Electrochemical determination of chloramphenicol in milk and honey using vertically ordered silica mesochannels and surfactant micelles as the extraction and anti-fouling element

Abstract

Chloramphenicol (CAP), an antibiotic, is closely related to the food safety, ecological environment and human health. It is therefore of great importance to develop simple and rapid methods for CAP determination. We report in this work the utilization of indium tin oxide (ITO) electrodes modified with a binary assembly of vertical silica mesochannels (VSMs) and cylindrical surfactant micelles (CSMs) for the electrochemical detection of CAP. Each hard VSM of 2–3nm in diameter supports and confines a soft CSM of cetyltrimethylammonium bromide (CTAB), which has a hydrocarbon core capable of extracting and concentrating lipophilic organic analytes from sample solutions. So the CSM@VSM modified electrode exhibited an analytical performance for CAP apparently superior to bare and VSM modified electrodes. Under optimized conditions, two linear dynamic concentration ranges were obtained for CAP determination using differential pulse voltammetry, namely 0.1 to 3.6ppm and 3.6 to 15.0ppm, as well as a low limit of detection at 40ppb. Moreover, thanks to the ultrasmall size of silica channels and the lipophilic microenvironment of micelle cores, the CSM@VSM film displayed an excellent hydrophobic selectivity and anti-fouling ability by preventing unwanted substances from accessing to and contaminating the underlying electrode surface. Therefore, reliable results were obtained for direct electrochemical determination of CAP in real samples, such as milk and honey, without pre-treatment.