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11.
2.
1.
6 Determination
(1) Liquid chromatography conditions
Chromatographic column: C 18 , 5μum, 150mm×2.
1mm, or equivalent: column temperature: 30°C; flow rate: 200μL/min; injection volume: 20μL; gradient elution, the elution procedure is shown in Table 11-4
.
Table 11-4 Gradient elution program of liquid chromatography
(2) Mass spectrometry conditions
Ion source: electrospray source ESI; scanning mode: multiple reaction monitoring (MRM), positive ion mode; ion source temperature: 490℃; atomizing gas, curtain gas, auxiliary heating gas, collision gas are all high-purity nitrogen and other suitable Gas; before use, adjust the flow of each gas to make the sensitivity of the mass spectrometer meet the detection requirements; voltage values such as spray voltage, declustering voltage, and collision energy should be optimized to the optimal sensitivity; qualitative ion pair, quantitative ion pair, declustering voltage and collision The energy is shown in Table 11-5
.
Table 11-5 Mass spectrometry parameters of 15 quinolones
(3) Qualitative determination
Choose 1 parent ion and 2 or more product ions for each component to be tested.
Under the same experimental conditions, the retention time of the test substance in the sample and the retention time of the corresponding concentration standard calibration solution in the mixed matrix standard calibration solution are within ± Within 2.
5%; and the relative abundance of the qualifier ions of each component in the sample spectrum is compared with the relative abundance of the corresponding qualifier ions in the spectrum of the mixed matrix standard calibration solution with close concentrations, and the deviation does not exceed the regulations in Table 1-5 Within the range, it can be determined that there is a corresponding analyte in the sample
.
(4) Quantitative determination
External standard method quantification: Under the best working conditions of the instrument, sample the mixed matrix standard calibration solution, draw a standard working curve with the peak area as the ordinate and the concentration of the mixed matrix calibration solution as the abscissa, and use the standard working curve to quantify the sample , The response value of the analyte in the sample solution should be within the linear range determined by the instrument
.
In the chromatographic conditions, 15 kinds of quinolone reference drug retention time shown in Table 11-5,15 quinolones multiple reaction monitoring (MRM) chromatogram shown in Figure 11-2
Figure 11-2 Multiple reaction monitoring (MRM) chromatograms of 15 quinolones
Related Links: Determination of 15 Quinolone Residues in Eel and Products by Liquid Chromatography-Tandem Mass Spectrometry