Method name: Determination of Vitamin E-Gas Chromatography.
Scope of application: This method uses the gas phase method to determine the content of vitamin E.
This method is suitable for vitamin E.
Principle of the method: The test product and the internal standard are made into methanol solution, enter the gas chromatograph for chromatographic separation and detect the absorption value of vitamin E (C31H52O3) and the internal standard n-tridodecane, and calculate their content.
Reagent: n-hexane
Equipment: instrument gas chromatograph
Chromatographic column : use silicone (OV-17) as the stationary phase, and the coating concentration is 2%, or use HP-1 capillary column (100% dimethyl polysiloxane ) as the analytical column; the number of theoretical plates is based on vitamin The E peak calculation should not be less than 500 (packed column) or 5000 (capillary column), and the resolution of the vitamin E peak and the peak of the internal standard substance should meet the requirements.
Chromatographic column and typical chromatographic conditions: column length 30 m, column inner diameter 0.53 mm or 0.32 mm, stationary liquid is 100% methyl polysiloxane
Column temperature: 265℃
Detector: hydrogen flame ionization detector , temperature 300℃
Injection port: temperature 290℃; split injection, split ratio 1:20; injection volume 1μL
Carrier gas: nitrogen , flow rate 5 mL/min
Sample preparation:
1. Weigh the test product
Accurately weigh 20 mg of the product and place it in a brown bottle with a stopper.
2. Preparation of reference solution
Accurately weigh 25mg of vitamin E reference substance and vitamin E reference substance, put them in a 100mL brown measuring flask, add 80mL of isooctane, avoid heating, sonicate for 1 minute to completely dissolve, and add isooctane to the mark, shake, rinse Nitrogen tightly plugged, protected from light, and stored below 0°C.
3. Preparation of internal standard solution
4. Preparation of test solution
Precisely add 10 mL of the internal standard solution to the above-mentioned test product, close it tightly, and shake to dissolve it to obtain the test product solution.
5. Determination of correction factor
Take another 20 mg of vitamin E reference substance, accurately weigh it, place it in a brown plug, add 10 mL of internal standard solution, close it tightly, shake to dissolve, take 1~3μL into the gas chromatograph, calculate the correction factor.
Note: "Precision weighing" means that the weighing should be accurate to one thousandth of the weight taken. "Precision measuring" means that the accuracy of measuring the volume should meet the accuracy requirements of the volume pipette in the national standard.
Steps:
Precisely draw 1~3μL of the above-mentioned test solution and reference solution respectively, and inject into the gas chromatograph for measurement and calculation.
Account not verified