Piotr Zerzucha

Excited and ionized states of the ozone molecule with full triples coupled cluster methods.

The role of connected triple excitations in coupled cluster (CC) calculations of vertical excitation energies, ionization potentials, and the electron affinity of the ozone molecule is evaluated. The equation of motion (EOM) and Fock space (FS) multireference CC approaches with full triples have been used in the calculations. The effect of the T(3) and R(3) operators significantly improve the EOM CCSD results for all considered quantities. A similar behavior is observed in the case of the FS-CC calculations. The FS-CC calculations with full triples have been obtained only for the intermediate Hamiltonian realization of the FS approach as the standard formulation diverges. The latter results are rigorously linked, and less expensive since smaller matrices are diagonalized.

Chemometric and environmental assessment of arsenic, antimony, and chromium speciation form occurrence in a water reservoir subjected to thermal anthropopressure

In the study, arsenic, antimony, and chromium concentrations and selected physicochemical parameters in water and sediment samples from the thermal anthroporessure subjected Rybnik Reservoir (Poland) were determined. As(III), As(V), Sb(III), and Sb(V) ions were successfully separated on Dionex IonPac AS7 column, and Cr(III) and Cr(VI) on Dionex IonPac AG7 column. The obtained limits of detection were 0.18, 0.22, 0.009, 0.012, 0.11, and 0.17xa0μg/L, respectively. Water and bottom sediment samples were collected monthly at three-point transect between January and November 2013. The As(III) and Sb(III) speciation forms dominated in the bottom water, and Cr(VI) concentration in the bottom water was twice as high as the value measured for the surface water. The oxidized arsenic, antimony, and chromium forms dominated in the bottom sediments in the heated water discharge zone of the Rybnik Power Plant. The location of sampling point had a significant influence on the observed transformations and contents of the analyzed speciation forms. The chemometric analysis coupled with the dissimilarity analysis and principal component analysis helped to visualize the variability in the concentrations of the element speciation forms within the researched period and analyzing correlations.

A study on adsorption of metals by activated carbon in a large-scale (municipal) process of surface water purification

AbstractElements that enter the aquatic environment may pose a health risk to wildlife and humans. The aims of this study were: to determine how the introduction of activated carbon for a water purification system will improve the quality of the water produced; and to investigate the sorption of metals on activated carbons, including determination of the accumulation, as well as changes in concentrations of elements in carbons. The tests were carried out on three types of activated carbons with different granular structure. All samples were collected from Water Treatment Plant Goczalkowice, Poland. Concentrations of elements were measured using an optical emission spectrometer with inductively coupled plasma. The experiment showed that metals accumulating in the activated carbons during the operation included: Ca, Mn, Zn, and Cu. In each of the three types of carbons, it can distinguish such elements as Ba, Al, Cr, Ni, Ti, which are characterized by irregular accumulation during the operation of the filter. The introduction of carbon sorbent for water treatment largely contributed to improvement in the quality of raw material supplied to customers, mainly with regard to taste and smell, as well as to reduction of basic parameters: color, absorbance in the UV range and oxidability.n

Non-parametric multivariate analysis of variance in the proteomic response of potato to drought stress

Spot detection is a mandatory step in all available software packages dedicated to the analysis of 2D gel images. As the majority of spots do not represent individual proteins, spot detection can obscure the results of data analysis significantly. This problem can be overcome by a pixel-level analysis of 2D images. Differences between the spot and the pixel-level approaches are demonstrated by variance analysis for real data sets (part of a larger research project initiated to investigate the molecular mechanism of the response of the potato to drought stress). As the method of choice for the analysis of data variation, the non-parametric MANOVA was chosen. NP-MANOVA is recommended as a flexible and very fast tool for the evaluation of the statistical significance of the factor(s) studied.

Assessment of elemental contamination in the bottom sediments from a dam reservoir using a sequential extraction technique and chemometric analysis

AbstractThe concentration of elements in sediments is an important aspect of the quality of water ecosystems. The element concentrations in bottom sediments from Goczalkowice Reservoir, Poland, were investigated to determine the levels, accumulation and distribution of elements; to understand the contamination and potential toxicity of elements; and to trace the possible source of pollution. Sediments were collected from 8 sampling points. The functional speciation, mobility and bioavailability of elements were evaluated by means of modified Tessier sequential extraction. The element contents were measured by optical emission spectrometry with inductively coupled plasma. The experimental results were analyzed using chemometric methods such as principal component analysis and cluster analysis to elucidate the metal distributions, correlations and associations. The highest concentrations of most elements were found at the center of the reservoir. The distribution of metals in the individual fractions was varied. To assess the extent of anthropogenic impact indices, contamination factor, degree of contamination, metal pollution index and risk assessment code were applied. The calculated factors showed the highest contamination factor and the ability of chromium to be released from sediments. The degree of contamination showed that the area is characterized by a very high contamination. Strontium and manganese showed high potential ecological risk for sediments.n

Spectrophotometric and Inductively Coupled Plasma–Optical Emission Spectroscopy Determination of Gallium in Natural Soils and Soils Polluted by Industry: Relationships between Elements

The aim of this work was to determine gallium contents in different soils of Poland using a sensitive spectrophotometric method based on the complex of Ga(III) with chrome azurol S and benzyldodecyldimethylammonium bromide and inductively coupled plasma–optical emission spectrometry technique. The total content of gallium in the soils clearly depends on the soil location and properties and ranged from 41.7 to 437 μg g–1. The contents of gallium determined in 10% nitric acid and 1 M of magnesium chloride extract ranges respectively from 38.0 to 81.9% and 20–40% of the total content of this element. A strong correlation has been found between gallium and zinc, cadmium, lead, and copper. The high Pearson correlation coefficient values and the proportional relationship between the concentrations of Ga and these metals may make it possible to treat gallium as an indicator of soil contamination with heavy metals.

A new concept for variance analysis of hyphenated chromatographic data avoiding signal warping

Analysis of variance of chromatographic data is usually performed on the peak table or on entire chromatograms. These two data forms require signal pretreatment. Peak table requires peak detection, their standards and quantification, and the second form of data organization requires warping of the studied chromatograms to eliminate the observed peak shifts, which occurs due to minor variations in chromatographic conditions. In our study, a new form of data representation well suited for chromatographic data originating from multi-channel detection is proposed. It requires neither warping of chromatograms, nor peak detection. Its principles and performance are demonstrated for a real data set (being a part of a larger research project initiated to characterize the infusion of fermented rooibos herbal tea in terms of phenolic composition and antioxidant activity). As the method of choice for the analysis of data variation, the Multiple Analysis of Variance applied to the pairwise data representation was chosen.

Spectroscopic and electric properties of C.I. Mordant Blue 29: a theoretical and experimental study

Hydroxytriphenylmethane dyes are organic compounds whose properties suggest a potential use in nonlinear optics. They are also widely used in chemical analysis. The most commonly used is C.I. Mordant Blue 29. However, in the literature there are no complete spectroscopic characteristics of the dye and there is a lack of detailed information on the electrical properties of C.I. Mordant Blue 29 dye. The optimum geometry of C.I. Mordant Blue 29 was determined by minimizing the energy with respect to all geometrical parameters without imposing molecular symmetry constraints. The UV-VIS spectra of C.I. Mordant Blue 29 and its charged species were computed with time-dependent density functional theory (TDDFT) by employing the B3LYP functional together with the 6-31++G(d,p) basis set at optimized geometries. The calculations of UV-VIS spectra also considered the presence of a solvent in terms of the polarized continuum model (PCM). The calculated spectra were compared with those obtained experimentally. The dipole moment (μ), polarizability (α), and first hyperpolarizability (β) of C.I. Mordant Blue 29 were calculated using the time-dependent Hartree–Fock method, and the electron correlation contribution to the electric properties was introduced by DFT using the functionals B3LYP, PBE0, and HCTH. Calculations were performed using several basis sets from 6-31G to 6-311++G(d,p).

6-Chloro-2-oxindole: X-ray and DFT-calculated study.

The molecule of the title compound (systematic name: 6-chloroindolin-2-one), C(8)H(6)ClNO, is almost planar, with a dihedral angle of 1.13 (9)° between the planes of the constituent pyrrolidine and benzene rings. Centrosymmetric dimers are formed in the crystal structure by N-H···O hydrogen bonds, and these dimers are additionally linked by Cl···Cl and C-H···O interactions. Density functional theory (DFT) calculations at the B3LYP/6-31 G(d,p) level of theory were used to optimize the molecular structure and the geometry was best reproduced by optimization of two interacting molecules. The bond orders in the molecule, estimated using the natural bond orbitals (NBO) formalism, are consistent with the observed bond lengths. In particular, the contribution of the lone pair of electrons on the N atom to the N-C bond in the N-C=O group is revealed. The measured IR spectrum of the compound shows a red shift of the N-H stretching frequency compared with the free molecule, due to the formation of the hydrogen bonds.