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82. Absorption Spectra of Ethanol and Water Using a Photothermal Lens SpectrophotometerHumberto Cabrera, Jehan Akbar, Dorota Korte, Imrana Ashraf, Evelio E. Ramírez- Miquet, Ernesto Marin, Joseph Niemela, 2018, original scientific article Keywords: Thermal lens spectrometry, TLS, absorption of water, absorption of ethanol, vibration overtones Published in RUNG: 08.06.2018; Views: 4559; Downloads: 0 This document has many files! More... |
83. Speciation and Determination of Ionic and Trace-Level Colloidal Silver in Selected Personal Care Products by Thermal Lens SpectrometryDorota Korte, Ales Grahovac, Andrej Jerkic, Olga Vajdle, Jasmina Anojčić, Valeria Guzsvány, Bojan Budič, Mladen Franko, 2018, original scientific article Keywords: Silver nanoparticles, Colloidal silver, Personal care
products, Thermal lens spectrometric determination, Flow injection
analysis Published in RUNG: 26.02.2018; Views: 4405; Downloads: 0 This document has many files! More... |
84. Trace Detection and Photothermal Spectral Characterization by a Tuneable Thermal Lens Spectrometer with White-Light ExcitationHumberto Cabrera, Dorota Korte, Mladen Franko, 2018, original scientific article Abstract: In the thermal lens experimental set-up we replaced the commonly employed pump laser by a halogen lamp, combined with an interference lter, providing a tuneable, nearly monochromatic pump source over the range of wavelengths 430–710 nm. Counter-propagating pump and probe beams are used and a 1 mm path-length sam- ple cell together with the interference lter makes an optical cavity, providing ampli cation of the thermal lens signal, which leads to enhancement of the measurement sensitivity, and enables detection of absorbances on the order of 5×10− 6. Ampli ed thermal lens signal allows us to replace the typical lock-in ampli er and digital os- cilloscope with a silicon photodetector, Arduino board, and a personal computer, offering the possibility for a compact, robust and portable device, useful for in- eld absorption measurements in low concentration or weakly absorbing species. The use of a white light source for optical pumping, an interference lter for wavelength selection and direct diagnostic of the thermal lens signal increase the versatility of the instrument and simpli- es substantially the experimental setup. Determination of Fe(II) concentrations at parts per billion levels was performed by the described white-light thermal lens spectrophotometer and the absorption spectrum for 50μg/ L Fe(II)-1,10-phenanthroline was well reproduced with an average measurement precision of 4%. The obtained limits of detection and quantitation of Fe(II) determination at 510nm are 3μgL− 1 and 11μgL− 1, respectively. The calibration curve was linear in the concentration range of LOQ-500μgL− 1 with reproducibility between 2% and 6%, con rming that this instrument provides good spectrometric capabilities such as high sensitivity, tune- ability and good reproducibility. In addition, the versatility of the instrument was demonstrated by recording the photothermal spectrum of gold nanostructured material and determination of excitation wavelength with most ef cient optical to thermal energy conversion, which differs considerably (cca 100 nm) from the absorption maximum of the investigated sample. Keywords: thermal lens spectrometry, Fe(II) determination, photothermal technique, multi-wavelength excitation Published in RUNG: 21.02.2018; Views: 4282; Downloads: 0 This document has many files! More... |
85. Thermoelectric properties of nanostructured porous siliconR.J. Martín-Palma, H. Cabrera, B. Martín-Adrados, Dorota Korte, E. Pérez-Cappe, Y. Mosqueda, M. A. Frutis, E. Danguillecourt, 2017, original scientific article Keywords: thermoelectric properties, nanostructured porous silicon Published in RUNG: 01.12.2017; Views: 3304; Downloads: 0 This document has many files! More... |
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