GB 5009.154-2023 (GB5009.154-2023) & related versions
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GB 5009.154-2023
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
National Food Safety Standard - Determination of Vitamin
B6 in Foods
ISSUED ON: SEPTEMBER 6, 2023
IMPLEMENTED ON: MARCH 6, 2024
Issued by: National Health Commission of the People’s Republic of China;
State Administration for Market Regulation.
Table of Contents
Foreword ... 4
1 Scope ... 5
Method I - Liquid Chromatography - Tandem Mass Spectrometry ... 5
2 Principle ... 5
3 Reagents and Materials ... 5
4 Instruments and Equipment ... 8
5 Analytical Procedures ... 9
6 Expression of Analysis Results ... 13
7 Precision ... 14
8 Others ... 14
Method II - Liquid Chromatography - Mass Spectrometry ... 14
9 Principle ... 14
10 Reagents and Materials ... 14
11 Instruments and Equipment ... 17
12 Analytical Procedures ... 18
13 Expression of Analysis Results ... 21
14 Precision ... 22
15 Others ... 22
Method III - High-performance Liquid Chromatography - Fluorescence Detection
Method ... 22
16 Principle ... 22
17 Reagents and Materials ... 22
18 Instruments and Equipment ... 24
19 Analytical Procedures ... 25
20 Expression of Analysis Results ... 26
21 Precision ... 27
22 Others ... 27
Method IV - Microbiological Method ... 27
23 Principle ... 27
24 Reagents and Materials ... 28
25 Instruments and Equipment ... 29
26 Analytical Procedures ... 30
27 Expression of Analysis Results ... 32
28 Precision ... 32
29 Others ... 33
Appendix A Concentration Correction Method of Standard Solution of Each
Component of Vitamin B6 ... 34
Appendix B MRM Mass Spectrometry Chromatogram ... 36
Appendix C ... 37
Appendix D Liquid Chromatogram of Vitamin B6 ... 38
Appendix E Culture Medium Components and Preparation Methods ... 39
National Food Safety Standard - Determination of Vitamin
B6 in Foods
1 Scope
This Standard specifies the method for the determination of vitamin B6 in foods.
The first method “liquid chromatography - tandem mass spectrometry” is applicable to the
determination of vitamin B6 in foods.
The second method “liquid chromatography - mass spectrometry” is applicable to the
determination of vitamin B6 (pyridoxamine, pyridoxal and pyridoxine) in formulated milk
powder, special dietary foods, ready-to-eat cereals, baked goods and beverages, in which,
vitamin B6 (pyridoxamine, pyridoxal and pyridoxine) is added as a nutritional fortifier.
The third method “high-performance liquid chromatography - fluorescence detection method”
is applicable to the determination of vitamin B6 (pyridoxamine, pyridoxal and pyridoxine) in
formulated milk powder, special dietary foods (except foods for special medical purposes),
ready-to-eat cereals, baked goods and beverages, in which, vitamin B6 (pyridoxamine,
pyridoxal and pyridoxine) is added as a nutritional fortifier.
The fourth method “microbiological method” is applicable to the determination of vitamin B6
in foods.
Method I - Liquid Chromatography - Tandem Mass
Spectrometry
2 Principle
Vitamin B6 (pyridoxamine, pyridoxal and pyridoxine) in foods is firstly hydrolyzed by acid,
then, enzymatically hydrolyzed into pyridoxamine, pyridoxal and pyridoxine. After dilution
and filtration, reversed-phase liquid chromatography separation, tandem mass spectrometry
detection, and isotope internal standard method for quantitative determination, the total vitamin
B6 content is calculated in terms of pyridoxine.
3 Reagents and Materials
Unless it is otherwise specified, the reagents used in this Method are all analytically pure, and
the water is Grade-1 water specified in GB/T 6682.
3.3.6 D3-pyridoxamine dihydrochloride (C8D3H11Cl2N2O2, CAS No.: 1173023-45-4): purity
98%.
3.4 Preparation of Standard Solutions
3.4.1 Pyridoxine standard stock solution (1.00 mg/mL): accurately weigh-take 60.8 mg of
pyridoxine hydrochloride reference material, use 0.1 mol/L hydrochloric acid solution to
dissolve it and dilute into a 50 mL brown volumetric flask. Then, transfer it to a brown glass
reagent bottle, and store it in the dark at 20 C. It shall remain valid for 3 months.
3.4.2 Pyridoxal standard stock solution (1.00 mg/mL): accurately weigh-take 60.9 mg of
pyridoxal hydrochloride reference material, use 0.1 mol/L hydrochloric acid solution to
dissolve it and dilute into a 50 mL brown volumetric flask. Then, transfer it to a brown glass
reagent bottle, and store it in the dark at 20 C. It shall remain valid for 3 months.
3.4.3 Pyridoxamine standard stock solution (1.00 mg/mL): accurately weigh-take 71.7 mg of
pyridoxamine dihydrochloride reference material, use 0.1 mol/L hydrochloric acid solution to
dissolve it and dilute into a 50 mL brown volumetric flask. Then, transfer it to a brown glass
reagent bottle, and store it in the dark at 20 C. It shall remain valid for 3 months.
3.4.4 Vitamin B6 standard mixed stock solution (50.0 g/mL): respectively and accurately draw
5.00 mL of pyridoxamine, pyridoxal and pyridoxine standard stock solution (1.00 mg/mL), use
0.1 mol/L hydrochloric acid solution to dilute into a 100 mL brown volumetric flask. Then,
transfer it to a brown glass reagent bottle, and store it in the dark at 20 C. It shall remain valid
for 3 months.
3.4.5 Vitamin B6 standard mixed working solution (5.00 g/mL): accurately draw 1.00 mL of
vitamin B6 standard mixed stock solution (50.0 g/mL), use mobile phase A to dilute into a 10
mL brown volumetric flask. Prepare it right before use.
3.4.6 Vitamin B6 standard mixed working solution (500 ng/mL): accurately draw 1.00 mL of
vitamin B6 standard mixed stock solution (5.00 g/mL), use mobile phase A to dilute into a 10
mL brown volumetric flask. Prepare it right before use.
3.4.7 Vitamin B6 standard mixed working solution (50.0 ng/mL): accurately draw 1.00 mL of
vitamin B6 standard mixed stock solution (500 ng/mL), use mobile phase A to dilute into a 10
mL brown volumetric flask. Prepare it right before use.
NOTE: the frozen stock solution shall be thawed at room temperature and evenly mixed before use.
3.5 Preparation of Isotope Internal Standard Solutions
3.5.1 13C4-pyridoxine isotope internal standard stock solution (100 g/mL): accurately weigh-
take 12.1 mg (accurate to 0.1 mg) of 13C4-pyridoxine hydrochloride, use 0.1 mol/L hydrochloric
acid solution to dilute into a 100 mL brown volumetric flask. Then, transfer it to a brown glass
reagent bottle, and store it in the dark at 20 C. It shall remain valid for 3 months.
4.8 Homogenizer.
4.9 Constant-temperature water bath or autoclave.
5 Analytical Procedures
5.1 Specimen Preparation
For meat, vegetables and fruits, etc., take the edible parts, use water to wash them, and use dry
gauze to wipe off the surface moisture, use a homogenizer to homogenize them and store in
sample bottles for later use. For powdery samples (milk powder and rice noodles, etc.), evenly
mix them and conduct direct sampling. For liquid samples, evenly shake them and reserve them
for later use. For liquid samples with granules, for example, large-grained yogurt, use a
homogenizer to homogenize them and reserve them for later use. For flaky and granular
samples, use a high-speed pulverizer to grind them into powder and seal for later use. The
prepared specimens shall be kept refrigerated in the dark and determined as soon as possible.
5.2 Specimen Treatment
5.2.1 Specimens containing starch
5.2.1.1 Solid specimens: accurately weigh-take 1 g ~ 5 g (accurate to 0.01 g) of evenly mixed
solid specimen into a 150 mL stoppered conical flask (with a soft stopper), and add 500 L of
vitamin B6 isotope internal standard mixed working solution (10.0 g/mL), add 50 mL of 0.1
mol/L HCl solution to disperse the sample, use a soft stopper to plug it. Place it in 100 C water
bath or 121 C autoclave to perform hydrolysis for 30 min; cool to room temperature and take
it out. After using sodium hydroxide solution (0.1 mol/L) to adjust the pH to 4.2 ~ 4.8,
accurately add 20 mg of acid phosphatase, 100 mg of papain and 10 mg of α-amylase. Fill the
conical flask with nitrogen, plug the flask and thoroughly mix it. In a constant-temperature
incubator at 37 C, conduct enzymatic hydrolysis for above 18 h. After the solution cools to
room temperature, transfer it to a 100 mL brown volumetric flask. Use water to dilute to the
scale and evenly mix it.
5.2.1.2 Liquid specimens: accurately weigh-take 5 g ~ 20 g (accurate to 0.01 g) of evenly mixed
liquid specimen into a 150 mL stoppered conical flask (with a soft stopper), and add 500 L of
vitamin B6 isotope internal standard mixed working solution (10.0 g/mL), add 50 mL of 0.1
mol/L HCl solution to disperse the sample, use a soft stopper to plug it. Place it in 100 C water
bath or 121 C autoclave to perform hydrolysis for 30 min; cool to room temperature and take
it out. After using sodium hydroxide solution (0.1 mol/L) to adjust the pH to 4.2 ~ 4.8,
accurately add 20 mg of acid phosphatase, 100 mg of papain and 10 mg of α-amylase. Fill the
conical flask with nitrogen, plug the flask and thoroughly mix it. In a constant-temperature
incubator at 37 C, conduct enzymatic hydrolysis for above 18 h. After the solution cools to
room temperature, transfer it to a 100 mL brown volumetric flask. Use water to dilute to the
scale and evenly mix it.
5.2.2 Starch-free specimens
5.2.2.1 Solid specimens: weigh-take 1 g ~ 5 g (accurate to 0.01 g) of evenly mixed solid
specimen into a 150 mL stoppered conical flask (with a soft stopper), and add 500 L of vitamin
B6 isotope internal standard mixed working solution (10.0 g/mL), add 50 mL of 0.1 mol/L
HCl solution to disperse the sample, use a soft stopper to plug it. Place it in 100 C water bath
or 121 C autoclave to perform hydrolysis for 30 min; cool to room temperature and take it out.
After using sodium hydroxide solution (0.1 mol/L) to adjust the pH to 4.2 ~ 4.8, accurately add
20 mg of acid phosphatase and 100 mg of papain. Fill the conical flask with nitrogen, plug the
flask and thoroughly mix it. In a constant-temperature incubator at 37 C, conduct enzymatic
hydrolysis for above 18 h. After the solution cools to room temperature, transfer it to a 100 mL
brown volumetric flask. Use water to dilute to the scale and evenly mix it.
5.2.2.2 Liquid specimens: weigh-take 5 g ~ 20 g (accurate to 0.01 g) of evenly mixed liquid
specimen into a 150 mL stoppered conical flask (with a soft stopper), and add 500 L of vitamin
B6 isotope internal standard mixed working solution (10.0 g/mL), add 50 mL of 0.1 mol/L
HCl solution to disperse the sample, use a soft stopper to plug it. Place it in 100 C water bath
or 121 C autoclave to perform hydrolysis for 30 min; cool to room temperature and take it out.
After using sodium hydroxide solution (0.1 mol/L) to adjust the pH to 4.2 ~ 4.8, accurately add
20 mg of acid phosphatase and 100 mg of papain. Fill the conical flask with nitrogen, plug the
flask and thoroughly mix it. In a constant-temperature incubator at 37 C, conduct enzymatic
hydrolysis for above 18 h. After the solution cools to room temperature, transfer it to a 100 mL
brown volumetric flask. Use water to dilute to the scale and evenly mix it.
NOTE 1: the operator may adjust the weighing amount of the specimen and the amount of isotope
internal standard added in accordance with the vitamin B6 content of the specimen and
the sensitivity of the mass spectrometer in this laboratory, and under conditions that are
not lower than the determination range requirements of the standard curve.
NOTE 2: to determine the products in which, vitamin B6 (pyridoxamine, pyridoxal and pyridoxine)
is added as a nutritional fortifier, please refer to 12.2 for the pre-treatment method.
5.2.3 Preparation of test solution
Take another 50 mL conical flask, put in a funnel and filter paper, evenly mix the diluted sample
solution and pour the solution into the flask. Naturally filter it to obtain more than 20 mL of
filtrate. Accurately draw 1.00 mL of the filtrate into a 10 mL brown volumetric flask, use mobile
phase A to dilute to the scale. After vortex mixing, use 0.22 m microporous membrane to filter
it, and transfer it to a brown sample injection bottle for later testing.
5.3 Determination Conditions of Instruments
5.3.1 Reference conditions of chromatography
The reference conditions of chromatography are as follows:
a) Chromatographic column: silica gel matrix pentafluorophenyl column (particle size
1.8 m, 3.0 mm 150 mm), or equivalent;
10.1.2 Formic acid (HCOOH): chromatographically pure.
10.1.3 Ammonium formate (HCOONH4): chromatographically pure.
10.1.4 Hydrochloric acid (HCl).
10.1.5 Sodium hydroxide (NaOH).
10.1.6 α-amylase: enzyme activity 50 U/mg.
10.2 Reagent Preparation
10.2.1 Hydrochloric acid solution (0.1 mol/L): accurately draw 9 mL of hydrochloric acid and
use water to dilute to 1,000 mL.
10.2.2 Sodium hydroxide solution (0.1 mol/L): accurately weigh-take 0.4 g of sodium
hydroxide, add 50 mL of water to dissolve it; after cooling, use water to dilute to 100 mL.
10.2.3 Mobile phase A (2% formic acid aqueous solution of 10 mmol/L ammonium formate):
weigh-take 0.63 g of ammonium formate, successively add about 950 mL of water to dissolve
it, accurately add 20 mL of formic acid, and use water to dilute to 1,000 mL. Then, evenly mix
it, conduct ultrasonic degassing and reserve it for later use.
10.2.4 Mobile phase B (0.1% formic acid - methanol solution): draw 1 mL of formic acid, use
methanol to dilute to 1,000 mL, and conduct ultrasonic mixing.
10.3 Reference Materials
10.3.1 Pyridoxine hydrochloride (C8H12ClNO3, CAS No.: 58-56-0): purity 98%, or a standard
substance certified by the state and awarded a reference material certificate.
10.3.2 Pyridoxal hydrochloride (C8H10ClNO3, CAS No.: 65-22-5): purity 99%, or a standard
substance certified by the state and awarded a reference material certificate.
10.3.3 Pyridoxamine dihydrochloride (C8H14Cl2N2O2, CAS No.: 524-36-7): purity 99%, or a
standard substance certified by the state and awarded a reference material certificate.
10.3.4 13C4-pyridoxine hydrochloride (13C4C4H12ClNO3): purity 98%.
10.3.5 D3-pyridoxal (C8D3H6NO3, CAS No.: 1173023-49-8): purity 98%.
10.3.6 D3-pyridoxamine dihydrochloride (C8D3H11Cl2N2O2, CAS No.: 1173023-45-4): purity
98%.
10.4 Preparation of Standard Solutions
10.4.1 Pyridoxine standard stock solution (1.00 mg/mL): accurately weigh-take 60.8 mg of
pyridoxine hydrochloride reference material, use 0.1 mol/L hydrochloric acid solution to
dissolve it, transfer into a 50 mL brown volumetric flask, and dilute to the scale. Then, transfer
it to a brown glass reagent bottle, and store it in the dark at 20 C. It shall remain valid for 3
months.
10.4.2 Pyridoxal standard stock solution (1.00 mg/mL): accurately weigh-take 60.9 mg of
pyridoxal hydrochloride reference material, use 0.1 mol/L hydrochloric acid solution to
dissolve it, transfer into a 50 mL brown volumetric flask, and dilute to the scale. Then, transfer
it to a brown glass reagent bottle, and store it in the dark at 20 C. It shall remain valid for 3
months.
10.4.3 Pyridoxamine standard stock solution (1.00 mg/mL): accurately weigh-take 71.7 mg of
pyridoxamine dihydrochloride reference material, use 0.1 mol/L hydrochloric acid solution to
dissolve it, transfer into a 50 mL brown volumetric flask, and dilute to the scale. Then, transfer
it to a brown glass reagent bottle, and store it in the dark at 20 C. It shall remain valid for 3
months.
10.4.4 Vitamin B6 standard mixed stock solution (50.0 g/mL): respectively and accurately
draw 5.00 mL of pyridoxamine, pyridoxal and pyridoxine standard stock solution (1.00 mg/mL)
into a 100 mL brown volumetric flask, and use 0.1 mol/L hydrochloric acid solution to dilute
to the scale. Then, transfer it to a brown glass reagent bottle, and store it in the dark at 20 C.
It shall remain valid for 3 months.
10.4.5 Vitamin B6 standard mixed working solution (5.00 g/mL): accurately draw 1.00 mL of
vitamin B6 standard mixed stock solution (50.0 g/mL) into a 10 mL brown volumetric flask,
use mobile phase A to dilute to the scale. Prepare it right before use.
10.4.6 Vitamin B6 standard mixed working solution (500 ng/mL): accurately draw 1.00 mL of
vitamin B6 standard mixed working solution (5.00 g/mL) into a 10 mL brown volumetric flask,
use mobile phase A to dilute to the scale. Prepare it right before use.
10.4.7 Vitamin B6 standard mixed working solution (50.0 ng/mL): accurately draw 1.00 mL of
vitamin B6 standard mixed working solution (500 ng/mL) into a 10 mL brown volumetric flask,
use mobile phase A to dilute to the scale. Prepare it right before use.
NOTE: the frozen stock solution shall be thawed at room temperature and evenly mixed before use.
10.5 Preparation of Isotope Internal Standard Solutions
10.5.1 13C4-pyridoxine isotope internal standard stock solution (1.00 mg/mL): weigh-take 12.1
mg (accurate to 0.1 mg) of 13C4-pyridoxine hydrochloride, use 0.1 mol/L hydrochloric acid
solution to dissolve it, transfer into a 10 mL brown volumetric flask and dilute to the scale.
Then, transfer it to a brown glass reagent bottle, and store it in the dark at 20 C. It shall remain
valid for 3 months.
10.5.2 D3-pyridoxal isotope internal standard stock solution (1.00 mg/mL): weigh-take 10.0 mg
(accurate to 0.1 mg) of D3-pyridoxal hydrochloride, use 0.1 mol/L hydrochloric acid solution
to dissolve it, transfer into a 10 mL brown volumetric flask and dilute to the scale. Then, transfer
it to a brown glass reagent bottle, and store it in the dark at 20 C. It shall remain valid for 3
11.9 Constant-temperature water bath.
12 Analytical Procedures
12.1 Specimen Preparation
For powdery samples (milk powder and rice noodles, etc.), evenly mix them and conduct direct
sampling. For liquid samples, evenly shake them and reserve them for later use. For flaky and
granular samples, use a high-speed pulverizer to grind them into powder or use a homogenizer
to homogenize them, and seal for later use. The prepared specimens shall be kept refrigerated
in the dark and determined as soon as possible.
12.2 Specimen Treatment
12.2.1 Specimens containing starch
12.2.1.1 Solid specimens: weigh-take 1 g ~ 5 g (accurate to 0.01 g) of evenly mixed solid
specimen, add 0.4 mL of vitamin B6 isotope internal standard mixed working solution, then,
add about 25 mL of warm water (45 C ~ 50 C) to dissolve it. Use hydrochloric acid solution
or sodium hydroxide solution to adjust the pH to 6.0 ~ 6.5, add 0.1 g of α-amylase into a 150
mL stoppered conical flask. Shake and evenly mix it, then, fill the conical flask with nitrogen,
plug the flask, and place it in an incubator at 50 C ~ 60 C for about 30 min. Take it out and
cool to room temperature.
12.2.1.2 Liquid specimens: weigh-take 5 g ~ 20 g (accurate to 0.01 g) of evenly mixed liquid
specimen, add 0.4 mL of vitamin B6 isotope internal standard mixed working solution, then,
add 20 mL of water. Use hydrochloric acid solution or sodium hydroxide solution to adjust the
pH to 6.0 ~ 6.5, add 0.1 g of α-amylase into a 150 mL stoppered conical flask. Shake and evenly
mix it, then, fill the conical flask with nitrogen, plug the flask, and place it in an incubator at 50
C ~ 60 C for about 30 min. Take it out and cool to room temperature.
12.2.2 Starch-free specimens
12.2.2.1 Solid specimens: weigh-take 1 g ~ 5 g (accurate to 0.01 g) of evenly mixed solid
specimen into a 150 mL stoppered conical flask, accurately add 0.4 mL of vitamin B6 isotope
internal standard mixed working solution, then, add about 25 mL of water to dissolve it, shake
and evenly mix it.
12.2.2.2 Liquid specimens: weigh-take 5 g ~ 20 g (accurate to 0.01 g) of evenly mixed liquid
specimen into a 150 mL stoppered conical flask, accurately add 0.4 mL of vitamin B6 isotope
internal standard mixed working solution, then, add 20 mL of water, and perform vortex mixing.
12.2.3 Preparation of test solution
Use hydrochloric acid solution to adjust the pH of the above-mentioned specimen solution to
1.7 0.1, and let it stand for about 1 min. Then, use sodium hydroxide solution (0.1 mol/L) to
17.4 Preparation of Standard Solutions
17.4.1 Pyridoxine standard stock solution (1.00 mg/mL): accurately weigh-take 60.8 mg
(accurate to 0.1 mg) of pyridoxine hydrochloride reference material, use 0.1 mol/L hydrochloric
acid solution to dissolve it, then, dilute to 50 mL. Store it in the dark in the refrigerator at 20
C. It shall remain valid for 3 months.
17.4.2 Pyridoxal standard stock solution (1.00 mg/mL): accurately weigh-take 60.9 mg
(accurate to 0.1 mg) of pyridoxal hydrochloride reference material, use 0.1 mol/L hydrochloric
acid solution to dissolve it, then dilute to 50 mL. Store it in the dark in the refrigerator at 20
C. It shall remain valid for 3 months.
17.4.3 Pyridoxamine standard stock solution (1.00 mg/mL): accurately weigh-take 71.7 mg
(accurate to 0.1 mg) of pyridoxamine dihydrochloride reference material, use 0.1 mol/L
hydrochloric acid solution to dissolve it, then dilute to 50 mL. Store it in the dark in the
refrigerator at 20 C. It shall remain valid for 3 months.
17.4.4 Vitamin B6 standard mixed working solution (20.0 g/mL): respectively and accurately
draw 1.0 mL of pyridoxine, pyridoxal and pyridoxamine standard stock solutions (1.00 mg/mL).
Use 0.1 mol/L hydrochloric acid solution to dilute to 50 mL. Prepare it right before use.
17.4.5 Vitamin B6 standard mixed working solution (2.00 g/mL): accurately draw 5.00 mL of
pyridoxine, pyridoxal and pyridoxamine standard mixed working solution (20.0 g/mL), use
0.1 mol/L hydrochloric acid solution to dilute to 50 mL. Prepare it right before use.
17.4.6 Vitamin B6 standard mixed series working solutions: respectively and accurately draw
an appropriate amount of vitamin B6 standard mixed working solution (2.00 g/mL) into a 100
mL volumetric flask, use water to dilute them. The concentrations of this standard series are
respectively: 0.04 g/mL, 0.10 g/mL, 0.20 g/mL, 0.40 g/mL, 0.60 g/mL and 1.00 g/mL.
Prepare them right before use.
NOTE 1: please refer to Appendix A for the concentration correction method of standard stock
solution.
NOTE 2: the frozen stock solution shall be thawed at room temperature and evenly mixed before
use.
18 Instruments and Equipment
18.1 High-performance liquid chromatograph: equipped with a fluorescence detector.
18.2 Balance: with a division value of 0.01 g and 0.1 mg.
18.3 pH meter: with an accuracy of 0.01.
18.4 Vortex mixer.
18.5 Ultrasonic oscillator.
18.6 Spectrophotometer.
18.7 Constant-temperature incubator, or one with equivalent performance.
19 Analytical Procedures
19.1 Specimen Preparation
19.1.1 Specimens containing starch
19.1.1.1 Solid specimens: weigh-take 1 g ~ 5 g (accurate to 0.01 g) of evenly mixed solid
specimen into a 150 mL conical flask, add about 25 mL of 45 C ~ 50 C water, and evenly mix
it. Add about 0.5 g of α-amylase. After evenly mixing it, fill the conical flask with nitrogen,
plug the flask and place it in an incubator at 50 C ~ 60 C for about 30 min. Take it out and
cool to room temperature.
19.1.1.2 Liquid specimens: weigh-take 5 g ~ 20 g (accurate to 0.01 g) of evenly mixed liquid
specimen into a 150 mL conical flask, and evenly mix it. Add about 0.5 g of α-amylase. After
evenly mixing it, fill the conical flask with nitrogen, plug the flask and place it in an incubator
at 50 C ~ 60 C for about 30 min. Take it out and cool to room temperature.
19.1.2 Starch-free specimens
19.1.2.1 Solid specimens: weigh-take 1 g ~ 5 g (accurate to 0.01 g) of evenly mixed solid
specimen into a 150 mL conical flask, add about 25 mL of 45 C ~ 50 C water, and evenly mix
it. Let it stand for 5 min ~ 10 min, then, cool to room temperature.
19.1.2.2 Liquid specimens: weigh-take 5 g ~ 20 g (accurate to 0.01 g) of evenly mixed liquid
specimen into a 150 mL conical flask. Let it stand for 5 min ~ 10 min.
19.1.3 Preparation of test solution
Use hydrochloric acid solution to adjust the pH of the above-mentioned specimen solution to
1.7 0.1 and let it stand for about 1 min. Then, use sodium hydroxide solution to adjust the pH
of the specimen solution to 4.5 0.1. Put the above-mentioned conical flask into an ultrasonic
oscillator and perform ultrasonic oscillation for about 10 min. Transfer the specimen solution
to a 50 mL volumetric flask and use water to rinse the conical flask. Combine the washing
solutions in a 50 mL volumetric flask and use water to dilute to 50 mL. Take another 50 mL
conical flask, put in a funnel and filter paper, pour the diluted specimen solution into it, and
naturally filter it. Filter the filtrate through 0.45 m microporous filter membrane, then, transfer
1 mL to a brown sample injection bottle, and use it as the specimen solution to be tested.
NOTE: during the operation, avoid strong light exposure; when extracting gel candies and jelly
specimens, they can be heated and dissolved in 70 C water bath.
......
GB 5009.154-2016
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
National Food Safety Standard -
Determination of Vitamin B6 in Foods
ISSUED ON. DECEMBER 23, 2016
IMPLEMENTED ON. JUNE 23, 2017
Issued by. National Health and Family Planning Commission of the
People’s Republic of China;
State Food and Drug Administration of the People’s Republic
of China.
Table of Contents
Foreword ... 3
1 Scope ... 4
Method I High-performance Liquid Chromatography ... 4
2 Principle ... 4
3 Reagents and Materials ... 4
4 Instruments and Equipment ... 6
5 Analytical Procedures ... 6
6 Expression of Analysis Results ... 8
7 Precision ... 9
8 Others ... 9
Method II Microbial Method ... 9
9 Principle ... 9
10 Reagents and Materials ... 9
11 Instruments and Equipment ... 11
12 Analytical Procedures ... 11
13 Expression of Analysis Results ... 13
14 Precision ... 14
15 Others ... 14
Appendix A Method of Concentration Correction of Vitamin B6 in Each
Component of Standard Solution ... 15
Appendix B Liquid Chromatogram of Vitamin B6 ... 17
Appendix C Medium Component and Preparation Method ... 18
National Food Safety Standard -
Determination of Vitamin B6 in Foods
1 Scope
This Standard specifies methods of determining vitamin B6 in foods.
In this Standard, Method I is high-performance liquid chromatography, which is
applicable to the determination of foods that contain vitamin B6; Method II is microbial
method, which is applicable to the determination of vitamin B6 in all kinds of food.
Method I -- High-performance Liquid Chromatography
2 Principle
After pre-processing of the sample, for example, extraction, the sample is separated
with C18 chromatographic column and detected with high-performance liquid
chromatography - fluorescence detector. The content of vitamin B6 (pyridoxine,
pyridoxal and pyridoxamine) is quantitatively determined with the external standard
method.
3 Reagents and Materials
Unless otherwise indicated, the reagents adopted under this method are of analytical
purity. The water is first-grade water as specified in GB/T 6682.
3.1 Reagents
3.1.1 Sodium octane sulfonate (C8H17NaO3S).
3.1.2 Glacial acetic acid (C2H4O2).
3.1.3 Triethylamine (C6H15N). chromatographic purity.
3.1.4 Methanol (CH4O). chromatographic purity.
3.1.5 Hydrochloric acid (HCl).
3.1.6 Sodium hydroxide (NaOH).
3.1.7 Amylase. enzyme activity ≥1.5 U/mg.
3.2 Preparation of Reagents
then, mix it up. Place it evenly for 5 min~10 min, then, cool it down to the room
temperature.
b) Liquid sample. weigh-take approximately 20 g (accurate to 0.01 g) of thoroughly
mixed liquid sample; place it in 150 mL conical flask. Place it evenly for 5 min~10 min.
5.1.3 Preparation of test solution
Use hydrochloric acid solution to adjust the above-mentioned sample solution to pH
1.7±0.1; place evenly for around 1 min. Use sodium hydroxide solution to adjust the
sample solution to pH 4.5±0.1. Place the above-mentioned conical flask into ultrasonic
oscillator; start ultrasonic oscillation for around 10 min. Transfer the sample solution
into 50 mL volumetric flask; use water to rinse the conical flask. Combine the lotion in
50 mL volumetric flask; use water to dilute to the constant volume of 50 mL. Take
another 50 mL conical flask, place a funnel and filter paper on top of it; pour the
constant-volume sample solution into the conical flask, then, naturally filter it. Use 0.45
μm microporous membrane to filter the filtrate, then, use a tube to collect it; transfer 1
mL of filtrate to inlet bottle as the test solution.
Note. avoid strong light exposure during the operation.
5.2 Instrument Reference Conditions
Please see instrument reference conditions below.
a) Chromatographic column. C18 column, length. 150 mm, internal diameter. 4.6
mm, particle size of column filling. 5 μm, or any equivalent;
b) Mobile phase. methanol 50 mL, sodium octane sulfonate 2.0 g, triethylamine 2.5
mL; use water to dissolve to the constant volume of 1,000 mL, then, use glacial
acetic acid to adjust to pH 3.0±0.1; use 0.45 μm microporous membrane to filter
it;
c) Flow rate. 1 mL/min;
d) Column temperature. 30 °C;
e) Detection wavelength. excitation wavelength. 293 nm, emission wavelength. 395
nm;
f) Inlet volume. 10 μL.
5.3 Draw a Standard Curve Line
Respectively inject vitamin B6 mixed standard series working solution into high-
performance liquid chromatograph, then, measure the peak area of each component;
take the concentration of corresponding standard working solution as x-coordinate,
take the peak area as y-coordinate to draw a standard curve line.
10.1.6 Sodium chloride (NaCl).
10.1.7 Bromo cresol green (C21H14Br4O5S).
10.2 Preparation of Reagents
10.2.1 Hydrochloric acid solution (0.01 mol/L). take 0.9 mL of hydrochloric acid; use
water to dilute to the constant volume of 1,000 mL.
10.2.2 Sulfuric acid solution (0.22 mol/L). add 700 mL of water and 12.32 mL of sulfuric
acid to 2,000 mL beaker; use water to dilute to 1,000 mL.
10.2.3 Sulfuric acid solution (0.5 mol/L). add 700 mL of water and 28 mL of sulfuric
acid to 2,000 mL beaker; use water to dilute to 1,000 mL.
10.2.4 Sodium hydroxide solution (10 mol/L). weigh-take 40 g of sodium hydroxide,
then, add 40 mL of water to dissolve it; cool it down and use water to dilute to the
constant volume of 100 mL.
10.2.5 Sodium hydroxide solution (0.1 mol/L). transfer-take 1 mL of 10 mol/L sodium
hydroxide solution, then, add water to dilute to the constant volume of 100 mL.
10.2.6 Saline (9 g/L). weigh-take 9 g of sodium chloride, use water to dissolve it to the
constant volume of 1,000 mL; start autoclaved sterilization under 121 °C for 15 min;
cool it down and reserve for later usage.
10.2.7 Bromo cresol green solution (0.4 g/L). accurately weigh-take 0.1 g of bromo
cresol green and place it in a mortar; add 1.4 mL of 0.1 mol/L sodium hydroxide solution
to grind it; add a little water and continue to grind it, till it completely dissolves; use
water to dilute to 250 mL.
10.3 Medium (refer to Appendix C for medium component and
preparation method)
10.3.1 Pyridoxine Y medium.
10.3.2 Pyridoxine Y agar medium.
10.3.3 Malt extract powder agar medium.
10.3.4 YM broth medium.
10.3.5 YM broth agar medium.
10.4 Standards
Pyridoxine hydrochloride (C8H12ClNO3, CAS No.. 58-56-0). purity≥99%, or standard
substance with a national-level certificate and a certificate of standard substance.
12.1.2 Monthly-reserved strain preparation. inoculate strain rejuvenation medium on
the bevel of YM broth agar medium (subculture medium) through streak inoculation;
start culture under 30 °C for 20 h~24 h; store in the refrigerator under 2 °C~8 °C. This
strain is the first generation of monthly-reserved strain. Inoculate the previous
generation of monthly-reserved strain on the bevel of YM broth agar medium
(subculture medium) through streak inoculation every month in the following period;
start culture under 30 °C for 20 h~24 h; store in the refrigerator under 2 °C~8 °C. This
monthly-reserved strain can remain valid for 1 month.
12.1.3 Weekly-reserved strain preparation. inoculate monthly-reserved strain on the
bevel of YM broth agar medium (subculture medium) every week; start culture under
30 °C for 20 h~24 h; store in the refrigerator under 2 °C~8 °C. It can remain valid for 7
days. Strain that’s reserved for over several weeks cannot be immediately adopted for
the preparation of inoculum. Before usage, it must be transferred once a day for 2
days~3 days in a row, otherwise, the growth cannot be guaranteed.
12.1.4 Inoculant suspension preparation. one day before the determination of vitamin
B6, transfer weekly-reserved strain in 10 mL of YM broth medium (seed culture
medium). 2 tubes can be prepared simultaneously. Start oscillating culture under 30 °C
for 20 h~24 h, then, obtain seed culture medium for determination. The number of total
generations from monthly-reserved strain to seed culture medium shall be ≤5. Start
centrifugation of the seed culture medium under 3,000 r/min for 10 min, dump the
supernatant; use 10 mL of saline to rinse it, start centrifugation and dump the
supernatant, then, use saline to repeatedly rinse it for 2 times. Add 10 mL of sterilized
saline, then, place centrifuge tube on vortex mixer to thoroughly mix it; turn the strain
into suspension, then, pour the suspension into a sterilized syringe; use it immediately.
12.2 Sample Processing
12.2.1 Weigh-take 0.5 g~10 g (accurate to 0.01 g, the content of vitamin B6 shall be
≤10 ng), place it in 100 mL conical flask, then, add 72 mL of 0.22 mol/L sulfuric acid
solution. Place it in autoclave under 121 °C and start hydrolysis for 5 h; take it out and
cool it down. Adopt 10.0 mol/L sodium hydroxide solution and 0.5 mol/L sulfuric acid
solution to adjust to pH 4.5; use bromo cresol green as the indicator (indicator turns
from yellow to yellow-green). Transfer the reagent in the conical flask into 100 mL
volumetric flask; use distilled water to dilute to the constant volume of 100 mL; use
filter paper to filter it, store the filtrate in the refrigerator for later usage (the period of
validity shall be ≤36 h).
Note. keep away from light during sample processing.
12.2.2 Preparation of standard curve line. respectively add 0.00 mL, 0.02 mL, 0.04 mL,
0.08 mL, 0.12 mL and 0.16 mL of pyridoxine working solution to 3 groups of tube; add
pyridoxine Y medium to 5.00 mL; mix it up, put on cotton plug.
12.2.3 Preparation of sample tube. respectively add 0.05 mL, 0.10 mL and 0.20 mL of
Appendix C
Medium Component and Preparation Method
C.1 Pyridoxine Y Medium
Solution (per liter) contains. glucose 40.0 g, L-asparagine 4.0 g, ammonium sulfate 4.0
g, potassium dihydrogen phosphate3.0 g, magnesium sulfate 1.0 g, calcium oxide 0.49
g, DL-methionine 40.0 mg, DL-tryptophan 40.0 mg, DL-isoleucine 40.0 mg, DL-proline
40.0 mg, histidine hydrochloride 20.0 mg, riboflavin 20.0 mg, biotin 8.0 mg, inositol 5.0
mg, ferrous sulfate 500.0 μg, thiamine hydrochloride 400.0 μg, calcium pantothenate
400.0 μg, choline acid 400.0 μg, boric acid 200.0 μg, potassium iodide 200.0 μg,
ammonium molybdate 40.0 μg, manganese sulfate 80.0 μg, copper sulfate 90.0 μg,
zinc sulfate 80.0 μg, distilled water 1,000 mL.
Weigh-take 5.3 g of the above-mentioned pyridoxine Y medium, then, dissolve it in 100
mL of distilled water; adjust to pH 4.1±0.05; start sterilization under 121 °C for 15 min;
reserve for later usage.
C.2 Pyridoxine Y Agar Medium
Weigh-take 5.3 g of the above-mentioned pyridoxine Y medium, then, dissolve it in 100
mL of distilled water; adjust to pH 4.1±0.05. Add 1.2 g of agar, heat it up and boil it to
melt the agar. Thoroughly mix it up and divide it into tubes (10 mL in each tube). Start
sterilization under 121 °C for 15 min; place it in a beveled state and reserve for later
usage.
C.3 Malt Extract Powder Agar Medium
Weigh-take 12.75 g of maltose, 2.75 g of dextrin, 2.35 g of glycerol and 0.78 g of
peptone; dissolve it in 1,000 mL of distilled water; adjust to pH 4.7±0.2. Add 15.0 g of
agar, heat it up and boil it to melt the agar. Thoroughly mix it up and divide it into tubes
(10 mL in each tube). Start sterilization under 121 °C for 15 min; place it in a beveled
state and reserve for later usage. It shall be adopted to prepare monthly and weekly-
reserved strain medium of Saccharomyces carlsbergensis.
C.4 YM Broth Medium
Solution (per liter) contains. yeast extract 3.0 g, malt extract 3.0 g, peptone 5.0 g,
glucose 10.0 g and distilled water 1,000 mL. Weigh the medium in accordance with the
proportion of 2.1 g/100 mL water. Add corresponding volume of distilled water, mix it
up; adjust to pH 6.2±0.2, then, divide it into tubes (10 mL in each tube). Start
sterilization under 121 °C for 15 min; cool it down, then, store it in the refrigerator under
4 °C. It shall remain valid for 1 month and serve as rejuvenation culture medium of
Saccharomyces carlsbergensis and seed culture medium for daily detection.
......
Standard ID | GB 5009.154-2023 (GB5009.154-2023) | Description (Translated English) | (National Food Safety Standard Determination of Vitamin D in Food) | Sector / Industry | National Standard | Classification of Chinese Standard | X09 | Word Count Estimation | 26,234 | Date of Issue | 2023-09-06 | Date of Implementation | 2024-03-06 | Issuing agency(ies) | National Health Commission of the People's Republic of China, State Administration for Market Regulation | Summary | This standard specifies the method for the determination of vitamin D in food. The first normal-phase chromatography purification-reverse-phase liquid chromatography method is suitable for the determination of vitamin D and vitamin D in foods added with ergocalciferol or cholecalciferol. The second method, online column switching-reverse-phase liquid chromatography, is suitable for the determination of vitamin D2 and vitamin D in food. The third method liquid chromatography-tandem mass spectrometry is suitable for the determination of vitamin D2 and vitamin D3 in food. | Standard ID | GB 5009.154-2016 (GB5009.154-2016) | Description (Translated English) | National food safety standard -- Determination of vitamin B6 in foods | Sector / Industry | National Standard | Classification of Chinese Standard | X09 | Word Count Estimation | 12,112 | Date of Issue | 2016-12-23 | Date of Implementation | 2017-06-23 | Older Standard (superseded by this standard) | GB 5413.13-2010; GB/T 5009.154-2003 | Regulation (derived from) | National Health and Family Planning Commission Notice No.17 of 2016 | Standard ID | GB/T 5009.154-2003 (GB/T5009.154-2003) | Description (Translated English) | Determination of vitamin B6 in foods | Sector / Industry | National Standard (Recommended) | Classification of Chinese Standard | C53 | Classification of International Standard | 67.040 | Word Count Estimation | 5,567 | Date of Issue | 2003-08-11 | Date of Implementation | 2004-01-01 | Older Standard (superseded by this standard) | GB/T 17407-1998 | Adopted Standard | AOAC 43.229-1995; NEQ | Drafting Organization | Chinese Academy of Preventive Medicine, Institute of Nutrition and Food Hygiene | Administrative Organization | People's Republic of China Ministry of Health | Proposing organization | Ministry of Health of the People Republic of China | Issuing agency(ies) | The People Republic of China Ministry of Health, China National Standardization Management Committee | Summary | This standard specifies: Determination of microbial method Vitamin B6-content. This standard applies to: all kinds of foods vitamin B6-determination. This standard also applies to feed Vitamin B6-determination. The detection limit was 0. 1ng, linear range of 0. 1ng ~ 6ng. |
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