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Simple and Equipment-Free Paper-Based Device for Determination of Mercury in Contaminated Soil

Authors :
Hikmanita Lisan Nashukha
Jirayu Sitanurak
Hermin Sulistyarti
Duangjai Nacapricha
Kanchana Uraisin
Source :
Molecules, Vol 26, Iss 7, p 2004 (2021)
Publication Year :
2021
Publisher :
MDPI AG, 2021.

Abstract

This work presents a simple and innovative protocol employing a microfluidic paper-based analytical device (µPAD) for equipment-free determination of mercury. In this method, mercury (II) forms an ionic-association complex of tetraiodomercurate (II) ion (HgI42−(aq)) using a known excess amount of iodide. The residual iodide flows by capillary action into a second region of the paper where it is converted to iodine by pre-deposited iodate to liberate I2(g) under acidic condition. Iodine vapor diffuses across the spacer region of the µPAD to form a purple colored of tri-iodide starch complex in a detection zone located in a separate layer of the µPAD. The digital image of the complex is analyzed using ImageJ software. The method has a linear calibration range of 50–350 mg L−1 Hg with the detection limit of 20 mg L−1. The method was successfully applied to the determination of mercury in contaminated soil and water samples which the results agreed well with the ICP-MS method. Three soil samples were highly contaminated with mercury above the acceptable WHO limits (0.05 mg kg−1). To the best of our knowledge, this is the first colorimetric µPAD method that is applicable for soil samples including mercury contaminated soils from gold mining areas.

Details

Language :
English
ISSN :
14203049
Volume :
26
Issue :
7
Database :
Directory of Open Access Journals
Journal :
Molecules
Publication Type :
Academic Journal
Accession number :
edsdoj.76f2b269db39402ab64e1fc3ee6bec1c
Document Type :
article
Full Text :
https://doi.org/10.3390/molecules26072004