A novel electrochemical chiral sensor for 3,4-dihydroxyphenylalanine based on the combination of single-walled carbon nanotubes, sulfuric acid and square wave voltammetry

Abstract

We demonstrate, for the first time, an electrochemical sensor that provides antipodal signals upon application of square wave voltammetry (SWV), for enantioselective recognition of 3,4-dihydroxyphenylalanine based on chiral single-walled carbon nanotubes (SWCNTs) in the presence of sulphuric acid. Interestingly, the enantioselectivity was not observed using the common method of cyclic voltammetry (CV) but the SWV peak currents of enantiomers were found to be quite different and hence the enantiomers could be successfully recognized. Moreover, the antipodal signals provided by two SWV scan modes offer the possibility for results to be confirmed mutually, showing a great practical value and analytical application prospects.

A Gold Nanoparticles–Enhanced Carbon Nanotubes Electrochemical Chiral Sensor

“…Based on our previous results , the cSWCNTs ( 6,5 ) is the best choice for enantioselective recognition of DOPA among several SWCNTs. Bundles of 10–20 nm cSWCNTs could be observed from its TEM image (Figure G).…”

“…So the study of chiral recognition of enantiomers is playing an increasingly important role in chemical biology and pharmacology significance. Taking 3,4‐dihydroxyphenylalanine (DOPA) for instance, several technologies for the discrimination of its enantiomers have been reported such as high performance liquid chromatography , capillary electrophoresis , tandem mass spectrometry and electrochemical methods , etc. In comparison, the electrochemical method might be the most cost‐effective option due to their low cost, high specificity, high sensitivity, and quick response as well as easy to regenerate in analyte detection.…”

“…Recently, Balaraman et al found that carbon nanotubes can facilitate amplification of the molecular chirality of a π‐gelator to supramolecular helicity through the formation of coaxial cylindrical nanocables . Our previous paper demonstrates an electrochemical sensor that provides antipode signals upon application of square wave voltammetry (SWV) for enantioselective recognition of DOPA based on cSWCNTs in the presence of sulphuric acid . The practical application of such an electrochemical chiral sensor corresponds to a reliable response range from 30 to 100 μM.…”

“…One is 8.9 and the other is 12.5 μA, with the current ratio ( I L ‐DOPA / I D ‐DOPA ) of 1.4. Like our previous report , DOPA enantiomers can be discriminated with SWV technique but not with CV. Third, more interestingly, for most of similar electrochemical chiral sensor, D ‐DOPA shows higher current response than L– DOPA ,, but the cSWCNTs ( 6,5 ) shows better stereospecificity for L– DOPA, meaning some uniqueness of such kind of cSWCNTs.…”

Novel chiral PEDOTs for selective recognition of 3,4-dihydroxyphenylalanine enantiomers: Synthesis and characterization

“…In other words, SWV makes limited recognition sites reused, which greatly increases the efficiency of chiral recognition. 79 According to literatures, there were two conventional electrolytes used to detect DOPA. Former was phosphate buffer solution of pH 7.0, and another was 0.25 M H 2 SO 4 .…”