DEVELOPMENT AND VALIDATION OF AN LC-DAD METHOD FOR THE ROUTINE ANALYSIS OF RESIDUAL QUINOLONES IN FISH EDIBLE TISSUE AND FISH FEED. APPLICATION TO FARMED GILTHEAD SEA BREAM FOLLOWING DIETARY ADMINISTRATION

Fish farming, metals and antibiotics in the eastern Mediterranean Sea: Is there a threat to sediment wildlife?

Chemical residues released from aquaculture farms may persist in the environment and may pose adverse ecological effects. The aim of this study was to assess the pollution status of marine sediments underneath or close to aquaculture farms in the Eastern Mediterranean Sea, the factors that affect the elemental distribution, and the exceedance of environmental quality standards and factors. To this end, surface sediment samples were collected (underneath fish cages, at 25 m distance and from a reference station) from 48 fish farms in Greece with variable environmental and geochemical characteristics. The content of 29 metals and major and trace elements, and three antibiotics (oxytetracycline, florfenicol, and flumequine), was determined in the sediment samples. Most of the elements found in the sediments originated from geological sources and their concentrations were close to Earth's Crust content. Below and close to fish farm cages, the sediment was enriched with P, Cu, Zn, Mo, and Cd mainly due to the aquaculture biosolid deposition, and changes in environmental conditions (increased organic matter, low redox potential). Cr and As were found to exceed twice the upper threshold limit of the available sediment quality guidelines in 13.5% and 7.3% of sampling stations, respectively. The potential ecological risk of V, Cr, Mn, Co, Ni, Cu, Zn, As and Pb was found to be low in the sediment close to fish cages except for Cd, which may pose a moderate to considerable risk in 12.5% of sampled fish farms. However, the estimated risks for this metal may be influenced by the high background levels found in the investigated areas. This study also shows that the occurrence of antibiotics in sediments below fish farms in the Eastern Mediterranean Sea is very sparse (i.e., only flumequine was found in two farms) and concentration levels are relatively low.

Collection and Separation of Fleroxacin and Ciprofloxacin in Ultrasound-Assisted Ionic Liquid Salting-Out Microextraction System

An ultrasound-assisted ionic liquid (IL) salting-out microextraction system was developed and applied for the extraction of quinolone antibiotics from urine. A precipitate was formed from the salt and IL, and it acted as the sorbent for the analytes. The precipitate containing the analyte was separated by filtration, redissolved, and the solution then was evaporated. The resulting extract was redissolved for high-performance liquid chromatographic analysis. Several parameters, including type and volume of IL, the type and amount of salts, sample pH, temperature and extraction time were optimized. Under the optimal experimental conditions, the limits of detection for fleroxacin and ciprofloxacin were 3.12 and 4.97 μg L-1, respectively. When the present method was applied to real urine sample analysis, the analyte recoveries ranged from 82.3 to 106.8%. This ultrasound-assisted IL salting-out microextraction system had the characteristics of high recoveries, shorter separation time and easy-to-perform collection procedure, which yielded the method to have potential for wide application.

Novel Approaches Utilizing Metal-Organic Framework Composites for the Extraction of Organic Compounds and Metal Traces from Fish and Seafood

The determination of organic and inorganic pollutants in fish samples is a complex and demanding process, due to their high protein and fat content. Various novel sorbents including graphene, graphene oxide, molecular imprinted polymers, carbon nanotubes and metal-organic frameworks (MOFs) have been reported for the extraction and preconcentration of a wide range of contaminants from fish tissue. MOFs are crystalline porous materials that are composed of metal ions or clusters coordinated with organic linkers. Those materials exhibit extraordinary properties including high surface area, tunable pore size as well as good thermal and chemical stability. Therefore, metal-organic frameworks have been recently used in many fields of analytical chemistry including sample pretreatment, fabrication of stationary phases and chiral separations. Various MOFs, and especially their composites or hybrids, have been successfully utilized for the sample preparation of fish samples for the determination of organic (i.e., antibiotics, antimicrobial compounds, polycyclic aromatic hydrocarbons, etc.) and inorganic pollutants (i.e., mercury, palladium, cadmium, lead, etc.) as such or after functionalization with organic compounds.