Viktor Kanický

Preconcentration of platinum group metals on modified silicagel and their determination by inductively coupled plasma atomic emission spectrometry and inductively coupled plasma mass spectrometry in airborne particulates

Modified silicagel (C18) was studied for separation and preconcentration of platinum group metals (Ru, Rh, Pd, Os, Ir and Pt) as ion associates of their chlorocomplexes with cation of onium salt N(1-carbaethoxypentadecyl)-trimethyl ammonium bromide. Sample containing HCl and the onium salt was pumped through the column. After elution with ethanol the eluate was evaporated in the presence of HCl. Resulting aqueous solutions were analysed with inductively coupled plasma atomic emission spectrometry (ICP-AES) and inductively coupled plasma mass spectrometry (ICP-MS). Recovery values of 1-20 mug Pt and Pd from 50 ml of synthetic pure solution were 100+/-3 and 100+/-1%, respectively, however, they diminished with increasing sample volume and in the presence of the real sample matrix or nitrate ions. Samples of engine soot (NIES No. 8), decomposed by low pressure oxygen high-frequency plasma, and airborne particulates from dust filters of meteorological stations, leached with HNO(3) and H(2)O(2), were analysed. A reasonable agreement was found between ICP-MS and ICP-AES results for airborne dust samples and the values comparable with those in literature were determined in NIES No. 8.

Quantitative analysis of Fe-based samples using ultraviolet nanosecond and femtosecond laser ablation-ICP-MS

The quantification capabilities of iron-based samples were investigated using three commercially available ultraviolet (UV) nanosecond (ns) and femtosecond (fs) laser ablation systems coupled to inductively coupled plasma mass spectrometry (LA-ICP-MS). A comparison of three pulsed laser ablation systems (ArF* excimer, Nd:YAG and Ti-sapphire) with different wavelengths and pulse time durations (15 ns, 4 ns and 150 fs, respectively) was performed. Minor and trace elements were determined using 57Fe as internal standard element. Using similar spatial resolution for all laser systems and commonly applied operating conditions for each system, higher ion-signals (25–30%) and more stable elemental ratios (10% TRSD) were obtained for UV-fs-LA-ICP-MS. Scanning electron microscope images and particle size distributions measured for UV-ns-LA systems showed a bimodal distribution formed by nano-sized agglomerates and micro-sized molten spherical particles. In contrast, due to reduced thermal effects achieved using ultra-short pulses, the particle size distribution measured using UV-fs-LA showed a broad monomodal distribution (nano-sized agglomerates in the range of 50–250 nm). Matrix-matched (within metallic samples) and non-matrix matched calibrations were applied for the analysis of Fe-based samples, using a silicate glass (SRM NIST 610) as non-matrix matched calibration sample (glass-metals). Improved analytical results in terms of precision and accuracy were obtained using femtosecond laser ablation when using similar matrices for calibration. Moreover, non-matrix matched calibration used for quantification provides more accurate results (5–15%) in comparison with both UV-ns-LA-ICP-MS (5–30% using Nd:YAG laser and 15–60% using ArF* laser).

Determination of elements in agricultural soils using IR laser ablation inductively coupled plasma atomic emission spectrometry

Abstract Direct sampling of soil samples was studied using laser ablation inductively coupled plasma atomic emission spectrometry (LA-ICP-AES). Samples were pressed into pellets together with a binder and an internal standard. The amount of ablated material for pellets with various binding materials was evaluated. Silver and aluminium powders were found as adequate binders for the pellet preparation. Optimisation of laser parameters, and sample displacement during interaction have been performed. Moderate laser pulse energy of 150 mJ together with a 20-Hz repetition rate was found to be the most suitable to obtain stable analytical signal. Sample displacement leads to more precise sampling and long time signal plateau that can be measured even with sequential spectrometers. Precision was approximately 5% for most of the elements studied. Calibration was performed using soil samples spiked with solutions. Internal standards improved correlation coefficients for calibration, which were at least 0.98. Germanium powder was the most efficient internal standard. Certified reference soils were analysed with an accuracy better than 10%.

Vapour generation inductively coupled plasma optical emission spectrometry in determination of total iodine in milk

Vapour generation inductively coupled plasma optical emission spectrometry (VG-ICP-OES) was used for the determination of the iodine content in milk samples. Modified alkaline ashing of the milk sample was employed for the total digestion of organic matrix constituents. A mixture of potassium hydroxide (2 mL, 2 mol L−1 in ethanol) and calcium nitrate (2 mL, 0.4 mol L−1 in ethanol) was used in the digestion step as an ashing aid for 2 ml of milk sample (or 200 mg of milk powder). Sample ash was then treated with hydrochloric acid (1.5 mL, 5 mol L−1) and sodium sulfite (1.25 mL, 1 mol L−1) for the elimination of carbonates, which would otherwise cause spectral interference. The vapour of elemental iodine was generated by means of oxidation of iodide by hydrogen peroxide (1 mol L−1) in sulfuric acid (5 mol L−1). Using a gas phase separator, matrix elements were completely eliminated; thus the spectral interference of phosphorus (178.222 nm) was removed and the most intense analytical line of iodine (178.218 nm) could be used for determination. The accuracy of the method was verified by analysis of CRM Non-Fat Milk Powder 1549 from NIST, as well as by the comparative study of VG-ICP-OES and ICP-MS results after alkaline solubilization (TMAH 2.5 mL, 10%). The limit of detection for the VG-ICP-OES method is 20 μg L−1 for original milk samples (based on 3σ of blank value). The concentration of iodine in real milk samples was found in the range 0.2–0.8 mg L−1 with a precision of determination from 0.5 to 3.5% (3 replicates).

Multielemental analysis of prehistoric animal teeth by laser-induced breakdown spectroscopy and laser ablation inductively coupled plasma mass spectrometry

Laser-induced breakdown spectroscopy (LIBS) and laser ablation (LA) inductively coupled plasma (ICP) mass spectrometry (MS) were utilized for microspatial analyses of a prehistoric bear (Ursus arctos) tooth dentine. The distribution of selected trace elements (Sr, Ba, Fe) was measured on a 26 mm×15 mm large and 3 mm thick transverse cross section of a canine tooth. The Na and Mg content together with the distribution of matrix elements (Ca, P) was also monitored within this area. The depth of the LIBS craters was measured with an optical profilometer. As shown, both LIBS and LA-ICP-MS can be successfully used for the fast, spatially resolved analysis of prehistoric teeth samples. In addition to microchemical analysis, the sample hardness was calculated using LIBS plasma ionic-to-atomic line intensity ratios of Mg (or Ca). To validate the sample hardness calculations, the hardness was also measured with a Vickers microhardness tester.

Investigation of the microstructure and mineralogical composition of urinary calculi fragments by synchrotron radiation X-ray microtomography: a feasibility study

The outcomes from the feasibility study on utilization of synchrotron radiation X-ray microtomography (SR-μCT) to investigate the texture and the quantitative mineralogical composition of selected calcium oxalate-based urinary calculi fragments are presented. The comparison of the results obtained by SR-μCT analysis with those derived from current standard analytical approaches is provided. SR-μCT is proved as a potential effective technique for determination of texture, 3D microstructure, and composition of kidney stones.

Off-line coupling of capillary electrophoresis to substrate-assisted laser desorption inductively coupled plasma mass spectrometry.

A novel off-line coupling of capillary electrophoresis (CE) and inductively coupled plasma mass spectrometry (ICPMS) is reported here. The coupling interface is based on the connection of a separation capillary to a deposition capillary via a liquid junction maintaining high separation efficiency and sample utilization due to the self-focusing effect and lack of pressure-induced flow in comparison with nebulizer-like interfaces. The separation is recorded in the form of droplets of CE effluent on a suitable substrate--a poly(ethylene terephthalate) glycol (PETG) sample plate placed inside a partially evacuated chamber. Substrate-assisted laser desorption (SALD) is used to vaporize the sample fractions and to enable further transfer to the ICPMS. The mechanism of SALD is examined using model samples deposited on a variety of substrates. The highest response is obtained for a PETG substrate; sample desorption due to ablation of PETG is found to outweigh direct ablation of sample. Detection limits are given for several metal elements. Finally, a rapid (2.5-min), high-resolution separation of Cr(III)/Cr(VI) species injected in subpicomolar quantity is shown.

Comparison of some analytical performance characteristics in inductively coupled plasma spectrometry of platinum group metals and gold.

The limits of detection, precision and matrix effects in the inductively coupled plasma spectrometry of platinum group metals (PGMs) and gold were measured and evaluated for four ICP-AES and one ICP-MS instrument. The sample matrix was a cationic surfactant used for the PGMs and gold preconcentration on a modified silica gel (C18). A sorption of ion associates of PGMs and gold chlorocomplexes with the cation of onium salt N(1-carbaethoxypentadecyl)-trimethyl ammonium bromide was considered. The calibration curves, limits of detection and matrix effects were evaluated in the presence of 0.003 mol dm(-3) of onium salt (1.3 mg cm(-3)) and 0.1 mol dm(-3) HCl. The values of limits of detection (3 sigma(bl)) of PGMs for all axial ICP instruments were mostly below 10 ng cm(-3). Lateral observation on dual view ICP instrument yielded only 3 times higher detection limits in comparison to the axial mode of the same spectrometer and the detection limits for ICP-MS instrument were on the levels of units or tens of pg cm(-3). These limits of detection did not significantly differ from values obtained with pure solutions. Matrix effects in the presence of onium salt did not exceed 12% depression in the analytical signals. Besides the coefficients of correlation, the uncertainties on centroids of concentrations were calculated for calibration graphs obtained by linear regression.

Elemental mapping in fossil tooth root section of Ursus arctos by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS)

Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) was used to map the matrix (Ca, P) and trace (Ba, Sr, Zn) elements in the root section of a fossilized brown bear (Ursus arctos) tooth. Multielemental analysis was performed on a (2.5 × 1.5)cm(2) area. For elemental distribution, a UP 213 laser ablation system was coupled either with a quadrupole or a time of flight ICP-MS. The cementum and dentine on the slice of the sample surface were clearly distinguishable, especially changes in elemental distribution in the summer and winter bands in the fossil root dentine. Migration and diet of U. arctos were determined on the basis of fluctuations in Sr/Zn ratio and their contents. Quantification was accomplished with standard reference material of bone meal (NIST 1486) and by the use of electron microprobe analysis (EMPA). Changes in Sr/Zn and Sr/Ba ratios relating to the season, and composition of food during the lifetime of the animal are discussed on basis of analysis of light stable isotopes. It was observed that there was an increase in the Sr/Zn ratio during the winter season caused by a reduction of food intake during hibernation. Above mentioned inferences drawn from elemental data obtained by LA-ICP-MS were confirmed independently by determination of carbon, nitrogen and strontium isotopes. Moreover, diagenesis and its interfering influence on the biogenic composition of cementum and dentine were resolved. According to the distribution and/or content of the element of interest, post-mortem alterations were revealed. Namely, U, Na, Fe, Mg and F predicate about the suitability of the selected area for determination of migration and diet.

Contribution to vapor generation-inductively coupled plasma spectrometric techniques for determination of sulfide in water samples

Vapor generation-inductively coupled plasma-optical emission spectrometry was used for the determination of sulfide in water samples preserved by the addition of a zinc acetate and sodium hydroxide solution. Hydrogen sulfide and acid-volatile sulfides were transformed, by acidification, to a gaseous phase in a vapor generator and subsequently detected by inductively coupled plasma optical emission spectrometry. Compounds interfering with iodometric titration and spectrophotometric determination were examined as potential chemical interferents. The proposed method provides results comparable to iodometric titration in the tested concentration range 0.06-22.0 mg L(-1). Limit of detection for the determination of hydrogen sulfide by this method is 0.03 mg L(-1).