Smartphone-Based Microfluidic Colorimetric Sensor for Gaseous Formaldehyde Determination with High Sensitivity and Selectivity.

Xiao-Liang Guo,Hong-Lan Jiang,Du-Li Yu,Yan Chen,Xian-Bo Qiu

doi:10.3390/s18093141

Abstract

Formaldehyde is one of the most dangerous air pollutants, which can cause sick building syndrome. Thus, it is very crucial to precisely determine formaldehyde with a low cost and simple operation. In this paper, a smartphone-based microfluidic colorimetric sensor is devised for gaseous formaldehyde determination with high sensitivity and selectivity. Specifically, a novel microfluidic chip is proposed based on the 4-aminohydrazine-5-mercapto-1,2,4-triazole (AHMT) method to determine formaldehyde; the chip consists of two reagent reservoirs, one reaction reservoir and a mixing column. In this design to prevent the fluid from flowing out while letting the gas molecule in, a hydrophobic porous poly tetra fluoroethylene (PTFE) membrane is put on the top of the reaction reservoir. Using the microfluidic chip sensor, a smartphone-based formaldehyde determination system is developed, which makes the measuring process automated and simple. As per the experiment results, the limit-of-detection (LOD) of the system is as low as 0.01 ppm, which is much lower than the maximum exposure concentration (0.08 ppm) recommended by the World Health Organization (WHO). Moreover, the sensor is hardly affected by acetaldehyde, volatile organic compounds (VOCs) or acidic-alkaline, which shows great selectivity. Finally, the performance of the proposed sensor is verified by using it for the determination of formaldehyde in a newly decorated house.

Highlights

Formaldehyde is an industrial chemical which is widely used to manufacture building materials and numerous household products, and a highly reactive compound which can be released into the indoor environment [1,2]
The sensor is hardly affected by the presence of the other gases, which proves the selectivity of the sensor for Selectivity of the Smartphone-Based Microfluidic Colorimetric Sensor formaldehyde
A formaldehyde gas sensor was proposed based on a novel microfluidic chip and a smartphone forpaper, the prevention and control of sickwas building syndrome

Summary

Introduction

Formaldehyde is an industrial chemical which is widely used to manufacture building materials and numerous household products, and a highly reactive compound which can be released into the indoor environment [1,2]. Formaldehyde is very harmful to human health and can cause irritation to the eyes and nose, central nervous system damage, immune system disorders, blindness and respiratory disease [3]. Formaldehyde is required to be determined in newly renovated houses. The World Health Organization (WHO) has set a standard for safe exposure to formaldehyde, i.e., 0.08 ppm averaged over 30 min. A high sensitivity is required for the formaldehyde sensor. Numerous kinds of interference gases often exist in houses due to human activities. Several methods have been reported for gas-phase formaldehyde determination [3,4]

Methods

Results

Conclusion