Mesoporous silica-based electrochemical sensor for simultaneous determination of honokiol and magnolol

Abstract

A kind of mesoporous SiO 2 was synthesized using cationic surfactant as the structure-directing template. After that, the resulting mesoporous SiO 2 was used to modify the carbon paste electrode (CPE). The electrochemical behaviors of honokiol and magnolol were examined. In pH 6.5 phosphate buffer, two well-shaped oxidation peaks at 0.31 and 0.44 V were observed at the mesoporous SiO 2 -modified CPE. Compared with the unmodified CPE, the mesoporous SiO 2 -modified CPE remarkably enhances the oxidation peak currents of honokiol and magnolol. This suggests that mesoporous SiO 2 exhibits considerable surface enhancement effects to honokiol and magnolol. After optimizing the parameters such as pH value, amount of mesoporous SiO 2 , and accumulation time, a sensitive and simple electrochemical method was proposed for the simultaneous determination of honokiol and magnolol. As to honokiol, the calibration curve is from 2.0 to 100.0 lg L -1 , and the limit of detection is 0.5 lg L -1 (1.8 9 10 -9 mol L -1 ). For magnolol, the linear range is from 20.0 to 200.0 lg L -1 , and the limit of detection is 10.0 lg L -1 (3.8 9 10 -8 mol L -1 ). Finally, the newly proposed method was successfully employed to determine honokiol and magnolol in Chinese traditional medicines.

Synthesis of 1-[3-(N-pyrrole)propyl]-3-[1-tert-butoxycarbonylamino-propyl]-imidazolium tetrafluoroborate ionic liquid for application in electrochemical sensing of magnolol

“…4, sweeping from −0.2 to 1.0 V, an irreversible oxidation peak was observed whether at the polymerized ionic liquid film electrode (curve a) or the bare GCE (curve b). After the polymerized ionic liquid film being deposited, the oxidation peak was found slightly shift from 0.44 to 0.46 V. No reduction peak was observed in the reverse scanning process, suggesting that the electrochemical response of magnolol was a totally irreversible reaction in accordance with other reports [25][26][27][28]. From the comparison of the curve a and the curve b in Fig.…”

“…This phenomenon can be attributed to the electrode contamination, resulting from the coupling reaction of the oxidative products of magnolol to form dimers or polymers which blocks the electron and mass transfer of magnolol to the electrode surface [32]. Similar behaviors have also been observed in the previous reports for the electrochemical oxidation of magnolol [26][27][28]. The influence of scan rate on the voltammetric behavior of magnolol at the polymerized ionic liquid film electrode was investigated.…”

“…Till now, many analytical techniques including liquid chromatography coupled with mass spectrometry [22], capillary electrophoresis [23], and fluorescence spectroscopy [24] have been developed for the determination of magnolol. Electrochemical techniques were also reported for the magnolol assay due to its electrochemical activity [25][26][27][28] and were proved to be very convenient, fast, and sensitive. Herein, a disposable sensor for magnolol was developed based on a polymerized ionic liquid film electrode.…”

Mesoporous Silica Electrochemical Sensors for the Detection of Ascorbic Acid and Uric Acid

“…The unique properties of mesoporous silica makes it an excellent component in fabricating electrochemical sensor. With the presence of mesoporous silica, a MCPE provides surface and adsorption enhancement towards the determination of favoured molecules [17][18][19]. The main objectives of this study was to successfully synthesize the mesoporous silica; SBA-15 and SBA-16 and to build a convenient, cheap, enhanced and sensitive electrochemical method (SBA-15/MCPE and SBA-16/MCPE) for the determination of AA and UA by utilizing the properties of SBA-15 and SBA-16.…”

Single Molecule Microscopy

“…Although there are several examples in which modified mesoporous silica is used for separation and as an electrode coating material for electrochemical sensing [144][145][146][147], little is known about the detailed behavior and interactions of the guest species inside the mesoporous silica host channels on a single-molecule basis.…”