This standard specifies the method for determining the relative density of liquid samples. This standard applies to the determination of the relative density of liquid samples. GB/T 5009.2-2003 Determination of relative density of food GB/T5009.2-2003 Standard download decompression password: www.bzxz.net

1cS 67.040
National Standard of the People's Republic of China
GB/T5009.2—2003
Replaces GB/T5009,2-1985
Determination of relative density of foods
Detcrmination of relative density of Foods2003-0B-11Promulgated
Ministry of Health of the People's Republic of China
Standardization Administration of the People's Republic of China
Implementation on 2004-01-01
CB/T509:2+2=3
1565 Method for determination of specific gravity of foods.
This standard replaces CB/5009.2
This standard is different from 5.2-108 of the Ministry of Health as follows: the Chinese name of the standard is adjusted, and the Chinese name of the standard is moved to Determination of the relative density of foods; the structure of the standard is carried out according to the abbreviation rules of GB/T 11-20013, Part 4, Chemical analysis method 3. This standard is proposed by the Ministry of Health of the People's Republic of China and officially compiled by the Ministry of Health of the People's Republic of China. This standard was first issued in 1935. This is the first time. S0
Determination of relative density of food
This standard specifies the determination method of relative density of liquid samples. This standard is used for the general determination of relative density of liquid samples. 2. Terminology and definitions
This standard adopts the following terms and definitions.
The mass of the substance in the unit volume is expressed in grams per milliliter, and the relative density is expressed as d.
The ratio of the mass of the substance to the mass of pure water at the same temperature is expressed as d.
The first method is to measure the mass of water and the sample filling the same drop bottle at 20~30℃, and then the relative density can be calculated. The volume of the density bottle, that is, the volume of the sample, can be determined by the amount of water. The density can be calculated according to the mass and volume of the sample. 3. 1 Instrument
Thermometer bottle: As shown in Figure 1,
A wide range
A standard:
3--Precision density bottle bzxZ.net
Thermostat.
3.2 Analysis steps
Field 1 Density bottle
I) Ordinary density
Take out the clean, dry, and accurately read the density. Put the sample in 20℃ water bath for 0.5h to make the humidity of the paste reach 20℃. Use a fine filter paper to remove the sample on the mark. After it is well, take it out and filter the whole surface with a filter paper. Place it in a large room for .5h and weigh it. Then take out the clean sample. Wash the whole density bottle, fill it with water, and continue the above "Put it in a 20℃ water bath for 5h..." according to GB/T 5009.2-2003. There should be no air pool in the density bottle, and the density should not exceed 20℃. Otherwise, this method cannot be used. 3. 3 Calculation of the relative density of the test sample at 21°C according to the formula (1>). p
mass of the density bottle, the total average is 1:
mass of the water in the density bottle, in grams (g) - mass of the water in the density bottle, in grams)! - relative density of the sample at 20%.
The result of the calculation is the effective digit of the viscosity of the sample. 4 Precision
The absolute difference between two independent determinations obtained under the measurement recording condition shall not exceed the arithmetic mean: . Second method relative density balance method
5 Relative density balance method
At 20°C, respectively Determine the relative density of the water and the buoyancy of the test sample. When the volume of water displaced is approximately the same as the volume of the sample displaced, the relative density of the test sample can be calculated based on the relative density of the sample in the water and the buoyancy of the test sample. 5.1 Service
Book sweeping density balance: As shown in Figure 2,
About the following:
5, 4-6:
Horizontal capital!
Nature:
: Surface;
Figure 2 Wei's relative density balance
Link:
Magnetic:
Smoke hand effect address,
GB/1' 5009.2—2003
It consists of a bracket 1, a beam 5, a suction chain 10, a glass surface 9 transmission code: 1 and a general code 8. The horizontal scale of the baby 5 is divided into 10 scales, the suction chain 10 has an accurate mass of 1=.00 in the air, and a display meter is attached. There is a red line or a thicker black line on the meter to indicate the accurate mass of water at this temperature. The initial relative density of water at this temperature is 1, and the glass is used to measure the sample. The mass of the base code 11 is the same as that of the sample: the mass of the base code 11 itself is 5, 3.55.05, 0.(005g. When placed on the relative density balance table, the mass ratio is 0.1, 0.01, 0.001, 0.0001. .1 is placed at 7, which means 0.8.0.3: 9 means 0.05. The rest is deduced by analogy. 5.2 Analysis Steps
During the measurement, place the bracket on the flat table, place the brick weight at the door, adjust the lifting button to the specified height, and press the rotation button to make the two pointers close. Then remove the weight, hang up the fee, add water to the section to four-fifths: sink the quick slope hammer into the wave tube, adjust the water to 20 (that is, the temperature inside the glass hammer indicates >, test the code, take out the two pointers, and read P. Then take out the broken rust and dry it, add the sample to be tested on the clean surface, make the glass rust legal person pull the same degree as before, keep the sample temperature 20%, and put four kinds of micro-codes until the two fingers on the model are closed, and record the reading as P. When the product is put into the circle, it will not touch the medical and commercial parts.
5.3 Calculation of results
The initial density of the sample is calculated according to formula 2). P
The initial density of the sample is calculated according to formula ():
Where:
Pc is the density of the sample at 20℃, in g/mr.), P is the reading of the floating code in the process, in g); F is the reading of the floating code in the process, in g) S——30℃ evaporation density (9932)g/m)d is the relative density of the sample.
The calculation results are shown in the same way as in 3.
6 Precision
The absolute difference of the results of the independent determinations obtained under the condition of stability shall not exceed the arithmetic mean. The third method is relative density meter (specific gravity meter) method 7 relative density meter (specific gravity meter> method
relative density meter: the upper part of the vascular tube is marked with a number, indicating that the system is complicated, and the lower part is thick and has internal requirements or teaching support. 7. Analysis steps
Special density meter: wipe it clean and dry, and then wait for the tester to wait for the sample to be properly placed in the appropriate base of the tester. Do not touch the container and the room. Hold the sample back to the 2nd place, wait for it to be combined, and then gently press a little. Then let it rise naturally, let it stand and be in the air, and observe the relative density of the sample in a horizontal position. 23
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