Synthesis and grafting of a BTP derivative onto a quartz crystal microbalance for lanthanide detection

The ability of bis-triazinylpyridine (BTP) molecules to complex lanthanides is well-known in solution and can be judiciously utilized to elaborate solid sensing surfaces. This was done by synthesizing a new BTP derivative and covalently anchoring it onto gold surfaces. The BTP grafting, its chemical modification and the resultant lanthanide complexation were evaluated by combining X-ray Photoelectron Spectroscopy (XPS) and Polarization Modulation-Infrared Reflection Absorption Spectroscopy (PM-IRRAS). The detection of neodynium and europium cations was measured by a Quartz Crystal Microbalance (QCM). Interestingly, when immobilized on gold, BTP appeared to show very distinct sensitivities towards Eu(3+) and Nd(3+). Moreover, these sensitivities could be controlled by varying the pH and/or the nitrate concentration in solution. This novel strategy, consisting of the immobilization of BTP sensing molecules, is thus very promising for sensitive and specific lanthanide detection.