Pilot Study on the Visualization of Latent Fingerprints and Naked Eye Detection of Hg²⁺ and Zn²⁺ Ions in Aqueous Media Using Ninhydrin-Based Thiosemicarbazone

Abstract

Here, we described a cheap and effective chemosensor (NHPyTSC) that can distinguish Hg2+ and Zn2+ ions from other metal ions and evaluated this phenomenon using several spectroscopy techniques. With the addition of mercury and zinc ions, the proposed chemosensor in particular showed noticeable changes in color and absorption spectra. Additionally, by including EDTA in the NHPyTSC-Hg2+ and NHPyTSC-Zn2+ solutions, colorimetry readings can be reversed. We developed a molecular-scale sequential information processing circuit and presented the “writing–reading–erasing–reading” and “multiwrite” behaviors in the form of binary logic based on the great reversibility of this process. Moreover, by sequentially adding Hg2+, Zn2+, and EDTA, NHPyTSC imitates a molecular keypad lock and molecular logic gates. Density functional theory (DFT) investigations provided more evidence of the Hg2+ and Zn2+ ions′ ability to attach to NHPyTSC. The most interesting part of this work is that a study on the latent fingerprint detection of the powder compound revealed that NHPyTSC exhibits good adherence and finger ridge features without background stains. When compared to black and white fingerprint powders, it is discovered that the NHPyTSC powder produces results that are remarkably clear on the majority of surfaces. This demonstrated their potential for real-world use, particularly in the area of criminal investigations.

Real-time visualization of latent fingermarks with level 3 details based on a solid state emissive organic fluorophore using the powder dusting method

“…2,8,25–29 However, most of the articles discussed only level 1–2 details with organic fluorophores and took longer time (>5 min) to develop LFM images. 30–35…”

Target-Controlled Redox Reaction and Ru(II) Release of a Smart Metal–Organic Framework Nanomaterial for Highly Sensitive Ratiometric Homogeneous Electroanalysis of Cadmium(II)

“…Cadmium­(II) (Cd 2+ ) is an important heavy metal ion but has posed severe harm to the environmental water and human health. − According to the United States Environmental Protection Agency, Cd 2+ has been listed as one of the most poisonous heavy metals, which is known for its nonbiodegradability, extra-long half-life, high toxicity, and accumulation ability into the body. − Therefore, there is an important need to design simple and sensitive methods to detect and quantify Cd 2+ . In the past years, several conventional methods including electrochemiluminescence, ICPMS, atomic absorption spectroscopy, fluorescence sensing, and colorimetry were usually used to monitor the level of Cd 2+ in environmental water, which can offer high accuracy and reliability. − However, most of the conventional methods require the existence of professionals, complex operation, and expensive equipment and are time-consuming.…”