Carbon nanotube disposable detectors in microchip capillary electrophoresis for water‐soluble vitamin determination: Analytical possibilities in pharmaceutical quality control

Abstract

In this work, the synergy of one mature example from "lab-on-chip" domain, such as CE microchips with emerging miniaturized carbon nanotube detectors in analytical science, is presented. Two different carbon electrodes (glassy carbon electrode (GCE) 3 mm diameter, and screen-printed electrode (SPE) 0.3 mm x 2.5 mm) were modified with multiwalled carbon nanotubes (MWCNTs) and their electrochemical behavior was evaluated as detectors in CE microchip using water-soluble vitamins (pyridoxine, ascorbic acid, and folic acid) in pharmaceutical preparations as representative examples. The SPE modified with MWCNT was the best electrode for the vitamin analysis in terms of analytical performance. In addition, accurate determination of the three vitamins in four different pharmaceuticals was obtained (systematic error less than 9%) in only 400 s using a protocol that combined the sample analysis and the methodological calibration.

Interference-blind microfluidic sensor for ascorbic acid determination by UV/vis spectroscopy

“…[10] Escarpa et al have proposed microchip electrophoresis coupled with electrochemical detection for the separation and quantification of water-soluble vitamin. [13] To date, microchip electrophoresis for the real food sample analysis is still in its infancy, and usually involves the utilization of high voltage for the separation of samples. [14] Another option for working under complex sample matrices is to develop enzymebased methods to selectively sense AA.…”

Nanomaterials as electrochemical detectors in microfluidics and CE: Fundamentals, designs, and applications

“…For example, Crevillén et al describe a small increase of S/N for ascorbic acid using carbon screen-printed electrode modified with multiwalled carbon nanotube (MWCNT), but this parameter was duplicated for folic acid [39]. Moreover, in another work, a noticeable improvement of S/N (420%) was reported for some polyphenols even in the analysis of real samples using the same electrode [16].…”

“…The underlying bulk electrode is modified with CNT film, usually by the deposition of a suspension of CNTs in solvent (e.g. DMF or aqueous solution of a polymer) and allowing the solvent to evaporate [16,34,35,39,[43][44][45][46][47]. The CNTs consequently create a random CNT films on the surface of the electrodes.…”

“…In addition, as a consequence of the faster electronic transfer, resolution during the analysis of vanilla flours was improved by a factor of 2 [16]. The analytical performance of different CNTs using different electrode substrates (GC and SPE electrodes) and the analytical behavior in terms of calibration and robustness have also been explored, revealing the birth of a new generation of analytical microsystems based on CE microchips incorporating electrochemical nanomaterials [39,47].…”

Rapid Determination of Ascorbic Acid in Fresh Vegetables and Fruits with Electrochemically Treated Screen-Printed Carbon Electrodes

“…With the appearance of carbon nanotubes (CNTs), recent electrochemical studies have revealed that CNTs can facilitate the oxidation of AA at a low potential, and demonstrated possible application of CNTs for selective determination of AA [13]. Crevillén et al developed carbon nanotube-modofied disposable detectors in microchip capillary electrophoresis for AA determination in pharmaceutical quality control [14]. However, Most of the above mentioned mehods showed a certain degree of complexity in the phase of electrode modification.…”