Optische Methoden

Ohne Zusammenfassung     

Finitely generated free tetravalent modal algebras

The purpose of this work is to prove that the tetravalent modal algebra with a finite set of free generators is finite and to determine its cardinal number.     

Toward understanding the influence of ethylbenzene in p-xylene selectivity of the porous titanium amino terephthalate MIL-125(Ti): adsorption equilibrium and separation of xylene isomers

The potential of the porous crystalline titanium dicarboxylate MIL-125(Ti) in powder form was studied for the separation in liquid phase of xylene isomers and ethylbenzene (MIL stands for Materials from Institut Lavoisier). We report here a detailed experimental study consisting of binary and multi-component adsorption equilibrium of xylene isomers in MIL-125(Ti) powder at low (≤0.8 M) and bulk (≥0.8 M) concentrations. A series of multi-component breakthrough experiments was first performed using n-heptane as the eluent at 313 K, and the obtained selectivities were compared, followed by binary breakthrough experiments to determine the adsorption isotherms at 313 K, using n-heptane as the eluent. MIL-125(Ti) is a para-selective material suitable at low concentrations to separate p-xylene from the other xylene isomers. Pulse experiments indicate a separation factor of 1.3 for p-xylene over o-xylene and m-xylene, while breakthrough experiments using a diluted ternary mixture lead to selectivity values of 1.5 and 1.6 for p-xylene over m-xylene and o-xylene, respectively. Introduction of ethylbenzene in the mixture results however in a decrease of the selectivity.     

Spintronic platforms for biomedical applications

Since the fundamental discovery of the giant magnetoresistance many spintronic devices have been developed and implemented in our daily life (e.g. information storage and automotive industry). Lately, advances in the sensors technology (higher sensitivity, smaller size) have potentiated other applications, namely in the biological area, leading to the emergence of novel biomedical platforms. In particular the investigation of spintronics and its application to the development of magnetoresistive (MR) biomolecular and biomedical platforms are giving rise to a new class of biomedical diagnostic devices, suitable for bench top bioassays as well as point-of-care and point-of-use devices. Herein, integrated spintronic biochip platforms for diagnostic and cytometric applications, hybrid systems incorporating magnetoresistive sensors applied to neuroelectronic studies and biomedical imaging, namely magneto-encephalography and magneto-cardiography, are reviewed. Also lab-on-a-chip MR-based platforms to perform biological studies at the single molecule level are discussed. Overall the potential and main characteristics of such MR-based biomedical devices, comparing to the existing technologies while giving particular examples of targeted applications, are addressed.     

Determination of bisphenol S in food and drink take away packaging by LC-MS/MS

ABSTRACT

Food packaging is a key part within the food safety. The components of these food contact materials should be studied with great caution because they can migrate to the food depending on several factors. Many of these food containers are made of materials such as polycarbonates or paper and cardboard. These polymeric materials can decompose at high temperatures and bisphenolic compounds, such as bisphenol S, can migrate from the contact material to the food. It is suspected that Bisphenol S is a Bisphenol A substitute and an endocrine disrupter with potential acute toxicity, genotoxicity and estrogenic activity, even in very low concentration on the order of tens to hundreds of nanograms per kilogram body weight. In this work, a method by liquid chromatography coupled to a triple quadrupole mass spectrometer (LC-MS/MS) has been developed for the analysis of bisphenol S in different cardboard take away packaging of food and drinks without any sample preparation step. The analyte was separated on a Kinetex C18 (100 × 2.1 mm, 2.6 μm size of particle) column and using methanol: water as mobile phase. The proposed method exhibited an appropriate sensitivity with a limit of detection of 1 µg/L, good linearity and the analysis is completed in only 3 min.