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The applicability of sensor system for the discrimination of sources of indoor pollution was investigated. As examples of indoor pollution sources, paint and lacquer coatings were considered. Commercially available preparations: Akrylux, Doamlux, Bejca and White Scandinavian were selected for headspace measurements using TGS sensor array. Following issues were investigated: (1) discrimination between...
Starting with Biller–Biemann's work [J.E. Biller, K. Biemann, Anal. Lett. 7 (1974) 515], various kinds of approaches have been proposed to extract GC/MS data to obtain pure components responses. In this paper, an integrated chemometric approach is proposed, which combine four sequential steps, data pretreatment, component perception, resolution and component identification, and then the proposed approach...
Gas chromatographic retention indices of nitrogen-containing polycyclic aromatic compounds (N-PACs) have been predicted by quantitative structure–property relationship (QSPR) analysis based on heuristic method (HM) implemented in CODESSA. In order to indicate the influence of different molecular descriptors on retention indices and well understand the important structural factors affecting the experimental...
A new antibody immobilization strategy was proposed for the fabrication of a label-free capacitive immunosensor based on electrodeposition of nanometer-sized bioactive hydroxyapatite (HAP). By a procedure of constant current cathodal electrodeposition, a nano-HAP film with bioactivity was formed on a self-assembled β-mercaptoethanol monolayer-modified gold electrode. A suitable amount of chitosan...
The goal of this study is to derive a methodology for modeling the biological activity of non-nucleoside HIV Reverse Transcriptase (RT) inhibitors. The difficulties that were encountered during the modeling attempts are discussed, together with their origin and solutions. With the selected multivariate techniques: robust principal component analysis, partial least squares, robust partial least squares...
A selective matrix removal/separation/enrichment method, utilizing a microcolumn of a chelating resin with SH functional groups (Duolite GT-73), was proposed for the determination of Sb(III) in waters by segmented flow injection-hydride generation atomic absorption spectrometry (SFI-HGAAS). The resin was selective to Sb(III) at almost all pH and acidity values employed, whereas Sb(V) was not retained...
An agarose-based anion exchanger (Q-Sepharose) was loaded with chromotropic acid (CTA) and used for column preconcentration and determination of copper by flame AAS. Preliminary experiments indicated that a sample pH of 5.7–6.5 is best suited for accumulation of copper and a 2.5ml portion of a 0.02moll −1 HCl solution can efficiently desorb the analyte from the column. An incomplete factorial...
A great mean value of recovery for extraction of 3,4-dichloroaniline from a soil is calculated from individual recovery values evaluated for four different fractions of the soil. Then the uncertainty associated to this great mean recovery is calculated and used to know whether to apply or not the correction in routine analysis performed for the same kind of soil and the same analyte. The most representative...
C/Fe nanocomposite (CFN) was synthesized by a procedure similar to an exfoliation/adsorption process to intercalate Fe 3+ into graphite oxide (GO) layers and would be reduced in a H 2 atmosphere. The results of X-ray diffractometry (XRD) and transimission electron microscopy (TEM) show that the form of CFN is carbon nanotube–Fe nanoparticle composite with α-Fe distributed on the nanotube...
Superheated hexane extraction has been tested for obtaining fatty acids from grape seed and compared with conventional Soxhlet and hot hexane extractions. Seeds from grape residues from a winery were dried for 46h at 105°C, milled and sieved by particle size (d<0.42mm, 0.42<d<0.84mm and d>0.84mm). An optimization study of influential variables on superheated hexane extraction (namely extraction...
An anodic stripping voltammetric method for the determination of cardiac troponin I (cTnI) at a MCM-41 mesoporous material modified carbon paste electrode (MCM-MCPE) was investigated. The test was based on the dual monoclonal antibody “sandwich” principle using colloidal gold as a labeled substrate. Four main steps were carried out to obtain the analytical signal, i.e. electrode preparation, immunoreaction,...
A 100-fold preconcentration procedure based on rare-earth elements (REEs) separation from water samples with an extraction chromatographic column has been developed. The separation of REEs from matrix elements (mainly Fe, alkaline and alkaline-earth elements) in water samples was performed loading the samples, previously acidified to pH 2.0 with HNO 3 , in a 2ml column preconditioned with...
The combination of attenuated total reflectance–fourier transform mid-infrared spectrometry (ATR–FTMIR) and multivariate pattern recognition is presented as a fast and convenient methodology to ascertain the source product an oil slick comes from and to evaluate the extent of its weathering. Different types of hydrocarbons (including crude oils, several heavy distillates and the Prestige's heavy fuel...
We have developed a new method for the determination of the widely used herbicide 2,6-dichlorobenzonitrile (dichlobenil) and its major metabolites 2,6-dichlorobenzamide (BAM) and 2,6-dichlorobenzoic acid (2,6-DCBA) in groundwater samples. The procedure is based on solid phase extraction (SPE) combined with a derivatization procedure before GC–MS analysis in order to quantify analytes simultaneously...
Solution calorimetry can be used to determine the amorphous content of a compound when the solubility and dissolution rate of the compound in the chosen solvent are reasonably high. Sometimes, it can be difficult find a solvent in which a sample is freely soluble. The present study evaluated the use of solution calorimetry for the assessment of the amorphous content of a sample that is poorly soluble...
The preparation and characterization of an amperometric glucose biosensor based on the entrapment of glucose oxidase (GOx) in a polyacrylamide microgel is described. This study proves that polyacrylamide microgels provide an excellent matrix for GOx immobilization that can be used as a biological material in amperometric biosensors. The interference produced by ascorbic and uric acid has been eliminated...
We report a new approach for detecting DNA hybridisation using non faradaic electrochemical impedance spectroscopy. The technique was applied to a system of DNA probes bearing amine groups that are immobilized by covalent grafting on a supporting polypyrrole matrix functionalised with activated ester groups.The kinetics of the attachment of the ss-DNA probe was monitored using the temporal evolution...
Panaxynol is a bioactive component in traditional Chinese medicines (TCMs), such as Saposhnikovia divaricata and Panax ginseng. In the work, two solvent-free sample techniques of pressurized hot water extraction (PHWE) and headspace liquid-phase microextraction (HS-LPME) were combined and developed for the determination of panaxynol in a TCM of S. divaricata. Panaxynol in the TCM samples from different...
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