Determination Of Mercury In Water Samples Research Articles

Repurposing eggshell membrane, a natural food waste, for in-syringe membrane solid phase extraction: Mercury determination in water samples

A rapid, simple, and cost-effective method for the determination of mercury in water samples using an eggshell membrane (ESM) as a sorbent material in the in-syringe membrane solid-phase extraction (ISMSPE) technique has been developed. The utilization of ESM, a natural waste product and a cost-effective sorbent material for ISMSPE, presents a promising approach for the determination of mercury ions, Hg(II), in water samples prior to cold vapor AAS (CV-AAS) analysis. The selectivity study of ESM shows that ESM's adsorption performance for Hg(II) is the highest among other metals, by 44.2%. The optimization for Hg(II) preconcentration, which includes the choice of eluting reagent, concentration, and volume of the eluting reagent, the number of cycles of adsorption and desorption, and sample volume, is discussed in this study. The range of linearity of this method was 0.5–100 μg/L, with a preconcentration factor of 80. This method exhibited good sensitivity, with an LOD and LOQ of 0.44 μg/L and 1.32 μg/L, respectively. The precision and accuracy of the method were also satisfactory, as indicated by the recoveries for three real water samples in the range of 89.3–99.7% and RSD% (n = 3), ranging from 1.0 to 8.0%. These findings demonstrate that the developed method is reliable and performs well in determining Hg(II) ions in real water samples. This study has successfully demonstrated ESM's potential as a valuable material for the preconcentration of Hg(II), offering an environmentally friendly approach that promotes sustainability.

Colorimetric detection of mercury (Hg2+) using UV-vis spectroscopy and digital image analysis based on gold nanoparticles functionalized with bromelain enzyme.

A very sensitive and selective colorimetric biosensor for the measurement of mercury ion (Hg2+) in environmental samples has been developed using functionalized gold nanoparticles with bromelain enzyme (brn-AuNPs). This work has shown that Hg2+ measurement based on spectrophotometer and digital image analysis is a very innovative and successful method for providing an effective preliminary system and has promise for the future of water quality biomonitoring. Response Surface Methodology (RSM), a Box-Behnken design-based technique, was used to identify the optimum levels of functionalization of bromelain to AuNPs. The created model's validity was confirmed, and statistical analysis revealed that the ideal functionalize conditions were 1mM of AuNPs, functionalize with 0.59mM bromelain concentration on 14℃ temperature and 72h incubation time. The lowest colorimetric detection concentration (LOD) of brn-AuNPs of Hg2+ was 0.0092ppm and 0.011ppm for spectrophotometer and digital image analysis. As shown, digital image analysis had advantages based on the LOD result comparable to UV-VIS spectrophotometer. The practical application of the brn-AuNPs sensing was proven with mercury determination in water samples. The present study developed a robust sensor, which successfully implemented in a compact portable sensor kit, turning this sensor into a very potent tool for the development water quality biomonitoring system of Hg2+ application.

Hg(II) Analysis Using Poly(cysteine)-rGO Electrode

In the present work, we have developed a sensitive platform for the selective determination of Hg(II) ions based on reduced graphene oxide (rGO) electrode modified with poly cysteine (Poly-Cys). The Poly-Cys/rGO modified electrode was characterised by SEM, ATR-IR and its electrochemical behaviour was investigated through cyclic voltammetry and square wave voltammetry. The synergistic effect of rGO and poly-cysteine favoured the complexation of Hg(II) ions onto the surface of the modified electrode. The ions were then anodically stripped and the corresponding voltammograms recorded. The process of complexation followed by stripping was repeated with increasing concentrations of the metal ion. The linear range for the electrochemical determination of Hg(II) using the modified electrode was found to be from 0.05 to 2.7 μM with a detection limit of 0.006 μM. In addition, the electrode also exhibited good stability with negligible sensitivity towards interfering metal ions. The analytical applicability of the modified electrode was investigated by carrying out mercury determination in water samples obtained from various sources.

Highly selective and portable chemosensor for mercury determination in water samples using curcumin nanoparticles in a paper based analytical device

Curcumin nanoparticle (CURNs) are employed in a paper based analytical device (PADs) for monitoring Hg2+ concentration.

Multiparametric optimization of a new high-sensitive and disposable mercury (II) electrochemical sensor

An electrochemical sensor for mercury (II) determination was developed by modifying the surface of a commercial screen-printed carbon electrode (SPCE) with a polystyrene sulfonate-NiO-carbon nanopowder composite material. Mercury measurements were performed by differential pulse anodic stripping voltammetry (DPASV). Sensor composition and measurement conditions were optimized using a multivariate experiment design. A screening experiment by using a Plackett-Burman design was first performed in order to determine the main contributing factors to the electrochemical response. The most important factors were employed to establish the interactions between different experimental variables and get the best conditions for mercury determination. For this purpose, a five level central composite design and a response surface methodology were used. The optimized method using the developed NiO-PSS-SPCE sensor presents a very low limit of detection of 0.021 μg L−1 and a linear response over two concentration ranges with two different slopes, from 0.05 to 2.0 μg L−1 and between 2.0 and 75 μg L−1. The sensor was successfully applied to mercury determination in water samples.

Polymer-supported ionic liquid solid phase extraction for trace inorganic and organic mercury determination in water samples by flow injection-cold vapor atomic absorption spectrometry

A simple and green technique named polymer-supported ionic liquid solid phase extraction (PSIL-SPE) was developed for mercury (Hg) species determination. Inorganic Hg (InHg) species was complexed with chloride ions followed by its introduction into a flow injection on-line system to quantitatively retain the anionic chlorocomplex (HgCl42−) in a column packed with CYPHOS® IL 101-impregnated resin. The trapped InHg was then reduced with stannous chloride (SnCl2) and eluted with the same flow of reducing agent followed by cold vapor atomic absorption spectrometry (CV-AAS) detection. Organic mercury species (OrgHg) did not interact with the impregnated resin and were not retained into the column. Total concentration of OrgHg was evaluated by difference between total Hg and InHg concentration. A 95% extraction efficiency was achieved for InHg when the procedure was developed under optimal experimental conditions. The limit of detection obtained for preconcentration of 40mL of sample was 2.4ngL−1 InHg. The relative standard deviation (RSD) was 2.7% (at 1µgL−1 InHg and n=10) calculated from the peak height of absorbance signals (Gaussian-shape and reproducible peaks). This work reports the first polymer-supported IL solid phase extraction approach implemented in a flow injection on-line system for determination of Hg species in mineral, tap and river water samples.

Optimization of a miniaturized DBD plasma chip for mercury detection in water samples

In this work, an optimization study was conducted to investigate the performance of a custom-designed miniaturized dielectric barrier discharge (DBD) microplasma chip to be utilized as a radiation source for mercury determination in water samples. The experimental work was implemented by using experimental design, and the results were assessed by applying statistical techniques. The proposed DBD chip was designed and fabricated in a simple way by using a few microscope glass slides aligned together and held by a Perspex chip holder, which proved useful for miniaturization purposes. Argon gas at 75-180 mL/min was used in the experiments as a discharge gas, while AC power in the range 75-175 W at 38 kHz was supplied to the load from a custom-made power source. A UV-visible spectrometer was used, and the spectroscopic parameters were optimized thoroughly and applied in the later analysis. Plasma characteristics were determined theoretically by analysing the recorded spectroscopic data. The estimated electron temperature (T(e) = 0.849 eV) was found to be higher than the excitation temperature (T(exc) = 0.55 eV) and the rotational temperature (T(rot) = 0.064 eV), which indicates non-thermal plasma is generated in the proposed chip. Mercury cold vapour generation experiments were conducted according to experimental plan by examining four parameters (HCl and SnCl(2) concentrations, argon flow rate, and the applied power) and considering the recorded intensity for the mercury line (253.65 nm) as the objective function. Furthermore, an optimization technique and statistical approaches were applied to investigate the individual and interaction effects of the tested parameters on the system performance. The calculated analytical figures of merit (LOD = 2.8 μg/L and RSD = 3.5%) indicates a reasonable precision system to be adopted as a basis for a miniaturized portable device for mercury detection in water samples.