Polytetrafluorethylene-Au as a substrate for surface-enhanced Raman spectroscopy

This study deals with preparation of substrates suitable for surface-enhanced Raman spectroscopy (SERS) applications by sputtering deposition of gold layer on the polytetrafluorethylene (PTFE) foil. Time of sputtering was investigated with respect to the surface properties. The ability of PTFE-Au substrates to enhance Raman signals was investigated by immobilization of biphenyl-4,4'-dithiol (BFD) from the solutions with various concentrations. BFD was also used for preparation of sandwich structures with Au or Ag nanoparticles by two different procedures. Results showed that PTFE can be used for fabrication of SERS active substrate with easy handle properties at low cost. This substrate was sufficient for the measurement of SERS spectrum of BFD even at 10-8 mol/l concentration

"Soft and rigid" dithiols and Au nanoparticles grafting on plasma-treated polyethyleneterephthalate

Surface of polyethyleneterephthalate (PET) was modified by plasma discharge and subsequently grafted with dithiols (1, 2-ethanedithiol (ED) or 4, 4'-biphenyldithiol) to create the thiol (-SH) groups on polymer surface. This "short" dithiols are expected to be fixed via one of -SH groups to radicals created by the plasma treatment on the PET surface. "Free" -SH groups are allowed to interact with Au nanoparticles. X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR) and electrokinetic analysis (EA, zeta potential) were used for the characterization of surface chemistry of the modified PET. Surface morphology and roughness of the modified PET were studied by atomic force microscopy (AFM). The results from XPS, FTIR, EA and AFM show that the Au nanoparticles are grafted on the modified surface only in the case of biphenyldithiol pretreatment. The possible explanation is that the "flexible" molecule of ethanedithiol is bounded to the activated PET surface with both -SH groups. On the contrary, the "rigid" molecule of biphenyldithiol is bounded via only one -SH group to the modified PET surface and the second one remains "free" for the consecutive chemical reaction with Au nanoparticle. The gold nanoparticles are distributed relatively homogenously over the polymer surface

Synthesis of phosphorus analog of DOTA by alkylation

Department of Organic ChemistryKatedra organické chemieFaculty of SciencePřírodovědecká fakult

Synthesis of phosphorus analog of DOTA by alkylation

Katedra organické chemieDepartment of Organic ChemistryPřírodovědecká fakultaFaculty of Scienc

Enantioseparation and Determination of Mephedrone and Its Metabolites by Capillary Electrophoresis Using Cyclodextrins as Chiral Selectors

Mephedrone, a psychoactive compound derived from cathinone, is widely used as a designer drug. The determination of mephedrone and its metabolites is important for understanding its possible use in medicine. In this work, a method of capillary electrophoresis for the chiral separation of mephedrone and its metabolites was developed. Carboxymethylated β-cyclodextrin was selected as the most effective chiral selector from seven tested cyclodextrin derivates. Based on the simplex method, the optimal composition of the background electrolyte was determined: at pH 2.75 and 7.5 mmol·L−1 carboxymethylated β-cyclodextrin the highest total resolution of a mixture of analytes was achieved. For mephedrone and its metabolites, calibration curves were constructed in a calibration range from 0.2 to 5 mmol·L−1; limits of detection, limits of quantification, precision, and repeatability were calculated, and according to Mandel’s fitting test, the linear calibration ranges were determined

Synthesis of phosphorus analog of DOTA by alkylation

Katedra organické chemieDepartment of Organic ChemistryPřírodovědecká fakultaFaculty of Scienc

Cyclodextrin-Functionalised Nanomaterials for Enantiomeric Recognition

Cyclodextrins, which are glucose-based cyclic oligosaccharides, are materials that can act inherently as chiral selectors, with many reports of the application of cyclodextrins in enantioseparation. However, many studies have encountered the problem of insufficient enantioselective performance of the chiral selector. One of the main reasons is due to low surface concertation's, whereby interaction between the chiral selector and analyte usually occurs at a surface. Thus, scientists have been trying for the last two decades to overcome this problem, with the incorporation of nanomaterials being promising as they possess a large surface area which allows for the accommodation of a higher concentration of the chiral selectors. Herein, we outline nanomaterial-cyclodextrin conjugates that work in tandem to achieve or enhance enantioselectivity through various methods such as chromatography, adsorption, and removal using magnetic nanoparticles, or enantiorecognition using electrochemical techniques