Search results for "Analyte"
showing 10 items of 303 documents
A mathematical model based on the limit dilution method to obtain linear calibration curves which eliminate the matrix effect in quantitative analysi…
1995
Abstract We propose a mathematical model from an analytical application viewpoint inspired in the limit dilution method. The theoretical development of the model and its results are given. The model shows that there is a linear relation between the inverse of fluorescence intensity and the inverse of the dilution factor; each analytic system (sample, diluent and analyte) is characterised by a general linear function which is easily obtained. The analytical applications arising from this linearity are of great importance in X-ray fluorescence analysis. The following immediate applications are proposed: direct procurement of the total correction factor Y/H, rapid calculation of the fluorescen…
Quantitative electron probe microanalysis of metallic oxide mixtures applying an empirical calibration technique
1997
Abstract An analytical procedure is proposed for the independent quantitative chemical analysis of each element in the presence of other elements in the matrix of a sample by Energy Dispersive Electron Probe Microanalysis. For this purpose, an empirical calibration technique (which we shall call here the JABO method), which studies the variation of the X-ray intensities in terms of the analyte concentration in a chemical system with a complex matrix, is established. The methodology consists of the modification of the unknown sample by addition of a diluent, an internal standard and the analyte itself (dilution-addition method). A mathematical model is proposed to calculate the K parameters …
Towards an automatic lab-on-valve-ion mobility spectrometric system for detection of cocaine abuse.
2017
A lab-on-valve miniaturized system integrating on-line disposable micro-solid phase extraction has been interfaced with ion mobility spectrometry for the accurate and sensitive determination of cocaine and ecgonine methyl ester in oral fluids. The method is based on the automatic loading of 500μL of oral fluid along with the retention of target analytes and matrix clean-up by mixed-mode cationic/reversed-phase solid phase beads, followed by elution with 100μL of 2-propanol containing (3% v/v) ammonia, which are online injected into the IMS. The sorptive particles are automatically discarded after every individual assay inasmuch as the sorptive capacity of the sorbent material is proven to b…
Off-line coupling of multidimensional immunoaffinity chromatography and ion mobility spectrometry: A promising partnership.
2015
The extreme specificity of immunoaffinity chromatography (IAC) columns coupled to the high sensitivity of ion mobility spectrometry (IMS) measurements makes this combination really useful for rapid, selective, and sensitive determination of a high variety of analytes in different samples. The capabilities of the IAC-IMS coupling have been highlighted under three different scenarios: (i) multiclass residue analysis using a single IAC column, (ii) multiclass residue analysis using stacked IAC columns, and (iii) isomer analysis. In the first case, the determination of three strobilurin fungicides - azoxystrobin, picoxystrobin, and pyraclostrobin - in water and strawberry juice was considered, …
“AND” luminescent “reactive” molecular logic gates: a gateway to multi-analyte bioimaging and biosensing
2014
This review outlines examples that illustrate a recent and highly innovative concept in the field of (bio)molecular sensing, namely the simultaneous multi-analyte detection using "reactive" luminescent probes that are able to produce an optical signal only in response to multiple (bio)chemical inputs and through covalent chemical reactions with target (bio)analytes. Unlike conventional "AND" molecular logic gates based on supramolecular photochemical mechanisms, these unusual "smart" optical (bio)probes are suitable tools to track the rise and fall of a wider range of biologically relevant analytes, in complex media and with higher selectivity. The potential utility of this concept for in v…
One-Pot Analysis: a New Integrated Methodology for Determination of TAG and FA Determination through LC/MS and in-silico Saponification
2017
Vegetable oils differ significantly for their lipid profile and are mainly constituted by triacylglycerols (TAGs). These are esters formed bonding glycerol to three fatty acids (FAs). To the best of our knowledge, FA and TAG profiles in oils and fats are obtained using at least two different experimental techniques. In particular, FA determination requires elaborated procedures for sample preparation and analyte derivatization. In this work, we propose a one-pot analysis able to determine both TAG and FA contents of edible oils, using experimental data obtained from a simple liquid chromatography/mass spectrometry determination of TAGs. This experimental procedure is followed by an in silic…
Multiplexed plasmon sensor for rapid label-free analyte detection.
2013
Efficient and cost-effective multiplexed detection schemes for proteins in small liquid samples would bring drastic advances to fields like disease detection or water quality monitoring. We present a novel multiplexed sensor with randomly deposited aptamer functionalized gold nanorods. The spectral position of plasmon resonances of individual nanorods, monitored by dark-field spectroscopy, respond specifically to different proteins. We demonstrate nanomolar sensitivity, sensor recycling, and the potential to upscale to hundreds or thousands of targets.
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…
Experimental Study of the Oriented Immobilization of Antibodies on Photonic Sensing Structures by Using Protein A as an Intermediate Layer
2018
[EN] A proper antibody immobilization on a biosensor is a crucial step in order to obtain a high sensitivity to be able to detect low target analyte concentrations. In this paper, we present an experimental study of the immobilization process of antibodies as bioreceptors on a photonic ring resonator sensor. A protein A intermediate layer was created on the sensor surface in order to obtain an oriented immobilization of the antibodies, which enhances the interaction with the target antigens to be detected. The anti-bovine serum albumin (antiBSA)-bovine serum albumin (BSA) pair was used as a model for our study. An opto-fluidic setup was developed in order to flow the different reagents and,…
Real-time polarimetric biosensing using macroporous alumina membranes
2013
We report the first demonstration of real-time biosensing in free standing macroporous alumina membranes. The membranes with their 200 nm diameter pores are ideal candidates for biosensing applications where fast response times for small sample volumes are needed as they allow analytes to flow through the pores close to the bioreceptors immobilized on the pores walls. A bulk refractive index sensitivity of 5.2x10 -6 refractive index units was obtained from signal responses to different concentrations of NaCl solutions flowing through the pores. Finally, after functionalizing the alumina pore surfaces with an epoxysilane and then spotting it with β-Lactoglobulin protein, the interactions bet…