Simultaneous separation and determination of Avermectins by MEEKC previous solid-phase extraction/pre-concentration

CASADO, CRISTIAN; FELICI, EMILIANO; CHIEN CHUN WANG; GOMEZ, MARÍA ROXANA

Congreso; 3° Reunión Internacional de Ciencias Farmacéuticas RICiFa; 2014

Ivermectin (IVM) and Moxidectin (MXD) are macrocyclic lactones belonging to Avermectin families, structurally related compounds. These were the first macrocyclic lactones (MLs) developed as antiparasitic agentin production animals and antifilarial treatment in humans. Due to their wild use, they have being identified as potential contaminant for the aquatic sediment ecosystem, it is therefore of particular interest to monitor the presence of these veterinary drugs in surface waters at low concentrations. Several analytical methods have been developed for the detection and quantification of Avermectin in different matrices such as HPLC, CE, LC?MS/MS among others. The aim of this study is to develop method for determine IVM and MXD at low concentrations in surface waters. For this purpose, non-polar XAD-4 resin is used for solid-phase extraction as pre-concentration step previous to sepation by MEEKC (Microemulsion Electrokinetic Chromatography). The studied Avermectins in aqueous solution were retained by polimeric resin due to theirs hydrophobic property. The adsorbates were then eluted with ethanol and recolected for further separation. The microemulsion buffer used for MEEKC was prepared with phosphate buffer at pH 2.5, n-octane as oil droplets, sodium dodecylsulphate as surfactant, 1-butanol as co-surfactant and appropriate types and amounts of organic co-solvent. Under optimal experimental conditions, a complete electrophoretic separation has been achieved within 12 min. The sensitivity of this methodology is adequate for separation and trace determination of IVM and MXD in environmental samples. Moreover, the proposed methology avoid the use of highly pollutant and toxic solvent commonly employed for this purpose, which could be considered as green chemistry.