Search results for "Particle"
showing 10 items of 15225 documents
In-tube solid phase microextraction coupled to miniaturized liquid chromatography for both, noble metal nanoparticle assessment and sensitive plasmon…
2021
Abstract Colorimetric localized surface plasmon resonance (LSPR) as analytical response is applied for a wide number of chemical sensors and biosensors. However, the dependence of different factors, such as size distribution of nanoparticles (NPs), shape, dielectric environment, inter-particle distance and matrix, among others, can provide non-reliable results by UV–vis spectrometry in complex matrices if NP assessment is not carried out, particularly at low levels of analyte concentrations. Miniaturized liquid chromatography, capillary (CapLC) and nano (NanoLC), coupled on line with in-tube solid phase microextraction (IT-SPME) is proposed for the first time for both, controlling suitabili…
Sensitive and selective plasmonic assay for spermine as biomarker in human urine.
2014
A simple, fast, and highly selective and sensitive colorimetric assay to detect nanomolar levels of spermine in human urine (healthy donors, cancer patients) is reported. This assay is based on the absence of a competitive organic capping on the gold nanoparticles together with the high affinity of the amine groups of the analyte for the nanoparticle surface.
A tailor-made nucleoside-based colourimetric probe of formic acid
2014
A ratiometric, specific probe of formic acid has been developed. It is based on intermolecular nucleobase-pairing of inosine-capped plasmonic nanoparticles to form nucleoside channels, which are destabilised by the analyte.
Inkjet printing Ag nanoparticles for SERS hot spots
2018
A novel inkjet printing based approach is developed for the fabrication of a customizable platform on glass substrates allowing for surface enhanced Raman spectroscopy (SERS) detection of analytes up to single hot spots generated by the spontaneous aggregation of Ag nanoparticles (Ag NPs) in pL scale droplets. After drying the printed droplets under ambient conditions, trace amounts of the analyte can be detected by SERS given the proximity to NP hot spots. By employing alizarin (10-5M) as a model system and scaling the ink droplet volume from 1 nL to 10 pL, the absolute quantity of hot spots has been derived in the printed droplets allowing detecting up to a few molecules in proximity to i…
Plasmonic Nanosensor Array for Multiplexed DNA-based Pathogen Detection
2019
In this research we introduce a plasmonic nanoparticle based optical biosensor for monitoring of molecular binding events. The sensor utilizes spotted gold nanoparticle arrays as sensing platform. The nanoparticle spots are functionalized with capture DNA sequences complementary to the analyte (target) DNA. Upon incubation with the target sequence, it will bind on the respectively complementary functionalized particle spot. This binding changes the local refractive index, which is detected spectroscopically as the resulting changes of the localized surface plasmon resonance (LSPR) peak wavelength. In order to increase the signal, a small gold nanoparticle label is introduced. The binding ca…
Stir bar sorptive-dispersive microextraction mediated by magnetic nanoparticles-metal organic framework composite: Determination of N-nitrosamines in…
2019
Abstract A new analytical method based on the recently proposed stir bar sorptive-dispersive microextraction (SBSDME) technique has been developed to determine eight hazardous N-nitrosamines in cosmetic products. As previous step, a simple clean-up is carried out with hexane to remove those highly lipophilic compounds that disturb the SBSDME step. Subsequently, SBSDME is performed by using magnetic nanoparticles–metal organic framework composite, CoFe2O4/MIL-101(Fe), as sorbent to entrap the target analytes, which are later chemically desorbed and measured by liquid chromatography–tandem mass spectrometry (LC–MS/MS). The experimental variables related to the SBSDME procedure were studied to…
Observation of interaction forces by investigation of the influence of eluent additives on the retention behavior of aqueous nanoparticle dispersions…
2020
The investigation and subsequent understanding of the interactions of nanomaterials with components of their surrounding media is important to be able to evaluate both potential use cases as well as potential risks for human health and for the environment. To investigate such interactions, asymmetrical flow field-flow fractionation (AF4) is an interesting analytical tool. This statement grounds on the fact that interactions of the analyte with the membrane and with components of the eluent are crucial for the retention behavior of the analyte within the field-flow fractionation (FFF) channel. Therefore, the investigation of the retention behavior provides an insight in the nature of the int…
Optimization of instrumental parameters for improving sensitivity of single particle inductively-coupled plasma mass spectrometry analysis of gold
2021
Single particle inductively-coupled plasma mass spectrometry (spICP-MS) is a promising technique for analysis of engineered nanoparticles, whose utilization has increased substantially over the past years. Optimization of instrumental conditions is, however, crucial to improve the sensitivity and precision of nanoparticle (NP) detection. In this study, the influence of ICP-MS instrumental parameters (nebulizer gas flow, plasma radiofrequency-power and sampling depth) on the signal intensity of gold in spICP-MS was evaluated using dispersions of Au NPs and a solution of dissolved gold. The interaction effects of the main factors were found to have a significant effect on the signal intensity…
Relationship between particle size and dissolution rate of bulk powders and sieving characterized fractions of two qualities of orthoboric acid
1996
Drug Dev. Ind. Pharm. ISI Document Delivery No.: VN279 Times Cited: 1 Cited Reference Count: 22 Tromelin, A Habillon, S Andres, C Pourcelot, Y Chaillot, B; International audience; We have carried out a study of the particle size distribution and aqueous dissolution rate of two commercially available qualities of orthoboric acid, labeled ''crystal'' (ABC) and ''powder'' (ABP). In a previous work, we have shown that the two commercial qualities of orthoboric acid chosen as model compound (''powder'' and ''crystal'') are related to the same crystal network in spite of their different names. However, these two qualities have very different size particle distributions, as previously determined b…
Understanding the role of Ti-rich domains in the stabilization of gold nanoparticles on mesoporous silica-based catalysts
2018
3 Tablae, 14 Figures.-- Supplementary material.-- © 2018. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/