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Conductivity detectors, capillary isotachophoresis

In the 1970s a new analysis method was developed, referred to as isota-chophoresis [247]. Capillary isotachophoresis with conductivity detector is very useful in detergent analysis for the determination of all kinds of ionic species [248]. It is also useful for the determination of MCA in ether carboxylates. [Pg.349]

Fanali et al. have described a capillary isotachophoresis method for the determination of procaine in pharmaceuticals [ 150]. The drug was determined in a 6 pL sample of solution (Spofa product, obtained from Czechoslovakia, and diluted 180-fold) by cationic isotachophoresis in the single column mode. The system used a PTFE capillary column (20 cm x 0.3 mm) and a conductivity detector. The separation was carried out at room temperature, at 50 pA (but switched to 25 pA during detection). [Pg.445]

Two kinds of conductivity detector are distinguished contact detectors and contactless detectors. Both types were originally developed for isotachophoresis in 0.2-0.5-mm-inner diameter (i.d.) PTFE tubes. Contactless detectors are based on the measurement of high-frequency cell resistance and, as such, inversely proportional to the conductivity. The advantage is that electrodes do not make contact with the buffer solution and are, therefore, outside the electric field. As these types of detectors are difficult to miniaturize down to the usual 50-75-jU.m capillar inner diameter, their actual application in capillary electrophoresis (CE) is limited. [Pg.431]

Figure 5 Configuration of capillary isotachophoresis. The arrangement shown is close to a real Instrument. The capillary is often made of plastic. The semipermeable membrane prevents electro-osmotic and hydrodynamic flows of the electrolyte but allows electromigration of ions. A conductivity detector is often used. It has miniature electrodes placed inside the capillary. Figure 5 Configuration of capillary isotachophoresis. The arrangement shown is close to a real Instrument. The capillary is often made of plastic. The semipermeable membrane prevents electro-osmotic and hydrodynamic flows of the electrolyte but allows electromigration of ions. A conductivity detector is often used. It has miniature electrodes placed inside the capillary.
Figure 9 ITP-ITP analysis of 5 jl of untreated heparin plasma of patients with diabetes mellitus. (A) The record from the conductivity detector in the preseparation capillary, ID 0.8 mm, LE 10 mmol I HCI + -alanine, pH 4.2. (B) The record from the analytical capillary, ID 0.3 mm, LE 5 mmol I HCI -i- glycine, pH 3.0. L, leading ion - chloride T, terminating ion - nicotinate. (Reprinted with permission from Kfivankova L and Bocek P (1990) Determination of pyruvate, acetoacetate, lactate, and 3-hydroxybutyrate in plasma of patients with diabetes mellitus by capillary isotachophoresis. Journal of Microcolumn Separation 2 83.)... Figure 9 ITP-ITP analysis of 5 jl of untreated heparin plasma of patients with diabetes mellitus. (A) The record from the conductivity detector in the preseparation capillary, ID 0.8 mm, LE 10 mmol I HCI + -alanine, pH 4.2. (B) The record from the analytical capillary, ID 0.3 mm, LE 5 mmol I HCI -i- glycine, pH 3.0. L, leading ion - chloride T, terminating ion - nicotinate. (Reprinted with permission from Kfivankova L and Bocek P (1990) Determination of pyruvate, acetoacetate, lactate, and 3-hydroxybutyrate in plasma of patients with diabetes mellitus by capillary isotachophoresis. Journal of Microcolumn Separation 2 83.)...
Kaniansky et al. [35] have also reported on a method for the determination of nitrate, sulphate, nitrite, fluoride and phosphate by capillary zone electrophoresis coupled with capillary isotachoelectrophoresis in the column coupling configuration. Such distributions of these anions are typical for many environmental matrices, and it is shown that capillary isotachophoresis-capillary zone electrophoresis tandem enables the capillary isotachoelectrophoresis determination of the macroconstituents, while capillary isotachophoresis-preconcentrated microconstituents cleaned up from the macroconstituents can be determined by capillary zone electrophoresis with a conductivity detector. This approach was effective when the concentration ratio of macro-microconstituents was less than (2-3) x 10. The limits of detection... [Pg.23]

ITP, also known as displacement electrophoresis, was first performed in capillary tubes by Ever-aerts et al. [69] for the separation of strong anions using a thermocouple detector. Since then, ITP has been used for the analysis of various important chemical and biological species such as amino acids [70], peptides [71], nucleotides [72], proteins [73,74], heavy metal ions [75], and other organic/inorganic ions [76,77] on a variety of detection platforms such as UV absorbance, conductivity and fluorescence detection. Over the past 15 years, ITP has been used as a preconcentration technique in conjunction with CE [78]. This mode of ITP, referred to as transient isotachophoresis (tITP), has been implemented on microchip platform in the recent years to achieve improved sensitivity [22,79,80]. [Pg.1108]


See other pages where Conductivity detectors, capillary isotachophoresis is mentioned: [Pg.19]    [Pg.22]    [Pg.299]    [Pg.13]    [Pg.217]    [Pg.701]    [Pg.606]    [Pg.956]    [Pg.299]    [Pg.227]    [Pg.21]    [Pg.24]   
See also in sourсe #XX -- [ Pg.204 , Pg.205 , Pg.206 , Pg.211 ]




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Capillary conduction

Capillary isotachophoresis

Conductivity capillary

Conductivity detectors, capillary

Detector conductance

Detectors conductivity

Isotachophoresis

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