Surface treatment solution—Determination of metal element contents—Inductively coupled plasma atomic emission spectrometric method
Some standard content:
ICS 25.220.40
People's Republic of China Baojia Luya
GB/T24916—2010
Surface treatment solution
Determination of metal element contents
Surface treatment solutionDetermination of metal element contents-Inductively coupled plasma atomic emission spectrometric method2010-08-09 Issued
General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China Standardization Administration of China
2010-12-31 Implementation
Normative references
Reagents and materials
Preparation
Preparation of standard solution
Preparation of standard working solution series for standard addition methodAnalysis conditions
Analysis steps
Blank test
Preparation and analysis of test solution
Calculation of results
Precision
Test report
Notes
GB/T24916—2010
This standard is proposed by China Machinery Industry Federation. Introduction
This standard is under the jurisdiction of the National Technical Committee for Standardization of Metallic and Non-metallic Coatings. Drafting unit of this standard: Chongqing Changan Automobile Co., Ltd. The main drafters of this standard are: Huang Xianming, Zhang Jianyang, Li Qihua, Yang Xuemei, Fan Chaoying, Zhu Jun. GB/T24916—2010
1 Scope
Determination of metal element content
Surface treatment solution
Inductively coupled plasma atomic emission spectrometry GB/T24916—2010
This standard specifies the method for determining the content of metal elements in surface treatment solutions by inductively coupled plasma atomic emission spectrometry. This standard is applicable to the determination of the content of metal elements such as aluminum, sodium, calcium, magnesium, iron, copper, chromium, lead, zinc, manganese, nickel, and antimony in surface treatment solutions. The determination range is shown in Table 1.
Measurement range/(g/L)
0, 000 020~5, 00
0, 000 010~5, 00
0, 000 020~5, 00
0, 000 010~5, 00
Normative reference documents
Measurement range
Measurement range/(g/L)Www.bzxZ.net
0, 000 016~5, 00
0, 000 010~20, 00
0, 000 040~5, 00
0, 000 020~5, 00
Measurement range/(g/L)
0, 000 010~5, 00
0, 000 010~~20, 00
0, 000 010~ 5, 00
0, 000 060~ 5, 00
The clauses in the following documents become the clauses of this standard through reference in this standard. For any dated referenced document, all subsequent amendments (excluding dated contents) or revisions are not applicable to this standard. However, the parties who reach an agreement based on this standard are encouraged to study whether the latest versions of these documents can be used. For any undated referenced document, the latest version is applicable to this standard. GB/T 6682
Specifications and test methods for water used in analytical laboratories (GB/T6682-2008, ISO3696:1987, MOD) 3 Principle
The sample is heated and decomposed with nitric acid and hydrogen peroxide to remove organic matter. After being treated with fuming perchloric acid and acidified with hydrochloric acid, the sample solution is evaporated and excited, emitting light with characteristic wavelengths of the elements contained. After being split by the spectroscopic system, the intensity of its spectral line is received by the photoelectric element and converted into an electrical signal and recorded. The content of each element is determined based on the relationship between the element concentration and the spectral line intensity. The standard addition method is used in the determination. 4 Reagents and materials
Unless otherwise specified, only analytically pure reagent hydrogen w(Ar) ≥99.99% is used in the analysis.
Water, in accordance with the specifications of secondary water in GB/T6682. Aluminum, w(A1) ≥99.95%.
Working standard reagent sodium chloride, solid.
Calcium carbonate, w(CaCO)≥99.95%.
Magnesium, w(Mg)≥99.95%.
Iron, te(Fe)≥99.95%.
Copper, (Cu)≥99.95%.
Chromium, w(Cr)≥99.95%.
Lead, w(Pb)≥99.95%.
Zinc, w(Zn)≥99.95%.
GB/T24916—2010
Manganese, w(Mn)≥99.95%.
Nickel, w(Ni)≥99.95%.
Antimony, w(Sb)≥99.95%.
Hydrochloric acid, oabout 1.19g/mL.
Nitric acid, p about 1.42g/mL.
Sulfuric acid, p about 1.84g/mL.
Perchloric acid, p about 1.67g/mL
30% hydrogen peroxide - p about 1.10g/mL.
Hydrogen peroxide solution (1 + 2).
Hydrochloric acid solution (1 + 1).
Hydrochloric acid solution (1 + 3).
Hydrochloric acid solution (1 + 5).
Hydrochloric acid solution (1 + 99).
Nitric acid solution (1 + 1).
Nitric acid solution (5 + 95).
Nitric acid solution (1 + 99).
Sulfuric acid solution (2 + 98).
Lithium chloride solution (5g/L).
5 Preparation
Preparation of standard solution
5.1.1 Aluminum standard solution
Weigh 1.0000g aluminum (4.3), heat and dissolve in 100mL hydrochloric acid solution (4.21), cool to room temperature, transfer to a 1000mL volumetric flask, dilute to scale with water, mix well. This solution contains 1mg aluminum in 1mL. 5.1.2 Sodium standard solution
Weigh 2.5421g of working standard reagent sodium chloride (4.4) burned at 500℃～600℃ to constant mass, dissolve in water, transfer to a 1000mL volumetric flask, dilute to scale with water, mix well, and store in a polyethylene bottle. This solution contains 1mg sodium in 1mL. 5.1.3 Calcium standard solution
Weigh 2.4970g of calcium carbonate (4.5) dried to a constant mass at 105℃~110℃, add about 50mL of water, then add hydrochloric acid (4.15) dropwise until the calcium carbonate is completely dissolved, then add 10mL of hydrochloric acid (4.15) in excess, cool to room temperature, transfer to a 1000mL volumetric flask, dilute to scale with water, mix, and store in a polyethylene bottle. This solution contains 1mg of calcium in 1mL. 5.1.4 Magnesium standard solution
Weigh 1.0000g of magnesium (4.6) and dissolve it in 60mL of hydrochloric acid solution (4.23) by heating, cool to room temperature, transfer to a 1000mL volumetric flask, dilute to scale with water, and mix. This solution contains 1mg of magnesium in 1mL. 5.1.5 Iron standard solution
Weigh 1.0000g of iron (4.7) and heat to dissolve in 50mL of nitric acid solution (4.25), cool to room temperature, transfer to a 1000mL volumetric flask, dilute to scale with water, and mix. This solution contains 1mg of iron in 1mL. 5.1.6 Copper standard solution
Weigh 1.0000g of copper (4.8) and heat to dissolve in 30mL of nitric acid solution (4.25), cool to room temperature, transfer to a 1000mL volumetric flask, dilute to scale with nitric acid solution (4.27), and mix. This solution contains 1mg of copper in 1mL. 5.1.7 Chromium standard solution
Weigh 1.0000g chromium (4.9) and heat it to dissolve in 30mL hydrochloric acid solution (4.21), cool to room temperature, transfer to a 1000mL volumetric flask, dilute to scale with water, and mix well. This solution contains 1mg chromium in 1mL.2
5.1.8 Lead standard solution
GB/T24916—2010
Weigh 1.0000g lead (4.10) and heat it to dissolve in 30mL nitric acid solution (4.25), cool to room temperature, transfer to a 1000mL volumetric flask, dilute to scale with water, and mix well. This solution contains 1mg lead in 1mL.5.1.9 Zinc standard solution
Weigh 1.0000g zinc (4.11) and heat it to dissolve in 30mL hydrochloric acid solution (4.21) or 30mL nitric acid solution (4.25), cool to room temperature, transfer to a 1000mL volumetric flask, dilute to scale with water, and mix. This solution contains 1mg zinc in 1mL. 5.1.10 Manganese standard solution
Weigh 1.0000g manganese (4.12) and heat to dissolve in 30mL hydrochloric acid solution (4.21) or 30mL nitric acid solution (4.25), cool to room temperature, transfer to a 1000mL volumetric flask, dilute to scale with water, and mix. This solution contains 1mg manganese in 1mL. 5.1.11 Nickel standard solution
Weigh 1.0000g nickel (4.13) and heat to dissolve in 30mL nitric acid solution (4.25), cool to room temperature, transfer to a 1000mL volumetric flask, dilute to scale with hydrochloric acid solution (4.24), and mix. 1 mL of this solution contains 1 mg of nickel. 5.1.12
Antimony standard solution
Weigh 1.0000 g of antimony (4.14) and heat to dissolve in 10 mL of hydrochloric acid (4.15) and 5.0 mL of hydrogen peroxide solution (4.20). Boil to remove hydrogen peroxide, cool to room temperature, transfer to a 1000 mL volumetric flask, dilute to scale with hydrochloric acid solution (4.22), and mix. 1 mL of this solution contains 1 mg of antimony.
5.2 Preparation of standard working solution series by standard addition method 5.2.1 Determination elements of various surface treatment solutions The determination elements of various surface treatment solutions in this standard are shown in Table 2. 5.2.2 Preparation of dilution solutions of gradient series of mixed standard working solutions According to Table 3, transfer aluminum, sodium, calcium and other standard solutions into three volumetric flasks to form a gradient series of mixed standard working solutions, add 3.00mL hydrochloric acid (4.15) and 1.00mL nitric acid (4.16), dilute with water to the scale, shake and store in a plastic bottle. Table 2 Determination elements of various surface treatment solutions Surface treatment solution name
Chromium plating solution
Nickel plating solution
Phosphating solution
Fluoroborate lead plating solution
Potassium salt zinc plating solution
Cyanide copper plating solution
Cyanide pin plating solution
Alkaline tin plating solution
Acidic tin plating solution
Acidic copper plating solution
Note: ★ is the determination element,
GB/T24916—2010
Unit is milliliter
Various surface treatment solutions mixed standard working solution gradient series Table 3
Absorbed standard solution volume | |tt||Surface treatment
Solution name
Chromium plating solution gradient series
Nickel plating solution gradient series
Ultrafiltrate gradient series
Phosphating solution gradient series
Fluoroborate lead plating
Solution gradient series
Potassium salt zinc plating solution gradient series
Cyanide copper plating solution gradient series
Cyanide radium plating solution gradient series
Alkaline tin plating solution series
Acidic tin plating solution gradient series
Acidic copper plating solution gradient series
Wavelength/nm
293.847,285.213,279. 553
267. 716,284. 325
293. 306,403. 076
Analysis conditions
Analysis spectrum of measured elements
Wavelength/nm
259.940,239.562,259.837
221. 647,231. 604,341. 476
Standard addition element concentration series
Instrument: Inductively coupled plasma atomic emission spectrometer. Light source: Argon plasma light source.
The working conditions of the instrument are as follows:
Analysis spectrum: The analysis spectrum of the elements to be determined is shown in Table 4; RF power: 950W~1200W;
Atomization pressure: 0.21MPa~0.24MPa;
Auxiliary gas flow rate: 1.0L/min;
Sample lifting volume: 1.4L/min~1.6L/min; Integration time: UV: 5s~8s; VIS: 5s~10s. Note: UV
Analysis steps
Ultraviolet light band; VIS—visible light band. Blank test
Carry out a blank test with the sample solution.
Pretreatment and preparation of analytical solution
Pretreatment and preparation of chromium plating analytical solution
7.2.1.1 Pretreatment
GB/T24916—2010
Wavelength/nm
317.933 (except zinc, nickel and lead plating), 336.229,422.673
Unit is microgram per milliliter
Put 5.00mL of sample (V) in a 150mL conical flask, add 5mL of water and 20mL of nitric acid (4.16). In a fume hood, heat to boil, cool slightly, add 2 mL of 30% hydrogen peroxide (4.19) in portions, boil for 3 min, cool slightly, add 5 mL of nitric acid (4.16), 5 mL of perchloric acid (4.18), heat and evaporate until perchloric acid smoke appears, until dry, cool slightly, add 20 mL of hydrochloric acid solution (4.21) to dissolve salts, boil for 2 min. Transfer to a 250 mL volumetric flask, dilute to scale with water, mix, this solution is the pretreatment test solution. 7.2.1.2 Preparation of analytical test solution
Pipette 10.00mL of pretreatment test solution (V) in 4 portions and place them in 4 100mL volumetric flasks. Do not add the standard solution of the element to be measured to one of them. Add 1.00mL of the gradient series of dilution solutions of the mixed standard working solution of the element to be measured to the other 3 volumetric flasks according to Table 3. Then, add 3.00mL of hydrochloric acid (4.15) and 1.00mL of nitric acid solution (4.16) to the 4 100mL volumetric flasks respectively, dilute to the scale with water, and shake well.
GB/T24916—2010
7.2.2 Pretreatment and preparation of nickel plating analytical test solution7.2.2.1 Pretreatment
Pipette 5.00mL of sample (V,) in a 150mL conical flask, add 5mL of water and 15mL of nitric acid (4.16). In a fume hood, heat to boil, cool slightly, add 3 mL of 30% hydrogen peroxide (4.19) in portions, boil for 3 min, cool slightly, add 5 mL of nitric acid (4.16), 5 mL of perchloric acid (4.18), heat and evaporate until perchloric acid smoke appears, until dry, cool slightly, add 20 mL of hydrochloric acid solution (4.21) to dissolve salts, boil for 2 min, cool to room temperature, transfer to a 250 mL volumetric flask, dilute to scale with water, and shake to hook. This solution is the pretreatment test solution. 7.2.2.2 Preparation of analytical solution
Pipette 10.00mL of pretreatment solution (V,) into 4 100mL volumetric flasks respectively, and perform the following treatment as in 7.2.1.2. 7.2.3 Pretreatment and preparation of ultrafiltrate analytical solution 7.2.3.1 Pretreatment
Pipette 10.00mL of sample (V,) into a 150mL conical flask, add 10mL of water and 20mL of nitric acid (4.16). In a fume hood, heat to boil, cool slightly, add 3 mL of 30% hydrogen peroxide (4.19) in portions, boil for 3 min, cool slightly, add 5 mL of nitric acid (4.16), 5 mL of perchloric acid (4.18), heat and evaporate until perchloric acid smoke appears, until dry, cool slightly, add 20 mL of hydrochloric acid solution (4.21) to dissolve salts, boil for 2 min, cool to room temperature, transfer to a 250 mL volumetric flask, dilute to scale with water, and shake to hook. This solution is the pretreatment test solution. 7.2.3.2 Preparation of analytical test solution
Pipette 10.00mL of pretreatment test solution (V2) in 4 portions and place them in 4 100mL volumetric flasks. The following treatment is the same as 7.2.1.2. 7.2.4 Pretreatment and preparation of phosphating solution analytical test solution 7.2.4.1 Pretreatment
Pipette 10.00mL of sample (V2) in a 150mL conical flask, add 10mL of water and 20mL of nitric acid (4.16). In a fume hood, heat to boil, cool slightly, add 3 mL of 30% hydrogen peroxide (4.19) in portions, boil for 3 min, cool slightly, add 5 mL of nitric acid (4.16), 5 mL of perchloric acid (4.18), heat and evaporate until perchloric acid smoke appears, until dry, remove and cool slightly, add 20 mL of hydrochloric acid solution (4.21) to dissolve the salts, boil for 2 min, cool to room temperature, transfer to a 250 mL volumetric flask, dilute to the mark with water, and shake. This solution is the pretreatment test solution. 7.2.4.2 Preparation of analytical test solution
Pipette 10.00 mL of pretreatment test solution (V,)) in 4 portions, place in 4 100 mL volumetric flasks, and perform the following treatments as in 7.2.1.2. 7.2.5 Pretreatment and preparation of fluoroborate lead plating analytical test solution 7.2.5.1 Pretreatment
Pipette 5.100mL test material (V1) is placed in a 150mL conical flask, and 5mL water and 20mL nitric acid (4.16) are added. In a fume hood, heat and boil, cool slightly, add 3mL of 30% hydrogen peroxide (4.19) in portions, and boil for 3min. Cool slightly, add 5mL nitric acid (4.16) and 5mL perchloric acid (4.18), heat and evaporate until perchloric acid smoke appears, until dry drops, remove and cool slightly, add 20mL hydrochloric acid solution (4.21) to dissolve salts, boil for 2min, transfer to a 250mL volumetric flask, dilute to the mark with water, mix well, and this solution is the pretreatment test solution. 7.2.5.2 Preparation of analytical test solution
Take 4 portions of 10.00mL pretreatment test solution (V2) respectively and place them in 4 100mL volumetric flasks. Add 2.00mL lithium chloride solution (4.29) respectively. The following treatment is the same as 7.2.1.2 and 7.2.6 Pretreatment and preparation of potassium salt zinc plating analysis test solution 7.2.6.1 Pretreatment
Put 5.00mL of sample (V,) in a 150mL conical flask, add 5mL water and 15mL nitric acid (4.16). Heat to boil in a fume hood, cool slightly, add 3mL of 30% hydrogen peroxide (4.19) in batches, and boil for 2min. Cool slightly, add 5mL nitric acid (4.16) and 5mL perchloric acid (4.18), heat and evaporate until perchloric acid smoke appears, until dry, remove and cool slightly, add 20mL hydrochloric acid solution (4.21) to dissolve salts, and boil for 2min. Remove and cool slightly, add 50mL water, filter into a 250mL volumetric flask, dilute to scale with water, mix well, and this solution is the pretreatment test solution.
7.2.6.2 Preparation of analytical test solution
Take 4 portions of 10.00mL pretreatment test solution (V,) and place them in 4 100mL volumetric flasks. Add 2.00mL lithium chloride solution (4.29) to each portion. The following treatment is the same as 7.2.1.2.6
7.2.7 Pretreatment and preparation of cyanide copper plating analytical test solution7.2.7.1 Pretreatment
GB/T24916—2010
Take 5.00mL of sample (V) in a 150mL conical flask and add 10mL water and 20mL nitric acid (4.16). Heat to boil in a fume hood, cool slightly, add 3mL of 30% hydrogen peroxide (4.19) in portions, and boil for 3 minutes. Cool slightly, add 5mL nitric acid (4.16), 5mL perchloric acid (4.18), heat and evaporate until perchloric acid smoke appears, until dry, cool slightly, add 20mL hydrochloric acid solution (4.21) to dissolve salts, boil for 2min, cool, transfer to a 250mL volumetric flask, dilute to scale with water, mix well, this solution is the pretreatment test solution. 7.2.7.2 Preparation of analytical test solution
Pipette 10.00mL of pretreatment test solution (V,)) 4 portions respectively, place in 4 100mL volumetric flasks, and the following treatment is the same as 7.2.1.2. 7.2.8 Pretreatment and preparation of cyanide plating analysis test solution 7.2.8.1 Pretreatment
Pipette 5.00mL of sample (V,) into a 150mL conical flask, add 10mL water, add 2mL hydrochloric acid (4.15) in a fume hood, and shake well. Add 20mL nitric acid (4.16), heat to boil, cool slightly, add 3mL 30% hydrogen peroxide (4.19) in portions, boil for 2min. Cool slightly, add 5mL nitric acid (4.16) and 5mL perchloric acid (4.18), heat and evaporate until perchloric acid smoke appears, until dry, cool slightly, add 20mL hydrochloric acid solution (4.21) to dissolve salts, boil for 2min, cool, transfer to a 250mL volumetric flask, dilute to scale with water, mix well, this solution is the pretreatment test solution.
7.2.8.2 Preparation of analytical solution
Pipette 10.00mL of pretreatment solution (V) in 4 portions, place in 4 100mL volumetric flasks, add 2.00mL of lithium chloride solution (4.29) in each portion, and perform the following treatments as in 7.2.1.2. 7.2.9 Pretreatment and preparation of alkaline tin plating analytical solution 7.2.9.1 Pretreatment
Pipette 5.00mL of sample (V,) in a 150mL conical flask, add 10mL of water and 2mL of hydrochloric acid (4.15), spread evenly. Heat to boil in a fume hood, cool slightly, add 3mL of 30% hydrogen peroxide (4.19) in portions, and boil for 2 minutes. Cool slightly, add 5mL nitric acid (4.16), 5mL perchloric acid (4.18), heat and evaporate until perchloric acid smoke appears, until dry, cool slightly, add 20mL hydrochloric acid solution (4.21) to dissolve salts, boil for 2min, transfer to a 250ml volumetric flask, dilute to scale with water, mix, this solution is the pretreatment test solution. 7.2.9.2 Preparation of analytical test solution
Pipette 10.00mL pretreatment test solution (V,) 4 times, place in 4 100mL volumetric flasks, and the following treatment is the same as 7.2.1.2. 7.2.10 Pretreatment and preparation of acidic tin plating analytical test solution 7.2.10.1 Pretreatment
Pipette 5.00mL sample (V,) into a 150mL conical flask, add 5mL water and 20mL nitric acid (4.16). In a fume hood, heat to boil, cool slightly, add 3 mL of 30% hydrogen peroxide (4.19) in portions, boil for 3 min, cool slightly, add 5 mL of nitric acid (4.16) and 5 mL of perchloric acid (4.18), heat and evaporate until perchloric acid fumes appear. Remove from the heat and cool slightly, add 20 mL of hydrochloric acid solution (4.21) to dissolve the salts, boil for 2 min, transfer to a 250 mL volumetric flask, dilute to the mark with water, mix well, and this solution is the pretreatment test solution. 7.2.10.2 Preparation of analytical test solution
Pipette 10.00mL of pretreatment test solution (V,) in 4 portions and place them in 4 100mL volumetric flasks. The following treatment is the same as 7.2.1.2. 7.2.11 Pretreatment and preparation of acid copper plating analytical test solution 7.2.11.1 Pretreatment
Pipette 5.00mL of sample (V,) in a 150mL conical flask, add 5mL of water and 20mL of nitric acid (4.16). In a fume hood, heat to boil, cool slightly, add 3 mL of 30% hydrogen peroxide (4.19) in portions, boil for 3 min, cool slightly, add 5 mL of nitric acid (4.16), 5 mL of perchloric acid (4.18), heat and evaporate until perchloric acid smoke appears, until dry, remove and cool slightly, add 40 mL of hydrochloric acid solution (4.21) to dissolve the salts, boil for 2 min, transfer to a 250 mL volumetric flask, dilute to the mark with water, mix well and this solution is the pretreatment test solution. 7.2.11.2 Preparation of analytical test solution
Pipette 10.00 mL of pretreatment test solution (V2) in 4 portions, place in 4 100 mL volumetric flasks, and the following treatment is the same as 7.2.1.2. GB/T24916—2010
7.3 Determination
7.3.1 Spectral line calibration
Calibrate the analytical spectrum of the element to be measured.
7.3.2 Determination
7.3.2.1 Power on the instrument for preheating. After the temperature of the optical chamber is stable, first pass argon gas for 30 minutes and then ignite. After burning for 15 minutes to 30 minutes, conduct detection.
7.3.2.2 Open the instrument analysis control interface of the computer, create a new standard addition method, select the corresponding analysis line in Table 4, enter the parameter values in the recommended instrument working conditions (see 6.3), and then enter the values of each element to be measured in the standard addition element concentration series in Table 5 in turn. 7.3.2.3 Conduct plasma spectrum measurement, and each sample shall be measured at least 3 times in a row. 7.3.2.4 During the measurement process, necessary corrections shall be made to the peak position and background interference of each analysis line of the element to be measured. 7.3.2.5 Re-determination of each element in the solution to be tested According to the measured element content value and the principle of the standard addition method, adjust the corresponding values in Table 3 and Table 5, and re-prepare the analysis test solution (7.2). Re-enter the values of each element in Table 5 after adjustment into the computer, and then re-measure. 8 Result calculation
8.1 Calculation
Calculate the content of the element in the sample according to the following formula: (Pms-rsn)×100×10-1_2
25×(pus-Pem)
Vi×250
Where:
The content of the element in the original sample solution, in grams per liter (g/L); P
The content of the element in the analytical solution, in micrograms per milliliter (ug/mL); Pis
P————The content of the element in the blank solution, in micrograms per milliliter (μg/mL); V,————The volume of the original sample solution, in milliliters (mL); V. --The volume of the test solution taken, in milliliters (mL). 8.2 Precision
Element content is less than 0.
When the element content is between 0.0001g/L and 0.01g/L, the absolute value of the difference between the two independent determination results obtained under repeated conditions should not exceed 40% of the arithmetic mean.
When the element content is between 0.0001g/L and 0.01g/L, the absolute value of the difference between the two independent determination results obtained under repeated conditions should not exceed 20% of the arithmetic mean.
When the element content is between 0.01g/L and 1.00g/L, the absolute value of the difference between the two independent determination results obtained under repeated conditions should not exceed 15% of the arithmetic mean.
When the element content is between 1.00g/L and 5.00g/L, the absolute value of the difference between the two independent determination results obtained under repeated conditions should not exceed 10% of the arithmetic mean.
When the element content is greater than 5.00g/L, the absolute value of the difference between the two independent determination results obtained under repeated conditions should not exceed 20% of the arithmetic mean.
9 Test report
The test report shall include the following:
All information required to identify the sample, laboratory and test date: Reference to the method used in this standard;
Test results and expression;
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