A new sol–gel optical sensor with nonporous structure for determination of trace zinc

Abstract

We report herein the development of a novel optical sensor based on incorporation of 1,5-diphenylcarbazone as a sensitive reagent into the nanopores of a transparent glass like material through the sol–gel process and suggest how it may be useful for determination of zinc in aqueous solutions. The sensors were fabricated by spin-coating onto glass substrates. To survey the catalysis type effect on leaching behavior of the sensor, both acid- and base-catalyzed sol–gel processes were studied. Results indicated that acid-catalyzed method is suitable to give more stable thin films with constant sensitivity and response time for a long period of time. The fabricated sensor can be used for determination of zinc in the range of 0.03–1.2μgmL−1 with a detection limit of 0.016μgmL−1. It also showed reproducible results with relative standard deviation of 3.6 and 2.2% for 0.1 and 0.8μgmL−1 of Zn (II), respectively, along with a fast response time of ∼150s. This optode is stable and could be stored for at least 2 months without observing any change in its sensitivity. The developed sensor was successfully applied to the determination of zinc in serum of diabetic patients and water sample and validated against inductively coupled plasma optical emission spectrometry method.