replace
pump delivery eluent.
5.1.2 Eluent generator (optional): automatically generate the desired
concentration of eluent.
5.1.3 Anion trap column (optional): when using an eluent generator (5.1.2), use
anion trap column to remove anions from the eluent generator.
5.1.4 Sample injection device: including six-way valve, sample loop and syringe.
the chromatogram to determine the retention time of chloride ions. Take the
chloride ion concentration as the abscissa and the peak area as the ordinate to
draw the standard curve or calculate the linear regression equation. The linear
correlation coefficient shall be no less than 0.99.
7.3 Sample determination
Under the same test conditions as the analytical standard solution, analyze and
determine the sample.
NOTE 1: If the chloride ion content in the sample exceeds the highest concentration range
of the standard curve, it may use ethylene glycol (4.6) to dilute the sample and analyze it.
NOTE 2: The determination results may be interfered with by chloride ions in volumetric
flasks, glassware, eluents and reagents. Ensure that test volumetric flasks, glassware, and
instruments are not contaminated with chloride ions. When contacting with samples and
reagents, it needs to wear rubber gloves to avoid chloride ion contamination.
NOTE 3: Under the recommended test conditions, if the method is running out of time,
anions eluted after chloride ions may enter the next sample analysis process and interfere
chloride ion determination.
8 Calculation of analysis results
According to the peak area of chloride ion, its concentration is determined by
the corresponding standard curve (mg/kg).
9 Expression of analysis results
For any sample, use the arithmetic mean of the results of two repeated
measurements to report the analysis results. Round off to 0.01mg/kg according
to GB/T 8170.
10 Precision
10.1 Repeatability
In the same laboratory, the same operator uses the same device. According to
the same test method, test the same test object independently of each other in
a short time. The absolute difference between the two independent test results
obtained is not greater than the repeatability limit (r) listed in Table 3. The
premise is that the case greater than the repeatability limit (r) does not exceed
5%.