Highly sensitive determination and selective immobilization of amoxicillin using carbon ionic liquid electrode

Carbon ionic liquid electrode (CILE) was used as a substrate for immobilization and determination of amoxicillin (AMX) in phosphate buffer solution. The electrochemical response of AMX showed an irreversible oxidation peak in the first scan and redox peaks corresponding to the electrooxidation of product in the subsequent scans which gradually grew upon repetitive scanning. Effect of experimental conditions on electrooxidation of AMX and its adsorbed intermediates was investigated, and possible mechanism for strong immobilization is suggested. The electrode response was linear in the concentration range of 5.0 to 400.0 mu mol L-1 AMX with a detection limit of 0.8 mu mol L-1 AMX. There was no serious interference from other beta-lactam family of antibiotics such as ampicillin and penicillin. The electrode showed good selectivity as well as high sensitivity toward quantification of AMX in pharmaceuticals and urine samples.