A Novel Planar Grounded Capacitively Coupled Contactless Conductivity Detector for Microchip Electrophoresis

Abstract

In the microchip electrophoresis with capacitively coupled contactless conductivity detection, the stray capacitance of the detector causes high background noise, which seriously affects the sensitivity and stability of the detection system. To reduce the effect, a novel design of planar grounded capacitively coupled contactless conductivity detector (PG-C4D) based on printed circuit board (PCB) is proposed. The entire circuit plane except the sensing electrodes is covered by the ground electrode, greatly reducing the stray capacitance. The efficacy of the design has been verified by the electrical field simulation and the electrophoresis detection experiments of inorganic ions. The baseline intensity of the PG-C4D was less than 1/6 of that of the traditional C4D. The PG-C4D with the new design also demonstrated a good repeatability of migration time, peak area, and peak height (n = 5, relative standard deviation, RSD ≤ 0.3%, 3%, and 4%, respectively), and good linear coefficients within the range of 0.05–0.75 mM (R2 ≥ 0.986). The detection sensitivity of K+, Na+, and Li+ reached 0.05, 0.1, and 0.1 mM respectively. Those results prove that the new design is an effective and economical approach which can improve sensitivity and repeatability of a PCB based PG-C4D, which indicate a great application potential in agricultural and environmental monitoring.

A Novel Overlapping ME Peaks Decomposition Algorithm Based on Iterative Derivative Sharpening

“…For Sample1, the stock solutions are L-histidine (His), 2-(N-morpholino)ethanesulfonic acid (MES), 18-Crown-6, and sodium hydroxide at concentrations (mM/L) of 40, 40, 20, and 150, respectively. The ME experimental setup of Sample1 is consistent with those of the recently published works [7] and [35]. From Table II, Sample2 is a soybean seedling extract.…”

A novel portable microchip electrophoresis system for rapid on-site detection of soil nutrient ions

“…To minimize the impact of the chip and detector mounting on stability, we designed a U-shaped limiting mechanism in the chip component, which controls the chip mounting error within ±0.5 mm [38]. Additionally, to reduce the background noise of the C4D, we implemented a planar grounded C4D, which significantly reduces stray capacitance and improves detection sensitivity [39]. To evaluate the stability of the system baseline, we compared the fluctuations in the electropherogram baseline in the absence and presence of samples, using the aforementioned conditions.…”

PCB-C4D coupled with paper-based microfluidic sampling for the rapid detection of liquid conductivity

“…[25][26][27] The application of printed circuit board (PCB) technology for the fabrication of capacitively coupled contactless conductivity detection (PCB-C 4 D) electrodes, in lieu of traditional li-off processes, presents a cost-effective and durable alternative. [28][29][30] This innovative approach, demonstrated by Yang et al, [31][32][33] showcases the versatility of PCB-C 4 D electrodes when combined with microchip electrophoresis, enabling the in situ detection of multiple ions. Furthermore, PCB-C 4 D can be independently utilized for direct conductivity measurements by simply dropping the solution onto the electrode, facilitating the determination of liquid electrical conductivity.…”