Spectrophotometric Determination of Mercury in Water Samples After Preconcentration Using Dispersive Liquid–Liquid Microextraction

Abstract

A simple method for the determination of mercury in water samples after preconcentration using dispersive liquid-liquid microextraction is described. The procedure is based on the extraction of mercury in the form of a complex and its subsequent determination by spectrophotometry. The complex is formed between Hg(II) and 2-(2-benzothiazolylazo)-p-cresol. The detection at 650 nm is performed directly in the metal-rich phase, which is spread on a triacetylcellulose membrane. The method eliminates the need to use a cuvet or large quantities of samples and reagents. The parameters that influence the preconcentration were studied, and the analytical characteristics were determined. The enrichment factor and the consumptive index for this method were 64 and 0.16 mL, respectively. The LOD (3.3 microg/L) and LOQ (11.1 microg/L) were also determined. The accuracy of the method was tested by the determination of mercury in certified reference materials BCR 397 (Human Hair) and SRM 2781 (Domestic Sludge). The method was applied to the determination of mercury in samples of drinking water, sea water, and river water.

Equilibrium, kinetic and thermodynamic biosorption studies of Hg(II) on red algal biomass ofPorphyridium cruentum

“…These results illustrated the presence of various functional moieties on the cell wall structure of algal biomass and the possible interaction between the metal ion and these functional groups. From the data, it can be seen that in the unloaded biomass, the broadband at 3394 cm −1 was due to H bonded -OH group stretching vibrations (26). Band at 2795 cm −1 was attributed to -CH stretching of methoxy group and 1614 cm −1 could be assigned to asymmetric -C=O stretching vibration (27).…”

“…The residual Hg(II) concentration was estimated in filtered samples using a UV-Vis spectrophotometer at an absorbance wavelength of 650 nm after complexation with 2-(2-benzothiazolylazo)-p-cresol (26). The metal uptake capacity (q, mg/g) and metal percentage removal were calculated as follows:…”

Spectrophotometric determination of mercury using vortex-assisted liquid--liquid microextraction

“…Gharehbaghi et al 39 described a method based on the complexation of Hg cations by 4,4'-bis(dimethylamino)thiobenzophenone (TMK) in the presence of sodium dodecyl sulfate as the antisticking agent, followed by extraction of Hg-TMK complex by 1-hexyl-3-methylimmidazolium bis(trifluormethylsulfonyl)imid ionic liquid as the extraction solvent dissolved in acetone as the disperser solvent with subsequent spectrophotometric detection at 575 nm. Lemos et al 40 developed a method for the determination of mercury in water samples after DLLME preconcentration in the form of a complex with 2-(2-benzothiazolylazo)-p-cresol. The spectrophotometric detection at 650 nm is performed on a triacetylcellulose membrane.…”

“…In comparison with other reported methods, our method has a comparable linear range and detection limit. However, our procedure does not require the use of a dispersive solvent, in contrast to 500 µ L of acetone, 39 2 mL of ethanol, 40 and 800 µ L acetonitrile, 41 and it does not require dilution of the sedimented phase 39 or evaporation of the residue on triacetylcellulose membrane. 40…”

A green photometric method for determination of mercuric ions in saline samples by a single-drop microextraction technique

“…Among the currently available extraction and preconcentration methods, miniaturized preconcentration methods have been attempted for liquid-liquid extraction systems based on single-drop microextraction (SDME), 25,26 solidied oating organic drop microextraction (SFODME), 27 and dispersive liquid-liquid microextraction (DLLME) 28 for the determination of mercuric ions in different samples. These techniques have recently aroused a great interest, due to their favorable characteristics of simplicity, rapidity, cost-effectiveness and minimized toxic and ammable organic solvent consumption.…”