Development of Azure-B modified pencil graphite electrode as an electrochemical sensor for the investigation of Levofloxacin in pharmaceutical and biological samples

Recent Developments in Voltammetric Analysis of Pharmaceuticals Using Disposable Pencil Graphite Electrodes

“…Electrical contact with the instrument is realized by means of a conductive wire which was soldered or wrapped to the metallic part of the mechanical pencil holder [9,19,21,22,[24][25][26][27][28][29][30][31][32][33][34][35][36][37] (Figure 1a). A micropipette tip [38], an insuline syringe [39], a glass cappilary [40,41], or a plastic [16,[42][43][44][45][46] (Figure 1b) or Teflon tube [47][48][49][50][51][52] (Figure 1c,d) can also act as holder. An araldite mixture (epoxy resin, 1:1) [16,41,[43][44][45], bentonite [38,39], or cyanoacrylate glue [40] was used to fix the graphite lead into the support.…”

“…A micropipette tip [38], an insuline syringe [39], a glass cappilary [40,41], or a plastic [16,[42][43][44][45][46] (Figure 1b) or Teflon tube [47][48][49][50][51][52] (Figure 1c,d) can also act as holder. An araldite mixture (epoxy resin, 1:1) [16,41,[43][44][45], bentonite [38,39], or cyanoacrylate glue [40] was used to fix the graphite lead into the support. Other PGEs were obtained by covering a part of the graphite lead with nail polish [53] or with Teflon tape [20,[54][55][56][57][58][59][60][61][62][63][64][65] (Figure 1e), leaving a constant length and area of nacked pencil mine to act as an electroative surface.…”

“…Sometimes, the graphite lead electrode is polished with an alumina slurry [25,41,47,59,67], on sandpaper with different granulometrics [40,42,68], on emery paper [41,[49][50][51][52]69] followed by a butter sheet [16,45], on butter paper [39], or on weighing paper [20,57,58,62,70]. Yen et al [71] reported that amoxicicllin presented a better electrochemical response at the PGE mechanically treated with polishing paper in comparison with the original electrode.…”

“…An easy way to cover the PGE surface is to apply multiple CV scans to a solution containing the desired modifier(s) [20,60,86,87,108], most often resulting in electrode surface polymeric films like polypyrrole [86,109,110], polyaniline [105,109], poly(2-thiobarbituric acid) [59], poly(Azure-B) [45], poly(xylenol orange) [46], poly(eriochrom black T) [111,112], poly(bromocresol green) [113], etc. or MIPs if the polymerization solutions contain both the monomer(s) and the analyte(s), which act as template molecule(s) [38,49,89,91,92,106,107,[114][115][116][117][118][119][120][121][122][123][124] (Table 3).…”

“…The electrochemical characterization of bare and modified electrodes was usually performed by CV [87,88,117,124,125,129] and electrochemical impedance spectroscopy (EIS) using [Fe(CN) 6 ] 3−/4− as a redox probe and KCl as a supporting electrolyte [17,20,37,41,43,45,47,53,56,57,59,[63][64][65]69,80,85,87,90,105,117,124,125,127,131,132,136,[141][142][143]147], but [Ru(NH 3 ) 6 ] 3+/2+ was also used [38].…”