Ready-to-Use Paper Ion Sensor for On-Site Analysis

Technology #33425

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Schematic representation of the fabrication and use of the ISE.
Karin Chumbimuni-Torres, Ph.D.
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Percy Calvo-Marzal
Samantha Mensah
Michelle Rich
Patent Protection

PCT Patent Application Filed
Nanomolar Detection Limits of Cd2+, Ag+, and K+ Using Paper-Strip Ion-Selective Electrodes
Analytical Chemistry, July 15, 2014, 86 (15), pp 7269–7273

Ion-selective electrodes (ISEs) are highly important for ion detection. Paper-based ISEs are a simple, low cost, and disposable alternative to conventional solid-contact ISEs. However, widespread use of paper-based ISEs has been limited due to poor detection limits (in the micromolar range), reliability, and selectivity. 

UCF researchers have developed novel ultra-sensitive paper-based ISEs that improves the applicability, reproducibility, reliability, and selectivity towards a target ion. Unlike other currently available ISEs, which require a pre-conditioning step in an analyte ion solution prior to measurement, these novel ISEs require no pre-conditioning and have demonstrated unprecedented limits of detection (2.5×10-9, 2.7×10-8, and 3.3×10-8 M) for cadmium, silver, and potassium ions, respectively. In addition to traditional ion detection, these new paper-strip ISEs can be used for in-situ analysis of bodily fluids (e.g., sweat, tears, etc.) and to assay biomolecules (e.g., proteins and DNA), providing cost-effective medical diagnostics. These electrodes can also be fabricated with glass, silica, or plastic.


  • Low-cost alternative to solid-contact ISEs
  • Ultra-sensitive, lower limits of ion detection in nanomolar range
  • Improved applicability, reproducibility, reliability, and selectivity
  • Does not require pre-conditioning, allowing for immediate on-site analysis


  • Biomedical analysis
  • Environmental analysis
  • Industrial and food processing
  • Sensors