Linear range for determination of residues of α-Trenbolone, β-Trenbolone, 19-ethylene nortestosterone and epi-19-ethylene nortestosterone in cow urine

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8 Linearity range and lower limit of determination

Prepare four analyte concentrations of 2.
5 ng/mL, 5 ng/mL, 10 ng/mL, 50 ng/mL and 100 ng/mL matrix mixed standard solutions according to this method.
The concentration of each tested component in the standard solution is plotted.
The four analyte concentrations show good linearity in the range of 2.
5-100ng/mL and meet the quantitative requirements.
The linear equations and correlation coefficients are shown in Table 8-33
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It can be seen that, under the operating conditions specified by the method, when the concentration of the four analytes in the sample is 2μg/L, the signal-to-noise ratio of the measured spectrum is greater than 10, which is higher than the minimum detection volume of the instrument
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Table 8-33 Linear equation, linear range and correlation coefficient

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9 Method recovery and precision

Use negative samples to do addition recovery and precision experiments.
After adding different concentration standards to the samples, perform extraction, purification and determination according to this method.
The analysis results are shown in Table 8-34
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Table 8-34 Recovery rate and precision of urine samples (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 8-35 The content range and repeatability and reproducibility equation of the four analytes

Related links: Selection of analysis conditions for determination of a-Trenbolone, β-Trenbolone, 19-ethylene nortestosterone and epi-19-ethylene nortestosterone residues in cow urine