Far infrared radiation was employed in the rapid removal of the solvents in the extracts of Plumula Nelumbinis and standard mixture solutions to prevent the interference of the solvent peaks toward their capillary electrophoretic measurements. The sample solutions in small vials were exposed to far infrared ray at 60°C for 3 min to remove solvent. The dried samples in the vials were each dissolved into running buffer with the aid of ultrasonication for capillary electrophoresis analysis. The far infrared‐assisted solvent removal approach was sucessfully applied in the rapid determination of neferine, liensinine, isoliensinine, rutin and hyperoside in Plumula Nelumbinis. The five analytes could be well separated within 12 min in a 40 cm long fused silica capillary at a separation voltage of 12 kV in a 50 mM borate buffer (pH 9.2). The results indicated that the interferences of the solvent peaks in the capillary electropherograms of the herbal drugs were eliminated completely.
An alkaline mixture containing copper(II) spices, graphene oxide and glucose was heated by far infrared radiations to synthesize graphene-cuprous oxide hybrid. The hybrid was blended with mineral oil and packed into tubes to fabricate paste electrodes. The electrodes were coupled with capillary electrophoresis for the detection of polyhydroxy compounds. The sensitivities of them on the hybrid electrodes were significantly enhanced by taking advantages of graphene and cuprous oxide. The contents of polyhydroxy compounds in tobacco method was determined by the electrodes with satisfactory assay results.
Aim:
The aim of this work is to fabricate pipette tip electrodes for the capillary electrophoretic determination of nicotine and phenolic compounds in tobacco.
Background:
The content of nicotine affects not only the quality of tobacco products but also the health of smokers. Phenolic compounds are important flavor precursors in tobacco. The quantity of phenolic compounds is one of the most important evaluation indicators of tobacco quality. It is of high importance to determine nicotine and phenolic compounds in tobacco for quality control and the health of smokers.
Objective:
A method based on capillary electrophoresis and amperometric detection was developed for the simultaneous determination of nicotine, rutin, chlorogenic acid, quercetin, ferulic acid, gallic acid and protocatechuic acid in tobacco leaves. Pipette electrodes were designed and fabricated for the amperometric detection of them.
Method:
Nicotine, rutin, chlorogenic acid, quercetin, ferulic acid, gallic acid and protocatechuic acid were determined by capillary electrophoresis in combination with the detection electrodes that were fabricated by packing the composite of carbon nanotube and epoxy in pipette tips.
Results:
Detection potentials, the acidity and concentrations of background electrolyte, separation voltages and injection times were optimized. At a high voltage of 12 kV, separation of the seven analytes could be achieved in less than 11 min in a piece of 40 cm long fused silica capillary with a background electrolyte of 50 mM borate buffer (9.2). Linearity was observed between the peak currents and the concentrations with the limits of detection ranging from 0.1 to 0.2 µM for the seven analytes at the pipette electrodes. The method was applied in the simultaneous determination of nicotine and phenolic compounds with satisfactory assay results.
Conclusions:
The pipette tip electrodes were successfully coupled with capillary electrophoresis for tobacco analysis. The CE-AD method provides not only a simple approach for the quality control of tobacco and its preparations but also an alternative technique for the constituent and fingerprint investigation of other plants.
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