Search results for "010401 analytical chemistry"

Innovative technologies for the recovery of phytochemicals from Stevia rebaudiana Bertoni leaves: A review.

2018

Stevia rebaudiana Bertoni has gained increased industrial and scientific interests in the last 20 years, representing a suitable nutritional alternative to sucrose and artificial sweeteners. Moreover, this plant contains polyphenols, chlorophylls, and carotenoids that may be extracted for production of nutraceuticals and functional foods. Because of nutritional and technological advantages over sucrose, innovative approaches for the extraction of highly valued compounds from Stevia leaves have been developed and optimized. In contrast to conventional alternatives, innovative extraction methods allow higher yields in a shorter time, less usage of organic solvents, and reduced energy consumpt…

Solid Contact Potentiometric Sensors Based on a New Class of Ionic Liquids on Thiacalixarene Platform

2018

New solid-contact potentiometric sensors have been developed for hydrogen phosphate recognition on the basis of ionic liquids containing tetrasubstituted derivatives of thiacalix[4]arene in cone and 1,3-alternate conformations with trimethyl- and triethylammonium fragments at the lower rim substituents. The recognition of selected anions including carbonate, hydrogen phosphate, perchlorate, oxalate, picrate, and EDTA was conducted using electrochemical impedance spectroscopy with ferricyanide redox probe. For the potentiometric sensor assembling, the ionic liquids were stabilized by multiwalled carbon nanotubes and carbon black deposited on the glassy carbon electrode. The influence of supp…

Deep Learning-Based Sign Language Digits Recognition From Thermal Images With Edge Computing System

2021

The sign language digits based on hand gestures have been utilized in various applications such as human-computer interaction, robotics, health and medical systems, health assistive technologies, automotive user interfaces, crisis management and disaster relief, entertainment, and contactless communication in smart devices. The color and depth cameras are commonly deployed for hand gesture recognition, but the robust classification of hand gestures under varying illumination is still a challenging task. This work presents the design and deployment of a complete end-to-end edge computing system that can accurately provide the classification of hand gestures captured from thermal images. A th…

Adapted processing of catadioptric images using polarization imaging

2009

A non parametric method that defines a pixel neighborhood within catadioptric images is presented in this paper. It is based on an accurate modeling of the mirror shape by using polarization imaging. Unlike the most of current processing methods in the literature, this method is non-parametric and can deal with the deformation of catadioptric images. This paper demonstrates how an appropriate neighborhood can be derived from the polarization parameters by estimation of the degree of polarization and the angle of polarization which in return directly provide an adapted neighborhood of each pixel that can be used to perform image derivation, edge detection, interest point detection and namely…

Smartphone determination of fat in cured meat products

2017

Abstract A method has been developed to determine the fat content in different cold meat products by image processing using the camera of a mobile phone. Salchichon , chorizo , salami and cured ham pictures were taken with a Meizu M2 Mini mobile phone camera under fixed lighting conditions of the light emitting diode flash of the mobile phone. Images were treated with Matlab to obtain the mean pixels of average red, green and blue camera values colours (RGB) of the pixels and different data pretreatments were taken into account to correlate colour parameters with fat content values determined in a series of commercially available samples by the Soxhlet method. RGB values were used as input …

Quantification of phenolic acids by partial least squares Fourier-transform infrared (PLS-FTIR) in extracts of medicinal plants.

2020

Introduction Phenolic compounds are ubiquitous compounds found in all plants as their secondary metabolites. Phenols are becoming increasingly important particularly because of their beneficial effects on health. Objective To provide a faithful calibration model for the simultaneous determination and quantification of phenolic acids, as salicylic, vanillic, p-hydroxybenzoic acids, eugenol and thymol in different extracts of medicinal plants, a comparative study was made between two methods of infrared measurements based on attenuated total reflectance (ATR) and transmission. Methods Characteristic absorbance peak heights of mid-infrared spectra of individual phenolic acids were measured for…

2020

The present study aimed at measuring the levels of legacy and emerging contaminants in fillet samples from four demersal fish caught in two fishing sites from Southern Norway, in order to assess possible implications for food safety. Levels of organochlorine compounds (OCs), organophosphate pesticides (OPs), polychlorinated biphenyls (PCBs), polybromodiphenyl ethers (PBDE), per- and polyfluoroalkyl substances (PFASs), and polycyclic aromatic hydrocarbons (PAHs) were measured in fillet from Atlantic cod (Gadus morhua), European plaice (Pleuronectes platessa), lemon sole (Microstomus kitt), and European flounder (Platichthys flesus) specimens. A negligible contamination by all the investigate…

Exploring Training Options for RF Sensing Using CSI

2018

This work analyzes human behavior recognition approaches using WiFi channel state information from the perhaps less usual point of view of training and calibration needs. With the help of selected literature examples, as well as with more detailed experimental insights on our own Doppler spectrum-based approach for physical motion/presence/cardinality detection, we first classify the diverse forms of training so far employed into three main categories (trained, trained-once, and training-free). We further discuss under which conditions it is possible to move toward lighter forms of calibration or even succeed in devising fully untrained model-based solutions. Our take home messages are main…

Analytical challenges to determine emerging persistent organic pollutants in aquatic ecosystems

2018

Emerging persistent organic pollutants (ePOPs) include polybrominated diphenyl ethers (PBDEs) and perfluorooctane sulfonyl fluoride/perfluorooctane sulfonate (POSF/PFOS), which are newly listed in the Stockholm Convention. Other ePOPs, which have not been regulated, include organophosphate flame retardants (PFRs), novel brominated flame retardants (NBFRs) and other perfluoroalkyl substances (PFASs). Often ePOPs data related to occurrence, toxicity, impact or environmental behavior are insufficient or inadequate because of the lack of proper analytical methods to obtain them. Thus, a critical review of the analytical procedures proposed in the last six years (2011–2017) for determining ePOPs…

The Use of Chromatographic Methods Coupled to Mass Spectrometry for the Study of Emerging Pollutants in the Environment.

2018

The consumption of compounds that improve the human health and wellness is increasing, and as a result, the residues of these substances reach the environment or food chain. For this reason, the scientific community is looking for new analytical methods that are more accurate and can detect the greatest number of compounds in different matrices. This manuscript compares different studies in abiotic and biotic matrices, where most of them (92%) uses Liquid Chromatography to separate the compounds. For the detection, most of the studies for both matrices uses, coupled to the chromatograph, a triple quadrupole mass spectrometer (50%) due to the precision to quantify the concentration of these …