Determination of 18 sulfonamide residues in puffer fish and eels by liquid chromatography-tandem mass spectrometry (4)

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8 Linear range and lower limit of determination

According to the sensitivity of sulfa drugs, a series of mass-based standard working solutions were prepared with sample blank extracts, and measured under selected chromatographic conditions and mass spectrometry conditions.
The injection volume was 20 μL, and the peak area was used to compare matrix standard working solutions.
The concentration of the tested component is plotted, and its range, linear equation and linear correlation coefficient are shown in Table 2-7
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Table 2-7 Linear ranges, linear equations and correlation coefficients of 18 sulfonamides

It can be seen that under the operating conditions of this method, the response values ​​of 18 sulfonamides in the concentration range of 5.

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9 Method recovery and precision

Use samples of puffer fish and eel that do not contain sulfonamides to perform addition recovery and precision experiments.
After adding different concentration standards to the samples, leave them for 1 hour to allow the standards to be fully absorbed by the sample, and then perform extraction and purification according to this method.
Chromatography-tandem quadrupole mass spectrometry determination, the recovery rate and precision results are shown in Table 2-8
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Table 2-8 The recovery rate and precision experiment results of sulfa addition in puffer fish (n=10)

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Under repeatability test conditions, the absolute difference between the two independent test results obtained does not exceed the repeatability limit (r).
If the difference exceeds the repeatability limit (r), the test results should be discarded and the two single tests should be completed again.
Determination
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Table 2-9 Content range and repeatability and re-limiting equation

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