GB 31614.1-2023 National food safety standard -Determination of sialic acid in foods +English, Anglais, Englisch, Inglés, えいご
1 Scope
This standard specifies the method for determination of sialic acid in foods.
For the purpose of this standard, Method I: liquid chromatography-ultraviolet detection is applicable to the determination of bound sialic acid in swiflets nest and swiflets nest products, Method II: liquid chromatography-fluorescence detection and Method III: liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS) are applicable to the determination of sialic acid in liquid milk, milk powder, cakes and beverages.
Method I Liquid chromatography-ultraviolet detection
2 Principle
The sample is hydrolyzed in hydrochloric acid solution by heating to release bound sialic acid. The sample test solution is separated by strong anion exchange chromatography column, detected by ultraviolet detector or diode array detector, and quantified by external standard method.
3 Reagents and materials
Unless otherwise specified, analytically-pure reagents and Grade I water (as specified in GB/T 6682) are adopted for the purpose of this method.
3.1 Reagents and materials
3.1.1 Acetonitrile (CH3CN): chromatographically pure.
3.1.2 Phosphoric acid (H3PO4): chromatographically pure.
3.1.3 Concentrated hydrochloric acid (HCl): 12mol/L.
3.1.4 Dialysis bag: be able to dialyze a compound with a relative molecular mass below 7,000, and to be soaked in water for 1h before use.
3.1.5 Microporous membrane: 0.45μm, organic phase.
3.2 Preparation of reagents
3.2.1 Hydrochloric acid solution (0.05mol/L): pipette 4.17mL concentrated hydrochloric acid, dissolve it in water and dilute to 1,000mL.
3.2.2 0.1% phosphoric acid solution: pipette 1mL phosphoric acid, dissolve it in water and dilute to 1,000mL.
3.2.3 0.1% phosphoric acid solution-acetonitrile (4+6): mix 0.1% phosphoric acid solution and acetonitrile in a volume ratio of 4:6.
3.3 Standard substance
Sialic acid (N-acetylneuraminic acid, C11H19NO9, CAS No.: 131-48-6): with a purity of greater than or equal to 96%, or a standard substance certified by the state and issued with a standard substance certificate.
3.4 Preparation of standard solutions
3.4.1 Sialic acid standard stock solution (1,000mg/L): accurately weigh an appropriate amount of sialic acid standard substance (converted according to purity), dissolve it in water and prepare into a standard stock solution with a mass concentration of 1,000mg/L, and store it at 4℃ away from light, with a shelf life of 6 months.
3.4.2 Sialic acid standard working solution series: pipette 0.1mL, 0.5mL, 1.0mL, 5.0mL, 10.0mL and 20.0mL sialic acid standard stock solution (1,000mg/L) into 100mL volumetric flasks respectively, add 0.1% phosphoric acid solution-acetonitrile (4+6), dilute to volume, and mix well. The mass concentration of sialic acid standard working solution series is 1.0mg/L, 5.0mg/L, 10.0mg/L, 50.0mg/L, 100.0mg/L and 200.0mg/L respectively. Prepare immediately before use.
4 Apparatus and equipment
4.1 Liquid chromatograph: equipped with ultraviolet detector or diode array detector.
4.2 Thermostat water bath.
4.3 Vortex mixer.
4.4 Analytical balance: with a sensitivity of 0.1mg and 0.01g respectively.
4.5 Homogenizer: with a rotating speed of not lower than 10,000r/min.
4.6 Oven.
Contents
Foreword i
1 Scope
2 Principle
3 Reagents and materials
4 Apparatus and equipment
5 Analysis steps
6 Expression of analysis results
7 Precision
8 Others
9 Principle
10 Reagents and materials
11 Apparatus and equipment
12 Analysis steps
13 Expression of analysis results
14 Precision
15 Others
16 Principle
17 Reagents and materials
18 Apparatus and equipment
19 Analysis steps
20 Expression of analysis results
21 Precision
22 Others
Annex A Liquid chromatogram of sialic acid standard solution
Annex B Liquid chromatogram of sialic acid standard solution
Annex C LC-MS/MS characteristic ion chromatogram of sialic acid standard solution
