Search results for " Sam"

Environmental applications (air)

2020

Abstract The use of solid sorbent-based devices for the monitoring of contaminants in the air is a widespread trend due to its versatility, physicochemical stability, and high enrichment factor. Active and passive sampling strategies have been developed for air monitoring using different materials, such as carbon-based organic polymers and inorganic sorbents. It has been updated in the literature regarding the most recent applications of the use of solid sorbent-based samplers for the monitoring of air in different sites such as rural, urban, industrialized, and indoor areas, including workplace environments for the evaluation of occupational exposure risks.

Passive Air Sampling

2016

«La scrittura era una questione di esistenza». Una conversazione sulla poesia russa con Michail Ajzenberg

2011

An interview to the Russian poet Mikhail Ajzenberg

Pitfalls to be considered on the metabolomic analysis of biological samples by HR-MAS

2014

HR-MAS (High-Resolution Magic AngleSpinning) is considered a powerfultechnique for metabolomic studies ofbiological samples that provides “intact”tissue spectra (Cheng et al., 1998; Waterset al., 2000; Sitter et al., 2002; Martinez-Bisbal et al., 2004; Payne et al., 2006;Coen et al., 2007; Bathen et al., 2010).The performance of HR-MAS, fol-lowed by quantitative histopathology hasdemonstrated that, despite some changes,HR-MAS can preserve approximately thetissue histopathologic features producingwell-resolved spectra of cellular metabo-lites (Cheng et al., 2000). Nevertheless,therearesomeaspectsarousedintheliter-ature about the possible biochemical andstructural changes that can occur durin…

Occurrence and risk assessment of mycotoxins, acrylamide, and furan in Latvian beer.

2018

This work reports data on the occurrence of nine mycotoxins and two food processing contaminants - acrylamide and furan - in a total of 100 beers produced in Latvia. Mycotoxins were detected by high-performance liquid chromatography (HPLC) coupled with time-of-flight mass spectrometry, acrylamide by HPLC coupled with quadrupole-Orbitrap mass spectrometry, and furan by headspace gas chromatography-mass spectrometry. The most frequently occurring mycotoxins were HT-2 and deoxynivalenol (DON), which were detected in 52% and 51% of the analysed samples. The highest content was observed for DON, reaching the maximum of 248 µg kg-1. Furan was ubiquitous, and 74% of the samples contained acrylamid…

Ceramics from Samshvilde (Georgia): A pilot archaeometric study

2020

Abstract This archaeometric study deals with seven samples of prehistoric pottery and, for the first time in Georgian studies, thirteen samples of glazed medieval pottery. All specimens were collected at Samshvilde, the most remarkable archaeological complex in southern Georgia and believed to represent locally-manufactured products. Two additional samples of raw materials composed of clay, silt, and sand were collected near the site and used to compare composition. Several analytical techniques were applied: Optical Microscopy (OM), Scanning Electron Microscopy (SEM), Electron Probe Microanalysis (EPMA), X-ray Diffraction (XRD) and X-ray Fluorescence (XRF). The results allowed to build a c…

A preliminary study on the stability of benzodiazepines in blood and plasma stored at 4 degrees C.

1997

An approach to determine the stability of benzodiazepines and some of their metabolites (n = 13) by means of a routinely applied gas chromatographic method using electron capture detection was made in this preliminary study. Validation data of the method are given. Spiked blood and plasma samples were stored at 4 degrees C and analysed at selected times up to 240 days. The concentrations of all analytes had decreased to at least 60% of the original levels at the end of the observation period. A clear pattern of breakdown could not be established. The data obtained suggest that results from long-term stored samples should be interpreted cautiously. Further investigations concerning the stabi…

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…

Noninvasive sampling of phenylalanine by reverse iontophoresis.

1999

While iontophoresis is typically associated with drug delivery across the skin, the symmetry of the technique permits its application to the essentially noninvasive withdrawal of biologically important analytes from the subcutaneous space to the body's surface. The identification of other substances which can be monitored by this procedure, and to its optimization and development as a more general clinical chemistry tool, is a long-term objective. In this paper, we describe a preliminary in vitro investigation into the feasibility of extracting and analyzing the amino acid, phenylalanine, with the ultimate aim to develop a diagnostic test for phenylketonuria, a potentially fatal metabolic d…

More about sampling and estimation of mercaptans in air samples

2013

[EN] Several strategies have been developed for sampling and determination of volatile thiols. The selectivity and sensitivity of the proposed methodologies are achieved by using a specific derivatizing reagent. The different procedures assayed are based on air sampling followed by derivatization of the analytes with OPA and isoleucine in alkaline solution. The derivatization products are separated and determined by liquid chromatography and fluorescence detection. To start, the derivatization conditions and stability of the derivates have been studied in order to establish the storage conditions. In general, the strategies studied consisted on trapping and detivatization the thiol compound…