Supramolecular Solvent-Based Microextraction of Selected Anticonvulsant and Nonsteroidal Anti-Inflammatory Drugs from Sediment Samples

The increase in the production and consumption of pharmaceuticals increases their presence in the global environment, which may result in direct threats to living organisms. For this reason, there is a need for new methods to analyze drugs in environmental samples. Here, a new procedure for separating and determining selected drugs (diclofenac, ibuprofen, and carbamazepine) from bottom sediment and water samples was developed. Drugs were determined by ultra-high performance liquid chromatography coupled with an ultraviolet detector (UHPLC-UV). In this work, a universal and single-step sample treatment, based on supramolecular solvents (SUPRAS), was proposed to isolate selected anticonvulsants and nonsteroidal anti-inflammatory drugs (NSAIDs) from sediment samples. The following parameters were experimentally selected: composition of the supramolecular solvent (composition THF:H₂O (v/v), amount of decanoic acid), volume of extractant, sample mass, extraction time, centrifugation time, and centrifugation speed. Finally, the developed procedure was validated. A Speedisk procedure was also developed to extract selected drugs from water samples. The recovery of analytes using the SUPRAS procedure was in the range of 88.8–115%, while the recoveries of the Speedisk solid-phase extraction procedure ranged from 81.0–106%. The effectiveness of the sorption of the tested drugs by sediment was also examined.     

Design of a device for the simultaneous application of uniaxial stress and hydrostatic pressure

Abstract

The design of a device for the simultaneous application of uniaxial stress and hydrostatic pressure is presented. We discuss its usefulness for the studies of semiconductor devices and high T_c superconductors.     

On accuracy of the wave finite element predictions of wavenumbers and power flow: A benchmark problem

This rapid communication is concerned with justification of the ‘rule of thumb’, which is well known to the community of users of the finite element (FE) method in dynamics, for the accuracy assessment of the wave finite element (WFE) method. An explicit formula linking the size of a window in the dispersion diagram, where the WFE method is trustworthy, with the coarseness of a FE mesh employed is derived. It is obtained by the comparison of the exact Pochhammer-Chree solution for an elastic rod having the circular cross-section with its WFE approximations. It is shown that the WFE power flow predictions are also valid within this window.     

Radiometric investigations on thermal expansion and transitions in polymers

Summary The present paper describes an improved radiometric method for the measurement of thermal expansion of solids, especially high polymers. The changes in the dimensions of the sample are recorded as the corresponding changes in the transmission of-rays. In the first place, the method is aimed at following thermal transitions in high polymers. A number of experimental examples shown in the paper demonstrate that the method is well suited for this purpose and that it gives results comparable with ordinary dilatometry. These examples relate to the glass transition in amorphous polymers, the room temperature transitions in PTFE including the accompanying hysteresis effect, differences in thermal expansion of PE of varying crystallinity, etc. A good agreement with the corresponding literature data was achieved.

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Zusammenfassung Die vorliegende Arbeit beschreibt eine verbesserte radiometrische Methode zur Messung der WÄrmeausdehnung fester Stoffe, insbesondere von Hochpolymeren. Die Änderungen der Probendimensionen werden als entsprechende Änderungen der Transmission der-Strahlen registriert. In erster Linie wird beabsichtigt, damit thermische Umwandlungen hochpolymerer Stoffe zu verfolgen. An einer Reihe von Meßresultaten wird gezeigt, daß die Methode für diesen Zweck wohl geeignet und mit normaler Dilatometrie vergleichbar ist. Die wiedergegebenen Beispiele beziehen sich auf die Glasumwandlung amorpher Hochpolymere, die Umwandlungen bei Zimmertemperatur in PTFE — wo auch der Hystereseffekt aufgelöst worden ist -, Unterschiede in der WÄrmeausdehnung von PE verschiedener KristallinitÄt usw. In sÄmtlichen FÄllen konnte eine gute übereinstimmung mit den entsprechenden Literaturangaben erzielt werden.

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Paper read at the Annual Meeting of the German Rheologists, Bad Ems, May 18–19, 1967.     

Infrared and raman spectra,conformation and force field of 3-methoxy propyne

The infrared spectra of 3-methoxy propyne (CH₃OCH₂CsolutionCH) in and in the crystalline and vapour states have been studied. The Raman spectra of 3-methoxy propyne and 3-methoxy propyne- 1-d have also been measured. The spectra are relatively simple, and no significant spectral alterations are revealed on conversion from vapour, to liquid, to the crystalline state. Together with vapour phase band contours and Raman polarization measurements this indicates that there is predominantly one conformer in all three states. An assignment has been proposed, based on a gauche conformation and supported by normal coordinate analysis.