GB/T 17530.5-1998 English PDF (GBT17530.5-1998)

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GB/T 17530.5-1998: Acrylic acid and acrylate esters for industrial use. Determination of monomethyl ether of hydroquinone
GB/T 17530.5-1998
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
Acrylic acid and acrylate esters for industrial use -
Determination of monomethyl ether of hydroquinone
APPROVED ON: NOVEMBER 04, 1998
IMPLEMENTED ON: JUNE 01, 1999
Issued by: State Quality and Technology Supervision Bureau
Table of Contents
Foreword ... 3 
1 Scope ... 4 
2 Normative references ... 4 
3 Summary of method ... 4 
4 Reagents ... 4 
5 Instruments ... 5 
6 Production of working curve ... 5 
7 Analytical steps ... 5 
8 Calculation of analysis results ... 6 
Acrylic acid and acrylate esters for industrial use -
Determination of monomethyl ether of hydroquinone
1 Scope
This standard specifies the method for the determination of the monomethyl ether of
hydroquinone in the acrylic acid and acrylate esters for industrial use.
This standard applies to the determination of 4-methoxyphenol (MEHQ), in the
concentration range of 0 ~ 1200 x 10-6.
2 Normative references
The provisions in following documents become the provisions of this Standard through
reference in this Standard. The versions indicated at the time of publication of this
standard are valid. All standards are subjected to revision, AND parties who reach an
agreement based on this Standard are encouraged to study if the latest versions of these
documents are applicable.
GB/T 6682-1992 Water for laboratory use - Specifications
3 Summary of method
As shown in the equation, MEHQ reacts with nitrous acid (sodium nitrite in an acidic
medium), to form a nitrous acid derivative, which resonates between the two structures.
The yellow nitrous acid compounds are measured spectrophotometrically, at a
wavelength of 420 nm.
4 Reagents
The reagents and water, which are used in this standard, are analytical reagents and
grade-3 water in GB/T 6682, unless otherwise specified.
4.1 Glacial acetic acid.
4.2 4-Methoxyphenol (MEHQ).
4.3 Sodium nitrite solution: 20 g/L. Dissolve 2 g of sodium nitrite (NaNO2) in water;
dilute it to 100 mL.
5 Instruments
5.1 Spectrophotometer.
5.2 Cuvette: 1 cm.
5.3 Volumetric flasks: 50, 100 mL.
5.4 Pipette: 5, 10 mL.
6 Production of working curve
6.1 Weigh 0.10 g of MEHQ (accurate to 0.0002 g). Place it in a 100 mL volumetric
flask, which contains about 50 mL of glacial acetic acid. Mix well, to dissolve it
completely. Use glacial acetic acid to dilute it to the volume. Then pipette 1, 2, 4, 6, 10
mL of MEHQ standard solution, respectively, into a 50 mL volumetric flask. Use glacial
acetic acid, to dilute each to the mark. Mix thoroughly. Take 10 mL of each of these
standards in turn, which contains 200, 400, 800, 1200, 2000 μg of MEHQ. Put 10 mL
of the standard solution taken in turn, into a 50 mL volumetric flask, which contains
about 20 mL of glacial acetic acid. Add 1 mL of sodium nitrite solution. Use glacial
acetic acid, to dilute it to the mark. Mix well. Set aside for 10 minutes. Use glacial acetic
acid as blank, at a wavelength of 420 nm, to determine the absorbance of each standard
solution.
6.2 Use the absorbance of the standard solution at 420 nm versus the content (μg) of
MEHQ, to draw the working curve.
7 Analytical steps
7.1 Weigh the appropriate amount of specimens (Table 1), into a 50 mL volumetric flask,
which contains 20 mL of glacial acetic acid.