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Four polar compounds, i.e. pantothenic acid, inositol, taurine and caffeine were used as probe solutes in conjunction with chemometric methods to find out meaningful implications of chromatographic conditions and detector settings on the system performance. Putting a premium on the conditions of hydrophilic interaction liquid chromatography (HILIC) and settings of evaporative light-scattering detection...
The development, optimization and validation of an ion-pairing high performance liquid chromatography method for the simultaneous determination of both nicarbazin (NIC) components: 4,4′-dinitrocarbanilide (DNC) and 2-hydroxy-4,6-dimethylpyrimidine (HDP) in bulk materials and feed additives are described. An experimental design was used for the optimization of the chromatographic system. Four variables,...
The use of a Dynamic Headspace System (DHS) device combined with a Thermal Desorption Unit (TDU) interfaced to a Gas Chromatography/Mass Spectrometry (GC/MS) system is proposed for the determination of furfurals in oenological products. An experimental design protocol has been employed for the optimization of the instrumental settings concerning DHS and TDU extraction and desorption steps. It has...
A strategy for the accurate determination in foodstuffs of seven elements liable to be interfered with (V, Cr, Fe, Co, Ni, As and Se), was successfully applied. Firstly, to reduce spectroscopic interferences, four influential factors (hexapole and quadrupole bias, helium and hydrogen flows) of the collision/reaction cell device were optimised through the experimental design methodology. Secondly,...
Comprehensive two-dimensional gas-chromatography (GC×GC) is a great tool to explore complex essential oils. In this work the different terpene composition of the aroma fraction of rosemary and oregano were studied. The present investigation is based on the optimization of the comprehensive two-dimensional gas-chromatographic method through the use of experimental designs and Multisimplex, and studying...
Supercritical fluid extraction (SFE) combined with dispersive liquid–liquid microextraction (DLLME) followed by gas chromatography with flame ionization detector (GC-FID) was developed for the extraction and determination of 4-nitrotoluene and 3-nitrotoluene in soil sample. The effects of different SFE experimental parameters on the extraction recovery were studied simultaneously using a central composite...
A methodology based on optical fiber (OF) sensing was developed to screen single walled carbon nanotubes (SWCNT) in aqueous solutions.This method was validated by the comparison of its analytical performance with that of an ultraviolet–visible (UV–Vis) technique by monitoring the absorbance intensities at 500nm, and no significant difference (p=0.854) was observed between such two methods.The results...
The possibilities of artificial neural networks (ANNs) “soft” computing to evaluate chemical kinetic data have been studied. In the first stage, a set of “standard” kinetic curves with known parameters (rate constants and/or concentrations of the reactants), which is some kind of “normalized maps”, is prepared. The database should be built according to a suitable experimental design (ED). In the second...
A simple and high sensitive technique based on three phase hollow fiber liquid phase microextraction (HF-LPME), optimized by using a four-variable experimental design and response surface methodology was performed to evaluate dextromethorphan hydrobromide (DEX) and chloropheniramine maleate (CLP) simultaneously in human plasma. The influence of source phase pH, HCl concentration of acceptor phase,...
Solid-phase extraction (SPE) is often used for preconcentration and determination of metal ions from industrial and natural samples. A traditional single variable approach (SVA) is still often carried out for optimization in analytical chemistry. Since there is always a risk of not finding the real optimum by single variation method, more advanced optimization approaches such as multivariable approach...
A novel electrochemical hydride generation (ECHG) system working in flow-injection (FI) mode was developed for determination of cadmium coupled to an electrically heated quartz tube atomizer (QTA) by atomic absorption spectrometry (AAS). A Plackett–Burman experimental design for screening has been used to evaluate the influence of several variables on the analytical response. Then, the significant...
A novel method for the simultaneous separation and determination of four benzimidazole fungicides (i.e., carbendazim, fuberidazole, thiophanate-methyl and thiophanate) in high salinity samples was developed by using salting-out assisted liquid–liquid extraction (SALLE) via water-miscible acetonitrile as the extractant coupled with high-performance liquid chromatography. Box–Behnken design and response...
Experimental design methodology was used to optimize an analytical method for determination of the mineral element composition (Al, Ca, Cd, Cr, Cu, Ba, Fe, K, Mg, Mn, P, S, Sr and Zn) of dog and cat foods. Two-level full factorial design was applied to define the optimal proportions of the reagents used for microwave-assisted sample digestion (2.0molL −1 HNO 3 and 6% m/v H 2 ...
The combination of two or more drugs using multidrug mixtures is a trend in the treatment of cancer. The goal is to search for a synergistic effect and thereby reduce the required dose and inhibit the development of resistance. An advanced model-free approach for data exploration and analysis, based on artificial neural networks (ANN) and experimental design is proposed to predict and quantify the...
An experimental design was applied for the optimization of extraction process of carbamates pesticides from surface water samples. Solid phase extraction (SPE) of carbamates compounds and their determination by liquid chromatography coupled to electrospray mass spectrometry detector were considered. A two level full factorial design 2 k was used for selecting the variables which affected the...
A fast, simple and environmentally friendly ultrasound-assisted dispersive liquid–liquid microextraction (USA-DLLME) procedure has been developed to preconcentrate eight cyclic and linear siloxanes from wastewater samples prior to quantification by gas chromatography–mass spectrometry (GC–MS). A two-stage multivariate optimization approach has been developed employing a Plackett–Burman design for...
A dynamic headspace sorptive extraction (DHS) combined with thermal desorption (TD) and coupled with gas chromatography–mass spectrometry (GC/MS) was developed for the determination of 11 esters which contribute to the fruity aroma in sweet wines. A full factorial (4 factors, 2 level) experiment design was used to optimize the extraction conditions and the results were evaluated by multiple linear...
Chaotropic agents recently gained popularity as interesting and useful mobile phase additives in liquid chromatography due to their effect on analytes retention, peak symmetry and separation efficiency. They mimic the role of classical ion-pairing agents, but with less drawbacks, so their use becomes attractive in the field of pharmaceutical analysis. In this paper, the influence of sodium trifluoroacetate...
A review about the application of response surface methodology (RSM) when several responses have to be simultaneously optimized in the field of analytical methods development is presented. Several critical issues like response transformation, multiple response optimization and modeling with least squares and artificial neural networks are discussed. Most recent analytical applications are presented...
A vortex assisted liquid–liquid microextraction (VALLME) method was developed and optimised for the determination of the main compounds that can cause cork taint in wines, 2,4,6-trichloroanisole (TCA), 2,3,4,6-tetrachloroanisole (TeCA), 2,4,6-tribromoanisole (TBA) and pentachloroanisole (PCA); and their corresponding halophenolic precursors. Target compounds were determined by gas chromatography combined...
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