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    Home > Chemicals Industry > Chemical Technology > Determination of 8 kinds of macrolides and lincosamide residues in royal jelly and royal jelly freeze-dried powder

    Determination of 8 kinds of macrolides and lincosamide residues in royal jelly and royal jelly freeze-dried powder

    • Last Update: 2021-09-20
    • Source: Internet
    • Author: User
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    6.
    2.
    3.
    6 Determination

    (1) Liquid chromatography conditions

    Chromatographic column: Atlantis C 18 , 3um, 150mm×2.
    1mm (inner diameter) or equivalent; mobile phase: A is acetonitrile , B is 0.
    1% formic acid aqueous solution, and C is methanol
    .


    See Table 6-15 for gradient elution conditions; flow rate: 0.


    (2) Mass spectrometry conditions

    Ion source: electrospray ion source; scanning method: positive ion scan; detection method: multi-reaction monitoring; electrospray voltage: 5500V; atomizing gas pressure: 0.
    24MPa; auxiliary gas flow rate: 0.
    4L/min; ion source temperature: 550 ℃; Collision cell outlet voltage: 2.
    0V; Qualitative ion pair, quantitative ion pair, collision gas energy and declustering voltage, see Table 6-4
    .

    (3) Qualitative determination

    Select one parent ion and two or more product ions for the tested component.
    Under the same test conditions, the retention time of the test substance in the sample is within ±2.
    5% of the corresponding retention time in the standard solution; and each of the samples The relative abundance of qualitative ions is close to the concentration of each qualitative ion relative abundance ratio k of the analyte in the standard working solution of the matrix, and the deviation does not exceed the range specified in Table 1-5, then it can be determined that there is a corresponding sample to be tested Things
    .

    (4) Quantitative determination

    Under the best working conditions of the instrument, draw a standard working curve with the concentration of the matrix standard working solution as the abscissa and the peak area as the ordinate
    .


    Use the working curve of the matrix standard working solution to quantify the sample.


    6.
    2.
    3.
    7 Selection of analysis conditions

    (1) Selection of extraction solution

    A comparative experiment was carried out on the efficiency of Tris solution extracting macrolides from royal jelly under different pH conditions.
    The experimental results are shown in Table 6-24
    .

    Table 6-24 Extraction effect of different extraction solutions (peak height, peak area)

    From the data in Table 6-24, it can be seen that the pH condition of the extract has a great influence on the efficiency of extracting macrolides from royal jelly
    .


    For peak height: the appropriate pH range for lincomycin determination is between 8.


    For the peak area: Lincomycin has no obvious change between the pH conditions of 8.
    5, 9.
    0, and 9.
    5, and there is no significant change between the pH conditions of 8.
    0, 8.
    5, 9.
    0, and 9.
    5.
    Erythromycin increases with the increase of pH.
    ; Tilmicosin did not change significantly between pH conditions 8.
    0, 8.
    5, 9.
    0, and 9.
    5.
    Tylosin did not change significantly between pH conditions 9.
    0 and 9.
    5.
    Spiramycin was the highest at pH 9.
    0.
    Kitasamycin is the highest when the pH is 9.
    0, and clindamycin is the highest in the pH range of 9.
    0 and 9.
    5.
    The most suitable pH range of josamycin is between 9.
    0 and 9.
    5; therefore, this method uses Tris with a pH of 9 The solution is used as the extract
    .

    (2) Optimization of mass spectrometry conditions

    Using a syringe pump to directly inject the sample, the mixed standard solution of macrolide antibiotics was injected into the ion source at a speed of 20μL/min.
    The positive ion detection method was used to perform one-stage mass spectrometry analysis of 8 macrolide antibiotics (Q1 Scanning), the protonated molecular ion peaks are 407, 734, 869, 916, 425, 843, 772, 828, respectively, and then the protonated molecular ion is analyzed by secondary mass spectrometry (product ion scan) to obtain fragment ion information
    .


    Then optimize the declustering voltage (DP), collision gas energy (CE), electrospray voltage, atomizing gas, etc.


    (3) Determination of mass spectrometry conditions by liquid chromatography-tandem mass spectrometry

    Mix the standard working solution with a series of matrices and inject the samples separately
    .


    Under the best working conditions of the instrument, draw the standard working curve with the concentration of the matrix mixed standard working solution as the abscissa and the peak area as the ordinate


     

     

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