Determination of Mercury Ions in Aqueous Medium and Urine Sample Using Thiocarbohydrazide Based Sensor

Abstract

The identification and quantification of toxic Hg 2 + ions in biological fluids is significant due to its harmful effects. The ion is an exceptional contaminant due to its manifestation in the environment through anthropogenic emissions besides other industrial processes. The bioaccumulation of Hg 2 + ions through water bodies, soil and food causes damage to the central nervous system and endocrine glands. This work describes the synthesis of Compd-2 (Compound 2), a thiocarbohydrazidebased UV-active sensor, that can detect Hg 2 + and Cu 2 + ions in the aqueous medium (HEPES buffer (3 mM) /acetonitrile = 99 : 1, v/v). Compd-2 responds linearly to the varying concentrations of Hg 2 + with a minimum detection limit of 27 nM and a 1 : 1 stoichiometry. 1 H NMR titration with increasing Hg 2 + ion concentrations confirmed its interaction by shifting of the peak. In-silico modelling using Gaussian 16.0 and IR spectroscopy verified a single binding site for the Hg 2 + ions. Aqueous solubility of Compd-2 was used as an advantage to develop a methodology for the detection and quantification of Hg 2 + ions in the human urine sample. The work also demonstrates the nM quantification of Hg 2 + ions in the urine sample by the standard addition method.

Synthesis and Optimization of Diphenyl Ether‐Based Receptors for the Selective Detection of Cyanide Ions in Neutral Semi‐Aqueous Medium

“…The unique acidity of the carboxylic acid proton in the diphenyl ether, due to the nitro and electron-rich methoxy groups, was expected to decide the selectivity of an anion. Therefore, aldehydes 1 [49] & 1 a were converted to corresponding carboxylic acids, compound-2 and compound-2 c, by oxidation using KMnO 4 in water (Scheme 1 & Scheme-S1). Similarly, compound-2 a and 2 b were obtained by esterification and reduction of compound-2 using methyl iodide and SnCl 2, respectively.…”

A Fluorescent Polymer Coated Sensor Chip for Mercury Ion (Hg2+) Determination in Lake Water

“…Selectivity is an important part of fluorescent sensors. To test the selectivity and sensitivity of the designed PCFCs [24] and dansyl unit affinity to heavy metal cations, [9b] the fluorescence responses of PCFC6 to different metal cations, including Cu 2 + , Cd 2 + , Fe 2 + , Co 2 + , Ni 2 + , Fe 3 + , K + , Li + , Ca 2 + , Na + and Mg 2 + , at different concentrations ranging from 1.66 μmol/L to 50.6 μmol/L in water were first analysed. The fluorescence intensity at 500 nm was recorded as F 0 and F in the absence and presence of metal cations, and the usual change in fluorescence intensity variation (F 0 /F) upon each representative quencher was used for the fluorescence examination, as shown in Figure 4.…”

“…Using DNS-EMA as a metal cation recognition unit, six PCFCs (PCFC1-PCFC6) were prepared as a fluorescent sensor for Hg 2 + determination in water. In comparison to fluorescent sensors based on molecules, [24] such as Schiff bases [25] thiocarbohydrazide, [24] chip-based sensors have advantages such as reproducibility and reversibility. [26] The sensor chip, an optimized PCFC6, responds only to Hg 2 + and not to other representative metal cations.…”

Colorimetric screening of elevated urinary mercury levels by a novel Hg2+-selective probe of resorufin phosphinothioate

“…22,23 In light of these, many colorimetric and/or fluorescence-based probes for the determination of urinary mercury levels have been reported. For example, carbothiohydrazide-appended diphenyl ether, 24 thiocarbonate derivative of perylene diimide dye, 25 dithioacetal derivative of bithiophene fluorophore, 26 and terbium complex of 7-amino-4-methyl-2(1 H )-quinolinone 27 have been exploited for the urinary mercury detection. In addition, carbon dots, 28 DNA templated gold nanoparticles, and gold nanoclusters have also been developed for the determination of Hg 2+ ions in urine samples.…”