GB/T 5009.39-2003 Analytical methods for hygienic standards of soy sauce

This standard specifies the analysis methods for various sanitary indicators of soy sauce. This standard is applicable to the analysis of various sanitary indicators of soy sauce brewed or prepared with grains and their by-products such as bean cakes and bran as raw materials. The second method detection limit of amino acid nitrogen in this standard is 0.070/μg/mL, and the linear range is 0-10μg/mL. GB/T 5009.39-2003 Analysis methods for sanitary standards of soy sauce GB/T5009.39-2003 Standard download decompression password: www.bzxz.net

ICS67.040
National Standard of the People's Republic of China
GB/T5009.39--2003
Replaces GB/T5009.39-1996
Method for analysis of hygienic standard of soybean sauce
Promulgated on August 11, 2003
Ministry of Health of the People's Republic of China
Standardization Administration of China
Implementation on January 1, 2004
GB/T5009.39—2003
This standard replaces GB/T5009.39—1996 "Method for analysis of hygienic standard of soybean sauce". Compared with GB/T5009.39-1996, this standard has the following major revisions: The structure of the original standard has been revised in accordance with GB/T20001.4-2001 "Standard Preparation Rules Part 4: Chemical Analysis Methods", and the colorimetric method for amino acid nitrogen has been added as the second method. This standard is proposed and managed by the Ministry of Health of the People's Republic of China. This standard is drafted by the Beijing Municipal Health and Epidemic Prevention Station, Handan Municipal Health and Epidemic Prevention Station, and Tangshan Municipal Health and Epidemic Prevention Station. This standard was first issued in 1985, revised for the first time in 1996, and this is the second revision. 318
1 Scope
Analysis methods for sanitary standards for soy sauce
This standard specifies the analysis methods for various sanitary indicators of soy sauce. GB/T5009.39-2003
This standard is applicable to the analysis of various sanitary indicators of soy sauce brewed or prepared with grains and their by-products such as bean cakes and bran as raw materials. The second method detection limit of amino acid nitrogen in this standard is 0.070μg/mL, and the linear range is 0~10μg/mL. 2 Normative references
The clauses in the following documents become clauses of this standard through reference in this standard. For all dated references, all subsequent amendments (excluding errata) or revisions are not applicable to this standard. However, parties who reach an agreement based on this standard are encouraged to study whether the latest versions of these documents can be used. For all undated references, the latest versions are applicable to this standard. GB/T5009.2 Determination of relative density of food GB/T5009.11 Determination of total arsenic and inorganic arsenic in food GB/T5009.12 Determination of lead in food
GB/T5009.22 Determination of aflatoxin B in food GB/T5009.29 Determination of benzoic acid and sorbic acid in food 3 Sensory examination
Take 2mL of sample in a 25mL stoppered colorimetric tube, add water to the scale, shake and observe the color and clarity. It should not be turbid and without sediment. 3.2Take 30mL of sample in a 50mL beaker and observe that there should be no musty smell and no moldy floating film. 3.3After stirring the sample in the beaker with a glass rod, taste it and it should not have sour, bitter, astringent or other peculiar smells. 4 Physical and chemical examination
4.1 Relative density
Operate according to the relative density meter method in GB/T5009.2. 4.2 Amino Acid Nitrogen
4.2.1 Method 1 Formaldehyde Value Method
4.2.1.1 Principle
Use the amphoteric effect of amino acids, add formaldehyde to fix the alkalinity of the amino group, make the carboxyl group show acidity, titrate with sodium hydroxide standard solution and determine the end point with an acidometer. 4.2.1.2 Reagents
4.2.1.2.1 Formaldehyde (36%): should not contain polymers4.2.1.2.2 Standard sodium hydroxide titration solution Lc (NaOH) = 0.050 mol/L7.4.2.1.3 Instruments
4.2.1.3.1 Acidometer.
4.2.1.3.2 Magnetic stirrer.
4.2.1.3.3 10mL microburette.
4.2.1.4 Analysis steps
Pipette 5.0mL of sample, place in a 100mL volumetric flask, add water to the mark, mix well, pipette 20.0mL, place in a 200mL beaker, add 60mL of water, start the magnetic stirrer, titrate with sodium hydroxide standard solution Lc(NaOH)=0.050mol/1J to pH8.2 indicated by the acidometer, record the number of milliliters of sodium hydroxide standard titration solution (0.05mol/L) consumed, and calculate the total acid content. Add 10.0mL of formaldehyde solution and mix well. Titrate with sodium hydroxide standard titration solution (0.05mol/L) to pH9.2, record the number of milliliters of sodium hydroxide standard titration solution (0.05mol/L) consumed. At the same time, take 80mL of water, first adjust it to pH 8.2 with sodium hydroxide solution (0.05mol/L), then add 10.0mL of formaldehyde solution, and titrate it to pH 9.2 with sodium hydroxide standard titration solution (0.05mol/L), and perform a reagent blank test at the same time. 4.2.1.5 Result calculation
The content of amino acid nitrogen in the sample is calculated according to formula (1). X=V-x0.014×100
5×V,/100
Where:
X is the content of amino acid nitrogen in the sample, in grams per hundred milliliters (g/100mL); (1)
V is the volume of sodium hydroxide standard titration solution consumed after adding formaldehyde to the sample diluent, in milliliters (mL): V. —The volume of sodium hydroxide standard titration solution consumed after adding formaldehyde in the reagent blank test, in milliliters (mL); V, —The amount of sample diluent used, in milliliters (mL); —The concentration of sodium hydroxide standard titration solution, in moles per liter (mo1/I); 0.014 —The mass of nitrogen equivalent to 1.00mL sodium hydroxide standard titration solution Lc (NaOH) = 1.000mol/L), in grams (g).
The calculation result shall retain two significant figures.
4.2.1.6 Precision
The absolute difference between two independent determination results obtained under repeatability conditions shall not exceed 10% of the arithmetic mean. 4.2.2 Second method Colorimetric method
4.2.2.1 Principle
In sodium acetate-acetic acid buffer at pH 4.8, amino acid nitrogen reacts with acetylacetone and formaldehyde to form yellow 3,5-diacetyl-2,6-dimethyl-1,4-dihydropyridine amino acid derivatives. Measure the absorbance at a wavelength of 400nm and compare it with the standard series. 4.2.2.2 Reagents
4.2.2.2.1 Acetic acid solution (1mol/L): Measure 5.8mL of glacial acetic acid and dilute to 100mL with water. 4.2.2.2.2 Sodium acetate solution (1mol/L): Weigh 41g of anhydrous sodium acetate or 68g of sodium acetate (CH,COONa·3H,O), dissolve it in water and dilute to 500mL.
4.2.2.2.3 Sodium acetate-acetic acid buffer: Measure 60mL sodium acetate solution (1mol/L) and mix with 40ml acetic acid solution (1mol/L). The solution has a pH of 4.8.
4.2.2.2.4 Color developer: Mix 15mL 37% methanol with 7.8mL acetylacetone, dilute with water to 100mL, and shake vigorously to mix (stable for three days at room temperature).
4.2.2.2.5 Ammonia nitrogen standard stock solution (1.0g/L): Accurately weigh 0.4720g of ammonium sulfate dried at 105℃ for 2h, dissolve in water, transfer to a 100mL volumetric flask, dilute to scale, and mix. Each milliliter of this solution is equivalent to 1.0mgNH-N (stable for more than 1 year when stored in a refrigerator at 10℃).
4.2.2.2.6 Ammonia nitrogen standard working solution (0.1 g/L). Use a pipette to accurately weigh 10 mL of ammonia cyanide standard stock solution (1.0 mg/mL) into a 100 mL volumetric flask, dilute to the mark with water, and mix well. Each mL of this solution is equivalent to 100 μg NH-NC. It is stable for 1 month when stored in a refrigerator at 10°C.
4.2.2.3 Instruments
4.2.2.3.1 Spectrophotometer.
4.2.2.3.2 Electric constant temperature water bath (100°C ± 0.5°C). 4.2.2.3.3
10 mL stoppered glass colorimetric tube.
4.2.2.4 Analysis steps
4.2.2.4.1 Accurately pipette 1.0mL of sample into a 50mL volumetric flask, dilute to scale with water, and mix well. GB/T5009.39—2003
4.2.2.4.2 Drawing of standard curve: Accurately pipette 0.0.05, 0.1, 0.2, 0.4, 0.6, 0.8, 1.0mL of ammonia nitrogen standard solution (equivalent to NH3-N0, 5.0, 10.020.0, 40.0, 60.0,80.0, 100.0μg) in 10mL colorimetric tubes. Add 4mL sodium acetate-acetic acid buffer solution (pH4.8) and 4mL color developer to each colorimetric tube, dilute to the mark with water, and mix. Heat in a 100℃ water bath for 15min, take out, cool to room temperature in the water bath, transfer to a 1cm cuvette, use the zero tube as a reference, measure the absorbance at a wavelength of 400nm, draw a standard curve or calculate a linear regression equation. 4.2.2.4.3 Sample determination: Accurately pipette 2mL of sample dilution solution (equivalent to 100μg of nitrogen base acidic nitrogen) into a 10mL colorimetric tube. The following procedures are in accordance with 4.2.2.4.2 starting from "Add 4mL sodium acetate-acetic acid buffer solution (pH4.8) and 4mL color developer...". Compare the sample absorbance with the standard curve for quantification or substitute it into the standard regression equation to calculate the sample content. 4.2.2.5 Calculation of results
The content of amino acid nitrogen in the sample is calculated according to formula (2). X=
Wherein:
X1000X1000
X is the content of amino acid nitrogen in the sample, in grams per 100 milliliters (g/100mL); c is the mass of nitrogen in the sample test solution, in micrograms (ug); V is the volume of the sample, in milliliters (mL); V.
is the volume of the sample solution used for determination, in milliliters (mL). 4.2.2.6 Precision
The absolute difference between two independent determination results obtained under repeatability conditions shall not exceed 10% of the arithmetic mean. 4.3 Salt (as sodium chloride)
4.3.1 Principle
Use standard silver nitrate solution to titrate the sodium chloride in the sample to generate silver chloride precipitate. When all the silver chloride is precipitated, the additional silver nitrate reacts with the potassium chromate indicator to generate silver chromate, which makes the solution orange-red, which is the end point. Calculate the sodium chloride content from the consumption of standard silver nitrate titration solution.
4.3.2 Reagents
4.3.2.1 Standard silver nitrate titration solution [c(AgNO,)=0.100mol/L]. 4.3.2.2 Potassium chromate solution (50g/L): Weigh 5g potassium chromate and dissolve it in a small amount of water and then dilute to 100mL. 4.3.3 Instrument
10mL microburette.
4.3.4 Analysis steps
Pipette 2.0mL of sample dilution, add 100mL of water and 1mL of potassium chromate solution (50g/L) into a 150mL~200mL conical flask, and mix well. Titrate with silver nitrate standard solution (0.100mol/L) until an orange-red color appears. Measure 100mL of water and perform a reagent blank test at the same time. 4.3.5 Result calculation
The content of salt (in terms of sodium chloride) in the sample is calculated according to formula (3). X (Vi-V)XeX 0. 058 5 × 1005X2/100
Wherein:
X—the content of salt (in terms of sodium chloride) in the sample, in grams per 100 milliliters (g/100mL); V,———the volume of the standard silver nitrate titration solution consumed by the sample diluent for determination, in milliliters (mL); V,—-the volume of the standard silver nitrate titration solution consumed by the reagent blank, in milliliters (mL); -the concentration of the standard silver nitrate titration solution, in moles per liter (mol/L); (3)
GB/T5009.39--2003
-the mass of sodium chloride equivalent to 1.00mL of the standard silver nitrate solution Cc(AgNO,)=1.000mol/L), in grams (g).
The calculation result should retain three significant figures.
4.3.6 Precision
The absolute difference between two independent determination results obtained under repeatability conditions shall not exceed 10% of the arithmetic mean. 4.4 Total Acid
4.4.1 Principle
Soy sauce contains a variety of organic acids. It is titrated with a standard sodium hydroxide solution, and the end point is determined by an acidometer. The result is expressed as lactic acid. 4.4.2 Reagents
Standard sodium hydroxide titration solution Cc(NaOH)=0.050mo1/LJ. 4.4.3 Instrument
Same as 4.2.1.3.
4.4.4 Analysis Steps
According to 4.2.1.4, measure 80mL of water, and perform a reagent blank test at the same time. 4.4.5 Calculation of Results
The total acid content in the sample (in terms of lactic acid) is calculated according to formula (4). X- (-VXX0.090×100
5×V./100
Wherein:
X is the total acid content in the sample (calculated as lactic acid), in grams per 100 milliliters (g/100mL); V is the volume of sodium hydroxide standard titration solution consumed by the sample diluent for determination, in milliliters (mL); Ve
is the volume of sodium hydroxide standard titration solution consumed by the reagent blank, in milliliters (mL); V is the amount of sample diluent taken, in milliliters (mL); the concentration of sodium hydroxide standard titration solution, in moles per liter (mol/L); (4)
0.090 is the mass of lactic acid equivalent to 1.00mL sodium hydroxide standard solution (c(NaOH)=1.000mol/L), in grams (g).
The calculated result shall be rounded to three significant figures.
4. 4.6 Precision
The absolute difference between two independent determination results obtained under repeatability conditions shall not exceed 10% of the arithmetic mean. 4.5 Arsenic
Operate in accordance with GB/T5009.11.
Operate in accordance with GB/T5009.12.
4.7 Aflatoxin B
Operate in accordance with GB/T5009.22.
4.8 Benzoic acid, sorbic acid||t t||Operate according to GB/T5009.29.
4.9 Ammonium salt (semi-micro nitrogen determination method)
4.9.1 Principle
The sample is heated and steamed in an alkaline solution to make the ammonia free and evaporated, which is absorbed by the ketoacid solution, and then the content is calculated by titration with a standard hydrochloric acid solution. 4.9.2 Reagents
4.9.2.1 Magnesium oxide.
4.9.2.2 Boric acid solution (20g/L). | |tt||4.9.2.3 Hydrochloric acid standard titration solution Ec(HCI)=0.100mol/LJGB/T5009.39-—2003
4.9.2.4 Mixed indicator solution: 1 part of methyl red-ethanol solution (2g/L) and 5 parts of bromocresol green-ethanol solution (2g/L), mix well before use. 4.9.3 Analysis steps
Pipette 2mL of sample and place in a 500mL distillation flask , add about 150mL of water and about 1g of magnesium oxide, connect the distillation device, and connect the lower end of the condenser to the elbow and extend it below the liquid level of the receiving bottle. The receiving bottle contains 10mL of boric acid solution (20g/L) and 2 to 3 drops of mixed indicator liquid. Heat and distill. It takes about 30 minutes to start from boiling. Rinse the elbow with a small amount of water and drip hydrochloric acid standard solution (0.100mo1/L) to the end point. Take the same amount of water, magnesium oxide, and boric acid solution according to the same method. The reagent blank test is performed by the method. 4.9.4 Calculation of results
The content of ammonium salt in the sample (in terms of ammonia) is calculated according to formula (5). x=(,-v)xcx0.017
Where:
X——the content of ammonium salt in the sample (in terms of ammonia), in grams per 100 milliliters (g/100mL); -the volume of the hydrochloric acid standard titration solution consumed by the test sample, in milliliters (mL); V
——the volume of the hydrochloric acid standard titration solution consumed by the reagent blank, in milliliters (mL); -the actual concentration of the hydrochloric acid standard titration solution, in moles per liter (mol/L); -(5)
0.017——the mass of ammonium salt (in terms of ammonia) equivalent to 1.00mL of hydrochloric acid standard solution [c(HCI)=1.000mol/L], in grams (g):
——the volume of the sample, in milliliters (mL). The calculation result shall retain two significant figures.
4.9.5 Precision
The absolute difference between two independent determination results obtained under repeatability conditions shall not exceed 10% of the arithmetic mean.2. Operate according to the law from "add 4mL sodium acetate-acetic acid buffer solution (pH4.8) and 4mL color developer...". Compare the absorbance of the sample with the standard curve for quantification or substitute it into the standard regression equation to calculate the sample content. 4.2.2.5 Calculation of results
The content of amino acid nitrogen in the sample is calculated according to formula (2). X=
Wherein:
X1000X1000
X-the content of amino acid nitrogen in the sample, in grams per hundred milliliters (g/100mL); c——the mass of nitrogen in the sample test solution, in micrograms (ug); V-the volume of the sample, in milliliters (mL); V.
-the volume of the sample solution used for determination, in milliliters (mL). 4.2.2.6 Precision
The absolute difference between two independent determination results obtained under repeatability conditions shall not exceed 10% of the arithmetic mean. 4.3 Salt (as sodium chloride)
4.3.1 Principle
Use standard silver nitrate solution to titrate the sodium chloride in the sample to generate silver chloride precipitate. When all the silver chloride is precipitated, the additional silver nitrate reacts with the potassium chromate indicator to generate silver chromate, which makes the solution orange-red, which is the end point. Calculate the sodium chloride content from the consumption of standard silver nitrate titration solution.
4.3.2 Reagents
4.3.2.1 Standard silver nitrate titration solution [c(AgNO,)=0.100mol/L]. 4.3.2.2 Potassium chromate solution (50g/L): Weigh 5g potassium chromate and dissolve it in a small amount of water and then dilute to 100mL. 4.3.3 Instrument
10mL microburette.
4.3.4 Analysis steps
Pipette 2.0mL of sample dilution, add 100mL of water and 1mL of potassium chromate solution (50g/L) into a 150mL~200mL conical flask, and mix well. Titrate with silver nitrate standard solution (0.100mol/L) until an orange-red color appears. Measure 100mL of water and perform a reagent blank test at the same time. 4.3.5 Result calculation
The content of salt (in terms of sodium chloride) in the sample is calculated according to formula (3). X (Vi-V)XeX 0. 058 5 × 1005X2/100
Wherein:
X—the content of salt (in terms of sodium chloride) in the sample, in grams per 100 milliliters (g/100mL); V,———the volume of the standard silver nitrate titration solution consumed by the sample diluent for determination, in milliliters (mL); V,—-the volume of the standard silver nitrate titration solution consumed by the reagent blank, in milliliters (mL); -the concentration of the standard silver nitrate titration solution, in moles per liter (mol/L); (3)
GB/T5009.39--2003
-the mass of sodium chloride equivalent to 1.00mL of the standard silver nitrate solution Cc(AgNO,)=1.000mol/L), in grams (g).
The calculation result should retain three significant figures.
4.3.6 Precision
The absolute difference between two independent determination results obtained under repeatability conditions shall not exceed 10% of the arithmetic mean. 4.4 Total Acid
4.4.1 Principle
Soy sauce contains a variety of organic acids. It is titrated with a standard sodium hydroxide solution, and the end point is determined by an acidometer. The result is expressed as lactic acid. 4.4.2 Reagents
Standard sodium hydroxide titration solution Cc(NaOH)=0.050mo1/LJ. 4.4.3 Instrument
Same as 4.2.1.3.
4.4.4 Analysis Steps
According to 4.2.1.4, measure 80mL of water, and perform a reagent blank test at the same time. 4.4.5 Calculation of Results
The total acid content in the sample (in terms of lactic acid) is calculated according to formula (4). X- (-VXX0.090×100
5×V./100
Wherein:
X is the total acid content in the sample (calculated as lactic acid), in grams per 100 milliliters (g/100mL); V is the volume of sodium hydroxide standard titration solution consumed by the sample diluent for determination, in milliliters (mL); Ve
is the volume of sodium hydroxide standard titration solution consumed by the reagent blank, in milliliters (mL); V is the amount of sample diluent taken, in milliliters (mL); the concentration of sodium hydroxide standard titration solution, in moles per liter (mol/L); (4)
0.090 is the mass of lactic acid equivalent to 1.00mL sodium hydroxide standard solution (c(NaOH)=1.000mol/L), in grams (g).
The calculated result shall be rounded to three significant figures.
4. 4.6 Precision
The absolute difference between two independent determination results obtained under repeatability conditions shall not exceed 10% of the arithmetic mean. 4.5 Arsenic
Operate in accordance with GB/T5009.11.
Operate in accordance with GB/T5009.12.
4.7 Aflatoxin B
Operate in accordance with GB/T5009.22.
4.8 Benzoic acid, sorbic acid||t t||Operate according to GB/T5009.29.
4.9 Ammonium salt (semi-micro nitrogen determination method)
4.9.1 Principle
The sample is heated and steamed in an alkaline solution to make the ammonia free and evaporated, which is absorbed by the ketoacid solution, and then the content is calculated by titration with a standard hydrochloric acid solution. 4.9.2 Reagents
4.9.2.1 Magnesium oxide.
4.9.2.2 Boric acid solution (20g/L). | |tt||4.9.2.3 Hydrochloric acid standard titration solution Ec(HCI)=0.100mol/LJGB/T5009.39-—2003
4.9.2.4 Mixed indicator solution: 1 part of methyl red-ethanol solution (2g/L) and 5 parts of bromocresol green-ethanol solution (2g/L), mix well before use. 4.9.3 Analysis steps
Pipette 2mL of sample and place in a 500mL distillation flask , add about 150mL of water and about 1g of magnesium oxide, connect the distillation device, and connect the lower end of the condenser to the elbow and extend it below the liquid level of the receiving bottle. The receiving bottle contains 10mL of boric acid solution (20g/L) and 2 to 3 drops of mixed indicator liquid. Heat and distill. It takes about 30 minutes to start from boiling. Rinse the elbow with a small amount of water and drip hydrochloric acid standard solution (0.100mo1/L) to the end point. Take the same amount of water, magnesium oxide, and boric acid solution according to the same method. The reagent blank test is performed by the method. 4.9.4 Calculation of results
The content of ammonium salt in the sample (in terms of ammonia) is calculated according to formula (5). x=(,-v)xcx0.017
Where:
X——the content of ammonium salt in the sample (in terms of ammonia), in grams per 100 milliliters (g/100mL); -the volume of the hydrochloric acid standard titration solution consumed by the test sample, in milliliters (mL); V
——the volume of the hydrochloric acid standard titration solution consumed by the reagent blank, in milliliters (mL); -the actual concentration of the hydrochloric acid standard titration solution, in moles per liter (mol/L); -(5)
0.017——the mass of ammonium salt (in terms of ammonia) equivalent to 1.00mL of hydrochloric acid standard solution [c(HCI)=1.000mol/L], in grams (g):
——the volume of the sample, in milliliters (mL). The calculation result shall retain two significant figures.
4.9.5 Precision
The absolute difference between two independent determination results obtained under repeatability conditions shall not exceed 10% of the arithmetic mean.2. Operate according to the law from "add 4mL sodium acetate-acetic acid buffer solution (pH4.8) and 4mL color developer...". Compare the absorbance of the sample with the standard curve for quantification or substitute it into the standard regression equation to calculate the sample content. 4.2.2.5 Calculation of results
The content of amino acid nitrogen in the sample is calculated according to formula (2). X=
Wherein:
X1000X1000
X-the content of amino acid nitrogen in the sample, in grams per hundred milliliters (g/100mL); c——the mass of nitrogen in the sample test solution, in micrograms (ug); V-the volume of the sample, in milliliters (mL); V.
-the volume of the sample solution used for determination, in milliliters (mL). 4.2.2.6 Precision
The absolute difference between two independent determination results obtained under repeatability conditions shall not exceed 10% of the arithmetic mean. 4.3 Salt (as sodium chloride)
4.3.1 Principle
Use standard silver nitrate solution to titrate the sodium chloride in the sample to generate silver chloride precipitate. When all the silver chloride is precipitated, the additional silver nitrate reacts with the potassium chromate indicator to generate silver chromate, which makes the solution orange-red, which is the end point. Calculate the sodium chloride content from the consumption of standard silver nitrate titration solution.
4.3.2 Reagents
4.3.2.1 Standard silver nitrate titration solution [c(AgNO,)=0.100mol/L]. 4.3.2.2 Potassium chromate solution (50g/L): Weigh 5g potassium chromate and dissolve it in a small amount of water and then dilute to 100mL. 4.3.3 Instrument
10mL microburette.
4.3.4 Analysis steps
Pipette 2.0mL of sample dilution, add 100mL of water and 1mL of potassium chromate solution (50g/L) into a 150mL~200mL conical flask, and mix well. Titrate with silver nitrate standard solution (0.100mol/L) until an orange-red color appears. Measure 100mL of water and perform a reagent blank test at the same time. 4.3.5 Result calculation
The content of salt (in terms of sodium chloride) in the sample is calculated according to formula (3). X (Vi-V)XeX 0. 058 5 × 1005X2/100
Wherein:
X—the content of salt (in terms of sodium chloride) in the sample, in grams per 100 milliliters (g/100mL); V,———the volume of the standard silver nitrate titration solution consumed by the sample diluent for determination, in milliliters (mL); V,—-the volume of the standard silver nitrate titration solution consumed by the reagent blank, in milliliters (mL); -the concentration of the standard silver nitrate titration solution, in moles per liter (mol/L); (3)
GB/T5009.39--2003
-the mass of sodium chloride equivalent to 1.00mL of the standard silver nitrate solution Cc(AgNO,)=1.000mol/L), in grams (g).
The calculation result should retain three significant figures.
4.3.6 Precision
The absolute difference between two independent determination results obtained under repeatability conditions shall not exceed 10% of the arithmetic mean. 4.4 Total Acid
4.4.1 Principle
Soy sauce contains a variety of organic acids. It is titrated with a standard sodium hydroxide solution, and the end point is determined by an acidometer. The result is expressed as lactic acid. 4.4.2 Reagents
Standard sodium hydroxide titration solution Cc(NaOH)=0.050mo1/LJ. 4.4.3 Instrument
Same as 4.2.1.3.
4.4.4 Analysis Steps
According to 4.2.1.4, measure 80mL of water, and perform a reagent blank test at the same time. 4.4.5 Calculation of Results
The total acid content in the sample (in terms of lactic acid) is calculated according to formula (4). X- (-VXX0.090×100
5×V./100
Wherein:
X is the total acid content in the sample (calculated as lactic acid), in grams per 100 milliliters (g/100mL); V is the volume of sodium hydroxide standard titration solution consumed by the sample diluent for determination, in milliliters (mL); Ve
is the volume of sodium hydroxide standard titration solution consumed by the reagent blank, in milliliters (mL); V is the amount of sample diluent taken, in milliliters (mL); the concentration of sodium hydroxide standard titration solution, in moles per liter (mol/L); (4)
0.090 is the mass of lactic acid equivalent to 1.00mL sodium hydroxide standard solution (c(NaOH)=1.000mol/L), in grams (g).
The calculated result shall be rounded to three significant figures.
4. 4.6 Precision
The absolute difference between two independent determination results obtained under repeatability conditions shall not exceed 10% of the arithmetic mean. 4.5 Arsenic
Operate in accordance with GB/T5009.11.
Operate in accordance with GB/T5009.12.
4.7 Aflatoxin B
Operate in accordance with GB/T5009.22.
4.8 Benzoic acid, sorbic acid||t t||Operate according to GB/T5009.29.
4.9 Ammonium salt (semi-micro nitrogen determination method)
4.9.1 Principle
The sample is heated and steamed in an alkaline solution to make the ammonia free and evaporated, which is absorbed by the ketoacid solution, and then the content is calculated by titration with a standard hydrochloric acid solution. 4.9.2 Reagents
4.9.2.1 Magnesium oxide.
4.9.2.2 Boric acid solution (20g/L). | |tt||4.9.2.3 Hydrochloric acid standard titration solution Ec(HCI)=0.100mol/LJGB/T5009.39-—2003
4.9.2.4 Mixed indicator solution: 1 part of methyl red-ethanol solution (2g/L) and 5 parts of bromocresol green-ethanol solution (2g/L), mix well before use. 4.9.3 Analysis steps
Pipette 2mL of sample and place in a 500mL distillation flask , add about 150mL of water and about 1g of magnesium oxide, connect the distillation device, and connect the lower end of the condenser to the elbow and extend it below the liquid level of the receiving bottle. The receiving bottle contains 10mL of boric acid solution (20g/L) and 2 to 3 drops of mixed indicator liquid. Heat and distill. It takes about 30 minutes to start from boiling. Rinse the elbow with a small amount of water and drip hydrochloric acid standard solution (0.100mo1/L) to the end point. Take the same amount of water, magnesium oxide, and boric acid solution according to the same method. The reagent blank test is performed by the method. 4.9.4 Calculation of results
The content of ammonium salt in the sample (in terms of ammonia) is calculated according to formula (5). x=(,-v)xcx0.017
Where:
X——the content of ammonium salt in the sample (in terms of ammonia), in grams per 100 milliliters (g/100mL); -the volume of the hydrochloric acid standard titration solution consumed by the test sample, in milliliters (mL); V
——the volume of the hydrochloric acid standard titration solution consumed by the reagent blank, in milliliters (mL); -the actual concentration of the hydrochloric acid standard titration solution, in moles per liter (mol/L); -(5)
0.017——the mass of ammonium salt (in terms of ammonia) equivalent to 1.00mL of hydrochloric acid standard solution [c(HCI)=1.000mol/L], in grams (g):
——the volume of the sample, in milliliters (mL). The calculation result shall retain two significant figures.
4.9.5 Precision
The absolute difference between two independent determination results obtained under repeatability conditions shall not exceed 10% of the arithmetic mean.2 Reagents
4.3.2.1 Silver nitrate standard titration solution [c(AgNO,)=0.100mol/L]. 4.3.2.2 Potassium chromate solution (50g/L): Weigh 5g potassium chromate and dissolve it in a small amount of water and then dilute to 100mL. 4.3.3 Instruments
10mL microburette.
4.3.4 Analysis steps
Pipette 2.0mL of the sample dilution, add 100mL of water and 1mL of potassium chromate solution (50g/L) into a 150mL~200mL conical flask, and mix well. Titrate with silver nitrate standard solution (0.100mol/L) until an orange-red color appears. Measure 100mL of water and perform a reagent blank test at the same time. 4.3.5 Result calculation
The content of salt (in terms of sodium chloride) in the sample is calculated according to formula (3). X (Vi-V)XeX 0. 058 5 × 1005X2/100
Wherein:
X—the content of salt (in terms of sodium chloride) in the sample, in grams per 100 milliliters (g/100mL); V,———the volume of the standard silver nitrate titration solution consumed by the sample diluent for determination, in milliliters (mL); V,—-the volume of the standard silver nitrate titration solution consumed by the reagent blank, in milliliters (mL); -the concentration of the standard silver nitrate titration solution, in moles per liter (mol/L); (3)
GB/T5009.39--2003
-the mass of sodium chloride equivalent to 1.00mL of the standard silver nitrate solution Cc(AgNO,)=1.000mol/L), in grams (g).
The calculation result should retain three significant figures.
4.3.6 Precision
The absolute difference between two independent determination results obtained under repeatability conditions shall not exceed 10% of the arithmetic mean. 4.4 Total Acid
4.4.1 Principle
Soy sauce contains a variety of organic acids. It is titrated with a standard sodium hydroxide solution, and the end point is determined by an acidometer. The result is expressed as lactic acid. 4.4.2 Reagents
Standard sodium hydroxide titration solution Cc(NaOH)=0.050mo1/LJ. 4.4.3 Instrument
Same as 4.2.1.3.
4.4.4 Analysis Steps
According to 4.2.1.4, measure 80mL of water, and perform a reagent blank test at the same time. 4.4.5 Calculation of Results
The total acid content in the sample (in terms of lactic acid) is calculated according to formula (4). X- (-VXX0.090×100
5×V./100
Wherein:
X is the total acid content in the sample (calculated as lactic acid), in grams per 100 milliliters (g/100mL); V is the volume of sodium hydroxide standard titration solution consumed by the sample diluent for determination, in milliliters (mL); Ve
is the volume of sodium hydroxide standard titration solution consumed by the reagent blank, in milliliters (mL); V is the amount of sample diluent taken, in milliliters (mL); the concentration of sodium hydroxide standard titration solution, in moles per liter (mol/L); (4)
0.090 is the mass of lactic acid equivalent to 1.00mL sodium hydroxide standard solution (c(NaOH)=1.000mol/L), in grams (g).
The calculated result shall be rounded to three significant figures.
4. 4.6 Precision
The absolute difference between two independent determination results obtained under repeatability conditions shall not exceed 10% of the arithmetic mean. 4.5 Arsenic
Operate in accordance with GB/T5009.11.
Operate in accordance with GB/T5009.12.
4.7 Aflatoxin B
Operate in accordance with GB/T5009.22.
4.8 Benzoic acid, sorbic acid||t t||Operate according to GB/T5009.29.
4.9 Ammonium salt (semi-micro nitrogen determination method)
4.9.1 Principle
The sample is heated and steamed in an alkaline solution to make the ammonia free and evaporated, which is absorbed by the ketoacid solution, and then the content is calculated by titration with a standard hydrochloric acid solution. 4.9.2 Reagents
4.9.2.1 Magnesium oxide.
4.9.2.2 Boric acid solution (20g/L). | |tt||4.9.2.3 Hydrochloric acid standard titration solution Ec(HCI)=0.100mol/LJGB/T5009.39-—2003
4.9.2.4 Mixed indicator solution: 1 part of methyl red-ethanol solution (2g/L) and 5 parts of bromocresol green-ethanol solution (2g/L), mix well before use. 4.9.3 Analysis steps
Pipette 2mL of sample and place in a 500mL distillation flask , add about 150mL of water and about 1g of magnesium oxide, connect the distillation device, and connect the lower end of the condenser to the elbow and extend it below the liquid level of the receiving bottle. The receiving bottle contains 10mL of boric acid solution (20g/L) and 2 to 3 drops of mixed indicator liquid. Heat and distill. It takes about 30 minutes to start from boiling. Rinse the elbow with a small amount of water and drip hydrochloric acid standard solution (0.100mo1/L) to the end point. Take the same amount of water, magnesium oxide, and boric acid solution according to the same method. The reagent blank test is performed by the method. 4.9.4 Calculation of results
The content of ammonium salt in the sample (in terms of ammonia) is calculated according to formula (5). x=(,-v)xcx0.017
Where:
X——the content of ammonium salt in the sample (in terms of ammonia), in grams per 100 milliliters (g/100mL); -the volume of the hydrochloric acid standard titration solution consumed by the test sample, in milliliters (mL); V
——the volume of the hydrochloric acid standard titration solution consumed by the reagent blank, in milliliters (mL); -the actual concentration of the hydrochloric acid standard titration solution, in moles per liter (mol/L); -(5)
0.017——the mass of ammonium salt (in terms of ammonia) equivalent to 1.00mL of hydrochloric acid standard solution [c(HCI)=1.000mol/L], in grams (g):
——the volume of the sample, in milliliters (mL). The calculation result shall retain two significant figures.
4.9.5 Precision
The absolute difference between two independent determination results obtained under repeatability conditions shall not exceed 10% of the arithmetic mean.2 Reagents
4.3.2.1 Silver nitrate standard titration solution [c(AgNO,)=0.100mol/L]. 4.3.2.2 Potassium chromate solution (50g/L): Weigh 5g potassium chromate and dissolve it in a small amount of water and then dilute to 100mL. 4.3.3 Instruments
10mL microburette.
4.3.4 Analysis steps
Pipette 2.0mL of the sample dilution, add 100mL of water and 1mL of potassium chromate solution (50g/L) into a 150mL~200mL conical flask, and mix well. Titrate with silver nitrate standard solution (0.100mol/L) until an orange-red color appears. Measure 100mL of water and perform a reagent blank test at the same time. 4.3.5 Result calculation
The content of salt (in terms of sodium chloride) in the sample is calculated according to formula (3). X (Vi-V)XeX 0. 058 5 × 1005X2/100
Wherein:
X—the content of salt (in terms of sodium chloride) in the sample, in grams per 100 milliliters (g/100mL); V,———the volume of the standard silver nitrate titration solution consumed by the sample diluent for determination, in milliliters (mL); V,—-the volume of the standard silver nitrate titration solution consumed by the reagent blank, in milliliters (mL); -the concentration of the standard silver nitrate titration solution, in moles per liter (mol/L); (3)
GB/T5009.39--2003
-the mass of sodium chloride equivalent to 1.00mL of the standard silver nitrate solution Cc(AgNO,)=1.000mol/L), in grams (g).
The calculation result should retain three significant figures.
4.3.6 Precision
The absolute difference between two independent determination results obtained under repeatability conditions shall not exceed 10% of the arithmetic mean. 4.4 Total Acid
4.4.1 Principle
Soy sauce contains a variety of organic acids. It is titrated with a standard sodium hydroxide solution, and the end point is determined by an acidometer. The result is expressed as lactic acid. 4.4.2 Reagents
Standard sodium hydroxide titration solution Cc(NaOH)=0.050mo1/LJ. 4.4.3 Instrument
Same as 4.2.1.3.
4.4.4 Analysis Steps
According to 4.2.1.4, measure 80mL of water, and perform a reagent blank test at the same time. 4.4.5 Calculation of Results
The total acid content in the sample (in terms of lactic acid) is calculated according to formula (4). X- (-VXX0.090×100
5×V./100Www.bzxZ.net
Wherein:
X is the total acid content in the sample (calculated as lactic acid), in grams per 100 milliliters (g/100mL); V is the volume of sodium hydroxide standard titration solution consumed by the sample diluent for determination, in milliliters (mL); Ve
is the volume of sodium hydroxide standard titration solution consumed by the reagent blank, in milliliters (mL); V is the amount of sample diluent taken, in milliliters (mL); the concentration of sodium hydroxide standard titration solution, in moles per liter (mol/L); (4)
0.090 is the mass of lactic acid equivalent to 1.00mL sodium hydroxide standard solution (c(NaOH)=1.000mol/L), in grams (g).
The calculated result shall be rounded to three significant figures.
4. 4.6 Precision
The absolute difference between two independent determination results obtained under repeatability conditions shall not exceed 10% of the arithmetic mean. 4.5 Arsenic
Operate in accordance with GB/T5009.11.
Operate in accordance with GB/T5009.12.
4.7 Aflatoxin B
Operate in accordance with GB/T5009.22.
4.8 Benzoic acid, sorbic acid||t t||Operate according to GB/T5009.29.
4.9 Ammonium salt (semi-micro nitrogen determination method)
4.9.1 Principle
The sample is heated and steamed in an alkaline solution to make the ammonia free and evaporated, which is absorbed by the ketoacid solution, and then the content is calculated by titration with a standard hydrochloric acid solution. 4.9.2 Reagents
4.9.2.1 Magnesium oxide.
4.9.2.2 Boric acid solution (20g/L). | |tt||4.9.2.3 Hydrochloric acid standard titration solution Ec(HCI)=0.100mol/LJGB/T5009.39-—2003
4.9.2.4 Mixed indicator solution: 1 part of methyl red-ethanol solution (2g/L) and 5 parts of bromocresol green-ethanol solution (2g/L), mix well before use. 4.9.3 Analysis steps
Pipette 2mL of sample and place in a 500mL distillation flask , add about 150mL of water and about 1g of magnesium oxide, connect the distillation device, and connect the lower end of the condenser to the elbow and extend it below the liquid level of the receiving bottle. The receiving bottle contains 10mL of boric acid solution (20g/L) and 2 to 3 drops of mixed indicator liquid. Heat and distill. It takes about 30 minutes to start from boiling. Rinse the elbow with a small amount of water and drip hydrochloric acid standard solution (0.100mo1/L) to the end point. Take the same amount of water, magnesium oxide, and boric acid solution according to the same method. The reagent blank test is performed by the method. 4.9.4 Calculation of results
The content of ammonium salt in the sample (in terms of ammonia) is calculated according to formula (5). x=(,-v)xcx0.017
Where:
X——the content of ammonium salt in the sample (in terms of ammonia), in grams per 100 milliliters (g/100mL); -the volume of the hydrochloric acid standard titration solution consumed by the test sample, in milliliters (mL); V
——the volume of the hydrochloric acid standard titration solution consumed by the reagent blank, in milliliters (mL); -the actual concentration of the hydrochloric acid standard titration solution, in moles per liter (mol/L); -(5)
0.017——the mass of ammonium salt (in terms of ammonia) equivalent to 1.00mL of hydrochloric acid standard solution [c(HCI)=1.000mol/L], in grams (g):
——the volume of the sample, in milliliters (mL). The calculation result shall retain two significant figures.
4.9.5 Precision
The absolute difference between two independent determination results obtained under repeatability conditions shall not exceed 10% of the arithmetic mean./100
Wherein:
X is the total acid content in the sample (calculated as lactic acid), in grams per hundred milliliters (g/100mL); V is the volume of sodium hydroxide standard titration solution consumed by the sample diluent for determination, in milliliters (mL); Ve
is the volume of sodium hydroxide standard titration solution consumed by the reagent blank, in milliliters (mL); V is the amount of sample diluent taken, in milliliters (mL); the concentration of sodium hydroxide standard titration solution, in moles per liter (mol/L); (4)
0.090 is the mass of lactic acid equivalent to 1.00mL sodium hydroxide standard solution (c(NaOH)=1.000mol/L), in grams (g).
The calculated result shall be rounded to three significant figures.
4.4.6 Precision
Under repeatability conditions The absolute difference between two independent determination results obtained under the following conditions shall not exceed 10% of the arithmetic mean. 4.5 Arsenic
According to GB/T5009.11.
According to GB/T5009.12.
4.7 Aflatoxin B
According to GB/T5009.22.
4.8 Benzoic acid, sorbic acid
According to GB/T5009.29 Operation.
4.9 Ammonium salt (semi-micro nitrogen determination method)
4.9.1 Principle
The sample is heated and steamed in an alkaline solution to make the ammonia free and evaporated, which is absorbed by the ketoacid solution, and then the content is calculated by titration with a standard hydrochloric acid solution. 4.9.2 Reagents
4.9.2.1 Magnesium oxide.
4.9.2.2 Boric acid solution (20 g/L).
4.9.2.3 Standard hydrochloric acid titration solution Ec (HCI) = 0.100 mol/L JGB/T5009.39--2003
4.9.2.4 Mixed indicator solution: 1 part of methyl red-ethanol solution (2g/L) and 5 parts of bromocresol green-ethanol solution (2g/L), mix well before use. 4.9.3 Analysis steps
Pull 2mL of sample and place it in a 500mL distillation flask, add about 150mL of water and about 1g of magnesium oxide, connect the distillation device, and connect the lower end of the condenser to the bend and extend it below the liquid level of the receiving bottle. The receiving bottle contains 10mL of boric acid solution (20g/L) and 2 to 3 drops of mixed indicator solution. Heat and distill. It takes about 30 minutes to steam from the beginning of boiling. Rinse the bend with a small amount of water and drip the hydrochloric acid standard solution (0.100mo1/L) to the end point. Take the same amount of water, magnesium oxide, and boric acid solution as reagent blanks in the same way Test. 4.9.4 Calculation of results
The content of ammonium salt in the sample (in terms of ammonia) is calculated according to formula (5). x=(,-v)xcx0.017
Wherein:
X——the content of ammonium salt in the sample (in terms of ammonia), in grams per 100 milliliters (g/100mL); -the volume of hydrochloric acid standard titration solution consumed by the test sample, in milliliters (mL); V
——the volume of hydrochloric acid standard titration solution consumed by the reagent blank, in milliliters (mL); -the actual concentration of hydrochloric acid standard titration solution, in moles per liter (mol/L); -(5)
0.017——the mass of ammonium salt (in terms of ammonia) equivalent to 1.00mL hydrochloric acid standard solution [c(HCI)=1.000mol/L], in grams (g):
——the volume of the sample, in milliliters (mL). The calculation result shall be rounded to two significant figures.
4.9.5 Precision
The absolute difference between two independent determination results obtained under repeatability conditions shall not exceed 10% of the arithmetic mean./100
Wherein:
X is the total acid content in the sample (calculated as lactic acid), in grams per hundred milliliters (g/100mL); V is the volume of sodium hydroxide standard titration solution consumed by the sample diluent for determination, in milliliters (mL); Ve
is the volume of sodium hydroxide standard titration solution consumed by the reagent blank, in milliliters (mL); V is the amount of sample diluent taken, in milliliters (mL); the concentration of sodium hydroxide standard titration solution, in moles per liter (mol/L); (4)
0.090 is the mass of lactic acid equivalent to 1.00mL sodium hydroxide standard solution (c(NaOH)=1.000mol/L), in grams (g).
The calculated result shall be rounded to three significant figures.
4.4.6 Precision
Under repeatability conditions The absolute difference between two independent determination results obtained under the following conditions shall not exceed 10% of the arithmetic mean. 4.5 Arsenic
According to GB/T5009.11.
According to GB/T5009.12.
4.7 Aflatoxin B
According to GB/T5009.22.
4.8 Benzoic acid, sorbic acid
According to GB/T5009.29 Operation.
4.9 Ammonium salt (semi-micro nitrogen determination method)
4.9.1 Principle
The sample is heated and steamed in an alkaline solution to make the ammonia free and evaporated, which is absorbed by the ketoacid solution, and then the content is calculated by titration with a standard hydrochloric acid solution. 4.9.2 Reagents
4.9.2.1 Magnesium oxide.
4.9.2.2 Boric acid solution (20 g/L).
4.9.2.3 Standard hydrochloric acid titration solution Ec (HCI) = 0.100 mol/L JGB/T5009.39--2003
4.9.2.4 Mixed indicator solution: 1 part of methyl red-ethanol solution (2g/L) and 5 parts of bromocresol green-ethanol solution (2g/L), mix well before use. 4.9.3 Analysis steps
Pull 2mL of sample and place it in a 500mL distillation flask, add about 150mL of water and about 1g of magnesium oxide, connect the distillation device, and connect the lower end of the condenser to the bend and extend it below the liquid level of the receiving bottle. The receiving bottle contains 10mL of boric acid solution (20g/L) and 2 to 3 drops of mixed indicator solution. Heat and distill. It takes about 30 minutes to steam from the beginning of boiling. Rinse the bend with a small amount of water and drip the hydrochloric acid standard solution (0.100mo1/L) to the end point. Take the same amount of water, magnesium oxide, and boric acid solution as reagent blanks in the same way Test. 4.9.4 Calculation of results
The content of ammonium salt in the sample (in terms of ammonia) is calculated according to formula (5). x=(,-v)xcx0.017
Wherein:
X——the content of ammonium salt in the sample (in terms of ammonia), in grams per 100 milliliters (g/100mL); -the volume of hydrochloric acid standard titration solution consumed by the test sample, in milliliters (mL); V
——the volume of hydrochloric acid standard titration solution consumed by the reagent blank, in milliliters (mL); -the actual concentration of hydrochloric acid standard titration solution, in moles per liter (mol/L); -(5)
0.017——the mass of ammonium salt (in terms of ammonia) equivalent to 1.00mL hydrochloric acid standard solution [c(HCI)=1.000mol/L], in grams (g):
——the volume of the sample, in milliliters (mL). The calculation result shall be rounded to two significant figures.
4.9.5 Precision
The absolute difference between two independent determination results obtained under repeatability conditions shall not exceed 10% of the arithmetic mean.
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