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14 results on '"Rocha, Diego G."'

8. A novel strategy for the detection of boldenone undecylenate misuse in cattle using ultra‐high performance liquid chromatography coupled to high resolution orbitrap mass spectrometry: From non‐targeted to targeted.

Author

Rocha, Diego G., Lana, Mary Ane G., de Assis, Débora C. S., de Macedo, Adriana N., Corrêa, Joane M. M., Augusti, Rodinei, and Faria, Adriana F.

Abstract

In this work multivariate strategies were employed in order to highlight new potential biomarkers of interest to detect the exogenous treatment of steers intramuscularly treated with boldenone undecylenate. Serum samples collected from treated (n = 4) and control (n = 8) crossbred animals of varying ages and weights were extracted using a simple sample preparation procedure based on salt assisted liquid–liquid extraction. Data acquisition was performed using liquid chromatography and Q‐Exactive™ Orbitrap mass spectrometry. Data processing and treatment were performed using two non‐targeted workflows: (1) Compound Discoverer software and (2) XCMS package on the open‐source R software combined with MetaboAnalyst. Three potential biomarkers were highlighted taking into account the chromatographic shapes, the feature location on the generated s‐plots, the fold change, the adjusted p values, the coefficient of variation in the QC samples and the area under the ROC curves. Predicted formulas based on mass accuracy, structural composition and spectra similarity were proposed. A robust statistical model to predict the boldenone treatment was further developed based on the weighted abundances of the selected biomarkers. The requirements for screening methods were successfully fulfilled, together with a wider detection window in comparison with the monitoring of the deconjugated metabolite boldenone, although biomarker identification studies are still ongoing. [ABSTRACT FROM AUTHOR]

Published
2022
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11. Validation of a LC-MS/MS Multiresidue Methodology Based on a QuEChERS Approach for the Determination of Fluoroquinolones, Sulfonamides and Trimethoprim in Poultry and Porcine Kidney According to the Normative Instruction 24/2009-MAPA

Author

Rocha,Diego G., Santos,Flavio A., Gomes,Aline A., and Faria,Adriana F.

Subjects
sample preparation, chromatography, mass spectrometry
Abstract

This work involved the validation of a multiresidue method according to the Normative Instruction 24/2009-MAPA for determining 25 analytes, among fluoroquinolones, sulfonamides and trimethoprim in samples of poultry and porcine kidney. The extraction procedure was based on a QuEChERS approach. A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed using the selected reaction monitoring mode (SRM) and ESI+ ionization. All of the validated figures of merit were evaluated as satisfactory. Accuracy was assessed by recovery studies, varying from 82.7 to 115.5% for porcine kidney and from 91.5 to 110.4% for poultry kidney. Relative standard deviations were lower than 25.5% for porcine kidney, and 29.8% for poultry kidney. Decision limits (CCα) comprised values from 10.37 to 3298.43 µg kg-1 for porcine kidney and 10.08 to 3176.59 µg kg-1 for poultry kidney. Detection capabilities (CCβ) varied from 10.73 to 3396.86 µg kg-1 for porcine kidney and 10.67 to 3253.19 µg kg-1 for poultry kidney. The developed method has been successfully employed in the routine analysis of incurred samples.

Published
2017

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