Lab-on-Paper with Dual Electrochemical/Colorimetric Detection for Simultaneous Determination of Gold and Iron

Abstract

A novel lab-on-paper device combining electrochemical and colorimetric detection for the rapid screening of Au(III) in the presence of a common interference, Fe(III), in industrial waste solutions is presented here. With dilute aqua regia (0.1 M HCl + 0.05 M HNO(3)) as the supporting electrolyte, square wave voltammetry on paper provided a well-defined reduction peak for Au(III) at approximately 287 +/- 12 mV vs Ag/AgCl. Under the optimized working conditions, the calibration curve showed good linearity in the concentration range of 1-200 ppm of Au(III) with a correlation coefficient of 0.997. The limit of detection (LOD) of the proposed method is 1 ppm. Interferences from various cations were also studied. Fe(III) is the only metal that affects the electrochemical determination of Au(III) when present above a 2.5-fold excess concentration of that of the Au(III). To overcome this limitation, a colorimetric method was used to simultaneously detect Fe(III) as a screening tool. The procedure was then successfully applied to determine Au(III) in gold-refining waste solutions. The results are in agreement with those obtained from inductively coupled plasma-atomic emission spectrometry (ICP-AES).

Screen-printed Electrochemical Sensors and Biosensors for Monitoring Metal Pollutants

“…The developed method was utilized for As 3+ measurements in groundwater of 'Blackfoot' endemic disease affected areas of south-western coast of Taiwan. A screen-printed lab-on-paper device has been recently reported for the stripping voltammetric determination of Au with the simultaneous colorimetric determination of Fe [51]. The use of paper as a substrate has a number of reported advantages including being inexpensive and readily available.…”

Biosensing of DNA oxidative damage: a model of using glucose meter for non-glucose biomarker detection

“…[1][2][3][4][5][6][7][8][9] Among them, paper-based POC devices are a special category due to the advantages of being simple, rapid, on-site, and cost-effective; they have been widely used in home health care and medical testing, [10][11][12] even environmental monitoring. [13][14][15] The lateral flow immunochromatographic assay, also called lateral flow test, is one of the simplest and most popular formats of paper-based POC devices and can be used to detect specific substances, including small molecules, [15][16][17][18] large proteins, [19][20][21] and even whole pathogens, 10 in a sample by using an immunological reaction. However, most of these tests are based on qualitative colorimetry, which is not sufficient in many cases.…”

Development of Point-of-Care Testing Sensors for Biomarker Detection

“…13,24,[163][164][165][166][167][168][169] Among them, paper-based POCT devices is a special category due to the advantages of being simple, rapid, on-site, and cost-effective; they have been widely used in home healthcare and medical testing, 56,61,138 even environmental monitoring. 39,40,170 LFS is one of the simplest and most popular formats of paper-based POCT devices, and can be used to detect specific substances including small molecules, 40,60,171,172 large proteins 15,58,173 and even whole pathogens, 138 in a sample by using an immunological reaction. However, most of these tests are based on qualitative colorimetry, which is not sufficient in many cases.…”

“…Determination of metal ions in waste solutions is important in public health and environmental monitoring, for example, measurement of Au(III), Fe(III), Pb(II) and Zn(II) in industrial waste solutions by incorporating electrochemical method and microfluidic platform. 28,39 Detecting and quantifying mycotoxins is essential for food safety monitoring. One group has developed a semi-quantitative detection of Ochratoxin A, a type of mycotoxin, by an aptamer-based chromatographic strip assay.…”