Contactless conductivity detection for analytical techniques: Developments from 2016 to 2018

Abstract

The publications concerning capacitively coupled contactless conductivity detection for the 2-year period from mid-2016 to mid-2018 are covered in this update to the earlier reviews of the series. Relatively few reports on fundamental investigations or new designs have appeared in the literature in this time interval, but the development of new applications with the detection method has continued strongly. Most often, contactless conductivity measurements have been employed for the detection of inorganic or small organic ions in conventional capillary electrophoresis, less often in microchip electrophoresis. A number of other uses, such as detection in chromatography or the gauging of bubbles in streams have also been reported.

Investigation of the Effects of Electrode Geometry on the Performance of C4D Sensor with Radial Configuration

“…The sensor with tubular electrodes can obtain a large and stable signal, which helps the improvement of detection performance [ 6 , 9 ]. Through decades of sustained development, C 4 D sensors have been studied by many researchers and are mostly employed for detection in capillary electrophoresis (CE) and microchip electrophoresis (MCE) (the inner diameter of the pipe is always less than 0.5 mm) [ 1 , 2 , 3 , 4 , 10 ]. In these fields, the tubular configuration can meet the measurement requirement well.…”

Advancements in capacitance‐to‐digital converter‐based C4D technology for detection in capillary electrophoresis using amplified excitation voltages and comparison to classical and open‐source C4Ds

“…The concentrations ranged between 3 and 1500 μM. As BGE, a 20 mM MES/His electrolyte (pH 6.1) was chosen since it proved advantageous for the CE-C 4 D [15,[35][36][37][38]. Over our entire investigation high migration time precision (<1.6% RSD [n = 3], 0.8% on average) was achieved.…”

Towards a versatile and economic Chagas Disease point-of-care testing system, by integrating loop-mediated isothermal amplification and contactless/label-free conductivity detection

“…The capacitively coupled contactless conductivity detector (C 4 D) is based on the detection of the conductivity of a medium without physical contact between the electrodes and the measuring solution [ 23 ]. Since the electrodes are separated from the solution by an insulating material, unwanted side reactions such as electrolysis and corrosion, or fouling effects, are precluded [ 24 , 25 ]. Moreover, portable C 4 D analytical instruments have undergone significant development recently [ 26 ], showing the advantage to be suited for miniaturized analytical systems compared to optical-based detection methods.…”