Search results for "D71"
showing 10 items of 14 documents
Extraction and Sample Preparation
2015
As everyone knows, the role played by extraction and sample preparation in the analytical sciences cannot be overemphasized. Despite tremendous advances in chromatography, detection, and other aspects of analysis, extraction and sample preparation remain a preanalysis ritual of critical importance. It has been estimated that around 50% to 70% possibly even more of the time and effort that goes into an analytical process comprises extraction and sample preparation. Sample preparation procedure can vary in the degree of selectivity, speed, and convenience, depending on the approach and conditions used, as well as on the geometric configurations of the extraction phase and conditions. Proper d…
New insights to assess the consolidation of stone materials used in built heritage: the case study of ancient graffiti (Tituli Picti) in the archaeol…
2020
AbstractTituli Picti are an ancient form of urban graffiti very common in the archaeological site of Pompeii (Naples, South—Italy). They are generally made of red pigments applied on walls of Campanian ignimbrite. This paper deals with a scientific investigation aimed to their conservation. This is a challenging task since it requires a multidisciplinary approach that includes restorers, archaeologists and conservation scientists. The study has provided suggestions on the proper way to conserve Tituli Picti over time. In the present work, several specimens of Campanian ignimbrite were painted with red earth pigment; lime and Arabic gum have been used as binders as well. Such painted stones …
Quick determination of Glyphosate and AMPA at sub µg/L in drinking water by direct injection into LC-MS/MS
2021
Abstract A sensitive, simple and quick method for the determination of glyphosate (Gly) and its degradation product, Aminomethyl phosphonic acid (AMPA), in water through ion chromatography coupled to quadrupole-linear ion trap mass spectrometry has been developed. Sample treatment was based on direct injection and acquisition was implemented in both MS2 and MS3 modes. The LoQs of the method were 0.03 µ/L for both Gly-and AMPA. The recoveries were between 91 and 118% and RSD was lower than 15%. The developed methodology was applied on 436 water samples.
Preliminary Results on the Use of Leather Chrome Shavings for Air Passive Sampling
2012
A new passive sampler based on low-density polyethylene (LDPE) layflat tube filled with chrome shavings from tannery waste residues was evaluated to determine volatile organic compounds (VOCs) in indoor and outdoor areas. VOCs were directly determined by head space-gas chromatography-mass spectrometry (HS-GC-MS) without any pretreatment of the sampler and avoiding the use of solvents. Limit of detection values ranging from 20 to 75 ng sampler−1and good repeatability values were obtained for VOCs under study with relative standard deviation values from 2.8 to 9.6% except for carbon disulfide for which it was 22.5%. The effect of the amount of chrome shavings per sampler was studied and resul…
Simultaneous detection of hazardous skin whitening agents in Indian cosmetic products using a green chromatographic technique
2021
The present work mainly highlights the simultaneous detection of four skin whitening agents i.e. hydroquinone (HQ), resorcinol (RS), catechol (CC) and 3,3′-dichlorobenzidine (DCB) in facial creams and body lotion. Among these, the first three are positional isomers of dihydroxybenzene so simultaneous separation is difficult with the conventional reverse-phase high-performance liquid chromatographic technique (RP-HPLC). The selected skin whitening agents were detected in facial cream and body lotion using micellar liquid chromatography coupled to a photodiode array detector (MLC-PDA). In the present study, optimization of the method was accomplished using response surface methodology (RSM) w…
Development and Validation of a Reversed-Phase Liquid Chromatography Method for the Simultaneous Determination of Indole-3-Acetic Acid, Indole-3-Pyru…
2011
A simple, sensitive, precise, and specific reverse HPLC method was developed and validated for the determination of plant hormones in barley (Hordeum vulgareL.). The method includes extraction in aqueous organic solvent followed by solid-phase extraction, sample evaporation, and reversed-phase HPLC analysis in a general purpose UV-visible (abscisic acid (ABA)) and fluorescence detection (indole-3-acetic acid (IAA) and indole-3-pyruvic acid (IPA)), high-performance liquid chromatography system. The separation was carried out on Zorbax Eclipse XDB C8 column (150 × 4.6 mm I.D) with a mobile phase composed of methanol and 1% acetic acid (60 : 40 v/v) in isocratic mode at a flow rate of 1 ml min…
The Use of Amberlite Adsorbents for Green Chromatography Determination of Volatile Organic Compounds in Air
2012
Passive samplers have been widely used for volatile organic compounds determination. Following the green chemistry tendency of the direct determination of adsorbed compounds in membrane-based devices through using head space direct chromatography analysis, this work has evaluated the use of Amberlite XAD-2, XAD-4, and XAD-16 adsorbents as a filling material for passive samplers. Direct analysis of the membranes by HS-GC-MS involves a solvent-free method avoiding any sample treatment. For exposed membranes, recoveries ranged from 10% to 203%, depending on the compound and adsorbent used. The limit of the detection values ranged from 1 to 140 ng per sampler. Acceptable precision and sensitivi…
Optimization of Resolving Power, Fragmentation, and Mass Calibration in an Orbitrap Spectrometer for Analysis of 24 Pesticide Metabolites in Urine
2019
Mass spectrometer parameters such as Resolving Power, type of fragmentation, and mass calibration mode were optimized in the analysis of 24 pesticide metabolites in human urine using Ultra-High Pressure Liquid Chromatography coupled to Orbitrap High-Resolution Mass Spectrometer (UHPLC-HRMS). The best results were achieved with a Resolving Power of 25,000 FWHM and by applying Collision Induced Dissociation fragmentation mode (40 eV).
Social Perceptions and Attitudes Towards Climate Change in Poland and in Turkey
2017
Climate change is perceived as a threat to future human well-being and a challenge to sustainable development of local communities and economies world-wide. While some countries and regions are expected to experience slight gains from the climatic changes the other are exposed to major losses. Ever more frequent natural disasters come as warning symptoms of the changes. However, for the sake of effective and efficient adaptation in various world regions answers to the following questions are important: do people notice this changes, do they experience their negative effects, are they satisfied with the climate change mitigation and adaptation actions taken by the governments, are they willi…
The three wives problem and Shapley value
2015
We examine the Talmudic three wives problem, which is a generalization of the Talmudic contested garment problem solved by Aumann and Maschler (1985) using coalitional procedure. This problem has many practical applications. In an attempt to unify all Talmudic methods, Guiasu (2010, 2011) asserts that it can be explained in terms of “run-to-the-bank”, that is, of Shapley value in a “cumulative game”. It can be challenged because the coalitional procedure yields the same result as the nucleolus, which corresponds to a “dual game”. As Guiasu's solution is paradoxical (it has all the appearances of truth), my contribution consists in explaining the concepts, particularly truncation, that play …