RESUMO
Rutin,a flavonoid found in fruits and vegetables,is a potential anticancer compound with strong anti-cancer activity.Therefore,electrochemical sensor was developed for the detection of rutin.In this study,CoWO4 nanosheets were synthesized via a hydrothermal method,and porous carbon(PC)was prepared via high-temperature pyrolysis.Successful preparation of the materials was confirmed,and character-ization was performed by transmission electron microscopy,scanning electron microscopy,and X-ray photoelectron spectroscopy.A mixture of PC and CoWO4 nanosheets was used as an electrode modifier to fabricate the electrochemical sensor for the electrochemical determination of rutin.The 3D CoWO4 nanosheets exhibited high electrocatalytic activity and good stability.PC has a high surface-to-volume ratio and superior conductivity.Moreover,the hydrophobicity of PC allows large amounts of rutin to be adsorbed,thereby increasing the concentration of rutin at the electrode surface.Owing to the syn-ergistic effect of the 3D CoWO4 nanosheets and PC,the developed electrochemical sensor was employed to quantitively determine rutin with high stability and sensitivity.The sensor showed a good linear range(5-5000 ng/mL)with a detection limit of O.45 ng/mL.The developed sensor was successfully applied to the determination of rutin in crushed tablets and human serum samples.
RESUMO
Porous carbon nanoparticles ( NPC) were prepared by ZnCl2 activation and carbonization using citrus waste as carbon source. A sample pretreatment method with NPC as dispersive solid phase extraction (d-SPE ) absorbent was established for the determination of organophosphorus pesticides in fruits and vegetables by gas chromatography. The NPC was characterized by scanning electron microscopy (SEM), X-ray diffraction ( XRD), FT-IR spectra, Raman spectroscopy, Brunauer, Emmett and Teller surface area(BET). Those results showed that the NPC was an amorphous porous carbon material with pore size in the range of 0-15 nm. Its specific surface area and pore volume were 1243 m2 / g and 1. 28 cm3 / g, respectively. The analysis conditions, including the amount and clean up time of adsorbent, were optimized by analysis of 14 kinds of oranophosphorus pesticides in fruits and vegetables with gas chromatography-flame photometric determination(GC-FPD). Moreover, the comparison for NPC with commercial materials of PSA, C18 and GCB was investigated in this study. The results indicated that the purification time was only 2 min using 0. 01 g NPC. The cost of NPC was about 25% of C18 , 21% of PSA and 16% of GCB. Because of the porous structure of NPC, the purification efficiency was significantly higher than the three commercial materials mentioned above. Under the optimum conditions, the calibration curves of the 14 organophosphorus pesticides were linear in the range of 0. 02-1. 00 mg / L with good correlation coefficients (R2>0. 99) and detection limits (S / N=3) of 0. 63-5. 30 μg / kg. The recoveries of the pesticides at three spiked levels ranged from 71. 3% to 114. 7%with the relative standard deviations (RSDs) of 0. 9% -12. 9% . The method is simple, rapid, sensitive, and low cost, and can satisfy the requirements of detection of organophosphorus pesticide residues in fruits and vegetables, displaying a good application prospect.