Selective Heavy Atom Effect-Promoted Photosensitization Colorimetric Detection of Ag⁺ in Silver Ore Samples

Abstract

Analytical methods capable of facile screening of silver ore samples are of vital importance for resource exploration and ore mining. Due to its extreme simplicity, colorimetric detection is desired for silver ore screening, but the analytical sensitivity of existing approaches is typically not sufficient. Here, an Ag+-selective heavy atom effect-promoted photosensitization colorimetric assay was developed. Specifically, Ag+ and dsDNA-staining dye (photosensitizer) were spatially adjoined in close proximity in dsDNA bearing several cytosine (C) mismatches, leading to enhanced 1O2 generation for photosensitized oxidation of chromogenic substrate 3,3′,5,5′-tetramethylbenzidine (TMB). Due to the stable C–Ag­(I)–C metallo-base pair, the C–C mismatches in dsDNA can selectively capture Ag+, thus allowing highly selective colorimetric detection of Ag+ with a visual limit of quantification (LOQ) as low as 0.2 ng/mL. For ore sample analysis, the visual LOQ was about 2 g/t, which was suitable for colorimetric screening analysis of ores of different values. The accuracy of the proposed method was verified through analyzing both certified reference material and real ore samples, the results of which agreed well with those obtained by electrothermal atomic absorption spectrometry (ET-AAS). To facilitate field silver ore screening, acid leaching of the samples was also adopted, and satisfactory analytical accuracy was also obtained at a rough leaching efficiency of 20%.

Integrating Recombinase Polymerase Amplification and Photosensitization Colorimetric Detection in One Tube for Fast Screening of C. sakazakii in Formula Milk Powder

“…The method rationale of PCA relies on photosensitization switching of SYBR Green I (SG, a well-known and popular nucleic acid dye) upon binding with double-stranded DNA (dsDNA, Figure A). ,, Specifically, upon cyan LED irradiation, singlet oxygen ( 1 O 2 ) is generated from the dsDNA-SG complex, which can quickly be captured by the chromogenic substrate TMB to trigger the oxidation, yielding a noticeable color change (colorless to blue). Similar to PCR, RPA undergoes exponential amplification, and the amplicons (dsDNA) can thus be quantified with PCA (Figure S1).…”

Dual-Channel Fluorescent/Colorimetric-Based OPD-Pd/Pt NFs Sensor for High-Sensitivity Detection of Silver Ions

“…Ag + is also often used to disinfect drinking water due to its strong antibacterial activity at low concentrations. However, residual Ag + in water can accumulate in the human body through direct consumption and the food chain [10][11][12]. Excessive levels of Ag + in the body may harm human health and even cause adverse symptoms, such as skin infections, diarrhea and nerve damage [13,14].…”