Complexometric Titration Research Articles

Sequential Injection Ion Chromatography with Flow Injection Post Column Derivatization Capable of Using the Unstable Reagent Murexide to Determine Calcium and Magnesium in a Mixture

A hyphenated sequential injection ion chromatography–flow injection analysis (SIIC–FIA) system is proposed for post column derivatization capable of using murexide, an unstable but commonly available reagent, for the determination of calcium and magnesium in a mixture. A short ion exchange column was modified from a 4.6 mm × 10 mm C18 monolithic guard column. Calcium/magnesium mixture and murexide were used as model analytes and derivatizing agent, respectively. The FIA post column allows the use of unstable chromogenic reagents. The continuous flow of liquid also helped to stabilize the signal baseline during detection. A single concentration based calibration graph was demonstrated. The system requires low volumes of standard/sample (5–50 µL) and mobile phase (4.50 mL), and offers sample throughput at 8 h−1 without the need for long column calibration. Detection limits were 0.5 and 0.1 µg for Ca2+ and Mg2+, respectively. Working ranges were 1–5 µg Ca2+ and 0.2–1 µg Mg2+. Analyses of well and drinking water samples were demonstrated and validated with the standard complexometric titration.

Mn(II), Fe(II), Co(II), Ni(II), Cu(II) and Zn(II) transition metals isonicotinate complexes: Thermal behavior in N2 and air atmospheres and spectroscopic characterization

Solid-state M(IN)2·nH2O complexes, where M stands for bivalent transition metals (Mn, Fe, Co, Ni, Cu and Zn), IN is isonicotinate and n = 0.5 to 4.0 H2O, were synthesized. Characterization and thermal behavior of the compounds were performed employing elemental analysis (EA), complexometric titration with EDTA, powder X-ray diffraction (PXRD), infrared spectroscopy (FTIR), simultaneous thermogravimetry and differential scanning calorimetry (TG–DSC) in dynamic dry air and nitrogen atmospheres, differential scanning calorimetry (DSC) and TG–DSC coupled to FTIR. The thermal behavior of isonicotinic acid and its sodium salt was also investigated in both atmospheres. The dehydration of these compounds occurs in a single step in both atmospheres. In air atmosphere, the thermal decomposition of the anhydrous compounds also occurs in a single step, except for the copper compound where two steps are observed. In N2 the thermal decomposition of the anhydrous compounds occurs in two consecutive steps, except for iron compound, where three steps are observed. The main gaseous products of thermal decomposition/pyrolysis of the compounds were identified as CO, CO2 and Pyridine. Mn, Co, Cu and Zn compounds show a physical transformation process in DSC curves. The ligand coordinates through the pyridine nitrogen atom to the metal and for the Zn compound, the carboxylate group also participates in the coordination. The IR absorption profile of hydrated and dehydrated compounds suggest that there is a probable change in the coordination mode of the ligand upon dehydration. This change needs to be further investigated, once it is not possible to ensure only with infrared spectroscopy data.

Study on the Specific Complexation of GMDTC and Metal Ion

Objective: Study the response of GMDTC to cadmium ions and metal ions in vivo to determine whether GMDTC are specifically complexed with cadmium ions to provide a reference for the safety and dfficacy of GMDTC. Methods: Complexometric titration, HPLC and HPLC-MS were applied to research the complexation reaction of GMDTC and various metal ions. The molecular ion peak of GMDTC, GMDTC-Cd complex and GMDTC-Pb complex also detected by LC-MS. Additionally, the initial structure was determined by DFT simulation method. Results: Results of complexometric titration and HPLC detection showed that GMDTC characteristic absorption peak area was proportional to the concentration of itself and there was no color change and peak time change when the GMDTC mixed with Ca(2+), Fe(2+), Mg(2+), Zn(2+). However, the color changed to black transition when the GMDTC mixed with Cu(2+) and the color changed from yellow precipitate to light yellow transparent transition when GMDTC mix with Hg(2+). Moreover, the peak area as well as the retention time has changed a lot which indicated that a chemical reaction has already happened. When the GMDTC mixed with Cd(2+) and Pb(2+), the color has changed from pale yellow to colorless transparent and the peak area of GMDTC has increased a lot. Finally, the GMDTC-Cd complex ratio both of which are 2:1 were calculated based on the results of LC-MS instrument and atomic calculations. Conclusion: The specific cadmium chelating agent GMDTC can not react with the Ca(2+), Fe(2+), Mg(2+), Zn(2+), but it can react chemically with Cu(2+) and Hg(2+), even specific complex with Pb(2+) and Cd(2+).

AVALIAÇÃO DOS TEORES DE ALUMÍNIO EM ANTITRANSPIRANTES

The antiperspirant works by diffusing the aluminum salt through the ducts of the sweat glands into the opening of the epidermis. After contact with perspiration sweat, a mucopolysaccharide complex is produced that reduces perspiration. When its content is high in blood, the bones capture and release it slowly causing bone dystrophy. The objective of this project was to determine the levels of aluminum in the antiperspirant, of different brands marketed in supermarkets, and to verify if the concentrations are in agreement with the label and in accordance with the legislation. The complexometric titration method was used. Of the three brands analyzed, the first one did not present aluminum, important for the antiperspirant effect, the second one contained lower amounts than the one informed on the label and the third one presented levels above that allowed by the legislation. Therefore, none of the analyzed brands presented positive results.

THE ADDITION OF SIWALAN BORASSUS FLABELLIFER WATER AGAINTS TOTAL HARDNESS LEVEL IN WELL WATER

Hardness is the ability of water to form foam when it is mixed with soap. If calcareous water enters the body in excessive amounts in long periods of time can lead to kidney stones disease thus the hardness level in the water must be decreased and one of the methods is the implementation of Siwalan Borassus Flabellifer water, containing lactic acid and alcohol which is capable of dissolving minerals Calcium (Ca2+) in water. The purpose of this study was to determine the effect of the addition of Siwalan Borassus Flabellifer water againts total hardness levels in well water. The analysis is conducted quantitatively and it was experimental study with complexometric titration method to 5 well water samples taken in the Tuban area by grab sampling technique. From the analyzed samples obtained the average value of total hardness control (without the addition of Siwalan Borassus Flabellifer water) 2626.26 mg/L CaCO3, with the addition of 10 mL Siwalan Borassus Flabellifer water of 2346.54 mg/L CaCO3, the addition of 20 mL of Siwalan Borassus Flabellifer water of 2284.38 mg/L CaCO3, and the addition of 30 mL of Siwalan Borassus Flabellifer water of 2206.68 mg/L CaCO3. The analysis results with statistical test One Way Anova can be concluded that there was no significant effect on the total hardness level of well water with the addition of Siwalan Borassus Flabellifer water.

Aqueous Metal Ion Extraction: Manganese (II), Nickel (II), Copper (II), and Zinc

Water discharged as result of coal mining activity, referred to as acid mine drainage (AMD), is acidic and laced with metal ions; such as those of iron, manganese, and aluminum. A common technique of removing pollutant metal ions from water is precipitation, which involves the formation of insoluble metal compounds that fall out of solution. We are proposing the extraction of metal ions from aqueous solution by complexation utilizing monoamine-, diamine-, and triamine-functionalized silica gels. The [M2+]i(0.01 M) were determined by complexometric titration using the disodium salt of EDTA with indicators Eriochrome Black T (Mn2+ and Zn2+) and Murexide (Cu2+ and Ni2+). The ligands: monoamine, diamine, and triamine; were then added in varying metal ion : ligand (M:L) ratios. After stirring and filtering the solutions, the [M2+]f was determined by complexometric titration. Metal ion extraction of over 90% for Mn2+ and Zn2+has been achieved utilizing monoamine-, diamine-, and triamine-functionalized silica gels, and up to ≈100% extraction for Cu2+ and Ni2+ using monoamine functionalized silica gel. We also investigated the possibility of recovering the extracted Mn2+ ions from previous trials using nitric acid and regenerating the diamine functionalized silica gel using sodium hydroxide. A 70 % recovery of the Mn2+ was achieved. This research was supported in part by WV NSF EPSCoR and NASA West Virginia Space Grant Consortium.

Complexometric and argentometric titrations using thread-based analytical devices

This work describes analytical approaches based on simple complexometric and argentometric titrations leading to the color change of a novel microfluidic thread-based analytical device (µTAD). The device was fabricated from a cotton thread (15 cm) treated with indicator solution, providing an easy-to-use platform for rapid measurement of analyte concentration in aqueous solution. The thread was immobilized onto a support, being a polypropylene sheet or box platform, to facilitate loading of liquid samples. Interaction between the deposited reagents and analytes in the samples then occurred within a few minutes. This resulted in zones of color change with different lengths along the thread depending on the analyte concentration. The interaction zones can be analyzed by human eyes based on comparison of the zone lengths with the printed scales which are correlated with the analyte concentrations. Complexometric titration using µTADs was initially investigated for Mg(II) determination in water and rubber latex samples. These devices consisted of two threads which were pretreated with Eriochrome Black T (EBT) and then treated with ethylenediaminetetraacetic acid (EDTA) in N-cyclohexyl-3-aminopropanesulfonic acid (CAPS) buffer at pH 10. Both threads were tied together with a central knot before being attached to the box platform prior to the analysis. Load of sample solution (6 µL) resulted in the length of red-violet color product on the threads being proportional to the concentration of Mg(II) in waters and rubber latex samples with the working concentration range of 25–1000 mg L−1. In addition, µTAD with a supporting polypropylene sheet consisting of several threads treated with AgNO3 and K2CrO4 indicators was applied for argentometric titration of chloride ion in water and food seasoning samples. After sample loading (3 µL), the initially red-brown threads turned into white corresponding to formation of AgCl(s) on the threads with a working concentration range of 75–600 mg L−1. Greater selectivity towards Mg(II) and chloride compared with potential interference ions was also observed. All the developed μTADs were applied for analysis of real samples which showed results being in agreement with those obtained by classical titrations.

Thermal, spectroscopic and antimicrobial activity characterization of some norfloxacin complexes

Coordination compounds of transition metals with norfloxacin (Nor) have potential to improve its effectiveness, as already discussed for some compounds found in the literature. The complexes in the solid state were prepared by precipitation of the respective metal cation (M = Mn(II), Co(II), Ni(II), Cu(II) and Zn(II)) with a norfloxacin sodium salt solution. The thermal behavior under oxidative and pyrolysis conditions was investigated employing thermogravimetry and differential thermal analysis (TG/DTG–DTA) and evolved gas analysis (EGA/TG-FTIR), and the complexes were characterized by elemental analysis (EA), EDTA complexometric titration, infrared spectroscopy (FTIR) and X-ray powder diffraction (XRD). By these results, the minimum formula was established as [M(Nor)2(H2O)2]·nH2O, where n = 3 (Ni), 2.5 (Mn Co, Zn), or 2 (Cu). The evolved gases identified during thermal decomposition of Ni and Cu complexes were ethylene, CO2 and CO for Ni; CO2 and ethane for Cu. Also, antimicrobial activity of the complexes was evaluated by in vitro susceptibility test using the agar diffusion method, and the results were compared with the uncomplexed molecule. It was found that norfloxacin complexation modifies its antibacterial activity. The activity depends on the type of metal ion and microorganism; Mn(II), Co(II) and Zn(II) complexes significantly increased activity against the tested gram-negative bacteria.

Safety study of intravitreal and suprachoroidal Laponite clay in rabbit eyes.

To study the safety and biocompatibility of Laponite clay (LAP) within an intravitreal and suprachoroidal administration in rabbit eyes. Thirty-two New Zealand albino rabbits were divided into two experimental groups to test intravitreal (IVT group) and suprachoroidal (SCS group) administration of a 100-μl and 50-μl Laponite suspension respectively. Following injection, the eyes were monitored by ocular tonometry, slit-lamp eye examination and indirect ophthalmoscopy, at 24h, 1, 4, 12, and 14weeks post administration. Histological examination was also performed to determine whether any ocular pathological change had occurred. Throughout the study, LAP presence in vitreous was estimated by complexometric titration with ethylenediaminetetraacetic acid (EDTA), taking advantage of the Laponite high content of magnesium ions. Neither significant differences in the intraocular pressure, nor relevant ocular complications were found in the two experimental groups after LAP administration. The histology of the retina remained unchanged. LAP presence in vitreous could be indirectly confirmed by complexometric titration until 14weeks post administration in eyes of IVT group. Laponite could be considered as a vehicle for potential clinical use in ocular drug administration, due to its proven ocular biocompatibility and its transparency in gel state.

Simultaneous assaying of famotidine, calcium carbonate and magnesium hydroxide in the extemporaneously prepared suspension

INTRODUCTION: The share of extemporaneously prepared drugs on the pharmaceutical market has been on the increase lately. The suspension of famotidine with calcium carbonate and magnesium hydrox- ide is one of such drugs. AIM: The aim of our study is to develop the assay methods for each component in the simultaneous sample of the suspension in order to decrease the volume of the medical form and the time for analysis. MATERIALS AND METHODS: The object of study is the extemporaneously prepared suspension with the content of active substances per 5 ml: famotidine 10 mg; calcium carbonate 400 mg; magnesium hydrox- ide 120 mg. Tablets with famotidine content (20 mg) were used for suspension preparation. The substance of famotidine was used as the working standard sample (WSS). The `Evolution 60S` spectro- photometer, the AB 204 S/A Mettler Toledo analytical balances, class A measuring vessels as well as reagents that meet the requirements of the State Pharmacopeia of Ukraine were used in the study. RESULTS: Complexometric titration for calcium carbonate and magnesium hydroxide using murexide and Eriochrome Black T as indicators and UV-spectrophotometric determination of famotidine at I»max=265 nm wavelength were carried out in the simultaneous sample of the suspension. The metrological character- istics confirm the correctness of the proposed methods. CONCLUSIONS: The developed methods can be used to determine the active compounds in the simultane- ous sample of the suspension. The uncertainty of the average results for calcium carbonate quantitative de- termination was 0.94%, for magnesium hydroxide - 1.14%, and for famotidine - 0.75%.

PENETAPAN KADAR KALSIUM PADA BEDAK TABUR DARI BAHAN BAKU CANGKANG KERANG BULU (Anadaraantiquata) SECARA KOMPLEKSOMETRI

Until now, the utilization of clamshell waste has been limited to handicraft materials, whereas shellfish waste has a high calcium carbonate composition of about 98% which can be used as a source of calcium in the synthesis of compounds containing calcium metal. The purpose of this study was to determine the level of calcium contained in the shells of mussels and to determine the levels of calcium in the preparation of talcum powder which was added with powdered shells of feathers as an abrasive. Complexometric titration is also used to determine calcium levels in powder preparations formulated with feather shells powder. The results showed that the shells of feather shells contained calcium levels of 19.49% while the loose powder preparations contained calcium levels of 1.475%. The test results of the research on the formulation of loose powder preparations met the physical evaluation requirements. The pH test on loose powder, namely pH 7, meets the requirements of SNI 16-4399-1996, the pH value of cream cosmetic products is required to range from 4.5 to 8.0. The fine degree test is qualified because the loose powder can pass the sieving using a 100 mesh.

Ionophore‐based Heterogeneous Calcium Optical Titration

AbstractRecently, the field of complexometric titration significantly progressed with the advent of ionophore‐based titration reagents. We present here for the first time an ionophore‐based heterogeneous optical titration method for calcium. The all‐in‐one reagent was composed of chromoionophore, ion‐exchanger and calcium ionophore in dichloromethane (DCM). The endpoint of this reverse titration scheme was determined by the color change of the DCM phase (blue to red). The ion‐exchange theory borrowed from ISE membranes was used to simulate the titration curve in a simplified manner. The phase separation speed during titration was found much faster at and beyond the endpoint. A mechanism was proposed for this phenomenon, with zeta‐potential measurements on ion‐selective nanospheres to support the hypothesis. Calcium titration in a urine sample was also successfully demonstrated and compared with EDTA titration with potentiometric ion‐selective electrodes as endpoint indicator. The proposed reagent serves as an alternative to the classical EDTA.

Evidence of Multi-Component Ion Exchange in Dolomite Formation during Low Salinity Waterflooding

Low salinity waterflooding is a technique performed in many oil reservoirs around the globe. The technique is simply implemented by injecting water with very low ionic activity compared to formation water into an injection well. The injected water will increase reservoir pressure that is compulsory to drive oil moving toward production well. More than just maintaining reservoir pressure as obtained from conventional waterflooding, low salinity water creates shifting of surface condition, resulting in additional amount of liberated oil. Nevertheless, exact oil recovery mechanisms are still discussed. Among these proposed mechanisms, Multi-component Ion Exchange (MIE) together with wettability alteration is believed to be a major mechanism leading to higher oil recovery compared to conventional waterflooding. In this study, detection of calcium and magnesium ions which are Potential Determining Ions (PDI) for carbonate reservoirs are detected during the coreflood experiment. Dolomite rock sample is used to represent carbonate formation and detection of previously mentioned ions is performed by complexometric titration of the effluents. From the study, it is observed that during conventional waterflooding and low salinity waterflooding at low temperature of 30 degrees Celsius, calcium and magnesium ions in the produced water is increased compared to the amount of these ions in the injected water. This incremental of ions can be explained by the dissolution of calcium and magnesium from dolomite which is chemically composed of calcium magnesium carbonate. At this temperature, the portion of calcium ion is always less than magnesium ion even though the amount of calcium ion is higher than magnesium ion in injected water. However, at higher temperatures which are 50 and 70 degrees Celsius, ratio of calcium and magnesium ions in injected and produced water is reversed. Disappearance of magnesium ion in the effluent is more obvious especially at 70 degrees Celsius and by low salinity waterflooding. This can be explained that at lower temperature, calcium ion disappears to form of calcium carboxylate complex with oil and at higher temperature, magnesium ion disappears as magnesium can start to form magnesium carboxylate complex with oil and hence, the amount of both calcium and magnesium ions is decreased compared to lower temperature. In dolomite reservoir, since both calcium ions and magnesium ions are provided from dissolution mechanism, the benefit from multi-component ion exchange will occur at high temperature as both calcium and magnesium ions will be consumed for oil recovery mechanism.

Visualization of Metal Ion Buffering via Three-Dimensional Topographic Surfaces (Topos) of Complexometric Titrations

Complexation TOPOS is a free software package to generate 3-D topographic surfaces (“topos”) for metal–ligand complexometric titrations in aqueous media. It constructs surfaces by plotting computed equilibrium parameters above a composition grid with “volume of ligand added” as the x-axis and overall system dilution as the y-axis. The sample systems in this paper are restricted to EDTA as a ligand. Other chelating ligands that form exclusively 1:1 complexes could also be modeled with this software. The surfaces show the quality of the equivalence point break under various conditions. More importantly, they develop the phenomenon of metal ion buffering. They clearly distinguish the difference between “pseudo-buffering” and “true buffering”. They introduce terminology for two different forms of metal ion buffering: (1) mass action metal ion buffering under excess ligand conditions and (2) precipitate metal ion buffering when hydroxide precipitates are present under excess metal ion conditions. Systems model...

Economical Colorimetric Smart Sensor to Measure Water Quality of Drinking Water in CKDu Prevalence Areas

Safe drinking water is essential for good health. Recommendations on drinking water sources of CKDu prevalence areas are utmost important due to health risk of long-term consumption. This paper focuses on designing a sensor to measure fluoride and hardness in well water with an automated mechanism. Here, a simple colorimetric approach was adapted to develop the proposed optical sensor using procedures of variation of color with SPADNS reagent and complexometric titration. Added measurement of conductivity and pH supports decision making. Reduced reagent volumes make the design to be eco-friendly and estimated cost of U.S. $1 per sample analysis is affordable to the communities with low income.

The Effect of Metal Concentration on the Parameters Derived from Complexometric Titrations of Trace Elements in Seawater—A Model Study

In this study we examine the impact of dissolved metal concentrations on the parameters that are commonly determined from complexometric titrations in seawater. We use the non-ideal competitive adsorption (NICA) model within the framework of the chemical speciation program visual MINTEQ with iron as a model metal. We demonstrate that dissolved iron concentrations effect the determined parameters for a heterogeneous binding site distribution with a fixed concentration of dissolved organic carbon. The commonly used terms ‘ligand concentration’ and ‘binding constant’ are therefore dependent on metal concentration, so we adopt the terminology suggested by Town and Filella (Limnology and Oceanography, 45, 1341-1357, 2000) and use the terms ligand quotient and stability quotient here. The systematic increase in the ligand quotient with dissolved iron concentration likely contributes towards the trend of increasing ligand quotient with dissolved iron concentration observed in field studies, and makes it hard to assign an objective meaning to the parameter. We suggest that calculation of the side reaction coefficient, a parameter that describes the probability that any added metal will be complexed, could be less prone to bias and misinterpretation than calculation of conditional stability and ligand quotients. We explore the impact of experimental design on side reaction coefficients by applying different detection windows, and multiwindow and reverse titration approaches. We identify the method that results in the best estimates of side reaction coefficients over a range of iron concentrations between 0.1 and 1.5 nmol L-1. We find that single window titrations can only reliably estimate side reaction coefficients over a limited range of iron concentrations. Multiwindow titrations provided estimates of side reaction coefficients within the 99 % confidence interval of the values calculated directly from the NICA model at all iron concentrations examined here. We recommend that future reports of speciation measurements consider the potential influence of metal concentrations on the determined parameters and future studies focus on developing and applying experimental designs that improve the robustness and rigor of chemical speciation analysis in the marine environment.

The n-propyl 3-azido-2,3-dideoxy-β-d-arabino-hexopyranoside: Syntheses, crystal structure, physical properties and stability constants of their complexes with Cu(II), Ni(II) and VO(II)

The structure, conformation and configuration of the n-propyl 3-azido-2,3-dideoxy-β-d-arabino-hexopyranoside (BAra-nPr) were determined by 1H NMR, 13C NMR, and IR spectroscopy, as well as by optical rotation. The crystal structure was confirmed by single-crystal X-ray diffraction studies at room temperature. The compound crystallizes in P21 space group symmetry of the monoclinic system. The molecule has a 4C1 chair conformation with azide group in the equatorial position both in a solution as well as in the crystal. The spatial arrangement of azide group is compared to other previously determined azidosugars. The hydrogen bonds between the hydroxyl group of sugar molecules lead to a ribbon structure observed also for the ethyl homolog. The packing of ribbons is dependent on the alkyl substituent length and with the elongation changes from pseudohexagonal to lamellar.Acidity constants for the n-propyl 3-azido-2,3-dideoxy-β-d-arabino-hexopyranoside (BAra-nPr) in an aqueous solution were evaluated by the spectrophotometric and potentiometric titrations methods. Title compound exhibit blue absorption with the maximum wavelengths in the range of 266 nm and 306 nm. Based on these measurements we showed equilibria existing in a particular solution and a distribution of species which have formed during the titration.We also investigated interactions between Cu(II), Ni(II) and VO(II) and title compound (as ligand L) during complexometric titration. On these bases we identified that in [CuII-BAra-nPr]2+ the ratio of the ligand L to metal ion M(II) was 3:1, while in [NiII-BAra-nPr]2+ and [VOII-BAra-nPr]2+ complexes 2:1 ratios were found. The cumulative stability constants (as log β) occurring in an aqueous solution for the complexes of BAra-nPr with Cu(II), Ni(II) and VO(IV) were 14.57; 11.71 and 4.20, respectively.

Stripping Voltammetry for the Real Time Determination of Zinc Membrane Diffusion Coefficients in High pH: Towards Rapid Screening of Alkaline Battery Separators

AbstractAn anodic stripping voltammetry (ASV) sensing platform which provides real time determination of zincate diffusion through membrane separators in alkaline electrolyte with total experimental times on the order of hours is presented. Advanced separators are essential for future rechargeable alkaline zinc batteries. In order to be screened, these membranes need to be evaluated for their zincate blocking performance. Current complexometric titration and elemental analysis methods for zincate membrane diffusion characterization can take days to weeks to obtain results as well as include large sample dilution factors and require additional sample processing. The anodic stripping voltammetry (ASV) sensing platform presented here provides real time determination of zincate diffusion in alkaline electrolyte with total experimental times on the order of hours. This method eliminates the need for sample dilution and post experiment sample processing. This technique significantly increases the throughput for the screening of advanced alkaline battery separators resulting in rapid turnaround times in the analysis of these vital membranes. To evaluate the utility of this method, zincate diffusion through commercial Celgard 3501 and Cellophane 350P00 was monitored using both ASV and inductively coupled plasma‐mass spectrometry (ICP‐MS) methods. The obtained zincate diffusion coefficients for both techniques were found to compare favorably.

Nitrogen and ash elements content in sub-horizons of forest floor

Nitrogen (N) and ash elements contents of forest floor (FF) depend on the fractional and chemical composition of falling litter. The elemental content in FF may be influenced as well by originated from the epipedon mineral particles due to soil fauna mixing activity. In actual work the contents (concentration and stocks) of N and ash elements were analysed in relation to phytogenic FF. In relation to total FF, the FF thickness, acidity, base saturation stage and C:N ratio as general characteristics were studied. The concentrations and amounts of N and ash elements of FF were studied on Gleyic Albic Fragic Glossic Retisols (group I), on Gleyic Albic Podzols (II) and on Ortsteinic Histic Podzols (III). The FF chemical parameters were researched in forest ecosystems with premature and mature (i.e. stabilized) forest stands. The dividing of FF into sub-horizons was possible only on soils with low soil faunal activity. The FF and its sub-horizons (OL, OF, OH) were sampled with a metallic frame (25×40cm). In the field conditions, the FF thickness (cm) and mass superficial density (gm−2) at field moisture content were determined. In the laboratory, the total and phytogenic FF dry mass superficial densities (Mgha−1) and their elemental contents (concentration – gkg−1 and amounts – kgha−1) were calculated. Content of N in FF samples was determined by Kjeldahl; content of K with flame-photometer; P by colorimetric method; Ca and Mg by complexometric titration with trilon B (using flame-photometer); Fe and Al colorimetrically, whereas in the case of Fe the sulfosalicylic acid and for Al the aluminon was used; the Si and remains were determined with weighing method. The soils of groups’ I and II are well drained aeromorphic, but group III hydromorphic. By WRB the soils of group I are Retisols, but soils of two rest groups - Podzols. The soils of group I have been formed on loamy sand under-layered by loam, but the texture of groups II and III soils is sand. By the humus covers the soils of group I may be classified as fresh and moist moder, of group II as fresh and moist mor and of III as wet and peaty mor. On soils of groups II and III only the pine forest, but on soils of group I as well the spruce forest are presented. In all three soil groups the sequence of chemical elemental concentration in OL horizon (as falling litter) was: N>Ca>Si>Mg>K= Fe=P>Al. In the course of further FF developments, the concentrations Si, Al and N are increased in considerable extent. Practically to the same level persist the concentrations of K, P and Mg. At the end of throughout flow of FF this sequence was: Si>N>Ca>Al>Fe>Mg>K=P. The greatest amounts of all studied elements were observed in the FF of soils’ group III on which the humus cover of wet and peaty mor type has been formed. The formation of this type of humus cover indicates the stagnation of elemental cycling between plant cover and soil cover.

Thermoanalytical, Spectroscopic and DFT Studies of Heavy Trivalent Lanthanides and Yttrium(III) with Oxamate as Ligand

Solid-state LnL3∙nH2O complexes, where Ln stands for trivalent lanthanides (Tb to Lu) or yttrium(III) and L is oxamate (NH2COCO2-), have been synthesized. The characterization of the complexes was performed by using elemental analysis (EA), complexometric titration with EDTA, thermoanalytical techniques such as simultaneous thermogravimetry and differential scanning calorimetry (TG-DSC), evolved gas analysis (TG-FTIR), infrared spectroscopy (IR) and powder X-ray diffraction (XRPD). The results provided information about thermal behavior, crystallinity, stoichiometry, coordination sites, as well as the products released during thermal degradation of the complexes studied. Theoretical calculation of yttrium oxamate, as representative of all complexes was performed using density functional theory (DFT) for studying the molecular structure and vibrational spectrum of the investigated molecule in the ground state. The optimized geometrical parameters and theoretical vibrational spectrum obtained by DFT calculations are in good agreement with the experimental results.