Solid-state Ion selective lab chip sensor for on-site measurement of orthophosphate in small volumes of liquid

This paper described the characterization of the assembled solid-state ion-selective lab chip sensor to potentiometrically measure phosphate ion. Since the assembled chip sensor is easy to setup and does not require any sample preparations, it is an ideal technique to study the measurement of phosphate in small volumes of liquids or in estuarine sediments. The size of the proposed lab chip is 12 mm x 21 mm, and the microfluidic channel has the width of 2 mm, length of 5 mm, and depth of 150 μm. All electrodes have the length of 500 μm, width of 200 μm, and spacing of 200 μm. The potential response of the assembled phosphate ion-selective lab chip sensor showed a linear regression in the range of 1×10-5 to 1×10-3 M with a slope of 54 mV/decade. In addition, the experimental results showed a good precision, indicating that relative standard deviation (RSD) was 3.5%.