Otimização e validação do método QuEChERS para a determinação de tetraciclina em cama de aviário

Abstract

The development of poultry production in Brazil, particularly in the broiler sector, has made the country an important producer and exporter of chicken meat. This fact made the poultry litter, the main residue of this activity, become an ecological and public health problem, both by the volume of waste generated and by its composition, it may contain several drugs used in this type of management, which have a high power of contamination of several environmental matrices. Among the substances thatmay be present in poultry litter are antimicrobials, used both for the treatment of infectious diseases and in the form of dietary supplements, acting as growth promoters. In Brazil, statistics on the amount of antimicrobials marketed for this purpose are few, as well as the work dedicated to investigating the occurrence and the environmental impact of these compounds on the environment. Thus, this work aimed to collaborate for the diagnosis of contamination of environmental resources by drugs, through theoptimization and validation of the QuEChERS extraction method by High­Performance Liquid Chromatography coupled to a fluorescence detector (HPLC­FLU) for the quantification of tetracycline (TCT) in poultry litter. In the optimization a rotational central compound design (DCCR) 2³ was applied to adapt the extraction protocol regarding the variables amount of magnesium sulfate (MgSO4) and sodium chloride (NaCl), and volume of water (H2O). In the tests, samples of the poultry litter matrix were fortified with a standard TCT solution and subsequently subjected to extraction procedures. Analysis of variance (ANOVA) and the study of lack of adjustment were used to assess the significance of the data at the 95% confidence level. The performance parameters analyzed or validation were matrix effect, linearity, selectivity, precision, accuracy, limit of detection and quantification. The DCCR 2³ provided, within the studied levels, the best option in the recovery values at the 95% significance level, since, the quadratic model adjusted satisfactorily to the data, suggesting that the best condition for the recovery of TCT in poultry litter was MgSO4= 2,96 g, NaCl = 1,02 g e H2O = 9,57 mL, with expected removal of 100,53%. The method presented linearity, selectivity and adequate accuracy, with average recoveries of 99,3% of the studied analyte. The value obtained for the detection limit is 0,02 mg L­1 and the quantification limit is 0,06 mg L­1. The validation carried out made it possible to consider thatthe QuEChERS method is satisfactory and has the necessary performance characteristics, being suitable for the investigation of TCT residues in poultry litter. For future studies, the use of liquid chromatography coupled with mass spectrometry is suggestedin order to identify and confirm the analyte studied.