Speciation analysis of mercury in water samples by dispersive liquid–liquid microextraction coupled to capillary electrophoresis

Abstract

In this study, a method of pretreatment and speciation analysis of mercury by dispersive liquid-liquid microextraction along with CE was developed. The method was based on the fact that mercury species including methylmercury (MeHg), ethylmercury (EtHg), phenylmercury (PhHg), and Hg(II) were complexed with 1-(2-pyridylazo)-2-naphthol to form hydrophobic chelates and L-cysteine could displace 1-(2-pyridylazo)-2-naphthol to form hydrophilic chelates with the four mercury species. Factors affecting complex formation and extraction efficiency, such as pH value, type, and volume of extractive solvent and disperser solvent, concentration of the chelating agent, ultrasonic time, and buffer solution were investigated. Under the optimal conditions, the enrichment factors were 102, 118, 547, and 46, and the LODs were 1.79, 1.62, 0.23, and 1.50 g/L for MeHg, EtHg, PhHg, and Hg(II), respectively. Method precisions (RSD, n = 5) were in the range of 0.29-0.54% for migration time, and 3.08-7.80% for peak area. Satisfactory recoveries ranging from 82.38 to 98.76% were obtained with seawater, lake, and tap water samples spiked at three concentration levels, respectively, with RSD (n = 5) of 1.98-7.18%. This method was demonstrated to be simple, convenient, rapid, cost-effective, and environmentally benign, and could be used as an ideal alternative to existing methods for analyzing trace residues of mercury species in water samples.

Colorimetric Detection of Mercury Species Based on Functionalized Gold Nanoparticles

“…5−8 In general, these element-specific detectors are typically coupled with gas chromatography, high performance liquid chromatography, and capillary electrophoresis. 9 However, these instrument techniques are generally rather complicated, costly, and time-consuming. Also, these conventional methods mostly cannot discriminate organic mercury from inorganic mercury and instead measure the total Hg.…”

Hg2+ion-imprinted polymers sorbents based on dithizone–Hg2+chelation for mercury speciation analysis in environmental and biological samples

“…[7][8][9][10] Hence, speciation analysis of mercury ion (Hg 2+ ) and its organic species is being increasingly investigated because the monitoring and remediation of heavy metal pollution has become a crucial global issue. The speciation and determination of mercury species is generally performed using chromatographic techniques, such as gas chromatography (GC), liquid chromatography (LC), ion chromatography (IC) and capillary electrophoresis (CE) for separation, 5,6,8,11 which are oen coupled with element selective detectors, e.g. inductively coupled plasma mass spectrometry (ICP-MS), 12 atomic absorption spectroscopy (AAS), 13 and atomic uorescence spectroscopy (AFS).…”

Dispersive liquid‐liquid microextraction for four phenolic environmental estrogens in water samples followed by determination using capillary electrophoresis

“…In DLLME, a good extraction solvent should have the following characteristics: density higher than water, high extraction capability of the interested analytes, low solubility in water and good chromatographic behavior [36]. Therefore, CH 2 Cl 2 , CHCl 3 , CCl 4 and C 6 H 5 Cl were selected as extraction solvents, with acetone as dispersive solvent.…”