Capillary zone electrophoretic determination of iodide in seawater using transient isotachophoresis with artificial seawater as the background electrolyte

Yokota, Kuriko; Fukushi, Keiichi; Ishio, Nobuhiro; Sasayama, Nobukazu; Nakayama, Yusuke; Takeda, Sahori; Wakida, Shin‐ichi

doi:10.1002/elps.200305420

Cited by 28 publications

(24 citation statements)

References 28 publications

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“…In the area of seawater analysis, Hirokawa and Timerbaev [62][63][64][65] and the group of Fukushi [66,67] have used tITP for the analysis of inorganic constituents. Seawater contains a high concentration of chloride which, combined with its high electrophoretic mobility, allows it to function perfectly as a leading ion to stack trace anionic components by tITP provided a suitable terminating ion is used.…”

Section: Isotachophoretic Stackingmentioning

confidence: 99%

Recent advances in enhancing the sensitivity of electrophoresis and electrochromatography in capillaries and microchips

2007

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Poor sensitivity is considered to be one of the major limitations of electrophoretic separation methods, particularly when compared to traditional liquid chromatographic techniques. To address this issue, various in-line preconcentration techniques have been developed over the past 15 years, ranging in power and complexity, and there are now a number of well understood approaches routinely capable of providing a 10,000- to 100,000-fold increase in sensitivity, as well as several that can be pushed above a million. Furthermore, these have been achieved with particularly troublesome and often difficult samples, such as those having high salinity from a biological or environmental origin. This review will discuss the most common methods for improving the sensitivity of CE, CEC and microchip version of these, with particular attention to those approaches developed over the last five years.

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Section: Isotachophoretic Stackingmentioning

confidence: 99%

Recent advances in enhancing the sensitivity of electrophoresis and electrochromatography in capillaries and microchips

2007

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“…To distinguish iodide, iodate, thyroxine and triiodthyronine, CZE was hyphenated with inductively coupled plasma mass spectrometry, a method with high sensitivity. Though no procedure has been published for the determination of iodide in urine by CZE so far, a series of studies on affecting iodide mobility with the aim to resolve iodide from other fast anions can be found in literature for various test mixtures [13][14][15][16][17][18][19][20][21][22][23][24][25][26][41][42][43][44][45][46][47][48][49][50], in waters [27,28,32,51], multivitamin supplement [29], antiseptics [52], dietary salt [30], blood plasma [31,40], or milk [30,31].…”

Section: Selection Of Electrolyte Systemmentioning

confidence: 99%

Fast and simple method for determination of iodide in human urine, serum, sea water, and cooking salt by capillary zone electrophoresis

Pantůčková

Křivánková

2004

Electrophoresis

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For the determination of iodide in urine, where 80-90% of consumed iodine is excreted, a fast, simple, and sensitive method of capillary zone electrophoresis was elaborated and tested also for additional complex matrices such as human serum, cooking salt, and seawater. Several approaches were examined for the separation of iodide from other macro- and microcomponents in the tested matrices, and the best results were obtained when host-guest interaction with alpha-cyclodextrin or ion-pairing with polyethylenimine was employed. In both cases comparable resolution and sensitivity were reached. Due to the relatively high price of cyclodextrin only the method with polyethylenimine was further optimized and a simple procedure enabling the determination of iodide in untreated human urine, serum, cooking salt, and seawater was elaborated. The samples were injected for 20 s at 0.5 psi (3.45 kPa) into a fused-silica capillary (0.18 mm ID, 50 cm effective length) coated with polyacrylamide (electroosmotic flow < 2 x 10(-9) m(2)V(-1)s(-1)) and filled with the optimized background electrolyte composed of 20 mM KH(2)PO(4) and 0.7% m/v polyethylenimine. For detection, UV absorption at 200 and 230 nm was measured. Concentration limits of detection reached at 230 nm were for human urine 0.14 microM, for human serum 0.17 microM, for seawater 0.17 microM, and for cooking salt 89 nM. Relative standard deviations of iodide peak area and height in all matrices ranged within 0.93 to 4.19%.

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“…A similar experimental design was independently developed by Yokota et al [24], who achieved an inferior limit of detection for the seawater iodide, but did so with a much shorter analysis time. Moreover, in the only known (to the authors) published account on iodine speciation measured by CE [25], a high-sensitivity analysis of related saline samples (human serum and urine) was achieved based on field-amplified stacking and ICP mass spectrometry detection.…”

Section: Introductionmentioning

confidence: 92%

“…The effect of cetyltrimethylammonium surfactant on the electrophoretic behavior of iodide and coexisting anions, such as bromide, nitrite, and nitrate, as well as iodate, has been investigated in depth by several research groups [22,24,26]. The effective mobility of iodide decreased rapidly with increased concentration of CTAC due to ion-pair formation.…”

Section: Effect Of Ctac On the Separation Of Iodide And Iodatementioning

confidence: 98%

Speciation studies by capillary electrophoresis ? simultaneous determination of iodide and iodate in seawater

Zhuo

Ito

Timerbaev

et al. 2004

Analytical and Bioanalytical Chemistry

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A capillary electrophoresis (CE) method was developed for the simple and highly-sensitive determination of iodine species in seawater. The proposed method is based on the on-capillary preconcentration of iodide and iodate using the principle of transient isotachophoresis (tITP) stacking, and direct UV detection of the separated species at 226 and 210 nm, respectively. The preconcentration procedure takes advantage of the electrokinetic introduction of the terminating ion [2-( N-morpholino)ethanesulfonate (MES)] into the capillary, that enables a longer tITP state. The appropriate conditions for the tITP step were optimized by varying the MES and sample injection time and the concentration of cetyltrimethylammonium chloride (CTAC). The latter component of the separation electrolyte (SE) was shown to strongly affect the migration and therefore the enrichment of iodide due to specific ion-association. The optimized separations were performed in 12.5 mM CTAC, 0.5 M NaCl (pH 2.4). Valid calibration is demonstrated in the range 3-60 microg x L(-1) iodide ( R=0.9992) and 40-800 microg x L(-1) iodate ( R=0.9994). The detection limits achieved were 0.23 microg x L(-1) (2 nM) for iodide and 10 microg x L(-1) (57 nM) for iodate. Such sensitivity and linearity thresholds allowed the reported tITP-CE system to be applied to direct speciation analysis of surface and seabed seawater. The comparison of CE results with those of an ion-chromatography (IC) technique proved that the method has acceptable accuracy.

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Capillary zone electrophoretic determination of iodide in seawater using transient isotachophoresis with artificial seawater as the background electrolyte

Cited by 28 publications

References 28 publications

Recent advances in enhancing the sensitivity of electrophoresis and electrochromatography in capillaries and microchips

Recent advances in enhancing the sensitivity of electrophoresis and electrochromatography in capillaries and microchips

Fast and simple method for determination of iodide in human urine, serum, sea water, and cooking salt by capillary zone electrophoresis

Speciation studies by capillary electrophoresis ? simultaneous determination of iodide and iodate in seawater

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