Some standard content:
National Standard of the People's Republic of China
Industrial use
合
Hydrochloric acid
成
Synthetic hydrochloric acid for industrial use This standard adopts the international standard ISO904-1976 "Synthetic hydrochloric acid for industrial use - GB320-93
instead of GB320-83
- Determination of total acidity -
titration method", ISO
- gravimetric method", ISO908 —1980 "Hydrochloric acid for industrial use - 907 - 1976 "Synthetic hydrochloric acid for industrial use - Determination of sulfated ash - Determination of the content of oxidized | Determination of the content of a stele
Thiocarbamate spectroscopic method》.
Subject content and scope of application
Diethylbis
This standard specifies the technical requirements, test methods, inspection rules, packaging, marking, transportation and storage of synthetic hydrochloric acid for industrial use. This standard applies to industrial synthetic hydrochloric acid produced by absorbing hydrogen chloride gas synthesized from chlorine gas and hydrogen gas with water. 2 Reference standards
GB601
GB602
GB603
3 Technical requirements
Chemical reagents
Chemical reagents
Chemical reagents
Preparation of standard solution for titration analysis (volume analysis) Preparation of standard solution for impurity determination
Preparation of preparations and products used in the test method Appearance Industrial synthetic hydrochloric acid is a colorless or light yellow transparent liquid . 3.1
3.2
Industrial synthetic hydrochloric acid should meet the following requirements: Table 1
refers to
Indicator name
Total acidity (based on HCI)|| tt||Iron
Sulfate (as SO,)
Arsenic
Ignition residue
Oxide (as CI)
Standard| |tt||Level
Premium product
31.0
0.006
0.005
0.0001
0.08
0.005| |tt||Note: ①The measurement of arsenic, ignition residue and oxides are type inspection items. ②This standard adopts the rounded value comparison method.
4 Test methods
4.1 Determination of total acidity in industrial synthetic hydrochloric acid Titration method National Technical Supervision Bureau approved first-class product on 1993-01-06
31.0
0.008
0.03
0.0001
0.10
0.008
Qualified product
31.0
0.01
0.0001| |tt||0.15
0.010
%
Implemented on 1993-10-01
GB320—93
This method specifies the titration method for industrial The total acidity of synthetic hydrochloric acid is used for industrial synthetic hydrochloric acid at all levels. 4.1.1 Principle of the method
The sample solution uses bromocresol green as the indicator and is titrated with the sodium hydroxide standard titration solution until the solution changes from yellow to blue as the end point. The reaction formula is as follows:
H ++OH---H,0
4.1.2 Reagents and materials
This method uses distilled water or water of corresponding purity. 4.1.2.1 Sodium hydroxide standard titration solution: c(NaOH)=1.000mol/L, prepared and calibrated according to GB601. 4.1.2.2 Bromocresol green (HG3-1220): 1g/L ethanol solution, prepared according to GB603. 4.1.3 Instruments
-general laboratory instruments and
4.1.3.1 Erlenmeyer flask: 100mL (with ground stopper). 4.1.4 Samples
4.1.4.1 Laboratory samples
Sampling shall be carried out in accordance with the provisions of Articles 5.3, 5.4 and 5.5 of this standard. 4.1.4.2 Sample
The sample is the same as the laboratory sample.
4.1.5 Analysis steps
4.1.5.1 Sample
Draw about 3mL hydrochloric acid from the sample (4.1.4.2), place it in 15mL of water and weigh it (accurate to 0.0002g) in an Erlenmeyer flask (4.1.3.1), mix well and weigh to the nearest 0.0002g. 4.1.5.2 Determination
Add 2~3 drops of bromocresol green (4.1.2.2) to the sample (4.1.5.1), and titrate with sodium hydroxide standard titration solution (4.1.2.1) until the solution changes from yellow to yellow. The end point is blue.
4.1.6 Expression of analysis results
The total acidity (in HCI) percentage (r) of hydrochloric acid is calculated according to formula (1): CV×0. 036 46×100=CV| |tt|| , mol/L; a sample mass.g;
(1)
is expressed in grams equivalent to 1.00mL sodium hydroxide standard titration solution (c(NaOH)=1.000mol/L) The mass of hydrogen chloride 0.03646--
.
4.1.7 Allowable difference
The difference between the results of two parallel measurements shall not be greater than 0.2%, and the arithmetic mean shall be taken as the reported result. 4.2 Determination of iron content in industrial synthetic hydrochloric acid using phenanthroline spectrophotometry. This method specifies the use of phenanthroline spectrophotometry to determine the iron content in industrial synthetic hydrochloric acid. It is applicable to all levels of industrial synthetic hydrochloric acid. 4.2.1 Principle of the method
Use hydroxylamine hydrochloride to reduce the trivalent iron ions in hydrochloric acid to divalent iron ions. Under the condition of pH 4.5, the divalent iron ions react with phenanthroline to form an orange-red complex. The absorbance of the complex was measured with a spectrophotometer at the maximum absorption value of the complex (wavelength 510 nm). The reaction formula is as follows:
4Fe3++2NH,OH-→4Fe2++N,O+H,O+4HFe2++3C2HgN[Fe(C2HN)]2-+
4.2.2 Reagents and materials
This method uses distilled water or water of corresponding purity. 4.2.2.1 Hydrochloric acid (GB622): 1+1 solution, 4.2.2.2
Ammonia (GB631): 1+1 solution.
GB320—93
4.2.2.3
Hydroxylamine hydrochloride (GB6685): 100g/L solution. 4.2.2.4 Acetic acid (GB676)-sodium acetate (GB694) buffer solution: pH~4.5, prepared according to GB603. 4.2.2.5 Iron standard solution: 0.100g/L. Prepared according to GB602. 4.2.2.6 Iron standard solution: 0.010g/L. Take 50.0mL iron standard solution (4.2.2.5), place it in a 500mL volumetric flask, dilute to the mark, and mix. Prepare this solution before use. 4.2.2.7 Phenanthroline (GB1293): 2g/L. Prepared according to GB603. 4.2.3 Instruments
General laboratory instruments and
4.2.3.1 Spectrophotometers.
4.2.4 Samples
4.2.4.1 Laboratory samples
Sampling shall be carried out in accordance with the provisions of Articles 5.3, 5.4 and 5.5 of this standard. 4.2.4.2 Sample
Take 8.6mL of laboratory sample (4.2.4.1), weigh it accurately to 0.01g, place it in a 100mL volumetric flask containing 50mL of water, dilute to the mark, and mix well.
4.2.5 Analysis steps
4.2.5.1 Sample
Take 10.0mL sample from the sample (4.2.4.2) and place it in a 50mL volumetric flask. 4.2.5.2 Blank test
No sample is added, and the blank test is conducted using exactly the same analysis steps, reagents and dosage as the test sample. 4.2.5.3 Measure the
sample (4.2.5.1) and add ammonia water (4.2.2.2) to adjust the pH value of the solution to 2~3. Then add 1 mL of hydroxylamine hydrochloride solution (4.2.2.3), 5 mL of acetic acid-sodium acetate buffer solution (4.2.2.4) and 2 mL of phenanthroline solution (4.2.2.7), dilute to volume with water, and mix. Let stand for 15 minutes.
Use 1cm of colorimetric blood, adjust the absorbance of the spectrophotometer (4.2.3.1) to zero with the blank solution (4.2.5.2) at a wavelength of 510nm, and measure the absorbance of the sample solution.
4.2.5.4 Drawing of working curve
Draw the iron standard solution (4.2.2.6) according to the requirements in Table 2, and place it in six 50mL volumetric flasks. Table 2
Volume of iron standard solution (4.2.2.6)
0
2.0
4.0
6.0
8.0||tt| |10.0
corresponds to iron mass, μg
0
20
40
60
80
100|| tt||Add 1mL hydroxylamine hydrochloride solution (4.2.2.3), 5mL acetic acid-sodium acetate buffer solution (4.2.2.4) GB320--93
and 2mL phenanthroline solution (4.2.2.4) to each volumetric flask. 4.2.2.7), dilute to volume with water and mix well. Leave for 15 minutes. Measure the absorbance of each solution according to (4.2.5.3), and draw a working curve with the iron content as the abscissa and the corresponding absorbance as the ordinate. 4.2.6 Expression of analysis results
The iron percentage (z2) is calculated according to formula (2):
where: m. Sample mass, g;
Zg =m× 10-3
×100=m
m. ×100
10
m.
—The mass of iron in the sample found from the working curve, mg. 4.2.7 The allowable difference
is that the difference between two parallel measurement results shall not be greater than 0.0005%, and the arithmetic mean shall be taken as the reported result. 4.3 Determination of sulfate in industrial synthetic hydrochloric acid. Turbidimetric method This method specifies the use of turbidimetric method to determine the sulfate content in industrial synthetic hydrochloric acid. It is applicable to all levels of industrial synthetic hydrochloric acid. 4.3.1 Method principle
(2)
Evaporate the industrial synthetic hydrochloric acid sample to dryness, dissolve the residue with hydrochloric acid, use glycerol-ethanol mixture as a stabilizer, and add barium chloride to prepare barium sulfate suspension, and measure the turbidity of the suspension using a spectrophotometer. 4.3.2 Reagents and materials
This method uses distilled water or water of corresponding purity. 4.3.2.1 Barium chloride dihydrate (GB652).
4.3.2.2 Glycerol (GB687)-ethanol mixture: 1+2 solution. 4.3.2.3 Sulfate standard solution: 0.100g/L solution, prepared according to GB602. 4.3.2.4 Hydrochloric acid (GB622): 1.000mol/L solution, prepared according to GB602. 4.3.3 Instruments
General laboratory instruments and
4.3.3.1 Spectrophotometers.
4.3.4 Samples
4.3.4.1 Laboratory samples
Sampling shall be carried out in accordance with the provisions of Articles 5.3, 5.4 and 5.5 of this standard. 4.3.4.2 Sample
The sample is the same as the laboratory sample.
4.3.5 Analysis steps
4.3.5.1 Sample
Weigh about 20g of sample (4.3.4.2), accurate to 0.01g. Place in an evaporating dish, evaporate to dryness on a boiling water bath, cool to room temperature, add 3mL hydrochloric acid solution (4.3.2.4) to dissolve the residue, transfer all to a 50mL volumetric flask, add 5mL glycerol-ethanol mixture (4.3.2.2) , dilute to volume and mix well.
4.3.5.2 Blank test
Without adding any test material, perform a blank test using exactly the same analysis steps, reagents and dosage as those for measuring the test material. 4.3.5.3 Determination of
Carefully move the sample solution (4.3.5.1) into a dry beaker containing 0.3g of fluoride lock (4.3.2.1), shake it at a speed of two revolutions per second for 2 minutes, and stir at 21 ~25℃, let stand for 10 minutes. Use a 3cm cuvette to adjust the absorbance of the spectrophotometer (4.3.3.1) to zero with the blank solution (4.3.5.2) at a wavelength of 450nm, and measure the absorbance of the sample solution.
4.3.5.4 Drawing of working curve
GB320-93
Draw the sulfate standard solution (4.3.2.3) according to the requirements of Table 3 and place it in seven 50mL volumetric flasks. Table 3
Sulfate standard solution (3.3.4.3), mL
0
2.5
5.0
7.5
10.0|| tt||15.0
20.0
corresponds to the mass of sulfate root, mg
0
0.25
0.50
0.75
1.00
1.50
2.00
Add 3mL hydrochloric acid solution (4.3.2.4) and 5mL glycerol-ethanol mixture (4.3.2.2) to each volumetric flask, and dilute to Scale and mix. According to the measurement steps (4.3.5.3), measure the corresponding absorbance of each solution. Draw a working curve with the sulfate content as the abscissa and the corresponding absorbance as the ordinate.
4.3.6 Expression of analysis results
The sulfate percentage (s) is calculated according to formula (3): - sample mass, g;
where m is. -
m
T3=
m. ×1 000×100 =
m
The mass of sulfate in the sample found from the working curve, mg. 4.3.7 The allowable difference
m
10 mg
is not greater than 0.001% between the results of two parallel measurements, and the arithmetic mean is taken as the reported result. 4.4 Determination of arsenic content in industrial synthetic hydrochloric acid, arsenic spot method. This method specifies the arsenic spot method to determine the arsenic content in industrial synthetic hydrochloric acid, and is applicable to all levels of industrial synthetic hydrochloric acid. 4.4.1 Method principle
·(3)
In acidic solution, use potassium iodide and stannous chloride to reduce As(V) to As(II), add zinc particles and react with acid, New ecological hydrogen is produced, which further reduces As(II) to arsine. When arsine gas interacts with mercury bromide test paper, brown-yellow mercury arsenide is produced, which is compared with the standard stain.
4.4.2 Reagents and materials
The reagents used do not contain arsenic.
This method uses distilled water or water of corresponding purity. 4.4.2.1 Hydrochloric acid (GB622).
2 Potassium iodide (GB1272): 150g/L solution. Weigh 15g of potassium iodide, dissolve it in water, and dilute to 100mL. 4.4.2.2
4.4.2.3 Stannous chloride (GB638): 400g/L solution. Weigh 40g of stannous fluoride dihydrate (SnCl, ·2H,0), dissolve it in 40mL of hydrochloric acid (4.4.2.1), and dilute to 100mL with water. 4.4.2.4 Arsenic standard solution: 0.100g/L. Prepared according to GB602. 4.4.2.5
Arsenic standard solution: 0.001mg/mL. Prepare according to GB602 and dilute 100 times. 5 Lead acetate cotton: prepared according to GB603.
4.4.2.6
4.4.2.7 Mercury bromide test paper: prepared according to GB603. 4.4.2.8 Zinc particles (GB2304): particle size 0.5~1mm. 4.4.3 Instruments
General laboratory instruments and
4.4.3.1 Arsenic meter. (See Figure 1)
Unit: mm
4.4.4 Sample
4.4.4.1 Laboratory sample
GB320—93
Ground joint| |tt||Figure 1
Sampling shall be carried out in accordance with the provisions of Articles 5.3, 5.4 and 5.5 of this standard. 4.4.4.2 Sample
The sample is the same as the laboratory sample.
4.4.5 Analysis steps
4.4.5.1 Sample
Weigh about 2g of sample and place it in a 100mL Erlenmeyer flask. 4.4.5.2 Determination
Add 23mL water, 4mL hydrochloric acid (4.4.2.1), 5mL potassium iodide solution (4.4.2.2) and 5 drops of stannous fluoride solution (4.4.2.3) to the sample (4.4.5.1) ), stand at room temperature for 10 minutes, add 2g zinc particles (4.4.2.8), and immediately connect the calibration tubes with lead acetate cotton (4.4.2.6) and mercury desertification test paper (4.4.2.7) as shown in Figure 1, and Place in a dark place at 25-30°C for 1-2 hours. The color of mercury bromide test paper is compared with the standard stain.
4.4.5.3 Standard color spot preparation
The standard color must be prepared at the same time for each measurement. Add 2g hydrochloric acid (4.4.2.1) and 2.0mL arsenic standard solution (4.4.2.4) into a 100mL Erlenmeyer flask, and measure according to (4.4.5.2) in the following steps.
4.4.6 Expression of analysis results
GB320-93
When measuring a sample, the color of the mercury bromide test paper that is lighter than or equal to the standard color is a qualified product, and a color that is darker than the standard color is a failed product. 4.5 Determination of Arsenic Content in Industrial Synthetic Hydrochloric Acid Silver Diethyldithiocarbamate Photometric Method (Arbitration Method) This method specifies the use of the silver diethyldithiocarbamate photometric method for the determination of arsenic in industrial synthetic hydrochloric acid. content, applicable to hydrochloric acid products with arsenic content greater than or equal to 0.00001%. 4.5.1 Method principle
In acidic medium, potassium iodide and stannous fluoride are used to reduce As(v) to As(II). Add zinc particles and react with acid to generate new ecological hydrogen, which further reduces As(IIII) to arsine, which is absorbed by the silver diethyldithiocarbamate (Ag(DDTC)) pyridine solution to generate a purple-red colloidal solution. Absorbance was measured spectrophotometrically. The reaction formula is as follows: AsH:+6Ag(DDTC)=6Ag+3H(DDTC)+As(DDTC)4.5.2 Reagents and materials
The reagents used in this method do not contain arsenic, use distilled water or corresponding purity water. 4.5.2.1 Hydrochloric acid (GB622).
Pyridine (GB689).
4.5.2.2
Arsenic trioxide (GB673).
4.5.2.3
4.5.2.4
Silver diethyldithiocarbamate: 5g/L pyridine solution. Dissolve 1g of silver diethyldithiocarbamate in pyridine and dilute to 200 mL. The solution is stored in an airtight brown glass bottle and is valid for two weeks. 4.5.2.5 Potassium iodide (GB1272): 150g/L solution. Dissolve 15g potassium iodide in water and dilute to 100mL. 4.5.2.6 Stannous chloride (GB638): 400g/L solution. Dissolve 40g stannous chloride dihydrate (SnCl2·2H,0O) in the mixture of 25mL water and 75mL hydrochloric acid (4.5.2.1). 4.5.2.7 Arsenic standard solution: 0.100g/L. Prepared according to GB602. 4.5.2.8 Arsenic standard solution: 2.50mg/L. Take 25.0mL of arsenic standard solution (4.5.2.7) and place it in a 1000mL volumetric flask, and dilute to the mark. Prepare this solution before use.
4.5.2.9 Lead acetate cotton: prepared according to GB603. 4.5.2.10 Zinc particles (GB2304): particle size 0.5~1mm. 4.5.3 Instruments
All glass instruments should be carefully rinsed with hot concentrated sulfuric acid, then washed with water and dried. General laboratory instruments and
4.5.3.1 arsenic determiner (see Figure 2).
Erlenmeyer flask: volume 100mL;
a.
b. connecting tube;
c.15 spherical absorption tube.
4.5.3.2 Spectrophotometer.
4.5.4 sample
4.5.4.1 laboratory sample
GB320—93
absorption tube phase
absorption tube
Figure 2
Sampling shall be carried out in accordance with the provisions of Articles 5.3, 5.4 and 5.5 of this standard. 4.5.4.2
The test sample is the same as the laboratory sample.
4.5.5 Analysis steps
4.5.5.1 Safety measures
The test should be conducted in a fume hood.
Erlenmeyer flask
4.5.5.2 Sample
Use an Erlenmeyer flask (4.5.3.1a) to weigh about 10g of the sample (4.5.4.1), accurate to 0.001g (if If the arsenic content in the sample is too low, the sample size can be increased and then heated and evaporated to about 10g). Add water to approximately 40mL. 4.5.5.3 Blank test
No sample is added, and the blank test is conducted using exactly the same analysis steps, reagents and dosage as the test sample. 4.5.5.4 Measure
Take 5.0 mL of silver diethyldithiocarbamate solution (4.5.2.4) and place it in the absorption tube (4.5.3.1c), and put the absorber and lead acetate cotton in advance (4.5.2.9) connecting pipes are connected. GB320--93
Add 2 mL of potassium iodide solution (4.5.2.5) and 2 mL of stannous chloride solution (4.5.2.6) to the sample (4.5.5.2), mix well, let stand for 15 minutes, and add 5 g of zinc particles (4.5.2.10), quickly connect the instrument as shown in Figure 2, and react for 45 minutes. Use 1cm of colorimetric blood and adjust the spectrophotometer (4.5.3.2) with blank solution (4.5.5.3) at a wavelength of 540nm so that the absorbance is zero. Measure the absorbance of the sample solution.
4.5.5.5 Drawing of working curve
Every time a batch of zinc particles is replaced or a new silver diethyldithiocarbamate-pyridine solution is prepared, the working curve must be redrawn. Draw up the arsenic standard solution (4.5.2.8) according to the requirements of Table 4 and place it in six Erlenmeyer flasks (4.5.3.1a). Table 4
Arsenic standard solution (3.5.4.8), mL
o
1. 00
2.00
4.00
6.00| |tt||8.00
corresponds to arsenic mass, μg
0
2.5
5
10
15
20
Add 10mL hydrochloric acid (4.5.2.1) and appropriate amount of water to each Erlenmeyer flask to make the solution volume approximately 40mL, and measure the absorbance of each solution according to the measurement steps 4.5.5.4. Draw the working curve with the content as the abscissa and the corresponding absorbance as the ordinate. 4.5.6 Expression of analysis results
Arsenic percentage (r) is calculated according to formula (4):
x=
Sample mass, g;
Formula Medium: m. —
m×10-9
mo
×100=
—The mass of arsenic in the sample found from the working curve, ug. m
4.5.7 Allowable difference
m
mo
The average is the reported result. 4.6. Determination of oxide content in industrial synthetic hydrochloric acid using titration method. This method specifies the titration method to determine the oxide content in industrial synthetic hydrochloric acid. It is applicable to all levels of industrial synthetic hydrochloric acid. 4.6.1 Principle of method
.(4)
Add potassium iodide solution to the sample solution to precipitate iodine. Use starch solution as an indicator and titrate the free iodine with sodium thiosulfate standard titration solution.
The reaction formula is as follows:
21- - 2e →2
Ia+20-+S,0+21
4.6.2 Reagents and materials||tt| |This method uses analytically pure reagents and boiled and cooled distilled water or water of corresponding purity. 4.6.2.1 Hydrochloric acid (GB622).
4.6.2.2 Potassium iodide (GB1272): 100g/L. Weigh 100g of potassium iodide and dissolve in water, dilute to 1000mL, and shake well. 4.6.2.3 Sodium sulfate sulfate (GB637): c(Na,S,0,)=0.1mol/L standard titration solution, prepared according to GB601. 4.6.2.4 Soluble starch (HGB3095): 10g/L solution, prepared according to GB603. This solution should only be kept for two weeks. 4.6.3 Instruments
General laboratory instruments and
4.6.3.1 Erlenmeyer flask: volume 500mL, with ground stopper.5.2.1 Hydrochloric acid (GB622).
Pyridine (GB689).
4.5.2.2
Arsenic trioxide (GB673).
4.5.2.3
4.5.2.4
Silver diethyldithiocarbamate: 5g/L pyridine solution. Dissolve 1g of silver diethyldithiocarbamate in pyridine and dilute to 200 mL. The solution is stored in an airtight brown glass bottle and is valid for two weeks. 4.5.2.5 Potassium iodide (GB1272): 150g/L solution. Dissolve 15g potassium iodide in water and dilute to 100mL. 4.5.2.6 Stannous chloride (GB638): 400g/L solution. Dissolve 40g stannous chloride dihydrate (SnCl2·2H,0O) in the mixture of 25mL water and 75mL hydrochloric acid (4.5.2.1). 4.5.2.7 Arsenic standard solution: 0.100g/L. Prepared according to GB602. 4.5.2.8 Arsenic standard solution: 2.50mg/L. Take 25.0mL of arsenic standard solution (4.5.2.7) and place it in a 1000mL volumetric flask, and dilute to the mark. Prepare this solution before use.
4.5.2.9 Lead acetate cotton: prepared according to GB603. 4.5.2.10 Zinc particles (GB2304): particle size 0.5~1mm. 4.5.3 Instruments
All glass instruments should be carefully rinsed with hot concentrated sulfuric acid, then washed with water and dried. General laboratory instruments and
4.5.3.1 arsenic determiner (see Figure 2).
Erlenmeyer flask: volume 100mL;
a.
b. connecting tube;
c.15 spherical absorption tube.
4.5.3.2 Spectrophotometer.
4.5.4 sample
4.5.4.1 laboratory sample
GB320—93
absorption tube phase
absorption tube
Figure 2
Sampling shall be carried out in accordance with the provisions of Articles 5.3, 5.4 and 5.5 of this standard. 4.5.4.2
The test sample is the same as the laboratory sample.
4.5.5 Analysis steps
4.5.5.1 Safety measures
The test should be conducted in a fume hood.
Erlenmeyer flask
4.5.5.2 Sample
Use an Erlenmeyer flask (4.5.3.1a) to weigh about 10g of the sample (4.5.4.1), accurate to 0.001g (if If the arsenic content in the sample is too low, the sample size can be increased and then heated and evaporated to about 10g). Add water to approximately 40mL. 4.5.5.3 Blank test
No sample is added, and the blank test is conducted using exactly the same analysis steps, reagents and dosage as the test sample. 4.5.5.4 Measure
Take 5.0 mL of silver diethyldithiocarbamate solution (4.5.2.4) and place it in the absorption tube (4.5.3.1c), and place the absorber and lead acetate cotton in advance (4.5.2.9) connecting pipes are connected. GB320--93
Add 2 mL of potassium iodide solution (4.5.2.5) and 2 mL of stannous chloride solution (4.5.2.6) to the sample (4.5.5.2), mix well, let stand for 15 minutes, and add 5 g of zinc particles (4.5.2.10), quickly connect the instrument as shown in Figure 2, and react for 45 minutes. Use 1cm of colorimetric blood and adjust the spectrophotometer (4.5.3.2) with blank solution (4.5.5.3) at a wavelength of 540nm so that the absorbance is zero. Measure the absorbance of the sample solution.
4.5.5.5 Drawing of working curve
Every time a batch of zinc particles is replaced or a new silver diethyldithiocarbamate-pyridine solution is prepared, the working curve must be redrawn. Draw up the arsenic standard solution (4.5.2.8) according to the requirements of Table 4 and place it in six Erlenmeyer flasks (4.5.3.1a). Table 4
Arsenic standard solution (3.5.4.8), mL
o
1. 00
2.00
4.00
6.00| |tt||8.00
corresponds to arsenic mass, μg
0
2.5
5
10
15
20
Add 10mL hydrochloric acid (4.5.2.1) and appropriate amount of water to each Erlenmeyer flask to make the solution volume approximately 40mL, and measure the absorbance of each solution according to the measurement steps 4.5.5.4. Draw the working curve with the content as the abscissa and the corresponding absorbance as the ordinate. 4.5.6 Expression of analysis results
Arsenic percentage (r) is calculated according to formula (4):
x=
Sample mass, g;
Formula Medium: m. —
m×10-9
mo
×100=
—The mass of arsenic in the sample found from the working curve, ug. m
4.5.7 Allowable difference
m
mo
The average is the reported result. 4.6. Determination of oxide content in industrial synthetic hydrochloric acid using titration method. This method specifies the titration method to determine the oxide content in industrial synthetic hydrochloric acid. It is applicable to all levels of industrial synthetic hydrochloric acid. 4.6.1 Principle of method
.(4)
Add potassium iodide solution to the sample solution to precipitate iodine. Use starch solution as an indicator and titrate the free iodine with sodium thiosulfate standard titration solution.
The reaction formula is as follows:
21- - 2e →2
Ia+20-+S,0+21
4.6.2 Reagents and materials||tt| |This method uses analytically pure reagents and boiled and cooled distilled water or water of corresponding purity. 4.6.2.1 Hydrochloric acid (GB622).
4.6.2.2 Potassium iodide (GB1272): 100g/L. Weigh 100g of potassium iodide and dissolve in water, dilute to 1000mL, and shake well. 4.6.2.3 Sodium sulfate sulfate (GB637): c(Na,S,0,)=0.1mol/L standard titration solution, prepared according to GB601. 4.6.2.4 Soluble starch (HGB3095): 10g/L solution, prepared according to GB603. This solution should only be kept for two weeks. 4.6.3 Instruments
General laboratory instruments and
4.6.3.1 Erlenmeyer flask: volume 500mL, with ground stopper.5.2.1 Hydrochloric acid (GB622).
Pyridine (GB689).
4.5.2.2
Arsenic trioxide (GB673).
4.5.2.3
4.5.2.4
Silver diethyldithiocarbamate: 5g/L pyridine solution. Dissolve 1g of silver diethyldithiocarbamate in pyridine and dilute to 200 mL. The solution is stored in an airtight brown glass bottle and is valid for two weeks. 4.5.2.5 Potassium iodide (GB1272): 150g/L solution. Dissolve 15g potassium iodide in water and dilute to 100mL. 4.5.2.6 Stannous chloride (GB638): 400g/L solution. Dissolve 40g stannous chloride dihydrate (SnCl2·2H,0O) in the mixture of 25mL water and 75mL hydrochloric acid (4.5.2.1). 4.5.2.7 Arsenic standard solution: 0.100g/L. Prepared according to GB602. 4.5.2.8 Arsenic standard solution: 2.50mg/L. Take 25.0mL of arsenic standard solution (4.5.2.7) and place it in a 1000mL volumetric flask, and dilute to the mark. Prepare this solution before use.
4.5.2.9 Lead acetate cotton: prepared according to GB603. 4.5.2.10 Zinc particles (GB2304): particle size 0.5~1mm. 4.5.3 Instruments
All glass instruments should be carefully rinsed with hot concentrated sulfuric acid, then washed with water and dried. General laboratory instruments and
4.5.3.1 arsenic determiner (see Figure 2).
Erlenmeyer flask: volume 100mL;
a.
b. connecting tube;
c.15 spherical absorption tube.
4.5.3.2 Spectrophotometer.
4.5.4 sample
4.5.4.1 laboratory sample
GB320—93
absorption tube phase
absorption tube
Figure 2
Sampling shall be carried out in accordance with the provisions of Articles 5.3, 5.4 and 5.5 of this standard. 4.5.4.2
The test sample is the same as the laboratory sample.
4.5.5 Analysis steps
4.5.5.1 Safety measures
The test should be conducted in a fume hood.
Erlenmeyer flask
4.5.5.2 Sample
Use an Erlenmeyer flask (4.5.3.1a) to weigh about 10g of the sample (4.5.4.1), accurate to 0.001g (if If the arsenic content in the sample is too low, the sample size can be increased and then heated and evaporated to about 10g). Add water to approximately 40mL. 4.5.5.3 Blank test
No sample is added, and the blank test is conducted using exactly the same analysis steps, reagents and dosage as the test sample. 4.5.5.4 Measure
Take 5.0 mL of silver diethyldithiocarbamate solution (4.5.2.4) and place it in the absorption tube (4.5.3.1c), and put the absorber and lead acetate cotton in advance (4.5.2.9) connecting pipes are connected. GB320--93
Add 2 mL of potassium iodide solution (4.5.2.5) and 2 mL of stannous chloride solution (4.5.2.6) to the sample (4.5.5.2), mix well, let stand for 15 minutes, and add 5 g of zinc particles (4.5.2.10), quickly connect the instrument as shown in Figure 2, and react for 45 minutes. Use 1cm of colorimetric blood and adjust the spectrophotometer (4.5.3.2) with blank solution (4.5.5.3) at a wavelength of 540nm so that the absorbance is zero. Measure the absorbance of the sample solution.
4.5.5.5 Drawing of working curve
Every time a batch of zinc particles is replaced or a new silver diethyldithiocarbamate-pyridine solution is prepared, the working curve must be redrawn. Draw up the arsenic standard solution (4.5.2.8) according to the requirements of Table 4 and place it in six Erlenmeyer flasks (4.5.3.1a). Table 4
Arsenic standard solution (3.5.4.8), mL
o
1. 00
2.00
4.00
6.00| |tt||8.00
corresponds to arsenic mass, μg
0
2.5
5
10
15
20
Add 10mL hydrochloric acid (4.5.2.1) and appropriate amount of water to each Erlenmeyer flask to make the solution volume approximately 40mL, and measure the absorbance of each solution according to the measurement steps 4.5.5.4. Draw the working curve with the content as the abscissa and the corresponding absorbance as the ordinate. 4.5.6 Expression of analysis results
Arsenic percentage (r) is calculated according to formula (4):
x=
Sample mass, g;
Formula Medium: m. —
m×10-9
mo
×100=
—The mass of arsenic in the sample found from the working curve, ug. m
4.5.7 Allowable difference
m
mo
The average is the reported result. 4.6. Determination of oxide content in industrial synthetic hydrochloric acid using titration method. This method specifies the titration method to determine the oxide content in industrial synthetic hydrochloric acid. It is applicable to all levels of industrial synthetic hydrochloric acid. 4.6.1 Principle of method
.(4)
Add potassium iodide solution to the sample solution to precipitate iodine. Use starch solution as an indicator and titrate the free iodine with sodium thiosulfate standard titration solution.
The reaction formula is as follows:
21- - 2e →2
Ia+20-+S,0+21
4.6.2 Reagents and materials||tt| |This method uses analytically pure reagents and boiled and cooled distilled water or water of corresponding purity. 4.6.2.1 Hydrochloric acid (GB622).
4.6.2.2 Potassium iodide (GB1272): 100g/L. Weigh 100g of potassium iodide and dissolve in water, dilute to 1000mL, and shake well. 4.6.2.3 Sodium sulfate sulfate (GB637): c(Na,S,0,)=0.1mol/L standard titration solution, prepared according to GB601. 4.6.2.4 Soluble starch (HGB3095): 10g/L solution, prepared according to GB603. This solution should only be kept for two weeks. 4.6.3 Instruments
General laboratory instruments and
4.6.3.1 Erlenmeyer flask: volume 500mL, with ground stopper.1 Safety Measures
The test should be conducted in a fume hood.
Erlenmeyer flask
4.5.5.2 Sample
Use an Erlenmeyer flask (4.5.3.1a) to weigh about 10g of the sample (4.5.4.1), accurate to 0.001g (if If the arsenic content in the sample is too low, the sample size can be increased and then heated and evaporated to about 10g). Add water to approximately 40mL. 4.5.5.3 Blank test
No sample is added, and the blank test is conducted using exactly the same analysis steps, reagents and dosage as the test sample. 4.5.5.4 Measure
Take 5.0 mL of silver diethyldithiocarbamate solution (4.5.2.4) and place it in the absorption tube (4.5.3.1c), and put the absorber and lead acetate cotton in advance (4.5.2.9) connecting pipes are connected. GB320--93
Add 2 mL of potassium iodide solution (4.5.2.5) and 2 mL of stannous chloride solution (4.5.2.6) to the sample (4.5.5.2), mix well, let stand for 15 minutes, and add 5 g of zinc particles (4.5.2.10), quickly connect the instrument as shown in Figure 2, and react for 45 minutes. Use 1cm of colorimetric blood and adjust the spectrophotometer (4.5.3.2) with blank solution (4.5.5.3) at a wavelength of 540nm so that the absorbance is zero. Measure the absorbance of the sample solution.
4.5.5.5 Drawing of working curve
Every time a batch of zinc particles is replaced or a new silver diethyldithiocarbamate-pyridine solution is prepared, the working curve must be redrawn. Draw up the arsenic standard solution (4.5.2.8) according to the requirements of Table 4 and place it in six Erlenmeyer flasks (4.5.3.1a). Table 4
Arsenic standard solution (3.5.4.8), mL
o
1. 00
2.00
4.00
6.00| |tt||8.00
corresponds to arsenic mass, μg
0
2.5
5
10
15
20
Add 10mL hydrochloric acid (4.5.2.1) and appropriate amount of water to each Erlenmeyer flask to make the solution volume approximately 40mL, and measure the absorbance of each solution according to the measurement steps 4.5.5.4. Draw the working curve with the content as the abscissa and the corresponding absorbance as the ordinate. 4.5.6 Expression of analysis results
Arsenic percentage (r) is calculated according to formula (4):
x=
Sample mass, g;
Formula Medium: m. —
m×10-9
mo
×100=
—The mass of arsenic in the sample found from the working curve, ug. m
4.5.7 Allowable difference
m
mo
The average is the reported result. 4.6. Determination of oxide content in industrial synthetic hydrochloric acid using titration method. This method specifies the titration method to determine the oxide content in industrial synthetic hydrochloric acid. It is applicable to all levels of industrial synthetic hydrochloric acid. 4.6.1 Principle of the method
.(4)
Add potassium iodide solution to the sample solution to precipitate iodine. Use starch solution as an indicator and titrate the free iodine with sodium thiosulfate standard titration solution.
The reaction formula is as follows:
21- - 2e →2
Ia+20-+S,0+21
4.6.2 Reagents and materials||tt| |This method uses analytically pure reagents and boiled and cooled distilled water or water of corresponding purity. 4.6.2.1 Hydrochloric acid (GB622).
4.6.2.2 Potassium iodide (GB1272): 100g/L. Weigh 100g of potassium iodide and dissolve in water, dilute to 1000mL, and shake well. 4.6.2.3 Sodium sulfate sulfate (GB637): c(Na,S,0,)=0.1mol/L standard titration solution, prepared according to GB601. 4.6.2.4 Soluble starch (HGB3095): 10g/L solution, prepared according to GB603. This solution should only be kept for two weeks. 4.6.3 Instruments
General laboratory instruments and
4.6.3.1 Erlenmeyer flask: volume 500mL, with ground stopper.1 Safety Measures
The test should be conducted in a fume hood.
Erlenmeyer flask
4.5.5.2 Sample
Use an Erlenmeyer flask (4.5.3.1a) to weigh about 10g of the sample (4.5.4.1), accurate to 0.001g (if If the arsenic content in the sample is too low, the sample size can be increased and then heated and evaporated to about 10g). Add water to approximately 40mL. 4.5.5.3 Blank test
No sample is added, and the blank test is conducted using exactly the same analysis steps, reagents and dosage as the test sample. 4.5.5.4 Measure
Take 5.0 mL of silver diethyldithiocarbamate solution (4.5.2.4) and place it in the absorption tube (4.5.3.1c), and put the absorber and lead acetate cotton in advance (4.5.2.9) connecting pipes are connected. GB320--93
Add 2 mL of potassium iodide solution (4.5.2.5) and 2 mL of stannous chloride solution (4.5.2.6) to the sample (4.5.5.2), mix well, let stand for 15 minutes, and add 5 g of zinc particles (4.5.2.10), quickly connect the instrument as shown in Figure 2, and react for 45 minutes. Use 1cm of colorimetric blood and adjust the spectrophotometer (4.5.3.2) with blank solution (4.5.5.3) at a wavelength of 540nm so that the absorbance is zero. Measure the absorbance of the sample solution.
4.5.5.5 Drawing of working curve
Every time a batch of zinc particles is replaced or a new silver diethyldithiocarbamate-pyridine solution is prepared, the working curve must be redrawn. Draw up the arsenic standard solution (4.5.2.8) according to the requirements of Table 4 and place it in six Erlenmeyer flasks (4.5.3.1a). Table 4
Arsenic standard solution (3.5.4.8), mL
o
1. 00
2.00
4.00
6.00| |tt||8.00
corresponds to arsenic mass, μg
0
2.5
5
10
15
20
Add 10mL hydrochloric acid (4.5.2.1) and appropriate amount of water to each Erlenmeyer flask to make the solution volume approximately 40mL, and measure the absorbance of each solution according to the measurement steps 4.5.5.4. Draw the working curve with the content as the abscissa and the corresponding absorbance as the ordinate. 4.5.6 Expression of analysis results
Arsenic percentage (r) is calculated according to formula (4):
x=
Sample mass, g;
Formula Medium: m. —
m×10-9
mo
×100=
—The mass of arsenic in the sample found from the working curve, ug. mwww.bzxz.net
4.5.7 Allowable difference
m
mo
The average is the reported result. 4.6. Determination of oxide content in industrial synthetic hydrochloric acid using titration method. This method specifies the titration method to determine the oxide content in industrial synthetic hydrochloric acid. It is applicable to all levels of industrial synthetic hydrochloric acid. 4.6.1 Principle of the method
.(4)
Add potassium iodide solution to the sample solution to precipitate iodine. Use starch solution as an indicator and titrate the free iodine with sodium thiosulfate standard titration solution.
The reaction formula is as follows:
21- - 2e →2
Ia+20-+S,0+21
4.6.2 Reagents and materials||tt| |This method uses analytically pure reagents and boiled and cooled distilled water or water of corresponding purity. 4.6.2.1 Hydrochloric acid (GB622).
4.6.2.2 Potassium iodide (GB1272): 100g/L. Weigh 100g of potassium iodide and dissolve in water, dilute to 1000mL, and shake well. 4.6.2.3 Sodium sulfate sulfate (GB637): c(Na,S,0,)=0.1mol/L standard titration solution, prepared according to GB601. 4.6.2.4 Soluble starch (HGB3095): 10g/L solution, prepared according to GB603. This solution should only be kept for two weeks. 4.6.3 Instruments
General laboratory instruments and
4.6.3.1 Erlenmeyer flask: volume 500mL, with ground stopper.
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