We supply several products for ion chromatography capillary electrophoresis, and microfluidic channel electrophoresis, using Capacitively Coupled Contactless Conductivity Detection (C4D).
The basis of contactless conductivity meaurements is explained by the figures below. As analyte ions pass into the detection region they cause small changes to the overall sample conductivity. Continous monitoring of the conductivity signal will show a series of peaks, the areas (or heights) of which are related to analyte concentration. The signal is processed like a conventional chromatogram.
Fig 1. C4D uses a transmitter electrode to subject a sample region to a large amplitude, high frequency electromagnetic signal. A corresponding, attenuated, AC signal registers at a receiver electrode.
Fig 2. The size of the received signal is affected by the conductivity of the sample.
Fig 3. The received AC signal is deconvoluted to convert the amplitude into a DC analog voltage signal appropriate for data collection.
The C4D electrodes do not make direct contact with the sample. Thus they are electrically isolated from the sample (ideal for electrophoresis detection), and electrode fouling is eliminated.
Since the the vast majority of analytes for CE are ionic, contactless conductivity functions as a 'universal' method of detection for virtually all charged species: inorganic anions and cations, as well as organic ions, such as carboxylic acids, amines, amino acids, peptides, proteins, DNA fragments, antibiotics and many other pharmaceutical compounds.
The C4D system is adaptable to your existing CE set-up (see application note below).
Tagging or other modification of the analytes is usually NOT required, while limits of detection are typically similar to UV-visible absorption techniques. The technique can also be used in parallel with UV-visible absorbance or fluorescent detection.
The C4D system is adaptable to Ion Chromatography set-ups with standard 1.6 mm outer diameter tubing (see application note below).
The C4D system is available either with integrated recording unit and software (ER125) or as a seperate amp (EA120) to be used with with e-corder or PowerChrom recording systems. Please download one of the brochures below, or see the list of applications.
Contact us for pricing information or to find out more.
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