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Tyburska A.,Warsaw University of Technology | Jankowski K.,Warsaw University of Technology | Ramsza A.,Institute of Applied Optics | Reszke E.,ERTEC Poland | And 2 more authors.
Journal of Analytical Atomic Spectrometry

The feasibility of the use of the NOVA-2 dual-flow ultrasonic nebulizer for the determination of selenium, antimony and arsenic in drinking and mineral waters by direct hydride generation inductively coupled plasma-optical emission spectrometry (HG-ICP-OES) has been investigated. The acidic sample and the borohydride solution are mixed directly on the surface of a quartz oscillating plate converting liquids into aerosol at the entrance of the spray chamber. The analytical figures of merit for the multielement determination of selenium, antimony and arsenic were evaluated. Results showed that the analytical performance of the new system was superior to that of conventional nebulization systems as well as conventional continuous HG with gas-liquid separation, regarding the susceptibility to non-spectroscopic interferences produced by transition metals. Detection limits between 0.7 and 2.1 ng mL-1 were achieved with ICP-OES detection. The precision of 10 replicate measurements at the 0.25 mg L-1 level was between 1.0 to 1.5% relative standard deviation. The utility of the system was demonstrated in the determination of selenium, antimony and arsenic in hard drinking water ERM-CA011a as well as selenium in mineral water samples. The advantages and limitations of this system, compared with existing techniques, are discussed. © 2010 The Royal Society of Chemistry. Source

Jankowski K.,Warsaw University of Technology | Ramsza A.P.,Institute of Applied Optics | Reszke E.,ERTEC Poland | Strzelec M.,Warsaw University of Technology
Journal of Analytical Atomic Spectrometry

A new 2.45 GHz frequency powered helium plasma source with rotating microwave field generated within the three electrodes has been developed. A stable symmetrical low-flow helium discharge is formed at atmospheric pressure with a minimum field strength at the axis. Thus, a triangle shaped ring plasma is obtained with a channel at the center through which the sample is introduced using a laminar dual-flow injector. The helium plasma operates at a microwave input power of 30-150 W and total gas flow of 200-1500 ml min-1 and it is self-igniting. The preliminary investigation of the plasma fundamental parameters provides a He excitation temperature up to 4000 K, rotational temperature (OH) up to 3100 K and electron number density up to 7.5 × 1014 cm-3. To demonstrate the plasma robustness, both the tolerance for water loading and the excitation and ionisation capability for hydride-forming elements as well as for ionic chlorine are presented. The detection limits for As, Sb and Hg obtained by continuous hydride generation without hydrogen separation were 12, 10 and 9 ng ml-1, respectively. © The Royal Society of Chemistry 2010. Source

Petelczyc K.,Warsaw University of Technology | Garcia J.A.,University of Zaragoza | Bara S.,University of Santiago de Compostela | Jaroszewicz Z.,Institute of Applied Optics | And 4 more authors.
Optics Express

We present results of numerical analysis of the Strehl ratio characteristics for the light sword optical element (LSOE). For comparison there were analyzed other optical imaging elements proposed for compensation of presbyopia such as the bifocal lens, the trifocal lens, the stenopeic contact lens, and elements with extended depth of focus (EDOF), such as the logarithmic and quartic axicons. The simulations were based on a human eye's model being a simplified version of the Gullstrand model. The results obtained allow to state that the LSOE exhibits much more uniform characteristics of the Strehl ratio comparing with other known hitherto elements and therefore it could be a promising aid to compensate for the insufficient accommodation range of the human eye. © 2011 Optical Society of America. Source

Jankowski K.,Warsaw University of Technology | Ramsza A.P.,Institute of Applied Optics | Reszke E.,ERTEC Poland
Spectrochimica Acta - Part B Atomic Spectroscopy

Four helium plasma sources operating at atmospheric pressure have been developed for analytical emission spectrometry by applying a synchronically rotating field with three or more phases operating at 1 kHz, 27 MHz or 2.45 GHz. The plasma takes the form of a disk and has minimum field strength at the axis. Thus, a channel is formed at the center through which the sample in the form of wet aerosol or a chemically generated vapor of halogen may be introduced. A dual-flow concentric ceramic injector was used to supply helium plasma gas and the sample to the plasma. The helium plasma operated at low power levels (40-300 W) and low gas flow rates of below 3 L min- 1 and was self-igniting. The acoustic, radio-frequency (rf) and microwave-driven plasmas can withstand wet aerosol loadings of 5, 30 and 100 mg min- 1, respectively, generated by an ultrasonic nebulizer without a desolvation unit. The plasma physical characteristics were compared at these three frequencies under otherwise similar operating conditions. The helium excitation temperature, OH rotational temperature and electron number density increased with increasing frequency in ranges of 2800-4000 K, 1100-3200 K and 0.1-7 × 10 14 cm- 3, respectively. To demonstrate the effect of frequency on the plasma excitation efficiency the emission intensity from halogen ions was evaluated using chemical vapor generation with continuous sampling without desiccation. Using 3-phase microwave, 6-phase microwave, 4-phase rf and 1 kHz helium plasma sources the detection limits (3σ) for chlorine at 479.40 nm were 26, 60, 230 and 1200 ng mL- 1, respectively. The microwave-driven plasma was the densest and had the highest excitation potential toward chlorine and bromine ions. © 2011 Elsevier B.V. All rights reserved. Source

Osuch T.,National Institute of Telecommunications | Jaroszewicz Z.,National Institute of Telecommunications | Jaroszewicz Z.,Institute of Applied Optics
Optics Communications

Scalar diffraction theory is applied to analyze the intensity distribution in the fiber core during fiber Bragg grating (FBG) fabrication using an apodized phase mask. The averaged diffraction field distribution in fiber core was calculated as a function of optical fiber position. The results show that in a case of apodized FBGs fabrication, averaged field intensity profile, and thus refractive index changes in fiber core have complex form. Moreover, it was shown that the influence of optical fiber position behind the phase mask on average intensity distribution in fiber core decreases with increasing of its diameter. Copyright © 2010 Published by Elsevier B.V. All rights reserved. Source

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