A conductometric detector for capillary separations

Müller, Dirk; Jelı́nek, Ivan; Opekar, František; Štulı́k, Karel

doi:10.1002/elan.1140080804

Cited by 22 publications

(19 citation statements)

References 11 publications

(2 reference statements)

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“…2 Two thin parallel selfadhesive Cu strips of 1 (2) mm width and 5 (4) mm length placed in 908angle across channel, detection gap 1 (2.5) mm, shielding, f = 100 kHz, amplitude 400 (300, 500) Vp -p [60,70,72,90] [ 59] acid/His (pH 4.9) [24,68], citric acid (pH 2.95) [26,42], and acetic acid (AcOH)/LiOH (pH 4.7) [29]. An alkaline sorbate/ Arg (pH 8.9) [9] or borate buffer (pH 7.5) [14,40] has been used as alternative BGEs for separation of anions or cations. Inorganic anions were also separated in succinate/1,3-bis[tris(hydroxymethyl)-methylamino]propane (Bis-Tris propane, BTP) (pH 3.55) and polyethylenglycol dicarboxylic acid (PEG-DC)/BTP (pH 3.5) [20].…”

Section: Applications Of Conductivity Detectors 41 Model Mixturesmentioning

confidence: 99%

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Recent applications of conductivity detection in capillary and chip electrophoresis

Šolínová

Kašička²

2006

J of Separation Science

137

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The review provides a comprehensive survey of the recent applications of contact and contactless conductivity detection in capillary electrophoretic and chip electrophoretic analyses of a broad scale of compounds, from low-molecular-mass highly mobile small inorganic and organic ions, via medium-molecular-mass peptides and oligo- and polynucleotides up to high-molecular-mass biopolymers, proteins and nucleic acids fragments. The review presents also the recent developments in the construction of different types of conductivity detectors (detectors with galvanic contact of the sensing electrodes with the BGE and sample components, contactless conductivity detectors with capacitively coupled tubular and semitubular electrodes and combined conductivity/optical detectors) applied in the capillary electromigration methods performed in classical fused silica, polytetrafluorethylene, and polyetheretherketone capillaries or on glass and polymethylmethacrylate microchips. In addition, the principle and theoretical bases of conductivity detection in capillary electromigration techniques, zone electrophoresis, ITP, micellar EKC, and electrochromatography are briefly described.

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Section: Applications Of Conductivity Detectors 41 Model Mixturesmentioning

confidence: 99%

“…Another construction of the end-column conductivity detector was designed by Opekar and coworkers [14]. A Pt ring electrode was chemically deposited at the capillary end and at the other electrode, a Pt wire was immersed together with the capillary in the electrode vessel.…”

Section: Contact Conductivity Detectorsmentioning

confidence: 99%

Recent applications of conductivity detection in capillary and chip electrophoresis

Šolínová

Kašička²

2006

J of Separation Science

137

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“…For an example of a ring platinum electrode chemically deposited inside the CE capillary, e.g., see ref. [76]. Such systems are useful in many applications, of course, the measurements suffer from the same problem as that with potentiometric and voltammetric electrodes, that is, the interactions of the test liquid with the surface of the electrode, which may adversely affect the measuring reliability.…”

Section: Low-and High-frequency Measurement Of Impedancementioning

confidence: 98%

An evaluation of the experimental approaches to detection of small ions in CE

2007

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This review points out some important trends in the development of the detection techniques for small ions in CE. On the basis of selected literature references it briefly discusses some general requirements on detection techniques in CE. Various optical measurements, mass spectrometric approaches and electrochemical detection techniques are dealt with. Some specific features of microchip CE separation and detection are pointed out and possibilities of dual detection are mentioned. The principal parameters of the above detection techniques are then briefly compared.

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“…7 Conductometric detection (CD) offers a good alternative for determining small ions separated by FSCE. [8][9][10][11][12][13][14][15][16][17] In this mode of detection, the response is proportional to the difference of mobilities between the analyte and the running electrolyte co-ion. In general, the greater the mobility difference, the greater the sensitivity achieved.…”

Section: Introductionmentioning

confidence: 99%

Improved separation of IA and IIA metal cations in matrices with high sodium concentration by capillary electrophoresis with contactless conductometric detection

Silva

Ricelli

Carvalho

et al. 2003

J. Braz. Chem. Soc.

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Um dos usos mais comuns da eletroforese capilar com detecção condutométrica é a análise de vários tipos de amostras contendo metais alcalinos e alcalinos terrosos. No entanto, a alta concentração de sódio, a qual é uma ocorrência bastante comum, pode causar perda de resolução de alguns picos. Neste trabalho, as condições e o eletrólito de corrida conveniente para análises de soro e fluído para hemodiálise são apresentados. A idéia básica é deslocar os picos de Ca 2+ e Mg 2+ pela redução de suas mobilidades pela adição de lactato e metanol ao eletrólito de corrida. Limites de detecção da ordem de 0,5 a 1,0 µmol L -1 e razão molar Na + /Ca 2+ da ordem de 1000 foram obtidos. Estas condições excedem as necessidades da aplicação pretendida.One of the most common uses of capillary electrophoresis with conductometric detection is the analysis of different samples containing alkaline and alkaline earth metals. However, the high sodium content, which is a very common occurrence, may cause loss of resolution of some peaks. In this work, the conditions and a running buffer suitable for serum and hemodialysis fluid analyses are presented. The approach basically consists in the reduction of mobilities of Ca 2+ and Mg 2+ by addition of methanol and lactate in the running buffer. Limits of detection in the range from 0.5 to 1.0 µmol L -1 with molar Na + /Ca 2+ ratios as high as 1000 were obtained, which are conditions that exceed the requirements of the proposed determination.Keywords: capillary electrophoresis, contactless conductivity detection, human serum, hemodialysis fluid IntroductionMetal cations from groups IA and IIA play an important role in numerous processes in the human body, such as volume and osmotic regulation, myocardial rhythm, blood coagulation, neuromuscular excitability, as cofactors in enzyme activation, in the regulation of ATPase ion pumps, and so on. The reference ranges for potassium, sodium, calcium, and magnesium in serum of normal individuals are 3.4-5.0, 135-145, 0.65-1.0, and 2.15-2.65 mmol L -1 , respectively. Abnormal concentration values for these ions can help in the diagnosis of many metabolism disorders, such as diabetes, advanced renal disease, polydipsia, aldosterone deficiency or excess, cardiac disorders, alcoholism etc. 1 Capillary electrophoresis (CE) is a separation technique based on differences of mobility of charged species and has been applied for determination of several kinds of analytes, from small ionic species to macromolecules. 2,3 Metal cations from groups IA and IIA have been mainly analyzed by free solution capillary electrophoresis (FSCE) with indirect UV-visible absorption detection. [4][5][6][7] Although these cations can be readily separated at low concentrations (typically 10 -6 mol L -1 ), separations of concentrated samples require the use of complexating agents to selectively modify the ion mobility and improve resolution. Examples of ligands widely used in FSCE separations include carboxylic acids 4-6 -such as oxalic, tartaric, lactic, α-hydroxyisobutyric (HIBA...

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A conductometric detector for capillary separations

Cited by 22 publications

References 11 publications

Recent applications of conductivity detection in capillary and chip electrophoresis

Recent applications of conductivity detection in capillary and chip electrophoresis

An evaluation of the experimental approaches to detection of small ions in CE

Improved separation of IA and IIA metal cations in matrices with high sodium concentration by capillary electrophoresis with contactless conductometric detection

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