Papers by Simona Carmen Litescu
Revista De Chimie, Aug 1, 2023
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Agro Buletin AGIR, 2010
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Chemosensors
In recent years, new sensor-based technologies have been developed to meet the demand for rapid a... more In recent years, new sensor-based technologies have been developed to meet the demand for rapid and accurate analysis of food and environment, as food safety and environmental monitoring are very important concerns nowadays. In this context, considerable attention has been paid to the development and design of electrochemical sensors, as these offer a number of advantages, such as portability, ease of use, low costs and fast response times. Molecularly imprinted polymers (MIPs) are robust synthetic polymers with special cavities designed for a target molecule, and they are used as selective tools through a mechanism of molecular recognition. Graphene is a 2D crystalline carbon that forms either a single or a coupled layer of hexagonally arranged carbon atoms and is referred to as a “wonder material”. The use of these two structures in the development of electrochemical sensors gives the newly created analytical tool enhanced properties, such as improved sensitivity and selectivity, ...
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Pharmacognosy Magazine, 2017
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Frequent occurrence of food contamination, growing concern about public safety, and the adoption ... more Frequent occurrence of food contamination, growing concern about public safety, and the adoption of more stringent legislations have promoted research efforts in the agrifood industry as well as in environmental monitoring, attempting to guarantee improvements in food quality and safety. In addition, the increasing demand for sustainable agriculture has led to the introduction of novel processing methods for raw materials to achieve stable foods. For this reason, it is imperative that effiffi cient and reliable diagnostic tools be developed to detect potential h azards in agriculture and for food safety. In this context, biosensor technology represents the cutting-edge frontier in the agrifood and environmental fifields. Indeed, smart monitoring of chemical contaminants (i.e., pesticides, heavy metals, toxins, allergenic compounds, and food additives) represents one of the evolving issues challenging the assessment of food quality and safety. Progress in multianalyte screening, functional materials, microflfluidics and nanotechnology is amplifying the potential market of biosensors, making this technology more competitive in comparison with conventional lab-based procedures in terms of speed of response and operational fifield usage. However, despite the large number of publications and patents on biosensors for food analysis, only a few systems have been able to reach the market. Among the main drawbacks to be faced are the limited lifetime of biological components, mass production, as well as portability. In this chapter, current and future trends in analytical diagnostic tools are discussed, with the aim of promoting a deeper cooperation between research and industries and encouraging the use of biosensing technology as a more attractive option for the commercial sector.
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Antioxidants
A simple and rapid differential pulse voltammetric (DPV) method using a single-use electroactivat... more A simple and rapid differential pulse voltammetric (DPV) method using a single-use electroactivated pencil graphite electrode (PGE*) is proposed for the rapid screening of the total content of polyphenolics (TCP) with intermediate antioxidant power (AOP) in grapefruit peel and fresh juice. The results were compared and correlated with those provided by the HPLC-DAD-MS method. NG voltammetric behavior at PGE* was studied by cyclic voltammetry and an oxidation mechanism was suggested. The experimental conditions (type of PGE, electroactivation procedure, pH, nature and concentration of supporting electrolyte) for NG DPV determination were optimized. The NG peak current varied linearly with the concentration in the ranges 1.40 × 10−6–2.00 × 10−5 and 2.00 × 10−5–1.40 × 10−4 mol/L NG and a limit of detection (LoD) of 6.02 × 10−7 mol/L NG was attained. The method repeatability expressed as relative standard deviation was 7.62% for the concentration level of 2.00 × 10−6 mol/L NG. After acc...
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Open Chemistry, 2014
The aim of this research was to investigate the chemical composition of Coreopsis tinctoria Nutt.... more The aim of this research was to investigate the chemical composition of Coreopsis tinctoria Nutt. fruits extract, to highlight the potential of ultrasound assisted extraction in the fast preparation of extracts rich in polyphenols using different solvents (55%, 78% and 96% hydrous ethanol) and to evaluate the antioxidant potential of formulated extracts. LC-MS/MS was used to characterize the ethanolic extract from Coreopsis tinctoria Nutt. dried fruits. The extract contains different flavonoids (marein, flavanomarein, quercetagetin-7-O-glucoside, okanin aurone, leptosidin, luteolin, apigenin) and phenolic acids (chlorogenic acid, caffeic acid). Several parameters that could affect extraction efficiency were evaluated. Finally, this study focused on determination of plant extracts total phenolic content and their antioxidant capacity. The experimental results allowed the selection of the optimum operating parameters leading to the highest total polyphenolic content, expressed as gall...
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RSC Advances, 2015
Schematic representation of the developed disposable dual sensor array.
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Sensors and Actuators B: Chemical, 2017
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TrAC Trends in Analytical Chemistry, 2016
Abstract Endocrine disrupting chemicals (EDCs) are harmful, xenobiotic compounds requiring a mult... more Abstract Endocrine disrupting chemicals (EDCs) are harmful, xenobiotic compounds requiring a multi-tiered analytical approach for a reliable management. Although worth efforts worldwide, comprehensive EDCs monitoring and risk-assessment still require improvements. This article covers possible risks for public health due to EDCs exposure, and revises the maturity reached in different analytical detection fields, with a special focus on biosensor technology. Among validated laboratory-techniques, hyphenated mass-spectrometry-based chromatography provides high selectivity and multi-analyte detection, while in vitro bioassays enable reliable toxicological testing. However, none of these methods is suitable for fast in field, continuous or semi-continuous operations. Due to advances in material science and synthetic biology, now biosensor technology holds the promise to close this gap and, although not included yet in routinely screening programs, fulfill the necessary requirements to sustain a coherent and global strategy to assess the state of environmental pollution.
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Journal of the Serbian Chemical Society, 2012
The paper reports the successful application of membranes processes to obtain the good quality ex... more The paper reports the successful application of membranes processes to obtain the good quality extracts with compounds of high antioxidative activity and therapeutic value. This study provided investigations on the phenolic compounds from two plant species used in Romanian ethno-medicine and evaluated the antioxidant and cytotoxic activities. Three extracts prepared from Geranium robertianum and Symphytum officinale were concentrated by microfiltration and ultrafiltration. The levels of phenolic compounds and flavonoids were determined by UV-Vis spectroscopy and HPLC. The freeradical scavenging activity of concentrated extracts was determined by DPPH method. The preliminary tests of cytotoxic activity for the concentrated extracts have been carried out on human epidermoid laryngeal carcinoma cell line (Hep-2p) and normal monkey kidneys cells (RM). The results showed that all concentrated extracts had a very low cytotoxicity against healthy cells, but a significant cytotoxic effect o...
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Analytical Letters, 2010
ABSTRACT A new HPLC method was developed for determination of papaverine in a papaverine naturall... more ABSTRACT A new HPLC method was developed for determination of papaverine in a papaverine naturally photooxidized solution using a Duet C18/SCX column. The mobile phase used was a mixture of phosphate buffer (pH = 3.80) and acetonitrile in 40:60 ratio. The compounds identified were: papaverinol, papaveraldine, papaverine, and pyrrocolonium ion. Very good resolutions, peak shapes, and asymmetries were obtained. An ion exchange experiment was developed in order to identify and separate the pyrrocolonium ion. This was retained completely by a cation exchange resin in its Na+ form, while papaverine, papaverinol, and papaveraldine were retained more or less, due to a retention explained by a combined ion exchange-solvent extraction mechanism. Voltammetric studies showed that natural photooxidation of papaverine occurs in three irreversible steps and yields to stable compounds in solution.
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Acest articol prezintă un nou instrument electroanalitic-electrod de aur modificat cu lipoprotein... more Acest articol prezintă un nou instrument electroanalitic-electrod de aur modificat cu lipoproteină umană de densitate mică-capabil să funcţionze ca un sistem biomimetic al răspunsului pereţilor celulari la stresul oxidativ indus prin atacul unor radicali liberi. Sunt prezentate rezultatele obţinute la aplicarea acestui instrument în evaluarea eficacităţii antioxidante a unor polifenoli în prevenirea lipoperoxidării. Aceşti polifenoliau fost ordonaţi în funcţie de eficienţa lor în prevenirea lipoperoxidării: acid cafeic >acid rosmarinic>acid clorogenic. This paper presents a new developed electro-analytical tool-gold modified electrode with low-density lipoprotein-able to mimic the biological response of cellular wall against the oxidative damage induced by free radicals attack. Results obtained when applying this tool in the assessment of the polyphenols antioxidative efficacy against lipoperoxidation are reported. These polyphenols have been ordered in function of their effic...
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Analytical Letters, 2019
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Food Chemistry, 2015
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Journal of Materials Science: Materials in Medicine, 2009
The association of magnetic nanoparticles, which could be controlled by a magnetic field and have... more The association of magnetic nanoparticles, which could be controlled by a magnetic field and have dimensions which facilitate their penetration in cells/tissues, with hydrogel type biopolymeric shells confer them compatibility and the capacity to retain and deliver bioactive substances. The main objective of this work is the development of a new system based on a biocompatible polymer with organic-inorganic structure capable of vectoring support for biologic active agents (L: -asparaginase, e.g.). Characterization of size and morphology of the hydrogel-magnetic nanoparticles with entrapped L: -asparaginase was made using Dynamic Light Scattering method, Transmission Electron Microscopy and Confocal Microscopy. The structure of magnetic nanoparticles coated with hydrogel was characterized by Fourier Transformed Infrared Spectroscopy. The cytotoxicity of nanoparticles was evaluated and also the interactions with microorganisms. We obtained hydrogel-magnetic nanoparticles with L: -asparaginase entrapped, with sizes below 30 nm in dried stage, capable to penetrate the cells and tissues.
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Journal of Archaeological Science, 2010
Amber beads from the Cioclovina hoard (Hunedoara County, Romania), dating from the transitional p... more Amber beads from the Cioclovina hoard (Hunedoara County, Romania), dating from the transitional period between the Late Bronze Age and the Iron Age, were analysed by Fourier transform infrared spectroscopy – variable angle reflectance (FTIR-VAR) and Fourier transform Raman spectroscopy (FT-Raman). The aim was to determine if the raw material came from the shores of the Baltic Sea, on the
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Papers by Simona Carmen Litescu