Visual quantification of Hg on a microfluidic paper-based analytical device using distance-based detection technique

Abstract

We presented a distance-based detection method for visual quantification of mercury ions on a microfluidic paper-based analytical device (μPAD). Dithizone in NaOH solution was used as chromogenic reagent and deposited onto paper channel delimited by hydrophobic wax barrier. Reactions happened between mercury ions and dithizone to form an insoluble colored complex, producing colored precipitate on the paper channel. The length of colored precipitate could be readily measured using the printed ruler along each device. The length of precipitate increase linearly with the mercury concentrations, mercury in sample solution could be quantified by measuring the length of the colored precipitate. Being free of any electronic instruments, this method has the advantages of portability, ease of use, low cost and disposability. This presented method was used to detect mercury ions in a synthetic sample, demonstrating its potential in on-site and real time analysis.

Sensitive distance-based paper-based quantification of mercury ions using carbon nanodots and heating-based preconcentration

“…The naked eye detection limit (LOD) was found to be 0.5 mg L À1 . The LOD of this developed method is comparable to the paper-based colorimetric quantication developed by Cai et al 32 which was 0.93 mg L À1 for Hg 2+ detection. In the method developed by Cai et al, a complexation reaction between Hg 2+ and dithizone was measured on a distance-based paper device.…”

Detection of Mercury in Water using Filter Paper Based Channel and Colorimetric-Android Readout

“…Multiple aqueous samples containing mercury (Hg) with varied concentrations were prepared for testing [14]. Initially, the stock standard solution of mercury (1.0 gm / L) was prepared by dissolving 0.148g, HgSO 4 in 10ml of water along with mercuric sulphate.…”

A Simple Distance Paper-Based Analytical Device for the Screening of Lead in Food Matrices

“…Furthermore, there are several reports of using distance-based applications for clinical diagnosis such as chloride test [ 26 ], potassium [ 27 ], alkaline phosphatase [ 28 ], and cardiac troponin I [ 29 ]. For the detection of metal ions, the dPADs have also been previously reported using the principle based on the deposition of chemical chelating compounds, such as dithizone [ 30 ] and a synthesized porphyrin [ 31 ]. Interestingly, the growing interest in dPAD application is reflected by the increasing number of publications during recent years, by using several strategies such as G-quadruplex-DNAzyme [ 32 ], starch hydrolysis [ 33 ], ionophore-doped ion-selective nanospheres [ 34 , 35 ], and synthesized fluorescent ligands [ 25 , 36 ].…”