Linear range of residues of α-Trenbolone, β-Trenbolone, 19-ethylene nortestosterone and epi-19-ethylene nortestosterone in milk and milk powder

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8 Linearity range and lower limit of determination

Prepare a series of standard working solutions with a fixed solution, and prepare a series of matrix standard working solutions with a blank solution of milk and milk powder samples.
The measurement is performed under selected chromatographic conditions and mass spectrometry conditions.
The injection volume is 15μL and the peak area of ​​the analyte is used.
Plot the concentration of the tested components in the matrix standard working solution.
The linear range (equivalent to milk sample mass 0-20μg/kg, equivalent to milk powder sample mass 0-100μg/kg) linear equations and linear correlation coefficients are shown in Table 8-21
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Table 8-21 Linear equation and range, correlation coefficient

According to the sample volume represented by the final sample solution, the constant volume, the injection volume and the interference during the measurement, the milk contains a-Trenbolone , β-Trenbolone, 19-ethylene nortestosterone and epi The detection limit of -19-vinyl nortestosterone is 1μg/kg, and the detection limit of a-trenbolone, β-trenbolone, 19-vinylnortestosterone and epi-19-vinyltestosterone in milk powder is 5μg/kg
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9 Method recovery and precision

Use negative samples for additive recovery and precision experiments.
After adding different concentration standards to the samples, they are extracted, purified and determined according to this method.
The analysis results of milk and milk powder samples at the four additive levels are shown in Table 8-22 and Table 8-23
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Table 8-22 Milk recovery rate and precision (n=10)

Table 8-23 Recovery rate and precision of milk powder (n=10)

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10 Repeatability and reproducibility

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 individual tests should be completed again.
Determination
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Table 8-24 Content range and repeatability and reproducibility equations of four analytes in milk

Table 8-25 The content range and repeatability and reproducibility equations of four analytes in milk powder

Related links: Analysis conditions for residues of α-Trenbolone, β-Trenbolone, 19-ethylene nortestosterone and epi-19-ethylene nortestosterone in milk and milk powder