A series of activated carbons (ACs) were derived from sugarcane bagasse under two activation schemes: steam-pyrolysis at 600-800°C and chemical activation with H 3 PO 4 at 500°C. Some carbons were treated at 400, 600°C, or for 1-3 h, and/or in flowing air during pyrolysis of acid-impregnated mass. XRD profiles displayed two broad diffuse bands centered around 2θ = 23 and 43°, currently associated with diffraction from the 002 and 100/101 set of planes in graphite, respectively. These correspond to the interlayer spacing, Lc, and microcrystallite lateral dimensions, La, of the turbostratic (fully disordered) graphene layers. Steam pyrolysis-activated carbons exhibit only the two mentioned broad bands with enhancement in number of layers, with temperature, and small decrease in microcrystallite diameter, La. XRD patterns of H 3 PO 4 -ACs display more developed and separated peaks in the early region with maxima at 2θ = 23, 26 and 29°, possibly ascribed to fragmented microcrystallites (or partially organized structures). Diffraction within the 2θ = 43° is still broad although depressed and diffuse, suggesting that the intragraphitic layers are less developed. Varying the conditions of chemical activation inflicts insignificant structural alterations. Circulating air during pyrolysis leads to enhancement of the basic graphitic structure with destruction and degradation in the lateral dimensions.

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1IntroductionThea ntitumoral activity of flutamide {2-methyl-N-[4-nitro-3-(trifluoro methyl) phenyl] propanamide}( Flu) and irinotecan {7-ethyl-10-[4-(1-piperidino)1-piperidino] carbonyloxy-camptothecin} (Irino)( Scheme 1) against certain types of cancers was previously reported.Flutamide seems to have antiandrogenics pecificity only in androgend ependentg enitalia organs,a nd its therapeuticu se is in prostatic cancer [1][2][3][4].A sf lutamide has as tructure similar to testosterone,i tw orksb ya ttaching itself to the receptors on the surface of the cancer cells to block and prevent the attachment of the male hormone [5].I rinotecan is one of the key drugs of anticancer chemotherapy,e specially for the treatment of colorectal and lung tumors as well as other types of cancers [6,7].T he large scale therapeutic use of Flu and Irino generated the need for the development of fast, simple accuratem ethodologies for detection and quality control for both drugs in biological fluids. In this context methods reporting the determinationo fFlu and Irino include chromatography ,s pectrophotometry [31-35],s pectrofluorimetry [36] and few electrochemical methods [37][38][39][40][41][42][43].P olarographicr eduction of Flu was performed at ad ropping mercurye lectrode usingd irect currentp olarographya nd differential pulse polarography [37,38,40].L inear sweep and square waveforms were optimized for the determination of Flu based on the reduction of its nitro aromatic moiety at the hanging mercury drop electrode [39].D etermination of Flu ins urfactant containingm edia at polymer filmm odified carbon paste electrodes usingd ifferential pulsev oltammetryw as reported [41].E lectroanalytical determination of Irino was achieved using fast Fourier transform continuous cyclic voltammetry at gold microelectrodes in aflow system [42].V oltammetric determination of Irino at polymethylene blue multiwalled carbon nanotubes modified glassy carbone lectrode was reported as well [43].T ot he best of our knowledge,t he controlled adsorptive accumulationo fF lu or Irino on the surface of pencil graphite electrodes (PGE) for square wave cathodic adsorptive stripping determinationw as not reported yet. In view of the biological importance of Flu and Irino, this work aims on the development of as imple and sensiAbstract:Asensitive electrochemical method based on square wave cathodic adsorptive strippingv oltammetry (SWCASV) using pencil graphite electrodes( PGE)w as developed for the individual and simultaneous determination of the anticancer drugs flutamide( Flu)a nd irinotecan (Irino) in biological fluids.C alibration curves showed an excellent linear response with limitso fd etection of 1.68 10 À9 and 1.55 10 À8 MI rino and Flu,r espectively. Thes tatistical evaluation of within-day repeatability (n = 5) and day to day precision (n = 5) showed satisfactory accuracy and precision. SWCASV using aPGE for individual and simultaneous determination of both drugs in bulk form, human urine and serums amples was demonstrated.