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The goal of this work is to emphasize the reliability of the thermal desorption technique in identifying mercury species. The analysis of mercury species in solids is essential for assessing the risk of disposal or re-use of mercury-contaminated materials. This study evaluates the accuracy and reliability of thermal desorption as a technique for identifying mercury species by means of different thermo-desorption...
We report a simple one-pot synthesis of highly fluorescent carbon dots (CDs) via modified hydrothermal (MHT) treatment of alkaline solution of dopamine and cysteine. These CDs (λex=320nm, λem=390nm, and quantum yield ∼5.1%) are of ∼2–3nm in diameter. Further attempt of synthesizing CDs in some common water-miscible solvents ends up the fact that the MHT product from acetone medium is nonfluorescent...
QSRR are mathematically derived relationships between the chromatographic parameters determined for a representative series of analytes in given separation systems and the molecular descriptors accounting for the structural differences among the investigated analytes. Artificial neural network is a technique of data analysis, which sets out to emulate the human brain's way of working. The aim of the...
A method with negligible blank values for the determination of total iron at the ultratrace level in seawater has been optimized and validated exploring for the first time the performance and limitations of Adsorptive Cathodic Stripping Voltammetry (AdCSV) in non-buffered solutions. The method is based on the CSV determination of the Fe-dihydroxynaphthalene (DHN) complex using atmospheric oxygen to...
A highly sensitive voltammetric sensor, based on reduced graphene oxide on SWCNTs modified glassy carbon electrode (GCE), was constructed and used for sensitive detection of hesperetin. The electrochemical behavior of hesperetin at this sensor was investigated systematically and a novel voltammetric method for determination of hesperetin was proposed. The redox characters of hesperetin was discussed...
An accurate and sensitive method for the determination of selected EDCs in soil and compost from wastewater treatment plants is developed and validated. Five parabens, six benzophenone-UV filters and the antibacterials triclosan and triclocarban were selected as target analytes. The parameters for ultrasound-assisted extraction were thoroughly optimized. After extraction, the analytes were detected...
In this paper, we present a compact handheld laser-induced fluorescence (LIF) detector based on a 450nm laser diode and quasi-confocal optical configuration with a total size of 9.1×6.2×4.1cm3. Since there are few reports on the use of 450nm laser diode in LIF detection, especially in miniaturized LIF detector, we systematically investigated various optical arrangements suitable for the requirements...
A new quantum dot (QD)-based pH sensor design is investigated. The sensor is synthesized based on the self-assembly of green QDs onto treated spores to form QD@spore nanocomposites. The nanocomposites are characterized using laser scanning confocal microscopy, transmission electron microscope, and fluorescence spectroscopy, among others. Fluorescence measurements showed that these nanocomposites are...
A simple and inexpensive method for chemical speciation of inorganic As in natural mineral drinking waters by using anodic stripping chronopotentiometry (ASCP) in an electrochemical flow-through cell with an Au wire as the working electrode was described in the present work. The presented method is an attractive alternative to laborious and time-consuming procedures requiring pre-separation of various...
The authenticity and composition of commercial essential oils requires strict quality control. Due to the importance of α-pinene containing essential oils, a rapid and efficient method for quantification of this terpene in oils of eucalyptus, pink pepper and turpentine using 1H NMR was developed and validated. All evaluated parameters (selectivity, linearity, accuracy/precision, repeatability, robustness,...
We report on a Lab-On-Valve (LOV) configuration for analyte preconcentration from milliliter sample volumes using confluent mixing in the holding coil for in-line addition of loading buffer. The system was applied to the spectrophotometric determination of iron(II) in acidified seawater using 1,10-phenanthroline as color reagent. A cellulose-based chelating sorbent containing 8-hydroxyquinoline was...
Organochlorine pesticides (OCPs) are ubiquitous environmental contaminants with adverse impacts on aquatic biota, wildlife and human health even at low concentrations. However, conventional methods for their determination in river sediments are resource intensive. This paper presents an approach that is rapid and also reliable for the detection of OCPs. Accelerated Solvent Extraction (ASE) with in-cell...
In this work, an automated system for the study of the interaction of drugs with human serum albumin (HSA) was developed. The methodology was based on the quenching of the intrinsic fluorescence of HSA by binding of the drug to one of its binding sites. The fluorescence quenching assay was implemented in a sequential injection analysis (SIA) system and the optimized assay was applied to ionic liquids...
The identification of trace levels of compounds in complex matrices by conventional low-resolution gas chromatography hyphenated with mass spectrometry is based in the comparison of retention times and abundance ratios of characteristic mass spectrum fragments of analyte peaks from calibrators with sample peaks. Statistically sound criteria for the comparison of these parameters were developed based...
A novel voltammetric sensor was constructed by simple dripping single-walled carbon nanotubes (SWCNTs) on to the glass carbon electrode (GCE) firstly and electro-polymerizing l-Citrulline film subsequently. The resulting poly(l-Citrulline)/SWCNTs/GCE showed a significant voltammetric response to picroside II due to the synergistic effect of SWCNTs and poly(l-Citrulline) film. The first electroanalytical...
Because of its high hydrophilicity, linear polyacrylamide (LPA) has often been used as a coating to suppress electroosmotic flow (EOF) in capillary electrophoresis (CE); however, its stability and effectiveness in acidic media, with or without organic modifiers, surfactants or ionic liquids is not well documented. In this work, the adequacy of LPA coating to suppress EOF in those different conditions...
A novel quantitative prediction and variable selection method called interval ridge regression (iRR) is studied in this work. The method is performed on six data sets of FTIR, two data sets of UV–vis and one data set of DSC. The obtained results show that models built with ridge regression on optimal variables selected with iRR significantly outperfom models built with ridge regression on all variables...
Perfluoroheptanoic acid was employed as a volatile micellar phase in background electrolyte for micellar electrokinetic chromatography–tandem mass spectrometry separation and determination of 15 selected naphthoyl- and phenylacetylindole- synthetic cannabinoids and main metabolites derived from JWH-018, JWH-019, JWH-073, JWH-200 and JWH-250. The influence of concentration of perfluoroheptanoic acid...
The reliable and accurate detection of explosives such as 2,4,6-trinitrophenol (TNP) and 2,4,6-trinitrotoluene (TNT) is in high demand for homeland security and public safety. Although extremely high sensitivity towards TNT has been demonstrated, detection of TNP remains a challenge. In this work, a fluorescent nanoscale complex composed of bis(8-hydroxyquinoline) and Al3+ ions has been prepared,...
The present study developed a new optical chemical sensor for detection of nitroaromatic explosives in liquid phase. The method is based on the fluorescence quenching of phenol red as fluorophore in a poly(vinyl alcohol) (PVA) membrane in the presence of nitroaromatic explosives as quenchers, e.g., 2,4,6-trinitrotoluene (TNT), 2,4-dinitrotoluene (2,4-DNT), 4-nitrotoluene (4-NT), 2,4,6-trinitrobenzene...
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