Design and fabrication of a novel optical sensor for determination of trace amounts of lutetium ion

In this study, for the first time we report a highly selective and sensitive lutetium ions chemical optical sensor based on immobilization of a asymmetrically S–N Schiff’s base, namely N-(thien-2-ylmethylene)pyridine-2,6-diamine (TPD) on a triacetylcellulose membrane. This optode exhibits a linear range of 5.0 ×10-7 –1.0 ×10-5 M of the Lu(III) ion concentration with a detection limit of 9.3 ×10-8 M at a wavelength of 336 nm. The influence of responsible factors for improving sensitivity of the sensor was studied and identified. Response time of the newly designed optode was within 20-30 s depending on the Lu(III) ion concentration. Response of the optical sensor is independent of the pH of the solution in the range of 3.0–9.0. It manifests advantages of fast response time, low detection limit and most significantly, very good selectivity with respect to a number of lanthanide ions. The sensor can readily be regenerated with thiourea solutions and its response was reversible and reproducible. This optode was applied to the determination of Lu(III) in aqueous and CRM samples