This standard specifies the determination of calcium in food by atomic absorption spectrophotometry and titration. This standard is applicable to the determination of calcium in various foods. GB/T 5009.92-2003 Determination of calcium in food GB/T5009.92-2003 Standard download decompression password: www.bzxz.net

TCS67.040
National Standard of the People's Republic of China
GR/T 5009.92—2003
Determination of calcium in foods
Determination of calcium in foods2003-08-11Promulgated
Ministry of Health of the People's Republic of China
Standardization Administration of China
2004-01-01Implementation
CB/T 5009.92—2003
This standard atomic absorption spectrophotometric method corresponds to 1% (1170/2 animal feed - determination of calcium content
atomic absorption spectrophotometric method also
3 (133 English version>. This standard atomic absorption spectrophotometric method and 190)6490/ are not equivalent.
This standard corresponds to the AC/RM1 standard for determination of calcium in dry fruits and vegetables (CAC/RM3). This standard corresponds to 5/2398-155C5 standard for determination of calcium in foods (CAC/RM3). This standard is mainly modified compared with 63/12398-1990, and the Chinese name of the standard is changed. The standard name is the determination of calcium in foods! HTA standard method from 1990
15205-.4-2001 standard writing rules Part: Chemical analysis method for factory verification
The standard was drafted by the Ministry of Health of the People's Republic of China and the Shandong Institute of Nursing and Product Science, Chinese Academy of Sciences. The authors of this standard are Zhou Xinghan, Men Jianhua and Tu Guangya. The original standard was first issued in 19, and this is the first revision: 355
1 Standard National
Determination of calcium in food
The national standard stipulates the determination of calcium in a wide range of products by atomic absorption spectrophotometry. This standard applies to the determination of calcium in various foods. GB/T 5009.92-2003
The test limit of atomic absorption spectrophotometry in this standard is 0.1R, and the linear range is 0.5~.2.3μg: The linear range of the method is 5a~-5ug.
Atomic absorption spectrophotometry
2 Principle
After wet digestion, the sample is introduced into the atomic absorption spectrophotometer, and the atomic absorption signal is roasted and the absorption is 422.? Tm: The absorption is proportional to the content, and the industry series has obtained the specified range. 3 Reagents
3. 1 Hydrochloric acid.
3.2 Nitric acid.
3.2 High efficiency limit,
3.4 ​​Mixed acid digestion, 1% nitric acid + 1% gaussian acid = 4+1. 3.50.51/1. Nitric acid solution: 32ml 1. Nitric acid, add 1% ion solution and dilute to 1000ml. 3.62g1. ​​Oxygen ion: 23.45% 1.0 ... Store in a deep bottle for 4 hours. This solution is equivalent to 3.8 liters of calcium standard solution. The preparation of the standard solution is shown in Table 1. The standard solution is prepared and stored in a bottle for 4 hours. Table 1 Preparation of calcium standard solution
Teaching method:
2 Instruments and equipment
Prepare the standard solution!
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Bath hydration
The product comes from a small place, wash it with water, rinse it repeatedly, and then rinse it with deionized water or dry it for ten months before it can be used. L.1 Common laboratory equipment,
4.2 Speed ​​absorption spectrophotometer:
+B/T5009.92-2CC3
5 Analyzer
5.1 Sample treatment
5.1.1 Sample preparation
Prepare new samples and pay special attention to prevent various pollution. All equipment used, such as electric grinders, meat grinders, pulpers, etc., must be opaque steel. New containers must be made of glass and ethylene. Fresh vegetables, fruits, fish, and meat must not be ground. Rinse with water to remove moisture. Samples of flour, milk, etc. must be sealed in containers to prevent dust and moisture from entering the air. 5.1.2 Sample digestion || tt || new ton test uniformity 0. > 6 ~ [, = g sample 2. U g ~.4. Yes: Beverage rate This formula is detailed:. 2--10, x) at: C m1. Add 23% acid digestion solution to a high temperature cup. Heat the digestion on a hot plate or sand bath. When the acidity decreases, add the standard acid digestion solution. Continue heating the digestion until it is colorless and transparent. Heat a few liters of water to remove excess aldehyde. When the temperature is close to 1-20 °C, cool it down. Then transfer the 23/1% solution to a 18l test tube and fill it to the mark to cancel the solid content of the acid digestion solution. Perform a blank test to determine the above standard. E.2 When the concentration of the standard solution is different, refer to the table. The test parameters are shown in the table. Table 2 Preparation method of standard solutions of different concentrations ||Said length m
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Table 3 Determination of operating state
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There is a standard chemical reaction rate
Procedure economic method
23 State chemical testing belt
Its actual collection method: Only the appearance of the instrument is obtained, the amount of air and acetylene, the height of the lamp holder, the width of the lamp current, etc. are all used. The instrument description is adjusted to the best condition to check
The digested sample solution, the blank and the standard concentration of calcium element are divided into the flame for measurement. 6 Results calculation
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—The content of the sample element, the unit is per gram (m), the concentration of the element in the sample is microgram per liter (μg/liter), the concentration of the reagent void element, the unit is milliliter (mm/liter), the total unit is milliliter (ml): 5
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Dilution multiple:
n—effective amount, unit is gram (g):
The calculation result is expressed in the last two digits of the potentiometric point.
7 Precision titration
CB/T5059.92—2003
Under negative conditions, the absolute difference between two titrations shall not exceed 10 of the potential balance titration method (IEITA method)
8 Original
Calcium and fine admixture can quantitatively form gold complexes, and their total qualitative comparison is consistent with the index technique The substance to be measured is strong. In an appropriate amount of H2O, use a complexing agent ETA to determine: when the RT point is reached, the indicator complex is converted into calcium ion and the free indicator color is shown (end point). According to the RT, the content of the complex can be calculated: 9 reagents || tt || 9.11.25m./l, potassium hydroxide is dissolved, weigh 70).13 sodium hydroxide, dilute with water at a selectivity of 1000mT.9.21Lg/L sodium fluoride solution: weigh: 0.0 & sodium cyanide. Dilute with water to 109ml. 9.3.mal. sodium salicylate: weigh 11.? Sodium citrate (NaCH:U.2H:0). Dilute to 1 mL with water, 9.5% sodium chloride, 9.5% sodium iodide, 4.5% sodium ethylenediamine tetrachloride, dilute to 1000 mL with water, dry in 7-well bottle, store in 4-well bottle, dilute to 1000 mL with 9.6% calcium standard, 0.1218% acidity (99% 135-11% dry), add 21 mL water to 10 mL sodium chloride, add 500 mL of volume, add water to dilute to 100 mL, store in polyethylene bottle, store for 1 hour. 9.7% calcium standard, dilute to 100% with water, store in 4-well bottle, store for 1 hour. 9.7% calcium standard, dilute to 100% with water, store in 4-well bottle, store in 5-well bottle.
10 Instruments
All glassware should be soaked in sulfuric acid-potassium dichloride solution for a few times, then rinsed with deionized water or dried for ten minutes before use. 10.1 Laboratory glassware:
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: 0. 1.2 micro urine clearing tube (1. or 2 mT), 10.1. Subtractive titration (50m).
10. 1.4 graduated tube (0. 5 L--1 rl.) 10.2 electric heating plate W~ center.
11 Analysis steps
11.1 Sample treatment
Absorption spectrophotometry:
11.2 Determination
11.2.1 Determination of EIDTA concentration
Absorb 0.%. Calcium standard is difficult to drop, and it is calibrated with ETA. Determine the return of E>TA. According to the titration result, calculate 65. GB/T per liter. 5009.92—2003
Real ITA is lower than the change in grams of calcium, titer (T): 11.2.2 Sample and blank self-titration
Pipette 1.1--5ml of sample digestion solution and blank test solution respectively, add: shrink liquid, 0.1.1ml of citric acid solution, use a titration tube to add 1.5ml. 1.25mol/1.3 drops of potassium hydroxide, fan and red indicator, immediately dilute 10 times the commercial value of EDTA and set the indicator from purple-red to blue. 12 Calculate the result
Where:
T (v V)nf Ju0
X----Calcium content in grams per gram (mg: 1cog): ELTA determination, unit r milligram per milliliter (mR/ml) EDT used in the test, unit (
V--II4 used in the blank determination, unit is milliliter (mT.2Ff
Test release number
Sample volume, unit is Beijing
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