Use of the UNB_TopoDens model for local modelling of chosen gravity field parameters in the Western Carpathians

The latest, global density model of topographical masses (UNB TopoDms model) was used to determine complete Bouguer anomalies and the differences between geoid undulations and height anomalies in an area of the Western Carpathians, within the Polish-Slovak-Czech border region. The ranges of the calculated values are between approximately -74 and +23 mGal for Bouguer anomalies and -10 and +5 cm for differences between geoid and quasigeoid heights. Calculations were also performed for constant densities of topographical masses (2200, 2500 and 2670 kg/m(3)). The results show significant differences due to the various densities adopted for the calculations. For example, differences between the version using densities from the UNB TopoDens model and the version using a constant density of 2670 kg/m(3) ranged between -3.4 mGal and +37.5 mGal, for Bouguer anomalies, and between -0.5 cm and +7.4 cm for differences between geoid undulation and height anomalies. It has also been shown that, for high mountain areas, differences between geoid and quasigeoid height should be determined on the basis of exact formula (not on the basis of Bouguer anomalies).Web of Science17111811

Flow-Injection Preconcentration of Chloramphenicol Using Molecularly Imprinted Polymer for HPLC Determination in Environmental Samples

The residue of antibiotic chloramphenicol (CAP) is important issue for food quality control and also for the environmental monitoring. It is banned for use in food-producing animals and has very limited use in human medicine, because of its severe impact on human health. Determination of trace level of CAP in environmental samples requires a very sensitive analytical method and efficient preconcentration procedure. CAP can be efficiently preconcentrated in flow-injection system using flow-through reactor packed with molecularly imprinted polymer (MIP), but determination of CAP in eluate from MIP requires the application of chromatographic separation, which was made in reversed-phase HPLC system with UV detection. In optimized conditions the limit of detection for 100 mL sample in HPLC with offline preconcentration on MIP was evaluated as 0.66 mg/L. In hyphenated FIA-HPLC system with zone sampling the LOD for developed method was evaluated as 15 ng/L, which indicates the possibility of using it for analysis of environmental samples

Replacement ion chromatography with potentiometric detection using a potassium-selective membrane electrode

The use of a simple potassium-selective membrane electrode as a detector in replacement ion chromatography of both cations and anions is examined. For cation chromatography, separated alkali metal ions are detected in the effluent of a suppressed chromatographic system by replacement with potassium ions via cation-exchange tubing bathed in potassium chloride solution. Subsequent downstream potentiometric measurement of the exchanged potassium ions is made with a wall-jet type valinomycin-based polymer membrane electrode. The same replacement stage and potentiometric detector can be used for anion chromatography, in which case counter hydrogen ions in the effluent are the cationic species replaced by potassium. The detection capabilities of the method are shown to depend on a number of factors, including the lengths of suppressor and replacement ion-exchange tubing, the nature and concentration of the bathing electrolytes in the suppressor and replacement stages and the system flow-rates. Under optimized experimental conditions, it is shown that the membrane electrode-based ion replacement scheme can rival the conventional conductivity methods for the detection of separated ions.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/28129/1/0000579.pd

Research on general theory and methodology in geodesy in Poland in 2019–2022

We present a summary of research carried out in 2019–2022 in Poland in the area of general theory and methodology in geodesy. The study contains a description of original contributions by authors affiliated with Polish scientific institutions. It forms part of the national report presented at the 28th General Assembly of the International Union of Geodesy and Geophysics (IUGG) taking place on 11-20 July 2023 in Berlin, Germany. The Polish authors developed their research in the following thematic areas: robust estimation and its applications, prediction problems, cartographic projections, datum transformation problems and geometric geodesy algorithms, optimization and design of geodetic networks, geodetic time series analysis, relativistic effects in GNSS (Global Navigation Satellite System) and precise orbit determination of GNSS satellites. Much has been done on the subject of estimating the reliability of existing algorithms, but also improving them or studying relativistic effects. These studies are a continuation of work carried out over the years, but also they point to new developments in both surveying and geodesy.We hope that the general theory and methodology will continue to be so enthusiastically developed by Polish authors because although it is not an official pillar of geodesy, it is widely applicable to all three pillars of geodesy

Direct and replacement ion chromatography with potentiometric detection using a silver/silver bromide electrode

The use of Ag/AgX electrodes as potentiometric detectors in modern ion chromatography methods is re-examined. Contrary to previous reports, in both flow-injection and chromatographic experiments the Ag/AgBr electrode is shown to exhibit the greatest sensitivity to the widest range of anions tested. For direct detection in non-suppressed ion chromatography systems, use of the Ag/AgBr electrode permits the measurement of separated anions at levels lower than those obtainable by the conventional conductivity method. The Ag/AgBr electrode is further shown to be useful as a sensitive detector in replacement ion chromatography. In this case, all anions separated in a suppressed system are quantitatively replaced by bromide before the effluent passes through the electrochemical detector. Cation measurements can also be made by monitoring the exchange of bromide for co-eluting counter hydroxide ions following the replacement stage of the system.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/28132/1/0000583.pd

In-line tubular ion-exchanger to enhance selectivity in enzyme-based flow-injection potentiometry; application to determination of -glutamine in bioreactor media

A new approach for reducing positive errors caused by endogenous cationic interference when using ammonium ion-selective electrodes as detectors in immobilized enzyme-based flow-injection analysis systems is described. The method involves the use of an in-line tubular cation-exchange unit (e.g., Nafion) placed between the injection valve and the downstream immobilized enzyme reactor/electrode detector portion of the system. Interferent cation species within the sample slug are exchanged for other cations (replacement ions; e.g., Li+) contained within a reservoir solution surrounding the ion-exchange tubing. The membrane electrode exhibits much less response toward the replacement cations; consequently, the detected concentration of ammonium ions generated downstream within the enzyme reactor is directly proportional to the level of analyte substrate present in the sample. The influence of various experimental parameters on the efficiency of the in-line exchanger as well as the general advantages and limitations of this approach are examined. The analytical utility of the concept is demonstrated by the rapid and accurate determination of -glutamine in bioreactor media via the use of immobilized glutaminase enzyme.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/30149/1/0000526.pd

Application of Gas Chromatography to Determination of Total Organic Fluorine after Defluorination of Perfluorooctanoic Acid as a Model Compound

Because of the global presence of anthropogenic perfluorinated organic compounds in the environment, foods and living organisms, and their large structural variety, it can be helpful to develop a method for determination of their total content at trace level in different matrices. In the developed method, the defluorination was carried with sodium biphenyl, derivatization of released fluoride to triphenylfluorosilane and determination by gas chromatography. Three detection methods were compared: flameionization detection, electron capture detection and mass spectrometry. Among them the MS detection was found to be the most favorable one in terms of the instrumental limit of detection (LOD) , whereas the flame-ionization detection was considered to be the most favorable in terms of the method limit of detection (MDL). For the initial sample volume of 1 L and performing the whole procedure of determination, including preconcentration, the MDL value for perfluorooctanoic acid was evaluated as 0.043 ppb. (doi: 10.5562/cca1798

New Analytical Methods Developed for Determination of Perfluorinated Surfactants in Waters and Wastes

Perfluorinated organic compounds have been recognized in recent years as globally distributed persistent organic pollutants of an entirely anthropogenic origin, but present already even in the most remote places of the globe, including organisms of wild fauna. Numerous studies have also shown that they are contained in human organisms all over the world. In this work a special attention is given to perfluorinated carboxylic acids (PFCAs), widely used in various areas of modern life. New methods developed for their determination using the HPLC with fluorescence detection and capillary electrophoretic methods are discussed, as well as the new method for the determination of total organic fluorine (TOF). (doi: 10.5562/cca1776