Sensor-containing microspheres of chitosan crosslinked with 8-hydroxyquinoline-5-sulphonic acid for determination of Cu(II) in instant coffee

Abstract

a b s t r a c tA novel carbon paste electrode containing chitosan microspheres for the determination of Cu(II) in instant coffee by anodic stripping voltammetry was developed. Chitosan was crosslinked with the chelating agent 8-hydroxyquinoline-5-sulphonic acid and glutaraldehyde. The microspheres of the crosslinked chitosan biopolymer were obtained by the spray drying technique and employed in the construction of the sensor. In acetate buffer solution (0.1 mol L À1 , pH 6.0), the calibration curve obtained was linear for concentrations of 5.0 Â 10 À7 to 1.4 Â 10 À5 mol L À1 (r = 0.9990); the detection limit was 5.5 Â 10 À8 mol L À1 . The relative standard deviation (n = 8) was lower than 3.0% for solutions containing 6.0 Â 10 À6 , 5.0 Â 10 À5 and 1.5 Â 10 À4 mol L À1 of Cu(II). The method was successfully employed for determination of Cu(II) in instant coffee and the results obtained showed good agreement when compared with those using electrothermal atomic absorption spectrometry.

Development of a carbon nanotubes paste electrode modified with crosslinked chitosan for cadmium(II) and mercury(II) determination

“…A similar electrode for Cu(II) determination was developed by our group [33], using as crosslinker epichlorohydrin instead of glutaraldehyde. Moreover, some research groups have been proposed electrodes for heavy metal determination using crosslinked chitosan with different crosslinker agents [55,56], which present different selectivity. Moreover, the accumulation potential, the supporting electrolyte and the structure of crosslinked chitosan with GA may influence selectivity and/or detection limit.…”

Preparation of a C6 quaternary ammonium chitosan derivative through a chitosan schiff base with click chemistry

“…The hydrated ion [Cu(H 2 O) 6 ] 2+ in aqueous solution is also more stable than the [Cu(H 2 O) 6 ] + ion 31. CTS and its derivatives can also easy chelate with the Cu 2+ ion to deactivate the catalyst 32. Therefore, in the Cu + ‐catalyzed click chemistry reaction of the CTS derivative, the addition of sodium ascorbate stabilized the Cu + and facilitated the click chemistry reaction.…”

Voltammetric Detection of Lead Using Chitosan-tripolyphosphate Crosslinked Electrode

“…18 However, there are reports about the use of 15 and 10% of this biopolymer when crosslinked with glutaraldehyde and epichlorohydrin. 12,47 The electrolyte evaluated in Pb determination was HNO3 due to the fact that it presents an optimal voltammetric response to Pb. 52 Among the concentrations evaluated, 0.15 mol L -1 (Fig.…”

“…9 The interactions that occur between these compounds and the CTS can be used for several purposes, such as decontamination of effluents and development of CMEs. 11,12 The CTS adsorption capacity as well as its stability can be easily improved through chemical or physical crosslinking processes. 13,14 The physical crosslinking process can be highlighted by using agents (e.g.…”