Ascorbic acid (AsA) content determination instructions - Huaqiang Electronic Network

Brand AVX TPSE226M035R0125 Low impedance tantalum capacitor AVX 22

ASA-3.6864MHZ-LT

Test probe P100-B can be customized for other specifications

Kaixin micro test

Ascorbic acid (AsA) content determination instructions for use in vitamin C

(English: Vitamin C, also known as L-

) is an essential nutrient for higher primates and other minorities.

Most organisms can be made from metabolism, but humans are the most notable exception.

Reduced ascorbic acid (AsA) can reduce iron ions to ferrous ions, and ferrous ions react with phenanthroline (4,7-diphenyl-1,10-phenanthroline, BP) to form a red chelate. The absorption at the wavelength of 534 nm is positively correlated with the AsA content, so it can be determined by colorimetry. Deoxyascorbic acid (DAsA) can be reduced to AsA by dithiothreitol (DTT). The total amount of AsA was measured, and the reduced AsA was subtracted from it, which is the DAsA content.

Second, instruments and appliances

Centrifuge; spectrophotometer; mortar; test tube.

Third, the reagent

5% tris(TCA); 20% TCA; absolute ethanol solution; 0.4% phosphoric acid-ethanol solution; 0.5% BP-ethanol solution; 0.03% FeCl3-ethanol solution; 0.6 g/L DTT; Na ₂ HPO ₄ -NaOH solution : mixing with 0.2 mol/L Na ₂ HPO ₄ and 1.2 mol/L NaOH in an equal amount; 60 mmol/L DTT-ethanol.

Fourth, the method

1. Prepare standard curve to prepare AsA series standard solution with concentration of 2mg/L, 4mg/L, 6mg/L, 8mg/L, 10mg/L, 12mg/L, 14mg/L. Take 1.0 ml of each standard solution in a test tube, add 1.0 ml of 5% TCA, 1.0 ml of ethanol, and then add 0.5 ml of 0.4% H ₃ PO ₄ -ethanol, 1.0 ml of 0.5% BP-ethanol, 0.5 ml of 0.03%. FeCl ₃ -ethanol, total volume 5.0 ml. The solution was allowed to react at 30 ° C for 90 min, and then A534 was determined. Taking the AsA concentration as the abscissa and A534 as the ordinate to draw the standard curve, the linear equation is obtained.

2. Extract 1.0g of plant leaves, add 5% TCA grinding at 1:5 (W/V), centrifuge at 4000r/min for 10min, and use the supernatant for determination.

3. Determination

(1) AsA measurement A 1.0 ml sample extract was taken in a test tube, and the measurement was carried out in the same manner as above, and the AsA content was calculated from the standard curve.

(2) DAsA determination Add 1.0ml of 60mmol/L DTT-ethanol solution to 1.0ml sample solution, adjust the pH of the solution to 7~8 with Na ₂ HPO ₄ -NaOH mixture, and let it rest at room temperature for 10min to reduce DAsA. . Then add 0.5 ml of 20% TCA and adjust the pH to 1~2. The measurement was carried out in the same manner as AsA, and the total AsA content was calculated, and AsA was subtracted therefrom to obtain the DAsA content.
Ascorbic acid is a series of services from testing, production and processing. Find Shanghai Jinma Biotechnology Co., Ltd., the world's leading procurement and wholesale platform.