• Journal of the Korean Chemical Society
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• v.36 no.2
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• pp.223-229
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• 1992

Mechanistic studies on the metal-exchange reactions of sparteine copper(II) dichloride [$SpCuCl_2$] with Hg(II) ion and Hg(0) metal have been carried out with the aid of Cyclic Voltammetry and UV-visible spectrophotometry. The metal exchange reaction of $SpCuCl_2$ with both Hg(II) ion and Hg(0) metal follows pseudo-first order kinetics. Rate constants and activation parameters of metal exchange reaction have been evaluated and reported. Experimental results indicate that the rate determining step for the exchange reaction is the cleavage of Cu(II)-N bond in the transient binuclear complex of Cu(II) and mercury(II) bound to sparteine ligand.

• Korean Journal of Environmental Biology
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• v.24 no.1 s.61
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• pp.46-52
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• 2006

The mercury is among the most highly bioconcentrated toxic trace metals. Many national and international agencies and organisations have targeted mercury for the possible emission control. The mercury toxicity depends on its chemical form, among which alkylmercury compounds are the most toxic. A human cervix uterus cancer cell line HeLa cells was employed to investigate the effect of the toxic heavy metal mercury (Hg) and ionizing radiation. In the in vitro comet assays for the genotoxicity in the HeLa cells, the group of Hg treatment after irradiation showed higher DNA breakage than the other groups. The tail extent moment and olive tail moment of the control group were $4.88{\pm}1.00\;and\;3.50{\pm}0.52$ while the values of the only Hg treatment group were $26.90{\pm}2.67\;and\;13.16{\pm}1.82$, respectively. The tail extent moment and olive tail moment of the only 0.001, 0.005, 0.01 Hg group were $12.24{\pm}1.82,\;8.20{\pm}2.15,\;20.30{\pm}1.30,\;12.26{\pm}0.52,\;40.65{\pm}2.94\;and \;20.38{\pm}1.49$, respectively. In the case of Hg treatment after irradiation, the tail extent moment and olive tail moment of the 0.001, 0.005, 0.01 Hg group were $56.50{\pm}3.93,\;32.69{\pm}2.48,\;62.03{\pm}5.14,\;31.56{\pm}1.97,\;72.73{\pm}3.70\;and \;39.44{\pm}3.23$, respectively. The results showed that Hg induced DNA single-strand breaks or alkali labile sites as assessed by the Comet assay. It is in good agreement with the reported results. The mercury inhibits the repair of DNA. The bacterial formamidopyrimidine-DNA glycosylase (Epg protein) recognizes and removes some oxidative DNA base modifications. Enzyme inactivation by Hg (II) may therefore be due either to interactions with rysteine residues outside the metal binding domain or to very high-affinity binding of Hg (II) which readily removes Zn (II) from the zinc finger.

• Journal of Plant Biology
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• v.36 no.3
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• pp.195-201
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• 1993

The room temperature fluorescence induction of chloroplasts was utilized as a probe to locate the site of inhibition by mercury, copper and zinc on PS II by mercury. Inhibitory effect of Hg2+ on electron transport activity was notable as compared with Cu2+ and Zn2+. At concentrations of HgCl2 over 50 $\mu$M, activities of PS II and whole-chain electron transport decreased more than 70%, while that of PS I decreased about 10~30%. This suggests that PS II is more susceptible to Hg2+ than PS I is. In the presence of diphenylcarbazide (DPC), 50 $\mu$M HgCl2 inhibited the reduction of dichlorophenolindophenol (DCPIP) about 50%. Addition of heavy metals induced marked decrease in maximal variable fluorescence/initial fluorescence [(Fv)m/Fo], but no changes in Fo. With various concentrations of heavy metals, changes of chlorophyll a fluorescence emitted by PS II showed gradual decrease in photochemical quenching (qQ), which indicates an increase in reduced state of electron acceptor, QA. Especially, the addition of HgCl2 caused a notable decrease of qQ. In the presence of 50 $\mu$M CuCl2, energy-depended quenching (qE) was completely reduced, whereas in the presence of 50 $\mu$M CuCl2 and ZnCl2 it was still remained. The above results are discussed on the effects of mercury in relation to water-splitting system and plastoquinone (PQ) shuttle system.

• Bulletin of the Korean Chemical Society
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• v.35 no.12
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• pp.3459-3464
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• 2014

Synthesis and structural characterization of mercury(II) halides and perchlorate complexes (1-4) of bis-$OS_2$-macrocycle (L) are reported. L reacts with mercury(II) chloride and bromide to yield an isostructural 2D coordination polymers with type $[Hg(L)X_2]_n$ (1: X = Cl and 2: X = Br). In 1, each Hg atom which lies outside the cavity is six-coordinate with a distorted octahedral geometry, being bound to four adjacent ligands via monodentate Hg-S bonds and two remaining sites are occupied by two terminal chlorido ligands to form a fishnet-like 2D structure. When reacting with mercury(II) iodide, L afforded a 1D coordination polymer $\{[Hg_2(L)I_4]{\cdot}CHCl_3\}_n$ (3) in which each exocyclic Hg atom is four-coordinate, being bound to two sulfur donors from different ligands doubly bridging the ligand molecules in a head-to-tail mode. The coordination sphere in 3 is completed by two iodo terminal ligands, adopting a distorted tetrahedral geometry. On reacting with mercury(II) perchlorate, L forms solvent-coordinated 1D coordination polymer $\{[Hg_2(L)(DMF)_6](ClO_4)_4{\cdot}2DMF\}_n$ (4) instead of the anion-coordination. In 4, the Hg atom is five-coordinate, being bound to two sulfur donors from two different ligands doubly bridging the ligand molecules in a side-by-side mode to form a ribbon-like 1D structure. The three remaining coordination sites in 4 are completed by three DMF molecules in a monodentate manner. Consequently, the different structures and connectivity patterns for the observed exocyclic coordination polymers depending on the anions used are influenced not only by the coordination ability of the anions but also by anion sizes.

• Journal of the Korean Applied Science and Technology
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• v.29 no.2
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• pp.302-310
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• 2012

Bio assay of mercury and cadmium ions were searched using voltammetric analysis using DNA doped carbon nanotube paste electrodes (DCP). The square-wave stripping voltammetryic optimized results indicated working ranges of 1-10.0 $ngL^{-1}$ and 20-100 $ugL^{-1}$, Hg(II) Cd(II) within an accumulation time of 120 seconds, in 0.1-M phosphate buffer solutions of pH 6.3. The relative standard deviations of 5 $ngL^{-1}$ Hg(II) and Cd(II) that observed were 0.14 and 0.22% (n=12), respectively, using optimum conditions. The low detection limit (S/N) was pegged at 0.1 $ngL^{-1}$ ($4.9{\times}10^{-11}M$) Hg(II) and 0.2 $ngL^{-1}$ ($1.77{\times}10^{-10}M$) Cd(II). The developed methods can be applied to assays in biological fish kidneys and water samples.

• Journal of the Korean Chemical Society
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• v.45 no.2
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• pp.131-137
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• 2001

The protonation and stability constants of complexation of Zn(II), Cd(II) and Pb(II), Hg(II) ion with sulfur-containing podand ligands such as tri(phenylthio-2-ethy1)amine (Podand N$_1$S$_3$)tetra(phenylthio-2-ethyl)ethylenediamine (Podand N$_2$S$_4$) , tris(1-benzylaminoethyl)amine (Podand N$_4$) have been determined by potentiometric titration in 95% methanol at variable temperatures, From these studies, we observed that podand N$_4$ ligand showed the largest protonation constant. Protonation constant, stability constant, enthalpy, entropy of Zn(II), Cd(II) and Pb(II), Hg(II),ions increased with the following order podand N$_1$S$_3$$_2$S$_4$$_4$.

• Analytical Science and Technology
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• v.7 no.4
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• pp.455-460
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• 1994

A selective extraction-spectrophotometric method for the determination of mercury(II) with nocotinaldehyde-4-phenyl-3-thiosemicarbazone(NPS) was described. The method is based on the formation of an insoluble mercury-NPS complex, which is extratable into chloroform from an aqueous solution at pH 3.5 by shaking for 3 min. The absorbance is measured at 365nm and the molar absorptivity is $2.45{\times}10^4L\;mol^{-1}\;cm^{-1}$. The complex system conforms to Beer's law for up to $18{\mu}g\;mL^{-1}$ of mercury(II). The proposed method is simple and selective and has been satisfactorily applied to the determination of mercury in standard human hair sample.

• Bulletin of the Korean Chemical Society
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• v.31 no.1
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• pp.140-145
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• 2010

The simultaneous detection of Cd (II), Pb (II), Cu (II), and Hg (II) ions in aqueous medium using a BDD electrode with DPASV is described. XPS was used to characterize the chemical states of trace metal ions deposited on the BDD electrode surface. Experimental parameters that affect response, such as pH, deposition time, deposition potential, and pulse amplitude were carefully optimized. The detection limits for Cd (II), Pb (II), Cu (II), and Hg (II) ions were 3.5 ppb, 2.0 ppb, 0.1 ppb and 0.7 ppb, respectively. The application of the BDD electrode on the electrochemical pretreatment for the simultaneous metal detection in the dye waste water was also investigated.

• Advances in environmental research
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• v.1 no.1
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• pp.15-35
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• 2012

Mercury (Hg) is a global environmental pollutant that has been the cause of many public concerns. One particular concern about Hg in aquatic systems is its trophic transfer and biomagnification in food chains. For example, the Hg concentration increases with the increase of food chain level. Fish at the top of food chain can accumulate high concentrations of Hg (especially the toxic form, methylmercury, MeHg), which is then transferred to humans through seafood consumption. Various biological and physiochemical conditions can significantly affect the bioaccumulation of Hg-including both its inorganic (Hg(II)) and organic (MeHg) forms-in fish. There have been numerous measurements of Hg concentrations in marine and freshwater fish worldwide. Many of these studies have attempted to identify the processes leading to variations of Hg concentrations in fish species from different habitats. The development of a biokinetic model over the past decade has helped improve our understanding of the mechanisms underlying the bioaccumulation processes of Hg in aquatic animals. In this review, I will discuss how the biokinetic modeling approach can be used to reveal the interesting biodynamics of Hg in fish, such as the trophic transfer and exposure route of Hg(II) and MeHg, as well as growth enrichment (the increases in Hg concentration with fish size) and biomass dilution (the decreases in Hg concentration with increasing phytoplankton biomass). I will also discuss the relevance of studying the subcellular fates of Hg to predict the Hg bioaccessibility and detoxification in fish. Future challenges will be to understand the inter- and intra-species differences in Hg accumulation and the management/mitigation of Hg pollution in both marine and freshwater fish based on our knowledge of Hg biodynamics.

• Applied Biological Chemistry
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• v.46 no.2
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• pp.74-78
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• 2003

To determine the urease inhibitory activity of various heavy metal ions, a photometric cuvette assay for measuring ammonia production was developed. In this assay, the absorbance values at 630 m were linearly increased according to the ammonia concentrations up to 3.0 mg/l (r : 0.998). The urease inhibitions upon addition of a single species of heavy metal ions were in the decreasing order of Hg(II) > Pb(II) > Cu(II) > Cd(II) > Zn(II) ions. As expected, the urease inhibitions at a fixed concentration of a single species and at varying concentrations of other species occurred in the additive way. The above results show the applicability of the current method to the selective detection on Hg(II) ions as well as the screening of heavy metal ions possibly present at various samples.