S. G. Dmitrienko

Recent advances in sample preparation techniques and methods of sulfonamides detection - A review

Sulfonamides (SAs) have been the most widely used antimicrobial drugs for more than 70 years, and their residues in foodstuffs and environmental samples pose serious health hazards. For this reason, sensitive and specific methods for the quantification of these compounds in numerous matrices have been developed. This review intends to provide an updated overview of the recent trends over the past five years in sample preparation techniques and methods for detecting SAs. Examples of the sample preparation techniques, including liquid-liquid and solid-phase extraction, dispersive liquid-liquid microextraction and QuEChERS, are given. Different methods of detecting the SAs present in food and feed and in environmental, pharmaceutical and biological samples are discussed.

Facile synthesis of magnetic hypercrosslinked polystyrene and its application in the magnetic solid-phase extraction of sulfonamides from water and milk samples before their HPLC determination.

In this study, a novel magnetic solid-phase extraction (MSPE) sorbent, magnetic hypercrosslinked polystyrene (HCP/Fe3O4), was prepared and used for preconcentration of four sulfonamides (sulfamethoxypyridazine, sulfamethazine, sulfamethoxazole and sulfachloropyridazine) from natural water and milk samples. This material was prepared by sorption of pre-synthesized Fe3O4 nanoparticles (NPs) onto HCP. A number of sorbents with varying Fe3O4NPs content were prepared, and their structural, magnetic and sorption properties were studied. Various experimental parameters affecting the extraction efficiencies such as the amount of the magnetic nanocomposite, extraction time, pH of the sample solution and desorption conditions were studied and optimized. Under the optimal conditions, a convenient and efficient method for the determination of sulfonamides in water and milk samples was developed by combining MSPE and high-performance liquid chromatography with amperometric detection. The results showed that the recoveries of these compounds were in the range of 84-105% with the relative standard deviations ranging between 3% and 10%; the limit of detection were in the range of 0.21-0.33 ng mL(-1) for water and 2.0-2.5 ng mL(-1) for milk.

Determination of gallic acid with 4-nitrobenzenediazonium tetrafluoroborate by diffuse reflectance spectrometry on polyurethane foam

AbstractThe present work describes a rapid and cost-effective analytical procedure for the determination of gallic acid. It is basedon the solid-phase extraction of gallic acid in the form of the azo compound by polyurethane foam (PUF) and measurementby diffuse reflectance spectrometry. The calibration graphs are linear over the range 0.2–6 gml −1 . The developed procedurewas applied to the determination of gallic acid in alcoholic beverages.© 2002 Elsevier Science B.V. All rights reserved. Keywords: Gallic acid; Polyurethane foam; Sorption; Diffuse reflectance spectrometry 1. IntroductionGallic acid (2,3,4-trihydroxybenzoic acid) is a natu-ral phenolic compound which is widely distributed inplants. Some pharmacological properties of this sub-stance have been described previously. For example,it has strong antimutagenic, anticarcinogenic and an-tioxidant activities [1–3]. The antioxidant activity andantiradicalar power of gallic acid have been estimatedquantitatively [1].Along with other polyphenolic compounds, gallicacid is often used as an indicator of adulteration of fruitjuices [2,4] and different alcoholic beverages [5–7].For instance, cognac and scotch whisky contain gal-lic acid, and as was shown [5], there was a good

Determination of the total content of some sulfonamides in milk using solid-phase extraction coupled with off-line derivatization and spectrophotometric detection.

A simple screening method for isolation and determination of the total content of some sulfonamides in milk using solid-phase extraction and a color reaction is described. This procedure is based on SPE of sulfonamides on hypercrosslinked polystyrene, elution with acetonitrile and off-line derivatization with p-dimethylaminocinnamaldehyde in acetonitrile followed by spectrophotometric determination. The reaction produces intense violet-red color and can be easily used both for quantitation of sulfonamides using spectrophotometry and for naked-eye semi-quantitative estimation. Maximum absorption of the reaction product was determined at 540 nm. The Lambert-Beers law was obeyed in the range of 0.07-3.0 μg mL(-1) in eluate, with the squared correlation coefficient (R(2)) of 0.9875-0.9995, and the relative standard deviation (RSD) of 3-4%. The limits of SAs detection using preconcentration were of 0.02-0.03 μg mL(-1). The proposed method can be recommended as a routine screening method for quantitation of sulfonamides in milk.

Solid-phase extraction of polycyclic aromatic hydrocarbons from aqueous samples using polyurethane foams in connection with solid-matrix spectrofluorimetry

A method for rapid determination of polycyclic aromatic hydrocarbons (PAHs) in water has been developed. The method involves solid-phase extraction of PAHs by polyurethane foams (PUFs) and their determination in solid phase by luminescence spectroscopy. Distribution coefficients were obtained for naphthalene, phenanthrene, anthracene, pyrene and benzo(a)pyrene. Polyether and polyester type PUFs have been shown to provide excellent effectiveness for PAHs preconcentration from water. The solid-matrix luminescence was measured from the absorbed luminophors using the appropriate excitation wavelengths. It is possible to determine at least three absorbed compounds. Benzo(a)pyrene was determined at the level of 0.02 ng ml−1.

Use of Molecular Imprinted Polymers for the Separation and Preconcentration of Organic Compounds

Data on the use of molecular imprinted polymers for the separation and preconcentration of organic substances in chemical analysis are summarized. The main approaches and methods used in the synthesis of these polymers are considered. The development of combined and hybrid methods of analysis with the use of these adsorbents is discussed.

Formation of plasmonic silver nanoparticles by flavonoid reduction: A comparative study and application for determination of these substances.

Formation of plasmonic silver nanoparticles by flavonoid reduction was studied. Effects of the nature and the concentration of a flavonoid and a stabilizer, composition of the solution and the interaction time were revealed. It was found that quercetin, dihydroquercetin, rutin and morin produced an intense surface plasmon resonance band of silver nanoparticles at 415 nm which was linearly related to the concentration of a flavonoid, while chrysin, naringenin and naringin did not produce any remarkable changes. It was used for the spectrophotometric determination of the former four flavonoids with the detection limits of 0.03; 0.06; 0.09 and 0.1 μg mL(-1), respectively. The developed method was applied for the determination of flavonoids in biologically active food additives.

Methods of extraction, preconcentration, and determination of quercetin

State-of-the-art methods of the extraction, preconcentration, and determination of quercetin and other flavonoids are described. Different methods of sample preparation of real samples are compared, including solvent extraction from solid matrices and liquid-liquid, supercritical fluid, and solid-phase extraction. The following main determination methods are discussed: HPLC, thin-layer chromatography, capillary electrophoresis, spectrophotometry, luminescence, and electrochemical methods. Some examples of quercetin determination in biological fluids, food products, biologically active food supplements, pharmaceutical preparations, and plant samples are given.

Determination of cysteamine using label-free gold nanoparticles

Label-free gold nanoparticles were applied as a colorimetric probe for the determination of cysteamine. The approach is based on aggregation of the nanoparticles leading to a change in the absorption spectra and color of the solution. The influence of different factors (the presence of EDTA, pH, the concentrations of cysteamine and the nanoparticles) on the aggregation and analytical performance of the procedure was investigated. The potentiality of EDTA as a masking agent to eliminate the interference of metal cations was estimated. The method allows the determination of cysteamine with a detection limit of 0.01 μg mL−1. It was applied to the analysis of a hair-waving formulation and urine.

Label-free gold nanoparticles for the determination of neomycin

A new spectrophotometric method for the determination of neomycin has been developed. The method is based on aggregation of label-free gold nanoparticles leading to change in absorption spectra and color of the solution. Influence of different factors (the concentration of ethylenediaminetetraacetate (EDTA), pH, the concentrations of neomycin and the nanoparticles) on the aggregation and analytical performance of the method was investigated. EDTA plays an important role not only as a masking agent to eliminate interferences of metal cations but strongly affects the sensitivity of the nanoparticles relative to neomycin. The method allows to determine neomycin with detection limit of 28ngmL(-1). It was applied to analysis of eye- and ear-drops. The sample pretreatment is simply done by diluting the formulation with water.