Optimization and validation method to evaluate the residues of β-lactams and tetracyclines in kidney tissue by UPLC-MS/MS.

The research developed and validated a method to detect and measure residues of β-lactam and tetracycline antibiotics in kidney tissues of birds, cows, horses, and pigs using ultra-performance liquid chromatography and tandem mass spectrometry (UPLC-MS/MS).

Method Development and Optimization

The researchers established a method for identifying and measuring residues of β-lactam and tetracycline antibiotics in kidney tissue from various animals. They achieved this by:

• Extracting these residues from the kidneys using a mix of water and acetonitrile.
• Purifying the extract using hexane and C18, a type of adsorbent material.

Method Validation

To validate and evaluate the effectiveness of their method, the researchers applied a variety of analytical performance parameters:

• Linearity: The method demonstrated a wide linear range, meaning it can accurately measure a broad range of concentrations.
• Matrix effect: The method showed a significant matrix effect, implying that the compound of interest (drug residues) and other components within samples (the matrix) can interact, potentially affecting analysis accuracy.
• Specificity: This parameter tested whether the method could selectively measure β-lactam and tetracycline residues without being affected by other substances present in the samples.
• Decision limits (CCα) and detection capability (CCβ): These parameters established the threshold levels for determining whether a specific sample is noncompliant with regulations.
• Accuracy, precision, and trueness: These parameters gauged the correctness, repeatability, and closeness of the method’s measurements to actual values, respectively.
• Limits of detection (LOD) and limits of quantification (LOQ): These parameters determined the smallest amount of β-lactam and tetracycline residues the method could reliably detect and measure. These were defined as ranging from 2.5 to 25.0 µg kg(-1) for LOD and from 5.0 to 50.0 µg kg(-1) for LOQ.
• Robustness: This determined whether minor changes in the method’s parameters would drastically affect its results.

Method Performance

The validity of the method was confirmed through recovery values, which measures the extent to which the original amount of β-lactam and tetracycline in the samples can be retrieved after the analysis process. The recovery values ranged:

• From 98.1% to 107.3% in repeatability conditions, indicating the method could consistently produce similar results when applied repeatedly under identical conditions.
• From 95.2% to 106% under intralaboratory reproducibility conditions, suggesting that the method can consistently produce similar results when conducted by different personnel or using different equipment within the same lab.

Overall, these results indicated that the proposed method is suitable for detecting and quantifying β-lactam and tetracycline residues in the kidney tissues of swine, horses, cows, and birds.