Search results for "010401 analytical chemistry"

Chromatographic fingerprint, antioxidant activity, and colour characteristic of polish goldenrod (Solidago virgaurea L.) honey and flower

2018

In recent times, the nutraceutical and pharmaceutical interest in honey due to its well-known health properties has increased. Consumers need clear and precise information, so that they can make informed choices about their diet and the foods they buy. Therefore, gas chromatography–mass spectrometry (GC–MS) and high-performance liquid chromatography with a photodiode array detector (HPLC-PAD) was revealed a general characteristic fingerprint of polish monofloral goldenrod honey and flowers. In addition, high-performance thin-layer chromatography (HPTLC) has proven to be a useful tool for determining similarity patterns of common bands among honey from the same floral source and thus can be …

A Selective Change Driven System for High-Speed Motion Analysis.

2016

Vision-based sensing algorithms are computationally-demanding tasks due to the large amount of data acquired and processed. Visual sensors deliver much information, even if data are redundant, and do not give any additional information. A Selective Change Driven (SCD) sensing system is based on a sensor that delivers, ordered by the magnitude of its change, only those pixels that have changed most since the last read-out. This allows the information stream to be adjusted to the computation capabilities. Following this strategy, a new SCD processing architecture for high-speed motion analysis, based on processing pixels instead of full frames, has been developed and implemented into a Field …

Toward fast and accurate emergency cases detection in BSNs

2020

International audience; In body sensor networks (BSNs), medical sensors capture physiological data from the human body and send them to the coordinator who act as a gateway to health care. The main aim of BSNs is to save peoples' lives. Therefore, fast and correct detection of emergencies while maintaining low-energy consumption of sensors is essential requirement of BSNs. In this study, the authors propose a new adaptive data sampling approach, where the sampling ratio is adapted based on the sensed data variation. The idea is to use the modified version of the cumulative sum (CUSUM) algorithm (modified CUSUM) that they previously proposed for wireless sensor networks to monitor the data v…

Recent advances on ionic liquid uses in separation techniques

2018

International audience; The molten organic salts with melting point below 100°C, commonly called ionic liquids (ILs) have found numerous uses in separation sciences due to their exceptional properties as non molecular solvents, namely, a negligible vapor pressure, a high thermal stability, and unique solvating properties due to polarity and their ionic character of molten salts. Other properties, such as viscosity, boiling point, water solubility, and electrochemical window, are adjustable playing with which anion is associated with which cation. This review focuses on recent development of the uses of ILs in separation techniques actualizing our 2008 article (same authors, J. Chromatogr. A…

Stable isotope profiles of nitrogen gas indicate denitrification in oxygen-stratified humic lakes

2011

Mid-summer N(2) profiles were analyzed from nine oxygen-stratified, humic-acid-rich lakes using a continuous flow isotope ratio mass spectrometer and a Gasbench II device. Sample preparation steps were performed under water to avoid air contamination. The instrument precision for the δ(15)N measurement was high (0.03‰), but for the whole sampling and analysis procedure the mean deviation between replicate samples was 0.13‰ for the δ(15)N measurements and 5.5% for the N(2) gas concentration analysis. The results show that the Gasbench peripheral was suitable for measurement of the (15)N natural abundance of dissolved nitrogen gas, with denitrification indicated by the oversaturation and slig…

Three-dimensional scanning electron microscopy of maxillofacial biomaterials

2017

Beer produced via hydrodynamic cavitation retains higher amounts of xanthohumol and other hops prenylflavonoids

2017

Abstract Some of the most valuable bioactive compounds in beer comes from hops polyphenols, mainly flavonoids, some of which are unique to inflorescences of that flowering plant. Although far from pharmacologically relevant concentrations, low doses of xanthohumol and related prenylflavonoids found in beer contribute to the overall antioxidant activity of the product, as well as to significant chemopreventive action about certain diseases, such as cardiovascular, neurodegenerative, and some cancer types. Hence, the efforts to explore both ingredients and brewing methods aimed at enhancing the concentration of such bioactive compounds. In this study, a novel brewing method assisted by hydrod…

Critical assessment of ionization patterns and applications of ambient desorption/ionization mass spectrometry using FAPA-MS

2016

Ambient desorption/ionization mass spectrometry (MS) has gained growing interest during the last decade due to its high analytical performance and yet simplicity. Here, one of the recently developed ambient desorption/ionization MS sources, the flowing atmospheric-pressure afterglow (FAPA) source, was investigated in detail regarding background ions and typical ionization patterns in the positive as well as the negative ion mode for a variety of compound classes, comprising alkanes, alcohols, aldehydes, ketones, carboxylic acids, organic peroxides and alkaloids. A broad range of signals for adducts and losses was found, besides the usually emphasized detection of quasimolecular ions, i.e. […

New optical paper sensor for in situ measurement of hydrogen sulphide in waters and atmospheres

2016

A novel and low-cost colorimetric sensor for the determination of hydrogen sulphide in environmental samples has been developed. This sensor is based on the immobilization of the reagent N,N-Dimethyl-p-phenylenediamine and FeCl3 in paper support, in which the H2S is adsorbed in order to give rise to the formation of methylene blue as reaction product. The sensor has been applied to determine H2S in water and air samples. Two different sampling systems for H2S caption from the air have been assayed: active and passive sampling. The analytical properties of the different systems have been obtained and compared. The analytical signals, corresponding to the methylene blue, have been obtained me…

Addition of thiourea and hydrochloric acid: Accurate nanogram level analysis of mercury in humic-rich natural waters by inductively coupled plasma ma…

2020

Abstract An analytical method was developed for the direct determination of total mercury in natural waters at low ng L−1 level by inductively coupled plasma mass spectrometry (ICP-MS). The presented method overcomes previously observed problems relating to poor spike recoveries by adding 0.12% thiourea in addition to 3% HCl to all samples and standards. The sample preparation is fast and easy to perform by the developed method since it requires only the addition of HCl and thiourea to the water samples. A very low instrument detection limit (0.4 ng L−1) was obtained without time-consuming preconcentration procedures. The accuracy and precision of the developed method were found excellent b…