Solid State Sensor for Simultaneous Measurement of Total Alkalinity and pH of Seawater


BRIGGS E. M. , SANDOVAL S., Erten A. C. , TAKESHITA Y., KUMMEL A. C. , MARTZ T. R.

ACS SENSORS, cilt.2, ss.1302-1309, 2017 (SCI İndekslerine Giren Dergi) identifier identifier identifier

  • Cilt numarası: 2 Konu: 9
  • Basım Tarihi: 2017
  • Doi Numarası: 10.1021/acssensors.7b00305
  • Dergi Adı: ACS SENSORS
  • Sayfa Sayıları: ss.1302-1309

Özet

A novel design is demonstrated for a solid state, reagent-less sensor capable of rapid and simultaneous measurement of pH and Total Alkalinity (A(T)) using ion sensitive field effect transistor (ISFET) technology to provide a simplified means of characterization of the aqueous carbon dioxide system through measurement of two "master variables": pH and A(T). ISFET-based pH sensors that achieve 0.001 precision are widely used in various oceanographic applications. A modified ISFET is demonstrated to perform a nanoliter-scale acid base titration of A(T) in under 40 s. This method of measuring A(T), a Coulometric Diffusion Titration, involves electrolytic generation of titrant, through the electrolysis of water on the surface of the chip via a microfabricated electrode eliminating the requirement of external reagents. Characterization has been performed in seawater as well as titrating individual components (i.e., OH-, HCO3-, B(OH)(4)(-), PO43-) of seawater A(T). The seawater measurements are consistent with the design in reaching the benchmark goal of 0.5% precision in A(T) over the range of seawater A(T) of similar to 2200-2500 mu mol kg(-1) which demonstrates great potential for autonomous sensing.