Development of an analytical method using modified QuEChERS and DLLME for the determination of erythromycin residues in fish by LC-MS/MS

Author(s)

Sarah Chagas Campanharo

• Document type: Master's Dissertation
• Press: Ribeirão Preto.
• Institution: Universidade de São Paulo (USP). Faculdade de Ciências Farmacêuticas de Ribeirão Preto (PCARP/BC)
• Defense date: 2021-06-14

Examining board members

Jonas Augusto Rizzato Paschoal; Eduardo Costa de Figueiredo; Bernardete Ferraz Spisso

• Advisor: Jonas Augusto Rizzato Paschoal

Abstract

Even though analytical tools have evolved significantly over the years, determining concentrations of organic compounds at residual levels (for example, <10 &mu;g kg-1) in complex matrices such as biological tissues, remains a major challenge in analytical development. Fish meat (muscle and skin in natural proportions), as well as other foods, is a complex matrix because it has several compounds that can be co-extracted with the target analyte (s), affecting selectivity and, consequently, the detectability/sensitivity and precision of the method. In this work, a modern sample preparation procedure was developed, optimized and validated for the determination of erythromycin (ERI) residues in fish meat. The method presented adequate linearity (r> 0.99, homoscedastic), high detectability (LOQ 1.0 &mu;g kg-1), precision (CV <6.3%) and accuracy (ER <9.62%), aiming to evaluate the residual depletion profile of ERI after oral administration in fish from an experimental study. Sample preparation applies the use of the modified QuEChERS procedure associated with dispersive liquid-liquid microextraction and an LC-MS/MS analytical system. To promote oral administration of the drug to fish, a method of incorporating ERI into feed was developed and validated (linearity with r> 0.99, homoscedastic; accuracy with CV <2.1%; veracity with CV <2.2%). The efficiency of incorporation of ERI into feed was 72% and the method was able to produce feed with adequate homogeneity (CV <2.0%) of the ERI concentration and low leaching (<1.1%) of the compound when in contact with the water for up to 15 minutes. The depletion study was carried out on pacu fish and involved a treatment with the medicated feed at a daily oral dose of 100 mg (kgPV)-1, during 7 consecutive days. The average water temperature was 30°C, and the minimum withdrawal period estimated was 8 days (or 240 degree-day) for elimination of ERI at levels below the concentration considered safe for this substance (MRL 100 &mu;g kg-1), with 95% confidence and considering the tolerance limit of 99%. (AU)

• FAPESP's process: 18/05536-0 - Erythromycin in aquaculture: studies for drug incorporation in feed and for residual depletion in fish
• Grantee: Sarah Chagas Campanharo
• Support Opportunities: Scholarships in Brazil - Master