Investigations on an electronic tongue with polymer microfluidic cell for liquid sensing and identification

Abstract

Design and experimental results of a surface acoustic wave (SAW) microsensor with polymer microfluidic cell for the sensing and identification of liquids is presented in this paper. This microsensor, which is a part of a smart tongue-nose system, uses a horizontally polarized SAW (SH-SAW) for the detection and identification of liquids. The SH-SAW microsensors are fabricated on 36 •-rotated Y-cut X-propagating LiTaO 3 (36Y X.LT) substrate. This design consists of a dual-delay-line configuration in which one line is free and other one is metallized and shielded. Polymer microfluidic cells were designed and fabricated on top of it using a microstereolithography system to avoid dielectric loading of the IDTs by liquid which leads to unwanted dielectric sensitivity to the sensor. Due to the high electromechanical coupling of the 36Y X.LT substrate, it could detect differences in electrical properties and hence distinguish different liquids. It is clear from these results that the microsensor based on 36Y X.LT is an effective liquid identification system for the electronic tongue application.

Microfluidic Electronic Tongue Applied to Soil Analysis

“…Recently, an electrochemical e-tongue has been successfully applied in the qualitative and quantitative analysis of distinct soil types based on their extractable components [13]. The microfluidic concept was incorporated in this sort of device, resulting in the benefits of a small size, and reduced volume and waste, in addition to an overall cost reduction [14,15]. Microfluidics, e-tongues, and soil analysis are well-established research lines, but their integration does not appear to have been made in the literature.…”

ZnO film for application in surface acoustic wave device

“…This is in agreement with Refs. [7,8]. A large shift in the peak positions compared with the (002) ZnO reference peak indicates the existence of a large compressive stress in the deposited films which increases from 1.23 to 3.2 GPa with as film thickness increases from 0.14 to 2.5 µm.…”

Microfluidic Mixer with Automated Electrode Switching for Sensing Applications

“…Different types of e-tongues have been reported in the literature [3] for numerous applications [4][5][6][7]. E-tongues have also been integrated into microfluidic devices [8][9][10][11][12], which offer many advantages including the use of continuous flow for faster analysis, reliable purge cycles with pure water, reduction in size, and volumes for sampling and discharge, which, in turn, reduces waste and cost in the analysis. A challenge in using such microfluidic devices is that mixing is not always effective due to laminar flow conditions, which can adversely affect the study of sensorial/gustative effects.…”