1. Test method: Dissolve the sample in methanol, use juglone as the internal standard, and use a UV-visible detector to separate and measure the juglone in the sample by gas chromatography. 6 Determination step 2. Preparation of standard solution. Precisely weigh 2.5 mg of juglone standard, dissolve it in methanol and dilute it to a volume in a 25ml volumetric flask to obtain juglone stock. The concentration is 0.1 mg/ml. Precisely measure juglone stock. Place 0.1ml, 1ml, and 2ml of the solution in a 10ml volumetric flask, and dilute to volume with methanol. The concentrations are 0.001mg/ml, 0.01mg/ml, and 20mg/ml respectively. 3. Measurement Under the above operating conditions, after the baseline of the instrument is stable, continuously inject several needles of standard solution until the change in the peak area of juglone substance in two adjacent needles is less than 2.0%. Follow the steps of standard solution, sample solution, and sample. Sequential determination of solutions and standard solutions. 4. Calculate the average peak area of juglone in the two injections of sample solution and the two injections of standard solution before and after the sample. Draw a standard curve with the concentration of the series standard solution as the abscissa and the juglone chromatographic peak area as the ordinate. y=Ax+B The content X of juglone in the sample expressed as mass fraction, calculated according to formula (1): Average value of quinone peak area; y—average value of juglone peak area in two adjacent needles of standard sample or sample solution; x—average value of juglone peak area in two adjacent needles of standard sample or sample solution, unit is mg/ml ; v—the volume of the sample, in milliliters (ml); M—the mass of the sample, in grams (g); A—the slope of the standard curve.
T/ZYNY 008-2023 history
2023T/ZYNY 008-2023 Inspection and detection methods for plant-based herbicides in traditional Chinese medicine agricultural inputs