Development of the Homogenous Liquid-Liquid Extraction in Combination with Deep Eutectic Solvent-based Dispersive Liquid-Liquid Microextraction for the Extraction of Antibiotics from Egg Samples and Their Quantitative Analysis Using High Performance Liquid Chromatography

Antibiotics are chemical compounds, which are extensively used in the treatment of diseases in animals worldwide. Ignorance or negligence of the withdrawal time and use of antibiotics more than that prescribed have resulted in the presence of antibiotic residues in food products such as eggs that can include adverse effects on the consumer health. The aim of this study was to develop an appropriate method to assess antibiotics in eggs.

In the present study, an efficient method called homogeneous liquid-liquid extraction in combination with deep eutectic solvent-based dispersive liquid–liquid microextraction was developed for the extraction of penicillin G, oxytetracycline, chloramphenicol and doxycycline from egg samples and then analyses were carried out using high performance liquid chromatography. To achieve high extraction recoveries, effects of various parameters including concentration and volume of the zinc acetate solution, salt quantity, type and volume of the extraction/dispersive solvent and vortexing time were investigated and optimized in HLLE step as well as type and volume of the extraction solvent, ionic strength and rate and time of the centrifuging procedure in DLLME step.

Under the optimum extraction conditions, extraction recoveries were in the ranges of 59–75%. Detection limits of the method for analytes were in the range of 3.7–4.4 ng g–1.  Consumption of small volumes of the organic solvents has been addressed as another advantage of this method. Moreover, 35 egg samples were analyzed with the highlighted method and results indicated that 28.58% of the investigated egg samples were contaminated by at least one of the listed antibiotics.

The developed method is well capable of measuring the mentioned antibiotics in eggs, so this method can be used with the aim of increasing food safety in various industries, including poultry