Selective Antibody-Free Sensing Membranes for Picogram Tetracycline Detection

As an antibody-free sensing membrane for the detection of the antibiotic tetracycline (TC), a liquid PVC membrane doped with the ion-pair tetracycline/theta-shaped anion [3,3 '-Co(1,2-C2B9H11)(2)](-) ([o-COSAN](-)) was formulated and deposited on a SWCNT modified gold microelectrode. The chosen transduction technique was electrochemical impedance spectroscopy (EIS). The PVC membrane was composed of: the tetracycline/[o-COSAN](-) ion-pair, a plasticizer. A detection limit of 0.3 pg/L was obtained with this membrane, using bis(2-ethylhexyl) sebacate as a plasticizer. The sensitivity of detection of tetracycline was five times higher than that of oxytetracycline and of terramycin, and 22 times higher than that of demeclocycline. A shelf-life of the prepared sensor was more than six months and was used for detection in spiked honey samples. These results open the way to having continuous monitoring sensors with a high detection capacity, are easy to clean, avoid the use of antibodies, and produce a direct measurement.

Automated summary

A liquid PVC membrane doped with the ion-pair tetracycline/theta-shaped anion was developed as an antibody-free sensing membrane for tetracycline detection. The membrane showed a high sensitivity, with a detection limit of 0.3 pg/L. It outperformed other tetracycline antibiotics and had a shelf-life over six months. The membrane was successfully used for detecting tetracycline in spiked honey samples.