Analysis of inorganic cations as their complexes by capillary electrophoresis

Liu, Bi‐Feng; Liu, Liang-Bin; Cheng, Jie

doi:10.1016/s0021-9673(98)01005-x

Cited by 71 publications

(44 citation statements)

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“…Many techniques have been used to separate the redox species of vanadium in natural waters, including capillary electrophoresis (CE) [14][15][16][17][18], reversed-phase liquid chromatography (RPLC) [19][20][21][22] (including ion-pairing (IP) RPLC), and, various forms of ion chromatography [1,3,4,14,15,[23][24][25][26]. After the species have been separated by any of these techniques, they are quantified by UV [14,17], chemiluminescence [27], ICP [28], or ICPMS [14].…”

Section: Introductionmentioning

confidence: 99%

Determination of Vanadium (IV) and (V) in Southern Nevada Groundwater by Ion Chromatography-Inductively Coupled Plasma Mass Spectrometry~!2009-12-24~!2010-02-10~!2010-05-11~!

Gamage¹,

Hodge²,

Cizdziel³

et al. 2010

TOCBMJ

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A rapid method is presented for measuring V(IV) and V(V) in groundwater, without preconcentration or complexing agents, using direct injection of the water samples (which were collected under an argon atmosphere) into an ion chromatograph-inductively coupled plasma mass spectrometer (ICPMS). The mobile phase is 1.5% v/v nitric acid, which minimizes the buildup of solids in the ultrasonic nebulizer, the torch, and on the entrance cones of the ICPMS -a problem with methods using organic complexing agents and inorganic salts. The result is much less instrument downtime for cleaning the affected parts. Limits of detection are 0.02 g L -1 for V(IV) and 0.06 g L -1 for V(V). The pentavalent form of vanadium represents 98% to 99% of the vanadium in these Southern Nevada groundwater samples and ranges from 3.7±0.1 g L -1 to 82.1±0.5 g L -1 . The remaining few percent is V(IV). Total vanadium was determined by ICPMS for a mass-balance comparison.

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Section: Introductionmentioning

confidence: 99%

Determination of Vanadium (IV) and (V) in Southern Nevada Groundwater by Ion Chromatography-Inductively Coupled Plasma Mass Spectrometry~!2009-12-24~!2010-02-10~!2010-05-11~!

Gamage¹,

Hodge²,

Cizdziel³

et al. 2010

TOCBMJ

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“…The development in CE determination of inorganic cations as their complexes is reviewed. [27][28][29][30][31][32][33][34][35] Based on precolumn complexation with a lacunary Keggin-type [PW11O39] 7-anion, we propose a new approach to the simultaneous determination of metal ions belonging to the same group in a periodic table, such as Sb(III) and Bi(III), 36 Sc(III) and Y(III), 37 or Zr(IV) and Hf(IV). 38 The determination of toxic metal ions is often required for environmental monitoring.…”

Section: Introductionmentioning

confidence: 99%

Selective Determination of Cadmium(II) from Divalent Metal Ions in Environmental Samples by Capillary Electrophoresis Using In-capillary Complexation with a Lacunary Keggin-type [PW11O39]7– Complex

2007

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IntroductionRecently, capillary electrophoresis (CE) has proved to be efficient for the separation and detection of transition-metal cations. For the CE determination of such non-UV absorbing metal ions, indirect UV detection is widely used. [1][2][3][4] To improve the detection sensitivities, a direct UV detection method is proposed using pre-and in-capillary complexation with various organic and inorganic ligands. 5-26The development in CE determination of inorganic cations as their complexes is reviewed. [27][28][29][30][31][32][33][34][35] Based on precolumn complexation with a lacunary 7-anion, we propose a new approach to the simultaneous determination of metal ions belonging to the same group in a periodic table, such as Sb(III) and Bi(III), 36 Sc(III) and Y(III), 37 or Zr(IV) and Hf(IV). 38 The determination of toxic metal ions is often required for environmental monitoring. However, the application of such complexation methods to seawater analysis is difficult, owing to high concentrations of matrix ions. 39 The CE determination of toxic metal ions in seawater is a challenging area in environmental chemistry.The present study focused on the development of a simple and sensitive CE method for the determination of Cd(II) in environmental samples. We found that trace amounts of Cd(II) reacted spontaneously with [PW11O39] 7-to form the Keggin-type [P(CdW11)O39] 5-anion. Because the ternary Keggin anion possesses high molar absorptivities in the UV region, the use of [PW11O39] 7-as a complexing reagent allows direct UV detection with a satisfactory detection limit. In this study, we developed a new in-capillary complexation method for the determination of Cd(II) in river-water and seawater samples. To our knowledge, this is the first report on the sensitive CE determination of Cd(II) in seawater. Experimental InstrumentationA P/ACE MDQ system (Beckman Instruments) equipped with a built-in UV diode-array detector was used for CE measurements. A fused-silica capillary (GL Sciences, Tokyo, Japan) with 75 μm i.d. and 70 cm total length was used as a separation and reaction capillary. The 31 P (202.46 MHz) NMR spectra were recorded on a Bruker Model AVANCE 500 spectrometer in a 5 mm diameter NMR tube with a concentric capillary containing D2O for an instrumental lock. Chemical shifts were expressed in parts per million with respect to 85% (v/v) H3PO4. The 31 P NMR measurements were made at 25 ± 0.1˚C. UV-visible spectra were recorded with a Hitachi Model U-3000 spectrophotometer. CE procedureFor in-capillary complexation, the capillary was filled with a running electrolyte consisting of 0.20 mM [PW11O39] 7-and 0.10 M malonate buffer (pH 3.0). Samples were injected at the cathodic end of the capillary by applying a pressure of 3.4 × 10 3 Pa for 10 -20 s. Throughout the work, direct UV detection was made at 250 nm, and the capillary temperature was held at 30˚C. ChemicalsAll chemicals were of analytical reagent grade and used as received. , which possesses high molar absorbtivities in the UV region, is formed in...

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“…Since its introduction, CE has also gained special attention for metal ion analysis with its advantages of multielement analysis and elemental speciation [2,3]. However, CE suffers from a low concentration sensitivity for absorbance detection because of the narrow (20-100 mm) inner capillary diameter being the optical path length [4].…”

Section: Introductionmentioning

confidence: 99%

Transient isotachophoresis of highly saline trace metals under strong electroosmotic flow conditions

Riaz

Chung

2005

Electrophoresis

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Transient isotachophoresis (TITP) is usually performed under low-electroosmotic flow (EOF) conditions using a coated capillary or a low pH background electrolyte. We used a bare fused-silica capillary for TITP stacking of anionic complexes of some heavy metals under high-EOF conditions (pH 9.0). The sample component chloride as a leading electrolyte induced stacking by an isotachophoretic mechanism and the complexing agent 4-(2-pyridylazo) resorcinol (PAR) acted as a terminating electrolyte. The optimized background electrolyte was composed of 150 mM N-tris(hydroxymethyl)methyl-3-aminopropanesulfonic acid, 127 mM triethylamine, and 0.1 mM PAR at pH 9.0. The strong EOF at pH 9.0 pulled the analytes against their mobilities toward the outlet side, allowing a separation in the normal polarity mode. The stacking efficiency, reproducibility, analysis time, and sample loading capacity in coated and bare capillaries were compared. The stacking efficiency and reproducibility were higher and the analysis time was shorter in the coated capillary. However, a larger volume of a sample could be injected in the bare capillary to achieve detection limits comparable to those for the coated one without compromising the resolution between the analyte peaks. The limits of detection (S/N = 3) were in the sub-ppb range for the selected metals (Fe2+, 0.3 ppb; Ni2+, 0.16 ppb; and Zn2+, 0.8 ppb) in a standard saline sample with 250 mM NaCl matrix. The proposed method was successfully applied to the analysis of reference urine samples and human urine samples.

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Analysis of inorganic cations as their complexes by capillary electrophoresis

Cited by 71 publications

References 100 publications

Determination of Vanadium (IV) and (V) in Southern Nevada Groundwater by Ion Chromatography-Inductively Coupled Plasma Mass Spectrometry~!2009-12-24~!2010-02-10~!2010-05-11~!

Determination of Vanadium (IV) and (V) in Southern Nevada Groundwater by Ion Chromatography-Inductively Coupled Plasma Mass Spectrometry~!2009-12-24~!2010-02-10~!2010-05-11~!

Selective Determination of Cadmium(II) from Divalent Metal Ions in Environmental Samples by Capillary Electrophoresis Using In-capillary Complexation with a Lacunary Keggin-type [PW11O39]7– Complex

Transient isotachophoresis of highly saline trace metals under strong electroosmotic flow conditions

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