Search results for "010401 analytical chemistry"
showing 10 items of 1284 documents
A hybrid nano-MOF/polymer material for trace analysis of fluoroquinolones in complex matrices at microscale by on-line solid-phase extraction capilla…
2021
Abstract A hybrid material (nano-metal organic framework@organic polymer, named as nano-MOF@polymer) was applied for the first time as sorbent for on-line solid-phase extraction capillary electrophoresis with ultraviolet detection (SPE-CE-UV). The resulting material was prepared building layer-by-layer a HKUST-1 (Hong Kong University of Science and Technology-1) nano-MOF onto the polymer surface, which allowed controlling the thickness and maximizing the active surface area. The sorbent was widely characterized at micro- and nano-scale to validate the synthesis and to establish the material properties. Then, fritless microcartridges (2 mm) were assembled by packing only a few micrograms of …
Dual mixed-mode poly (vinylpyridine-co-methacrylic acid-co-ethylene glycol dimethacrylate)-based sorbent for acidic and basic drug extraction from or…
2021
Abstract In this study, a dual mixed-mode polymer sorbent was prepared via one-step thermally initiated polymerization of 4-vinylpyridine (VP), methacrylic acid (MAA) and ethylene glycol dimethacrylate (EGDMA) for the solid-phase extraction (SPE) of basic and acidic drugs. The use of VP and MAA as ionizable functional monomers allowed the tailoring of ion-exchange and hydrophobic features of the polymer. The obtained polymer was characterized by Fourier-transform infrared spectroscopy and scanning electron microscopy. Next, the retention behavior of dual mixed-mode polymer towards basic and acidic drugs was investigated. Moreover, the practical capability of this novel material was tested f…
Polymer-based materials modified with magnetite nanoparticles for enrichment of phospholipids
2018
[EN] A polymeric material modified with magnetic nanoparticles (MNPs) has been synthesized and evaluated as sorbent both for solid-phase extraction (SPE) and dispersive magnetic solid-phase extraction (MSPE) of phospholipids (PLs) in human milk samples. The synthesized sorbent was characterized by scanning electron microscopy and its iron content was also determined. Several experimental variables that affect the extraction performance (e.g. loading solvent, breakthrough volume and loading capacity) were investigated and a comparison between conventional SPE and MSPE modalities was done. The proposed method was satisfactorily applied to the analysis of PLs in human milk fat extracts in diff…
Psychoacoustic Annoyance Implementation With Wireless Acoustic Sensor Networks for Monitoring in Smart Cities
2020
Soundscape standard (ISO 12913) is mainly oriented to describe the psychoacoustic annoyance (PA) due to the perceived sound in different environments. The evaluation of this annoyance is commonly based on the Zwicker and Fastl model that defines several components related to this subjective annoyance, such as loudness, sharpness, roughness, and fluctuation strength. But due to their complexity, these components are difficult to be calculated on small board computers (SBCs) in real time in order to enable a wireless acoustic sensor network for PA monitoring. In this article, we describe the necessary procedures to implement the complete psychoacoustic model by Zwicker and Fastl in a precise …
Spatio-Temporal Analysis of Urban Acoustic Environments with Binaural Psycho-Acoustical Considerations for IoT-Based Applications
2018
Sound pleasantness or annoyance perceived in urban soundscapes is a major concern in environmental acoustics. Binaural psychoacoustic parameters are helpful to describe generic acoustic environments, as it is stated within the ISO 12913 framework. In this paper, the application of a Wireless Acoustic Sensor Network (WASN) to evaluate the spatial distribution and the evolution of urban acoustic environments is described. Two experiments are presented using an indoor and an outdoor deployment of a WASN with several nodes using an Internet of Things (IoT) environment to collect audio data and calculate meaningful parameters such as the sound pressure level, binaural loudness and binaural sharp…
Rapid and Nondestructive Determination of Egg Freshness Category and Marked Date of Lay using Spectral Fingerprint
2020
The potential of nondestructive prediction of egg freshness based on near-infrared (NIR) spectra fingerprints would be beneficial to quality control officers and consumers alike. In this study, handheld NIR spectrometer in the range of 740 nm to 1070 nm and chemometrics were used to simultaneously determine egg freshness based on marked date of lay for eggs stored under cold and ambient conditions. The spectra acquired from the eggs were preprocessed using multiplicative scatter correction and principal component analysis (MSC-PCA). Linear discriminant analysis (LDA) was used to build identification model to predict the category of freshness, while partial least square regression (PLS-R) wa…
The New Generation of Resonant Laser Ionization Mass Spectrometers: Becoming Competitive for Selective Atomic Ultra-Trace Determination?
2002
A critical assessment of the present status of resonant laser ionization mass spectrometry (RIMS) as a specialized analytical technique for the field of atomic ultra-trace determination is attempted and a comparison with established mass spectrometric methods is made. Within the last years RIMS on atomic species has rapidly developed towards becoming a versatile experimental technique, in particular addressing those applications that require high selectivity in respect of isobaric or isotopic interferences. This progress is mainly based on the advent of easy-to-handle tunable solid-state laser systems for both pulsed and continuous operation, which are used in combination with modern compac…
Reduction of Convective Low-Frequency Noise in Thermal Lens Spectrometry
1990
The construction and optimization of a thermal lens spectrometer with coaxial pump/probe configuration is reported. The low-frequency noise of convective origin is studied in detail, and it is demonstrated that a horizontal slit, instead of a pinhole, can be used as a simple way of reducing the noise to a negligible level without losing sensitivity.
Mycotoxin Identification and In Silico Toxicity Assessment Prediction in Atlantic Salmon
2020
The present study aimed to identify mycotoxins in edible tissues of Atlantic salmon (Salmo salar) using liquid chromatography coupled to hybrid quadrupole time-of-flight mass spectrometry (LC-Q-TOF-MS). After using a non-targeted screening approach and a home-made spectral library, 233 mycotoxins were analyzed. Moreover, the occurrence of mycotoxins in fish filets was evaluated, and their potential toxicity was predicted by in silico methods. According to the obtained results, forty mycotoxins were identified in analyzed salmon samples, the predominant mycotoxins being enniatins (also rugulosin and 17 ophiobolins), commonly found in cereals and their by-products. Thus, mycotoxin carry-over …
Identification and quantification of phosphatidylcholines containing very-long-chain polyunsaturated fatty acid in bovine and human retina using liqu…
2010
The retina is one of the vertebrate tissues with the highest content in polyunsaturated fatty acids (PUFA). A large proportion of retinal phospholipids, especially those found in photoreceptor membranes, are dipolyunsaturated molecular species. Among them, dipolyunsaturated phosphatidylcholine (PC) molecular species are known to contain very-long-chain polyunsaturated fatty acids (VLC-PUFA) from the n-3 and n-6 series having 24-36 carbon atoms (C24-C36) and four to six double bonds. Recent interest in the role played by VLC-PUFA arose from the findings that a protein called elongation of very-long-chain fatty acids 4 (ELOVL4) is involved in their biosynthesis and that mutations in the ELOVL…