Some standard content:
ICS 13.300;71.100.40
National Standard of the People's Republic of China
GB/T 22237—2008
Surface active agents
Determination of surface tension
Surface active agents--Determination of surface tension Issued on 2008-06-19
General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China Administration of Standardization of the People's Republic of China
Implementation on 2008-09-01
GB/T 22237—2008
This standard is equivalent to BSEN14370:2004 Surface active agents-Determination of surface tension (English version). For ease of use, the following editorial changes have been made to this standard: the foreword and introduction of the original standard have been deleted;
b) the table of contents of the original standard has been deleted;
c) the decimal point ',\ is used instead of the comma, which is used as a decimal point. This standard is proposed and managed by the National Technical Committee for Standardization of Dangerous Chemicals Management (SAC/TC251). The drafting units of this standard are China National Chemical Standardization Research Institute and Jiangsu Exit-Entry Inspection and Quarantine Bureau. The main drafters of this standard are Tang Lijun, Wang Xiaobing, Liu Junfeng, Mei Jian, Chen Ming, Zhou Wei, Wang Hongsong, Zhang Junxi and Wang Rong. This standard is published for the first time.
1 Scope
Determination of surface tension of surfactants
This standard specifies the method for determining the surface tension of liquids, especially surfactant solutions. This standard is applicable to the determination of static surface tension of liquids, such as inorganic or organic liquids and solutions. 2 Normative references
GB/T22237—2008
The clauses in the following documents become the clauses of this standard through reference in this standard. For all referenced documents in the note period, all subsequent amendments (excluding errata) or revisions are not applicable to this standard. However, parties to an agreement based on this standard are encouraged to study whether the latest versions of these documents can be used. For undated references, the latest edition of the referenced document applies to this standard. ISO 304:1985 Detergents — Determination of surface tension — Ring pull-up method 3 Principle
3.1 The surface tension F of a plate in vertical contact with a liquid and completely wetted is measured (static method) or the surface tension F required to pull a horizontally suspended mirror or ring out of the liquid surface is measured (quasi-static method), see references [1] and [2]. The surface tension is calculated using the corresponding formula, see Chapter 8. 3.2 In the static method, the plate is kept fixed in order to obtain an equilibrium value. The quasi-static method requires the movement of the mirror or ring during the measurement process, so the deviation from equilibrium is minimized by very small and slow movements of the mirror or ring during the measurement process.
4 Apparatus
4.1 Tension The tensiometer should be designed according to the plate, stack or ring to be tested and generally consists of the following main parts: a) A small horizontal platform for supporting the sample container and which can be moved up and down, for example by means of a micrometer. b) A device for measuring the force exerted on the plate, stack or ring. The uncertainty of measurement should not exceed ± 10-6 N and the maximum error in relative mass measurement should be ± 0.1 mg. NOTE A beam balance or an electronic balance (laboratory balance, analytical balance or microbalance) can be used instead of a torsion balance. For greater efficiency and repeatability, an automatic tensiometer with a balance, automatic lifting platform and evaluation device can be used. 4.2 Plate
The plate should be made of platinum or platinum/iridium sheet, about 20 mm long, 0.2 mm thick, at least 10 mm high and preferably roughened to improve wetting.
Note: In order to obtain the ideal roughing effect, a spray gun or gold pot sand can be used for grinding. The plate should be suspended with a point on the axis as the center, and the effective height should be at least 10 mm to minimize the wetting error, as shown in Figure 1. GB/T 22237—2008
4.3 Plate
Figure 1 Schematic diagram of plate
Unit: mm
The plate should be made of platinum wire or platinum/iridium wire. The diameter of the measuring wire is 0.1 mm ± 0.01 mm, the length is between 10 mm and 40 mm, and the two side frames are at least 10 mm long. Note: Two small platinum balls can be tied to the bottom of the two side frames as relative measurement or the two frames can be connected by a platinum wire, as shown in Figure 2.
Unit: mm
0.↓±0.01
Figure 2 Key
4.4 Ring
The ring should be made of platinum wire or platinum/iridium wire, with a thickness not exceeding 0.4 mm and an average circumference of 60 mm, for example: inner diameter 18.7 mm, outer diameter 19.5 mm. The ring must be suspended horizontally on a wire frame on a metal sample connected to the tensiometer, as shown in the example in Figure 3.
1 Metal building
2——Wire frame;
3——Ring.
4.5 Sample container
Figure 3 Measuring ring of tensiometer
GB/T22237—2008
Unit: mm
The sample container for liquids must be a glass container and should be suitable for use in an automatic thermostat. The volume of the sample container should be large enough and the temperature of the gas phase above the liquid level should also be kept constant by an automatic thermostat. If measurements are taken at room temperature, there is no need for an automatic thermostat. The sample container should consist of a cylindrical glass container with an inner diameter of at least 45 mm. Note: If a container with an inner diameter less than 45 mm must be used (e.g. only a small amount of sample is available), this effect will cause errors in the surface tension measurement, depending on the distance between the container wall and the edge of the object or shape. 5 Preparation of the instrument
5.1 Cleaning
5.1.1 First, thoroughly clean the glass container with a suitable solvent, such as isopropyl alcohol or acetone, then rinse with distilled water and dry. 5.1.2 Clean the plate, lamp or ring in a similar manner and then heat it in a methanol or ethanol flame, preferably ethanol because of its low vapor pressure and high flash point, to a red-hot temperature and to a non-luminous natural gas flame. It is only necessary to heat it to red heat, not to white heat. Note: To remove contaminants such as silica or calcium surface agents from the surface of the plate, bell or ring, a mixture of sulfuric acid and hydrochloric acid may be used for cleaning or according to ISO304.
5.2 Test preparation
5.2.1 Principle
The zero point of the instrument used needs to be calibrated. Adjust the tensiometer so that the measurement results are reliable and directly displayed in mN/m. 3
GB/T 22237—2008
5.2.2 Horizontal adjustment
The instrument is horizontally balanced by adjusting the screws at the bottom of the instrument. A protective cover can be used to prevent airflow. Note: The instrument should be installed with rubber pads at the bottom and placed on a 30 kg stone plate to avoid mechanical shock and vibration. 5.2.3 Zero point adjustment
When adjusting the zero point of the tensiometer, the following points should be considered: If a flat plate is used
The instrument zero point should be adjusted after the flat plate is installed. b) If a lamp-shaped object is used, the zero point of the instrument should be adjusted when the button is immersed to the depth at which the tension is maximum. This eliminates the need to correct for the buoyancy caused by the volume of the immersed connecting wire or the two platinum frames. Note: At the time of maximum tension, the thin layer extending from the measuring wire will be destroyed or if no thin layer is formed, the height of the tensiometer platform can be fixed by measuring the screws, see 4.1. c) If a ring-shaped object is used, the zero point of the instrument should be adjusted after the ring is installed. 5.2.4 Calibration procedure
The torsion balance can be calibrated by one of the following two methods. a) Place an object with a known mass between 0.1 B and 1.0 Å on the plate, mirror or ring. This method is more time-consuming, but the potential error is lower.
The instrument parameters can also be calculated according to formula (1), and the measured value should be multiplied by the medium. ：d.
Where:
m, XE
mass of the added object, in grams (g); -gravitational acceleration,981 cm/s3
The wetted portion of a plate, bell or ring, twice the length of the plate, twice the thickness of the plate, or twice the length of the measuring line in a bell or ring, or twice the average circumference of a ring, in centimeters (cm)d,-The reading of the tensiometer when the object is placed on the plate, bell or ring, in mN/m. Use a pure substance with known tension. The density of the pure calibration substance used must be consistent with the density of the sample to be measured to avoid different tensions. The instrument parameters can be calculated according to formula (3), and the measured value should be multiplied by: pure
Where:
-theoretical value of surface tension
-the actual measured value of surface tension.
Note: The automatic tensiometer can be calibrated by the setting of the pressure divider, so that the subsequent readings do not need to be converted. 6 Sample preparation
6.1 Prepare the aqueous solution with double distilled water. ++*++++++( 3 )
6.2 During the entire measurement process, adjust the temperature of the solution so that it is homogeneous at the given concentration and the temperature change of the solution is within ±0.5℃. Micelles should not be considered as a separate phase in this standard. If the solution has an upper solubility limit, such as the aqueous solution of ethylene oxide, the measurement should be selected at a temperature below the upper limit. Choose an appropriate measurement temperature. Measuring at room temperature will cause the least problems. Use a constant temperature jacket to keep the sample temperature constant during the measurement. Note: For every 1°C change in temperature, the surface tension will change by at least 0.1 mN/m. For pure water, equation (4) holds true: - 0.15
GB/T 22237--2008
6.3 Because the surface tension of a solution changes with time and the chemical properties of the surfactant, of which the concentration and adsorption capacity of the surfactant are the most important, it is impossible to specify an exact time to start the measurement. The surface tension is a function of time and needs to be measured repeatedly during the measurement process. Generally, the system has a characteristic: after a period of time, the system reaches equilibrium and the surface tension does not change.
Note: For time-based measurements, the static plate method is an option. If an automatic tensiometer is used, the quasi-static method and the static method can be regarded as the number of times, such as ±/t-
6.4 The surface tension of surfactants is very sensitive to contamination, such as dust or solvent vapor in the air. Therefore, do not use volatile agents in the measuring room. Use a bell-shaped cover to protect the instrument from time to time. This will help to keep the instrument at a constant temperature. 7 Procedure
7.1 General
Check the repeatability of the method by making several consecutive measurements under the same conditions. Carefully transfer the liquid to be measured into a clean sample container and place the sample container on the platform of the tensiometer. 7.2 Plate method
7.2.1 In the static method, move the sample container so that the plate is in contact with the liquid. To avoid measurement errors caused by buoyancy, make sure that the lowest part of the plate is at the same height as the liquid surface. Record the current reading, which is proportional to the surface tension. 7.2.2 To check whether the plate is fully wetted, touch the plate with the liquid, record the current reading, and then raise the container containing the liquid to be measured by 2 mm and then lower it to its original height. The lowest part of the plate is at the same height as the liquid surface. The instrument reading should now be the same as the initial reading. If the plate is not completely wetted or the concave meniscus of the surfactant solution is not level, re-clean the apparatus as in step 5.1.
7.3 Forged object/ring method
7.3.1 Raise the sample container on the platform so that the forged object/ring is below the level of the solution to be measured. 7.3.2 If a torsion balance is used, during the measurement the torque of the measuring line should be increased and read on the instrument, while the level of the liquid should be lowered to keep the balance beam of the torsion balance in the same position. The maximum force required to pull the forged object/ring out of the liquid is recorded as the measured value. If the solution forms a film, avoid the film from separating and re-immerse the forged object/ring in the liquid after the measurement. This will reduce the disturbance of the adsorption equilibrium on the liquid surface after the measurement. 7.3.3 To obtain an accurate surface tension, measure the maximum force required to pull the forged object/ring out of the liquid. During manual filling, the film can easily separate and must be operated very slowly. The measured value before the film separates is not equal to the maximum value, and is usually ten times smaller than the maximum value. The automatic tensiometer can automatically measure the maximum value and quickly control the platform to move in the opposite direction before the film separates. Therefore, the automatic tensiometer can obtain a reliable and consistent series of measurement data without destroying the film. 7.3.4 When measuring with shapes/rings, the surface area of the liquid will increase. If the rate at which the surfactant diffuses to the surface is slower than the rate at which the surface is formed, measurement errors will occur. Generally, only very dilute surfactant solutions will take into account the above errors and the speed is faster than the critical micelle concentration.
7.3.5 In addition, the kinetic process of establishing half-equilibrium should be taken into account. Usually, when the solution concentration is greater than or around the critical micelle concentration, the establishment of equilibrium is very rapid. With increasing dilution and molecular size, especially for water-soluble surfactants, the time required to reach equilibrium increases, sometimes up to several hours. Therefore, when measuring, it is necessary to ensure that the equilibrium value has been achieved. 7.3.6 Automatic tensiometers with built-in evaluation devices can check whether equilibrium has been established by screening multiple measurements (such as five measurements). If the standard deviation of multiple measurements is lower than a specified value, such as 0.1 mN/m, the measurement can be ended. The surface tension of the static method should be the average of the last five measurements.
GB/T 22237—2008
8 Result expression
8. 1 General
For more practicality, all calculation units in this standard are centimeters, grams, and seconds, such as g=981cm/s°, the diameter of the wire d=0.0370cm, so the unit of surface tension is mN/m, 1mN/m=1dyn/cm. The surface tension can be calculated according to formula (5) in mN/m: a
where:
F—the force acting on the plate, forged object or ring, in Newton (N); m—the mass of the liquid pulled up by the plate, forged object or ring, in grams (g); g—the acceleration due to gravity, 981cm/g:
{--the wetted portion of the outer periphery of the plate, forged object or ring, specifically twice the length of the plate, twice the thickness of the upper surface, or twice the length of the measuring line in a forged object, or twice the average circumference of a ring, in centimeters (cm). 8.2 Plate method
When using formula (5) to evaluate the test results, the instrument parameters, see 5.2.4, must be taken into account. 8.3 Short object method
Taking the instrument parameters, see item a) of 5.2.4 into account, the value calculated according to formula (5) is only an approximate value and should be corrected according to Leonard 1 formula (6):
o =a-号×(V2axpxg-4)+d××pxg4
wherein,
o——surface tension after correction according to formula (6), unit is millinewton meter (mN/m) (6)
c——surface tension calculated according to formula (5) taking into account the instrument parameters, see item a) of 5.2.4, unit is millinewton meter (mN/m);
d——diameter of the measuring line in the lamp-shaped object, unit is meter (cm);β——density of the measured liquid, unit is gram per centimeter (g/cm);g——direct force acceleration, 981cm/s;
1 length of the line in the lamp-shaped object, unit is centimeter (cm)If correction is performed according to item b) of 5.2.4, there is no need to calibrate according to formula (6). At this time, the original value obtained by formula (5) only needs to be multiplied by the instrument parameters
8.4 Ring method
8.4.1 Taking the instrument coupon number (see item a) or item b) of 5.2.4) into consideration, c calculated according to formula (5) is also an approximate value, and the following four parameters should be considered for correction: original surface tension, density P, diameter D of the ring and diameter d of the ring line. Note that if the ring method is used, formula (5) can also be expressed as formula (7): F
0=2 yuan
where;
D-diameter of the ring, in centimeters (cm). -(7)
8.4.2 Formula (7) is also only a rough approximation, because it is determined before the liquid film separates, and the surface tension acts on the inner and outer edges of the ring. But in fact, since the concave liquid surface is not symmetrical, the assumption does not hold. Therefore, a correction factor f needs to be introduced in formula (7). 8.4.3 Harkins and Jordan-tl have calculated that f is a function of D/V and D/d, where V is m/p (i.e. the volume of liquid pulled out by the ring immediately before the film separates), D is the diameter of the ring, d is the diameter of the line in the ring, m is the mass of the liquid pulled out by the ring. Reference [10] gives empirical values of D/V and D/d in a broad range of domestic applications.
GB/T22237—2008
8.4.4 Zuidema and Waters reported a reasoning equation for low D°/V values, while Fox and Chrisman reported a reasoning equation for high D'/V values [13]. Automatic tensiometers with built-in evaluation devices have corresponding software to perform the necessary corrections. For example, the method reported by Zuidema and Waters can be used for correction. If f must be calculated based on the table in reference [1o] for each measurement, it will be very cumbersome. It is therefore more convenient to use the table provided by Finzel and Seemann in reference [10] to calibrate the surface tension directly. This assumes that the instruments used have been calibrated according to item a) of 5.2.4. For relative measurements, they can also be calibrated according to item b) of 5.2.4. 8.4.5 The corrected surface tension of water or aqueous solution (density, p1 cm2) obtained by the ring method (ring diameter D = 19.100 mm, line diameter d = 0.370 mm) is shown in Table 1. Where is the measured value multiplied by , or (see 5.2.4); is the surface tension obtained by calibrating according to the method in reference [13] for the steps of item a) or item b) of 5.2.4, and has been normalized to the surface tension of 20°C water, 72.0 mN/m. Table 1 Corrected surface tension of water or aqueous solution (density, p1 g/cm2) obtained by the ring method (diameter of the ring D = 19.100 mm; diameter of the line in the ring {= 0.370 mu n) a
(mN/n)
9 Precision
5.2.4 a)
(mN/m)
(mN/m)
9.1 The uncertainty of the surface tension determination of this standard depends mainly on the properties of the liquid to be measured. 5.2.4 a)
(mN/m）
5.2, 1 b)
9.2 If the liquid is physically pure, the uncertainty of the correction using item a) in 5.2.4 is ±0.1 mN/m. In this standard, a liquid with pure physical properties refers to a liquid that does not contain any foreign compounds that affect the surface properties. 9.3 The surface tension of a solution varies greatly as a function of time, especially for surfactants with relatively large molecules and solution concentrations far below the critical micelle concentration. This change is more obvious. For this type, a relatively long waiting time is required before measurement, and the same retention time should be maintained in continuous multi-pass measurements, see references! 14 and 1519. 4 During the measurement, a small amount of highly surface-active contaminants in the sample to be measured will accumulate on the surface of the liquid to a concentration exceeding the concentration of the substance to be measured itself. This situation will cause measurement errors, so the top layer of the liquid is continuously pumped away with a water pump during the measurement process to completely avoid this source of error.
GB/T 22237—2008
Test report
The test report should contain the following information!
Reference to this standard;
Type, name and purity of solute;
Type, name and purity of solvent;
Concentration of solvent;
Test temperature;
How long the surface is formed during the actual measurement;
Time required for equilibrium to be established before measurement; Calibration used;
Method of measurement adopted (plate method, lamp method or ring method); Value and arithmetic mean of the surface tension for each measurement: if possible, the mean and standard deviation of the last five measurements; Any deviation from this standard;
Date of test.
Food examination literature
GB/T22237—2008
[1] Padday,JF in Surface and Colloid Science, edited by Matjevic,E.; industrial chemistry),3r cd, ,vol. I /1,1961,770-776.[3] Stahlbergcr,B. Guyer,A, Helvet, Chim, Acta,1950,33.243.[4] | |tt | 4.220.[7]
Schwuger,MJ ,Rostek,H, M. Chemie-Ing. Techn. ,1971,43 1075Lenard,P.Ann.Phys..1924,74.381[8]bzxz.net
Du Nouy,PL Gen, Physiol, , New York, 1919,1.1751.[1o]Harkins,WD,Jordan,HFJAmer.Chem.Soc.,193o,52.1751.[11] Zuidema,H.; Warers,CW Ind. Eng. Chem, Analyt. Edit.,1941,13:312.[12] Fox,HW,Chrisman jr,CHJPhys.Chcm.,1952, 56.284. [13] Finzel, R.; Seemann, FWPTB-Mitt., 1977, 87.296. Lunkcnhcimcr,K. \On the determination of eguilibrium surlace tension val-ues of surfactant solutions\,Colloid & Science.1983,261,585.4 Zuidema and Waters reported the inference equation E111 for relatively low values of D°/V, while Fox and Chrisman reported the inference equation for relatively high values of D'/V [13]. Automatic tensiometers with built-in evaluation devices have corresponding software to perform the necessary corrections. For example, the method reported by Zuidema and Waters can be used for correction. It would be very cumbersome if f had to be calculated according to the table in reference [1o] for each measurement. It is therefore more convenient to directly use the table provided by Finzel and Seemann in reference [10] to correct the surface tension. This assumes that the instruments used have been calibrated according to item a) of 5.2.4. For relative measurements, they can also be calibrated according to item b) of 5.2.4. 8.4.5 The corrected surface tension of water or aqueous solution (density, p1 cm2) obtained by the ring method (diameter of the ring D = 19.100 mm, diameter of the wire in the ring d = 0.370 mm) is shown in Table 1. where is the measured value multiplied by . or , (see 5.2.4); is the surface tension obtained after correction according to the method in reference [13] for the procedure of item a) or item b) in 5.2.4, and has been normalized to the surface tension of water at 20°C, 72.0 mN/m. Table 1 Corrected surface tension of water or aqueous solution (density, p1 g/cm2) obtained by the ring method (diameter of the ring D = 19.100 mm; diameter of the wire in the ring {= 0.370 mu n) a
(mN/n)
9 Precision
5.2.4 a)
(mN/m)
(mN/m)
9.1 The uncertainty of the surface tension determination of this standard depends mainly on the properties of the liquid to be measured. 5.2.4 a)
(mN/m）
5.2, 1 b)
9.2 If the liquid is physically pure, the uncertainty of the correction using item a) in 5.2.4 is ±0.1 mN/m. In this standard, a physically pure liquid is one that does not contain any foreign compounds that affect the surface properties. 9.3 The surface tension of a solution varies greatly as a function of time. This is especially true for surfactants with large molecules and solution concentrations far below the critical micelle concentration. For this type of solution, a relatively long waiting time is required before the measurement. The retention time should be kept the same in consecutive multiple measurements. See references 14 and 1519.4 During the measurement, small amounts of highly surface-active contaminants in the sample to be measured can accumulate on the surface of the liquid to a concentration that exceeds the concentration of the substance to be measured. This can cause measurement errors. Therefore, the uppermost layer of the liquid is continuously pumped away during the measurement to completely avoid this source of error.
GB/T 22237—2008
Test report
The test report should contain the following information!
References to this standard;
Type, name and purity of the solute,
Type, name and purity of the solvent,
Concentration of the solvent;
Test temperature;
How long the surface is formed during the actual measurement;
Time required for equilibrium to be established before measurement; Correction used;
Measurement method (plate method, lamp method or ring method); Value and arithmetic mean of the surface tension for each measurement: If possible, the average and standard deviation of the last five measurements; Any deviation from this standard;
Test date.
Food examination literature
GB/T22237—2008
[1] Padday,JF in Surface and Colloid Science, edited by Matjevic,E.; industrial chemistry),3r cd, ,vol. I /1,1961,770-776.[3] Stahlbergcr,B. Guyer,A, Helvet, Chim, Acta,1950,33.243.[4] | |tt | 4.220.[7]
Schwuger,MJ ,Rostek,H, M. Chemie-Ing. Techn. ,1971,43 1075Lenard,P.Ann.Phys..1924,74.381[8]
Du Nouy,PL Gen, Physiol, , New York, 1919,1.1751.[1o]Harkins,WD,Jordan,HFJAmer.Chem.Soc.,193o,52.1751.[11] Zuidema,H.; Warers,CW Ind. Eng. Chem, Analyt. Edit.,1941,13:312.[12] Fox,HW,Chrisman jr,CHJPhys.Chcm.,1952, 56.284. [13] Finzel, R.; Seemann, FWPTB-Mitt., 1977, 87.296. Lunkcnhcimcr,K. \On the determination of eguilibrium surlace tension val-ues of surfactant solutions\,Colloid & Science.1983,261,585.4 Zuidema and Waters reported the inference equation E111 for relatively low values of D°/V, while Fox and Chrisman reported the inference equation for relatively high values of D'/V [13]. Automatic tensiometers with built-in evaluation devices have corresponding software to perform the necessary corrections. For example, the method reported by Zuidema and Waters can be used for correction. It would be very cumbersome if f had to be calculated according to the table in reference [1o] for each measurement. It is therefore more convenient to directly use the table provided by Finzel and Seemann in reference [10] to correct the surface tension. This assumes that the instruments used have been calibrated according to item a) of 5.2.4. For relative measurements, they can also be calibrated according to item b) of 5.2.4. 8.4.5 The corrected surface tension of water or aqueous solution (density, p1 cm2) obtained by the ring method (diameter of the ring D = 19.100 mm, diameter of the wire in the ring d = 0.370 mm) is shown in Table 1. where is the measured value multiplied by . or , (see 5.2.4); is the surface tension obtained after correction according to the method in reference [13] for the procedure of item a) or item b) in 5.2.4, and has been normalized to the surface tension of water at 20°C, 72.0 mN/m. Table 1 Corrected surface tension of water or aqueous solution (density, p1 g/cm2) obtained by the ring method (diameter of the ring D = 19.100 mm; diameter of the wire in the ring {= 0.370 mu n) a
(mN/n)
9 Precision
5.2.4 a)
(mN/m)
(mN/m)
9.1 The uncertainty of the surface tension determination of this standard depends mainly on the properties of the liquid to be measured. 5.2.4 a)
(mN/m）
5.2, 1 b)
9.2 If the liquid is physically pure, the uncertainty of the correction using item a) in 5.2.4 is ±0.1 mN/m. In this standard, a physically pure liquid is one that does not contain any foreign compounds that affect the surface properties. 9.3 The surface tension of a solution varies greatly as a function of time. This is especially true for surfactants with large molecules and solution concentrations far below the critical micelle concentration. For this type of solution, a relatively long waiting time is required before the measurement. The retention time should be kept the same in consecutive multiple measurements. See references 14 and 1519.4 During the measurement, small amounts of highly surface-active contaminants in the sample to be measured can accumulate on the surface of the liquid to a concentration that exceeds the concentration of the substance to be measured. This can cause measurement errors. Therefore, the uppermost layer of the liquid is continuously pumped away during the measurement to completely avoid this source of error.
GB/T 22237—2008
Test report
The test report should contain the following information!
References to this standard;
Type, name and purity of the solute,
Type, name and purity of the solvent,
Concentration of the solvent;
Test temperature;
How long the surface is formed during the actual measurement;
Time required for equilibrium to be established before measurement; Correction used;
Measurement method (plate method, lamp method or ring method); Value and arithmetic mean of the surface tension for each measurement: If possible, the average and standard deviation of the last five measurements; Any deviation from this standard;
Test date.
Food examination literature
GB/T22237—2008
[1] Padday,JF in Surface and Colloid Science, edited by Matjevic,E.; industrial chemistry),3r cd, ,vol. I /1,1961,770-776.[3] Stahlbergcr,B. Guyer,A, Helvet, Chim, Acta,1950,33.243.[4] | |tt | 4.220.[7]
Schwuger,MJ ,Rostek,H, M. Chemie-Ing. Techn. ,1971,43 1075Lenard,P.Ann.Phys..1924,74.381[8]
Du Nouy,PL Gen, Physiol, , New York, 1919,1.1751.[1o]Harkins,WD,Jordan,HFJAmer.Chem.Soc.,193o,52.1751.[11] Zuidema,H.; Warers,CW Ind. Eng. Chem, Analyt. Edit.,1941,13:312.[12] Fox,HW,Chrisman jr,CHJPhys.Chcm.,1952, 56.284. [13] Finzel, R.; Seemann, FWPTB-Mitt., 1977, 87.296. Lunkcnhcimcr,K. \On the determination of eguilibrium surlace tension val-ues of surfactant solutions\,Colloid & Science.1983,261,585.370 mun) after the correction of the surface tension a
(mN/n)
9 Precision
5. 2. 4 a)
(mN/m)
(mN/m)
9.1 The uncertainty of the surface tension determination of this standard depends mainly on the properties of the liquid to be measured. 5. 2. 4 a)
(mN/m）
5. 2, 1 b)
9.2 If the liquid is physically pure, the uncertainty of the correction using item a) in 5.2. 4 is ±0.1 mN/m. In this standard, a physically pure liquid means a liquid that does not contain any foreign compound on the surface that affects the surface properties. 9.3 The surface tension of a solution varies greatly as a function of time. This change is particularly evident for surfactants whose molecules are relatively large and whose solution concentration is far below the critical micelle concentration. For this type, it is necessary to wait for a relatively long time before measuring, and keep the same retention time in continuous multi-pass measurements, see references! 14 and 1519. 4 During the measurement process, a small amount of highly surface-active contaminants in the sample to be measured will accumulate on the liquid surface to a concentration that exceeds the concentration of the substance to be measured. This situation will cause measurement errors, so the top layer of the liquid is continuously pumped away with a water pump during the measurement process to completely avoid this source of error.
GB/T 22237—2008
Test report
The test report should contain the following information!
Reference to this standard;
Type, name and purity of solute;
Type, name and purity of solvent;
Concentration of solvent;
Test temperature;
How long the surface is formed during the actual measurement;
Time required for equilibrium to be established before measurement; Calibration used;
Method of measurement adopted (plate method, lamp method or ring method); Value and arithmetic mean of the surface tension for each measurement: if possible, the mean and standard deviation of the last five measurements; Any deviation from this standard;
Date of test.
Food examination literature
GB/T22237—2008
[1] Padday,JF in Surface and Colloid Science, edited by Matjevic,E.; industrial chemistry),3r cd, ,vol. I /1,1961,770-776.[3] Stahlbergcr,B. Guyer,A, Helvet, Chim, Acta,1950,33.243.[4] | |tt | 4.220.[7]
Schwuger,MJ ,Rostek,H, M. Chemie-Ing. Techn. ,1971,43 1075Lenard,P.Ann.Phys..1924,74.381[8]
Du Nouy,PL Gen, Physiol, , New York, 1919,1.1751.[1o]Harkins,WD,Jordan,HFJAmer.Chem.Soc.,193o,52.1751.[11] Zuidema,H.; Warers,CW Ind. Eng. Chem, Analyt. Edit.,1941,13:312.[12] Fox,HW,Chrisman jr,CHJPhys.Chcm.,1952, 56.284. [13] Finzel, R.; Seemann, FWPTB-Mitt., 1977, 87.296. Lunkcnhcimcr,K. \On the determination of eguilibrium surlace tension val-ues of surfactant solutions\,Colloid & Science.1983,261,585.370 mun) after the correction of the surface tension a
(mN/n)
9 Precision
5. 2. 4 a)
(mN/m)
(mN/m)
9.1 The uncertainty of the surface tension determination of this standard depends mainly on the properties of the liquid to be measured. 5. 2. 4 a)
(mN/m）
5. 2, 1 b)
9.2 If the liquid is physically pure, the uncertainty of the correction using item a) in 5.2. 4 is ±0.1 mN/m. In this standard, a physically pure liquid means a liquid that does not contain any foreign compound on the surface that affects the surface properties. 9.3 The surface tension of a solution varies greatly as a function of time. This change is particularly evident for surfactants whose molecules are relatively large and whose solution concentration is far below the critical micelle concentration. For this type, it is necessary to wait for a relatively long time before measuring, and keep the same retention time in continuous multi-pass measurements, see references! 14 and 1519. 4 During the measurement process, a small amount of highly surface-active contaminants in the sample to be measured will accumulate on the liquid surface to a concentration that exceeds the concentration of the substance to be measured. This situation will cause measurement errors, so the top layer of the liquid is continuously pumped away with a water pump during the measurement process to completely avoid this source of error.
GB/T 22237—2008
Test report
The test report should contain the following information!
Reference to this standard;
Type, name and purity of solute;
Type, name and purity of solvent;
Concentration of solvent;
Test temperature;
How long the surface is formed during the actual measurement;
Time required for equilibrium to be established before measurement; Calibration used;
Method of measurement adopted (plate method, lamp method or ring method); Value and arithmetic mean of the surface tension for each measurement: if possible, the mean and standard deviation of the last five measurements; Any deviation from this standard;
Date of test.
Food examination literature
GB/T22237—2008
[1] Padday,JF in Surface and Colloid Science, edited by Matjevic,E.; industrial chemistry),3r cd, ,vol. I /1,1961,770-776.[3] Stahlbergcr,B. Guyer,A, Helvet, Chim, Acta,1950,33.243.[4] | |tt | 4.220.[7]
Schwuger,MJ ,Rostek,H, M. Chemie-Ing. Techn. ,1971,43 1075Lenard,P.Ann.Phys..1924,74.381[8]
Du Nouy,PL Gen, Physiol, , New York, 1919,1.1751.[1o]Harkins,WD,Jordan,HFJAmer.Chem.Soc.,193o,52.1751.[11] Zuidema,H.; Warers,CW Ind. Eng. Chem, Analyt. Edit.,1941,13:312.[12] Fox,HW,Chrisman jr,CHJPhys.Chcm.,1952, 56.284. [13] Finzel, R.; Seemann, FWPTB-Mitt., 1977, 87.296. Lunkcnhcimcr,K. \On the determination of eguilibrium surlace tension val-ues of surfactant solutions\,Colloid & Science.1983,261,585.I /1,1961,770-776.[3] Stahlbergcr,B. Guyer,A, Helvet, Chim, Acta,1950,33.243.[4]
Dognon,A.:Abribat,M.Compt. Rend.Acad.Sci.Paris,1g39,2oo8.1881.[5]
Padday,JF Proc. lind. Intern. Congr.Surface Activity London, Butterworths,l957,l:l.[6] || tt||Neumann,AW ; Tanner, W. Tenside,1967,4.220.[7]
Schwuger,MJ ,Rostek,H, M. Chemie-Ing. Techn. ,1971,43 1075Lenard,P.Ann.Phys..1924,74.381[8]
Du Nouy,PL Gen, Physiol, , New York, 1919,1.1751.[1o]Harkins,WD,Jordan,HFJAmer.Chem.Soc .,193o,52.1751.[11] Zuidema,H.; Warers,CW Ind. Eng. Chem, Analyt. Edit.,1941,13:312.[12] Fox,HW,Chrisman jr,CHJPhys.Chcm.,1952 ,56.284.[13]Finzel,R.;Seemann,FWPTB-Mitt.,1977,87.296.[14T Hofmann, A, and Hartmann, R, Oberflachenaktive Substanzen-Moderne Methode zurCharaktcrisicrung\,Chem.-AnlagcnVerfahrcn,1992,25.123.[15] Millcr,R, and Lunkcnhcimcr,K. \On the determination of eguilibrium surlace tension val-ues of surfactant solutions\,Colloid & Science.1983, 261,585.I /1,1961,770-776.[3] Stahlbergcr,B. Guyer,A, Helvet, Chim, Acta,1950,33.243.[4]
Dognon,A.:Abribat,M.Compt. Rend.Acad.Sci.Paris,1g39,2oo8.1881.[5]
Padday,JF Proc. lind. Intern. Congr.Surface Activity London, Butterworths,l957,l:l.[6] || tt||Neumann,AW ; Tanner, W. Tenside,1967,4.220.[7]
Schwuger,MJ ,Rostek,H, M. Chemie-Ing. Techn. ,1971,43 1075Lenard,P.Ann.Phys..1924,74.381[8]
Du Nouy,PL Gen, Physiol, , New York, 1919,1.1751.[1o]Harkins,WD,Jordan,HFJAmer.Chem.Soc .,193o,52.1751.[11] Zuidema,H.; Warers,CW Ind. Eng. Chem, Analyt. Edit.,1941,13:312.[12] Fox,HW,Chrisman jr,CHJPhys.Chcm.,1952 ,56.284.[13]Finzel,R.;Seemann,FWPTB-Mitt.,1977,87.296.[14T Hofmann, A, and Hartmann, R, Oberflachenaktive Substanzen-Moderne Methode zurCharaktcrisicrung\,Chem.-AnlagcnVerfahrcn,1992,25.123.[15] Millcr,R, and Lunkcnhcimcr,K. \On the determination of eguilibrium surlace tension val-ues of surfactant solutions\,Colloid & Science.1983, 261,585.
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