4 research outputs found
LOW-COST CAPILLARY ELECTROPHORESIS INSTRUMENTATION FOR ASSESSMENT OF RAIN WATER IONIC COMPOSITION
The objective of this Short Term Scientific Mission was to test the suitability of capillary electrophoresis for determination of rain water chemical composition. The fully functional, open-hardware, low-cost instrument was assembled and tested. An original protocol for determination of the chemical content of rain water was established and validated in the pilot test. Capillary electrophoresis proofed its highest suitability for the detection and quantification of ions in different samples, indicating substantial differences between clean and dirty snow waters. The hydrostatic sample injection method has been found very efficient and straightforward in manual and laboratory routines. An important deliverable of the Short Term Scientific Mission was a set of multimedia materials for the promotion of CE technique and especially low-cost CE instrumentation
Improved C5D Electronic Realization of Conductivity Detector for Capillary Electrophoresis
The axial C4D (Capacitively Coupled Contactless Conductivity Detection) measurement electronics for capillary electrophoresis is considered and a new improved C5D compensated detection concept is proposed and tested. Using the idle compensation channel with inversed signal and immediate analogue summation of the active and idle channel currents yields effective suppression of the influence of the parasitic stray capacitance. Preliminary experiments have confirmed at least three-fold improvements of measurement resolution. Realisation of electronics allows flexible tuning of frequency from 0.2 MHz to 2 MHz. The relatively high voltage supply of 15 V for the AC measurement units together with 24- bit accurate analogue-to-digital converter yields additional improvement for the sensitivity
Capillary Electrophoresis as a Monitoring Tool for Flow Composition Determination
Flow analysis is the science of performing quantitative analytical chemistry in flowing streams. Because of its efficiency and speed of analysis, capillary electrophoresis (CE) is a prospective method for the monitoring of a flow composition withdrawn from various processes (e.g., occurring in bioreactors, fermentations, enzymatic assays, and microdialysis samples). However, interfacing CE to a various flow of interest requires further study. In this paper, several ingenious approaches on interfacing flow from various chemical or bioprocesses to a capillary electrophoresis instrument are reviewed. Most of these interfaces can be described as computer-controlled autosamplers. Even though most of the described interfaces waste too many samples, many interesting and important applications of the devices are reported. However, the lack of commercially available devices prevents the wide application of CE for flow analysis. On the contrary, this fact opens up a potential avenue for future research in the field of flow sampling by CE
Capillary Electrophoresis Sensitivity Enhancement Based on Adaptive Moving Average Method
In the present work, we demonstrate
a novel approach to improve
the sensitivity of the “out of lab” portable capillary
electrophoretic measurements. Nowadays, many signal enhancement methods are
(i) underused (nonoptimal), (ii) overused (distorts the data), or
(iii) inapplicable in field-portable instrumentation because of a
lack of computational power. The described innovative migration velocity-adaptive
moving average method uses an optimal averaging window size and can
be easily implemented with a microcontroller. The contactless conductivity
detection was used as a model for the development of a signal processing
method and the demonstration of its impact on the sensitivity. The
frequency characteristics of the recorded electropherograms and peaks
were clarified. Higher electrophoretic mobility analytes exhibit higher-frequency
peaks, whereas lower electrophoretic mobility analytes exhibit lower-frequency
peaks. On the basis of the obtained data, a migration velocity-adaptive
moving average algorithm was created, adapted, and programmed into
capillary electrophoresis data-processing software. Employing the
developed algorithm, each data point is processed depending on a certain
migration time of the analyte. Because of the implemented migration
velocity-adaptive moving average method, the signal-to-noise ratio
improved up to 11 times for sampling frequency of 4.6 Hz and up to
22 times for sampling frequency of 25 Hz. This paper could potentially
be used as a methodological guideline for the development of new smoothing
algorithms that require adaptive conditions in capillary electrophoresis
and other separation methods