Application of Liquid-Liquid Extraction for the Determination of Antibiotics in the Foodstuff: Recent Trends and Developments

Nowadays, the presence of antibiotic residues in foods with animal origin has become an important challenge for public health authorities in many countries. Antibiotic residues are associated with several health problems in the human body such as acute allergic or toxic reactions, chronic toxic effects, and disturption of the natural balance of intestinal microflora as well as the emergence of antimicrobial resistance pathogenic bacteria. In order to determine the trace levels of antibiotics in the foodstuff, the development of rapid, sensitive and accurate analytical methods is necessary. Besides the great advances in the development of analytical instruments in recent years, sample preparation remains a critical step of any analytical procedure. Since food samples have complex and heterogeneous matrices, the sample preparation method can affect the accuracy, precision and overall performance of an analytical technique. Liquid-liquid extraction (LLE) is one of the most commonly used techniques for sample preparation which allows the selective concentration of target analytes in the aqueous samples. The aim of this study was to provide an updated overview of the recent trends and development in LLE techniques over the past 5 years. Different variations of this method such as hollow fiber liquid-phase microextraction, dispersive liquid-liquid microextraction, salting-out LLE, and aqueous two-phase system extraction are given in the present study. This review is focused on recent innovations and modifications in the LLE procedure which try to improve the efficiency and safety of this technique.