Vancomycin selective electrode based on molecularly imprinted polymer

Vancomycin (VCM) is an antibiotic used in the treatment of serious gram-positive infections. However, antibiotic contamination has induced the emergence of resistant microorganism, especially for VCM. Accordingly, detection and control of VCM in aqueous samples after the cleaning process of pharmaceutical equipment employed to prepare injections is very important. For this, routine analyses require simple, sensitive and low-cost analytical methods. In this work, a selective electrode type all-solid-state for the determination of VCM antibiotic was developed. A molecularly imprinted polymer (MIP) based on silicon alkoxysilanes was used as recognition element in a polyvinyl chloride membrane, with o-nitrophenyl octyl ether as a mediating solvent. The influence of the MIP particle size on sensor response was studied. The best results were obtained for the electrode containing particles smaller than 15 & mu;m. This sensor exhibited sensitivity of 55.5 mV dec-1, limit of detection of 6.6 & mu;M and a linear response starting on 10 & mu;M. An electrode response time of 10 s and a lifetime of 21 days were achieved. Selectivity study showed that antibiotics like cefotaxime, ciprofloxacin and amoxicillin were interfering compounds, while chloramphenicol, metronidazole and inorganic cations Ca2+, Mg2+, Na+ did not interfere.