Principle of determination of glycyrrhetinic acid: Glycyrrhetinic acid (GCA) is the main bile salt component in bile, synthesized in the liver and gallbladder, discharged from the bile into the intestine, ingested by small intestinal epithelial cells, and then entered the liver through the portal vein. Under normal circumstances, GCA in the portal vein system is taken up by hepatocytes and synthesized into Cholesteryl ester in hepatocytes, which enter the blood of the liver through the portal vein system. The content of Bile acid in bile is very low, and the concentration in plasma is also very low. Therefore, the bile acid content in plasma is used to indirectly reflect the degree of biliary obstruction.
Detection method: Quantitative determination using internal standard method. Take 25 mL of plasma, add 9 mL of internal standard (1 mmol/L), and use 0.45 μ Filter with m microporous membrane, add 1.0 mL of Potassium dichromate solution, shake for 30 min, take 1 mL of supernatant after filtration and pass 0.45 μ Filter with a microporous membrane and use it as a blank control solution. Take 10 mL and inject it into a liquid chromatograph for quantitative detection of glycyrrhetinic acid in plasma using the external standard method.
Sample preparation: Take the sample and store it in a 4 ℃ refrigerator. Immediately after specimen collection, store it in a refrigerator at 4 ℃ at room temperature (using glycyrrhetinic acid as the standard).
Sample determination: take 30 mL of sample, add 9 mL of internal standard into a 50 mL volumetric flask, and use 0.45 μ After m microporous membrane filtration, take 1 mL of supernatant, add 10 mL of Potassium dichromate solution and 0.1 mol/L of NaOH solution mixture (1 mol/L), shake for 30 min, then add 1.0 mL of Potassium dichromate solution and 0.1 mol/L of NaOH solution mixture (1 mol/L), shake for 30 min, take 1 mL of supernatant, add 10 mL of Potassium dichromate solution and 1.0 mL of NaOH solution mixture (1 mol/L), shake for 30 min, Add 1.0 mL of Potassium dichromate solution and 0.1 mol/L of NaOH solution mixture (1 mol/L), shake for 30 min, and then take 1 ml of supernatant into a small flask.
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