Selective determination of potassium ions by SPR based molecularly imprinted sensor

Abstract

Novel potassium ions imprint polymer sensor were successfully prepared by applying a facile combination of a reversible addition chain transfer mechanism (RAFT) and surface plasmon resonance (SPR). UV photopolymerization in synergy with 2-methyl-2-[(dodecylsulfanylthiocarbonyl)sulfanyl]propanoic acid (DDMAT) as a chain transfer reagent was employed for film synthesis on an SPR sensor chip for the detection of potassium ions using ethylene glycol dimethacrylate (EGDMA) as a cross linker. The modified surface of the sensor was characterized by contact angle measurements, frontier transfer infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The results of potassium ion imprint polymer film showed a high adsorption capacity and excellent selectivity in comparison to other analogues and non-imprinted polymer (NIP) film. Through 5 adsorption–desorption cycles, the high recoverability of MIP film was confirmed. Consequently, within the concentration range of 10−15-10−5 mol/L, the coupling angle change of SPR versus the negative logarithm of concentration showed excellent linearity: R2 = 0.98. Based on a linear equation, MIPs showed excellent values for the limit of detection(1.6×10−16M). Furthermore, it was also used to detect potassium ions in real sample, and in the tap water it showed high recovery and low detection limit. Hence, potassium ions imprint polymer film in combination with an SPR sensor chip demonstrated potential applications for rapid and highly effective sensing even in tap water.