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1.
Surg Technol Int ; 35: 253-264, 2019 11 10.
Artigo em Inglês | MEDLINE | ID: mdl-31687784

RESUMO

BACKGROUND: In 1989, we reported the use of the radial artery as a second target conduit for coronary artery bypass grafting. However, underpowered randomized trials have reported differences in clinical outcomes between the radial artery and other grafts. As we approach 50 years of experience with radial artery grafting, we reviewed the literature to determine the second-best target vessel for coronary operations. METHODS: An electronic review of the literature with an emphasis on randomized controlled trials, propensity-matched observational series, and meta-analyses identified a large population of patients who received arterial conduit and saphenous vein grafts. RESULTS: The radial artery has been proven to be reliable as a second target conduit for coronary artery bypass grafting, with outcomes and patency rates superior to those for saphenous vein graft. It has also been proven to be both safe and effective as a third conduit in the territory of the right coronary artery. A paucity of evidence with few comparable series limits the use of the gastroepiploic artery. CONCLUSION: In its fifth decade of use, we can definitively conclude that the aorto-to-coronary radial bypass graft is the conduit of choice for coronary operations after the left internal thoracic artery to the left anterior descending artery.


Assuntos
Ponte de Artéria Coronária , Artéria Radial , Humanos , Artéria Radial/transplante , Ensaios Clínicos Controlados Aleatórios como Assunto , Estudos Retrospectivos , Resultado do Tratamento
2.
Analyst ; 144(1): 152-156, 2018 Dec 17.
Artigo em Inglês | MEDLINE | ID: mdl-30489574

RESUMO

In this study, Fe3O4-based composite magnetic nanoparticles were found to separate volatile compounds directly in the gas phase for the first time. The phenomenon of H2Se sorption on the magnetic nanoparticles was studied in detail and applied for separation and preconcentration. The developed approach was applied for the determination of selenium in dietary supplement samples after microwave digestion by ETA-AAS as a proof-of-concept example.

3.
Vet World ; 16(2): 272-280, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-37042002

RESUMO

Background and Aim: Histophilus somni is a Gram-negative bacterium belonging to the Pasteurellaceae family that can cause bovine histophilosis. Histophilus may act as a commensal or opportunistic bacterial cattle pathogen. Comparing genomes of the pathogenic strain 2336 with the non-pathogenic preputial 129Pt isolate revealed some putative virulence factors. The study of the complete genomes of H. somni strains circulating in Russia has never been conducted before. This study aimed to identify genetic features of the H. somni strains isolated in Russia and evaluate the possibility of using strains for vaccine development. Materials and Methods: Three strains of H. somni were isolated from different sources. Strain 188-VIEV was isolated from a vaginal swab sample of cattle with endometritis. 532-VIEV and 551-VIEV were cultured from the cryopreserved bull semen samples imported from Canada. Histophilus somni strain ATCC 700025 provided by ATCC (American Type Culture Collection) was also used in the study. DNA extraction was performed using QIAamp DNA Mini Kit (QIAGEN, USA). The whole-genome sequencing of the four strains was performed using Illumina Miseq. The comparison of the resulting sequences with the complete genomes of H. somni 2336 and 129Pt, and detection of the resistance genes and virulence factors, was performed using the ResFinder and Virulence Factor Database web services. Results: The genome size of the samples varied from 1.9 to 2.3 Mb. The number of coding sequences varied from 1795 to 2256. The average sequence density was 90%. The total guanine-cytosine (GC) content was 36.8%-37.2%, which coincided with data previously obtained for H. somni. Three out of four studied strains encoded putative virulence factors such as filamentous hemagglutinin homologs, lipooligosaccharide biosynthesis proteins, and proteins involved in iron transport and utilization. The Ser83Ile substitution was identified in the DNA topoisomerase II (gyrA) in H. somni strains 532-VIEV and 551-VIEV cultured from bull semen which led to resistance to fluoroquinolones. The gene (AAC-6-Ia + APH-2'') encoding a bifunctional aminoglycoside modification enzyme was detected in strain 551-VIEV. Conclusion: Strains with virulence genes identified could be candidates for designing vaccines and potentially represent antigen sources. The results show that antibiotic-resistant H. somni can be spread with semen used for artificial insemination.

4.
Front Vet Sci ; 10: 1154520, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37415963

RESUMO

Over the past 10 years, immunization of cattle in Russia has been performed using vaccines from Brucella abortus strains 82, 19 and 75/79. To prevent brucellosis in small ruminants, two vaccines have been used, from the Brucella melitensis strain REV-1 and the B. abortus strain 19; note that twice as many animals have been immunized with the former vaccine than with the latter vaccine. The disadvantage of using these preparations is the formation of prolonged post-vaccination seropositivity, which is especially pronounced in animals after immunization with vaccines from B. abortus strain 19 and B. melitensis strain REV-1. This study aims to perform the whole genome sequencing of Brucella vaccine strains from the Russian collection. A bioinformatics analysis of the genomic data proved that the vaccine strains 75/79AB, 82, R-1096, and the KV 17/100 belong to ST-2, 104 M to ST-1, KV 13/100 to ST-5. This analysis allowed us to characterize vaccine strains's phylogenetic relationships and to prove the close relation of vaccine strains 75/79AB, 82, R-1096. Also, we defined candidate mutations in genes pmm, wbdA, wbkA, wboA, and eryB, which could be responsible for the attenuated virulence of vaccine strains. The complete genomic sequences of B. abortus strains make further studies of bacterial pathogenicity determinants and virulence phenotype feasible, as well as their use in quality control of animal medicines.

5.
Talanta ; 250: 123709, 2022 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-35763953

RESUMO

An effervescence-assisted dispersive liquid-liquid microextraction approach using three-component deep eutectic solvent based on short-chain and medium-chain carboxylic acids and terpenoid was developed for the first time. The microextraction procedure was applied to the determination of fluoroquinolone antibiotics in foods (milk and shrimp samples) by high-performance liquid chromatography with fluorometric detection. In this microextraction procedure three-component deep eutectic solvent acted as a proton donor agent and an extractant. The carbon dioxide bubbles caused by the fast reaction between precursor of deep eutectic solvent (short-chain carboxylic acid) and effervescent agent (sodium carbonate) promoted the dispersion of the extractant in an aqueous sample phase. Various carboxylic acids were studied as hydrogen bond donors for the formation of deep eutectic solvents and proton donor agents for the generation of CO2 bubbles. Two natural terpenoids (menthol and thymol) were studied as the hydrogen bond acceptors for the formation of three-component solvent. The extraction system based on heptanoic acid and thymol (1:2, mol/mol) containing formic acid (proton donor for generating CO2 bubbles) provided maximum extraction recovery (86-99%) and a higher extraction efficiency of analytes compared to their extraction into individual hydrophobic precursors of the system. The LODs, calculated from the blank tests based on 3σ, were varied from 0.03 to 0.06 µg L-1 and from 0.3 to 0.6 µg kg-1 for fluoroquinolone antibiotics in milk and shrimp samples, respectively. The proposed approach provided effective dispersion of extractant speeding up the extraction process and fast separation of phases without any external energy assistance.


Assuntos
Ácidos Heptanoicos , Microextração em Fase Líquida , Antibacterianos/análise , Dióxido de Carbono/análise , Solventes Eutéticos Profundos , Fluoroquinolonas/análise , Formiatos , Ácidos Heptanoicos/análise , Limite de Detecção , Microextração em Fase Líquida/métodos , Mentol , Prótons , Solventes/química , Timol/análise
6.
Talanta ; 224: 121888, 2021 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-33379097

RESUMO

In this work, an automated surfactant-assisted dispersive liquid-liquid microextraction approach based on in-a-syringe concept was developed for the first time. The procedure assumed mixing aqueous sample phase and hydrophilic emulsion containing hexanoic acid and sodium hexanoate in a syringe of flow system. Sodium hexanoate acted as an emulsifier in dispersive liquid-liquid microextraction process and it was required for the formation of supramolecular solvent phase. After spontaneous separation of phases in the syringe, the upper supramolecular solvent phase containing target analytes was withdrawn and analyzed. The procedure was applied to the determination of 13 polycyclic aromatic hydrocarbons in tea infusion by high performance liquid chromatography with fluorescence detection. It was shown that the supramolecular solvent provided effective extraction of polycyclic aromatic hydrocarbons and fast phase separation in the syringe without centrifugation. The enrichment factors were in the range of 38-46. The automated microextraction procedure lasted 4 min including syringe cleaning. Under optimal experimental conditions the linear detection ranges were found to be 0.05-50.00 µg L-1 with limits of detection calculated from a blank test, based on 3σ, 0.02-0.04 µg L-1. Recovery values in the range of 85-105% were achieved for tea infusion with a reproducibility expressed as RSD less than 4.1%.

7.
Spectrochim Acta A Mol Biomol Spectrosc ; 263: 120160, 2021 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-34284279

RESUMO

A derivatization and air-assisted dispersive liquid-liquid microextraction procedure with organic phase solidification on a paper template was developed for the first time. The procedure was used for the spectrofluorometric determination of formaldehyde in milk samples. The Hantzsch reaction of formaldehyde with acetylacetone in the presence of ammonia to form a derivative (3,5-diacetyl-1,4-dihydrolutidine) was implemented for the microextraction and detection of analyte. Thymol was investigated as the extraction solvent for the air-assisted dispersive liquid-liquid microextraction for the first time. In the developed procedure, molten thymol was added to the thermostated aqueous sample solution containing reagents for formaldehyde derivatization, and cloudy solution of fine thymol droplets was formed by air bubbling. After separation of phases the liquid extract phase was withdrawn with a dispenser and distributed on the black paper template in a thin layer to be solidified. The solidified extract phase on the template was inserted to a sample holder of a spectrofluorometer and fluorescence intensity was measured without using cuvettes. Under optimal experimental conditions the linear detection range was found to be 45-500 µg L-1 with LOD calculated from a blank test, based on 3σ, 15 µg L-1. The developed procedure does not require the dilution of the solid extract phase in organic solvent to be introduced in an analytical instrumentation and the use of cuvettes for spectrofluorometric detection.


Assuntos
Microextração em Fase Líquida , Leite , Animais , Formaldeído/análise , Leite/química , Solventes , Água
8.
Spectrochim Acta A Mol Biomol Spectrosc ; 253: 119556, 2021 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-33611218

RESUMO

A chemosensor for on-site sensing of ammonia precursor in concrete to avoid a problem of ammonia emission into the indoor space of concrete buildings was designed and implemented. It was found that aqueous extracts of concrete samples containing antifreeze additives and excreting ammonia were colored in the presence of p-dimethylaminobenzaldehyde. This phenomenon was used for the fast visual sensing of main ammonia precursor (urea) in concrete for the first time. The developed sensor consisted of a sensing solid phase based on an adsorbent modified with p-dimethylaminobenzaldehyde. Various adsorbents were investigated for the immobilization of the reagent and it was established that silica adsorbent Silochrom C-120 provided effective retention of the reagent and Schiff's base formation during the sampling. Moreover, Silochrom C-120 modified with ascorbic acid was proposed to eliminate the oxidant interference. The sensor displayed excellent selectivity and sensitivity with the visual detection limit of 15 mg kg-1 in terms of urea. The chemosensor was successfully applied by builders on different construction sites. Sample preparation and sensing times were about 2 min and 1 min, respectively.

9.
Clin Med Insights Cardiol ; 14: 1179546820960729, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33088184

RESUMO

Aortic valve replacement is the commonest cardiac surgical operation performed worldwide for infective endocarditis (IE). Long-term durability and avoidance of infection relapse are goals of the procedure. However, no detailed guidelines on prosthesis selection and surgical strategies guided by the comprehensive evaluation of the extension of the infection and its microbiological characteristics, clinical profile of the patient, and risk of infection recurrence are currently available. Conventional mechanical or stented xenografts are the preferred choice for localized aortic infection. However, in cases of complex IE with the involvement of the root or the aortomitral continuity, the use of homograft is suggested according to the surgeon and center experience. Homograft use should be counterbalanced against the risk of structural degeneration. Prosthetic bioroot or prosthetic valved conduit (mechanical and bioprosthetic) are also potentially suitable alternatives. Further development of preservation techniques enabling longer durability of allogenic substitutes is required. We evaluate the current evidence for the use of valve substitutes in aortic valve endocarditis and propose an evidence-based algorithm to guide the choice of therapy. We performed a systemic review to clarify the contemporary surgical management of aortic valve endocarditis.

10.
J Thorac Dis ; 12(5): 2926-2935, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32642205

RESUMO

Patients undergoing transcatheter aortic valve replacement (TAVR) might have an associated significant MR that can potentially lead to left ventricular (LV) failure after procedure. Considering the specific alterations in the mitral valve in TAVR scenario and the widespread use of TAVR in recent years, it appears important to know and understand the anatomical, functional and clinical implications to develop adequate strategies for the future. Patients with severe mitral regurgitation (MR) have been generally excluded from randomized clinical trials, making poor the impact that associated MR can have on clinical outcomes after TAVR. Several factors must be considered whose presence influences the severity of MR. For example, the elevated prevalence of coronary disease with consequent ischemic MR may account for LV dilation observed at the end stage of aortic stenosis. Evidence randomized studies and registries suggests that the rate of concomitant moderate-to-severe MR in patients undergoing TAVR oscillates between 2% and 33%, and patients with moderate to severe MR may have hemodynamic frailty with clinical deterioration during mechanical intervention. Short- and long-term outcomes, including cardiac mortality, appear to be influenced by the existence of preoperative moderate-to-severe MR or by the postprocedural worsening of mild MR, generally due to adverse LV remodeling. The incidence and the prognostic effect of concomitant MR in patients undergoing TAVR requires specific attention as might trigger adjunctive strategy treatment which should be carefully evaluated in clinical trials. KEYWORDS: Mitral regurgitation (MR); mitral valve; transcatheter aortic valve; transcatheter aortic valve replacement (TAVR).

11.
J Thorac Dis ; 12(5): 2919-2925, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32642204

RESUMO

The role of the aortic root is to convert the accumulated elastic energy during systole into kinetic flow energy during diastole, in order to improve blood distribution in the coronary tree. Therefore, the sinuses of Valsalva of the aortic root are not predisposed to accept any bulky material, especially in case of uncrushed solid calcific agglomerates. This concept underlines the differences between surgical aortic valve replacement, in which decalcification is a main part of the procedure, and transcatheter aortic valve replacement (TAVR). Cyclic changes in shape and size of the aortic root influence blood flow in the Valsalva sinuses. Recent papers have been investigating the dynamic changes of the aortic root and whether those differences might be correlated with clinical effects, and this paper aims to summarize part of this flourishing literature. Post-TAVR aortic root remodeling, dynamic flow and TAVR complications might have a fluidodynamic background, and clinically observed side effects such as thrombosis or leaflet degeneration should be further investigated in basic researches. Also, aortic root changes could impact valve type and size selection, affecting the decision of over-sizing or under-sizing in order to prevent valve embolization or coronary ostia obstruction.

12.
J Thorac Dis ; 12(5): 2936-2944, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32642206

RESUMO

Recent studies about percutaneous treatment of secondary mitral regurgitation (MR) underlined the importance of left ventricular geometry and features of mitral valve as determinants of procedural and long-term success. Guideline-directed medical therapy (GDMT), transcatheter mitral valve treatment (TMVT) and surgical procedures (mitral valve replacement, mitral valve repair at level of the annulus or subvalvular apparatus) have been extensively evaluated but not adequately compared in current clinical studies. A detailed analysis of the results of the study about transcatheter mitral valve repair would allow to evaluate the safety and effectiveness of such procedure and would provide potential indications for improving the quality of percutaneous and surgical repair in patients with moderate-to-severe secondary MR. Patients with proportionate MR (i.e., MR severity is proportional to the amount of left ventricular dilatation) are prone to respond to the optimization of medical therapy, while patients with disproportionate MR (i.e., MR severity is disproportionately higher than predicted by left ventricular dilatation, with high EROA and small left ventricle) are likely to benefit from additional repair. The identification of specific subpopulation of "high responders", based on the anatomic characteristics of the mitral valve and the relative dimensions of the annulus, the regurgitation and the left ventricle, can also apply to medical therapy. However, some pivotal component of MR (such as the symmetry of tethering and the differences in biomechanical features of leaflets) are not adequately investigated in current studies and warrant further evaluation.

13.
J Chromatogr A ; 1588: 1-7, 2019 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-30579637

RESUMO

A simple and highly-available air-assisted dispersive liquid-liquid microextraction procedure with organic phase solidification (AA-DLLME-OPS) was developed as new approach for pretreatment of complex sample matrix. Menthol was investigated as novel extractant for the AA-DLLME-OPS. In this procedure, a cloudy solution of fine molten menthol droplets is formed when a mixture of molten menthol and aqueous sample is rapidly aspirated into a dispenser and injected into an extraction vial. In the AA-DLLME-OPS, air bubbles promote molten menthol dispersion into aqueous sample phase. Finally, the obtained mixture is cooled and menthol phase is solidified because of the low melting point, which facilitates collection for analysis. To demonstrate the efficiency of the suggested approach, the AA-DLLME-OPS procedure was applied for the HPLC-UV determination of benzoic and sorbic acids as proof-of-concept analytes in beverages and soy sauce samples. The procedure developed provides microextraction of benzoic and sorbic acids from samples with recovery from 93 to 105% and from 96 to 101%, respectively. Under optimal experimental conditions the linear detection ranges were found to be 0.1-150 mg L-1 for benzoic acid and 0.05-100 mg L-1 for sorbic acid with LODs calculated from a blank test, based on 3σ, 0.03 mg L-1 and 0.02 mg L-1, respectively.


Assuntos
Ácido Benzoico/isolamento & purificação , Bebidas/análise , Cromatografia Líquida de Alta Pressão , Análise de Alimentos/métodos , Microextração em Fase Líquida , Ácido Sórbico/isolamento & purificação , Alimentos de Soja/análise , Limite de Detecção , Raios Ultravioleta
14.
Violence Against Women ; 14(4): 483-95, 2008 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-18359881

RESUMO

This exploratory study examines which risk factors are associated with intimate partner violence against women in St. Petersburg, Russia. Women attending two crisis centers and a birthing house constituted the study sample. The male partner's frequent alcohol consumption and seeing his father hit his mother in childhood were associated with an increased risk of violence, whereas living in a communal apartment reduced the risk of intimate partner violence. The importance of crisis centers in Russia is highlighted by the study, as the women who turn to them are likely to have experienced more severe forms of violence.


Assuntos
Mulheres Maltratadas/estatística & dados numéricos , Relações Interpessoais , Estupro/estatística & dados numéricos , Maus-Tratos Conjugais/estatística & dados numéricos , Saúde da Mulher , Adulto , Agressão/psicologia , Mulheres Maltratadas/psicologia , Feminino , Humanos , Masculino , Estupro/psicologia , Federação Russa/epidemiologia , Fatores Socioeconômicos , Maus-Tratos Conjugais/psicologia , Inquéritos e Questionários
15.
Talanta ; 179: 246-270, 2018 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-29310229

RESUMO

This article highlights the most important developments in flow analysis with chemiluminescence (CL) detection, describing different flow systems that are compatible with CL detection, detector designs, commonly applied CL reactions and approaches to sample treatment. Recent applications of flow analysis with CL detection (focusing on outputs published since 2010) are also presented. Applications are classified by sample matrix, covering foods and beverages, environmental matrices, pharmaceuticals and biological fluids. Comprehensive tables are provided for each area, listing the specific sample matrix, CL reaction used, linear range, limit of detection and sample treatment for each analyte. Finally, recent and emerging trends in the field are also discussed.

16.
Anal Chim Acta ; 976: 35-44, 2017 Jul 11.
Artigo em Inglês | MEDLINE | ID: mdl-28576316

RESUMO

A switchable hydrophilicity solvent membrane-based microextraction (SHS-MME) strategy for simple and highly-available sample pretreatment of complex matrices has been proposed. The SHS-MME procedure based on extraction of target analytes from an aqueous sample into a porous hydrophobic membrane impregnated with a switchable hydrophilicity solvent (SHS) followed by SHS ionization and back-extraction of the analytes in alkaline acceptor solution. The medium-chain fatty acids were investigated as SHS for the SHS-MME of fluoroquinolones (fleroxacin, lomefloxacin, norfloxacin and ofloxacin). The SHS-MME was successfully coupled with a HPLC-FLD for the determination of fluoroquinolones in shrimp samples with no further sample pretreatment. The calibration graphs were linear over the concentration ranges of 3-1500 µg L-1 for ofloxacin, 10-1000 µg L-1 for norfloxacin, 15-1500 µg L-1 for lomefloxacin and fleroxacin. The limits of detection, calculated from a blank test based on 3σ, were 1 µg L-1 for ofloxacin, 3 µg L-1 for norfloxacin and 5 µg L-1 for lomefloxacin and fleroxacin. The SHS ionization can be considered as new potential fields in analytical application of membrane-based liquid phase microextraction.


Assuntos
Cromatografia Líquida de Alta Pressão , Fluoroquinolonas/análise , Microextração em Fase Líquida , Frutos do Mar/análise , Animais , Decápodes , Interações Hidrofóbicas e Hidrofílicas , Solventes
17.
J Chromatogr A ; 1512: 107-114, 2017 Aug 25.
Artigo em Inglês | MEDLINE | ID: mdl-28728929

RESUMO

A sample pre-treatment technique based on evaporation-assisted dispersive liquid-liquid microextraction (EVA-DLLME), followed by HPLC-MS/MS has been developed for the determination of organophosphate insecticides (malathion, diazinon, phosalone) in wine samples. The procedure includes the addition of mixture of organic solvents (with density higher than water), consisting of the extraction (low density) and volatile (high density) solvents, to aqueous sample followed by heating of the mixture obtained, what promotes the volatile solvent evaporation and moving extraction solvent droplets from down to top of the aqueous sample and, as a consequence, microextraction of target analytes. To initiate the evaporation process an initiator is required. It was established that hexanol (extraction solvent) and dichloromethane (volatile solvent) mixture (1:1, v/v) provides effective microextraction of the insecticides from wine samples with recovery from 92 to 103%. The conditions of insecticides' microextraction such as selection of extraction solvent, ratio of hexanol/dichloromethane and hexanol/sample, type and concentration of initiator, and effect of ethanol as one of the main components of wine have been studied. Under optimal experimental conditions the linear detection ranges were found to be 10-7-10-3gL-1 for malathion, 10-9-10-4gL-1 for diazinon, and 10-6-10-2gL-1 for phosalone. The LODs, calculated from a blank test, based on 3σ, found to be 3×10-8gL-1 for malathion, 3×10-10gL-1 for diazinon and 3×10-7gL-1 for phosalone. The advantages of EVA-DLLME are the rapidity, simplicity, high sample throughput and low cost. As an outcome, the analytical results agreed fairly well with the results obtained by a reference GC-MS method.


Assuntos
Contaminação de Alimentos/análise , Inseticidas/análise , Inseticidas/isolamento & purificação , Microextração em Fase Líquida/métodos , Vinho/análise , Cromatografia Líquida de Alta Pressão/métodos , Limite de Detecção , Microextração em Fase Líquida/instrumentação , Espectrometria de Massas em Tandem/métodos
18.
Anal Chim Acta ; 949: 35-42, 2017 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-27876143

RESUMO

In this article, dispersive liquid-liquid microextraction (DLLME), based on the use of so-called switchable polarity dispersive solvent (SPDS) for microextraction, is presented for the first time. The new extraction technique makes use of a mixture of extraction solvent (dichloromethane) and the SPDS (acrylic acid). This mixture is injected into the aqueous sample solution, which was previously fortified with the alkaline agent (NaOH). The SPDS is dissolved in aqueous phase and a cloudy solution consisting of fine droplets of extraction solvent fully dispersed in the aqueous phase is observed. Simultaneously, as a consequence of the fast neutralization reaction, the SPDS investigated is converted into water-soluble salt and phase separation is achieved because the SPDS switches its polarity. Conversion of the SPDS excludes the negative influence of the conventional dispersive solvents used in DLLME on the solubility of target analytes in aqueous phase and, as a result, increases the DLLME efficiency. The proposed extraction technique was automated based on a flow system and coupled with high performance liquid chromatography system with fluorescence detection (HPLC-FLD) and demonstrated by the determination of ofloxacin (OFLX) in chicken meat samples. This analytical task was used as a proof-of-concept example. The automated method includes on-line ultrasound assisted solid-liquid extraction of OFLX from chicken meat samples followed by DLLME using SPDS, solvent exchange and the determination by HPLC-FLD. Under the optimal conditions, the detector response for OFLX was linear in concentration range of 6·10-9 - 5·10-7 mol L-1. The limit of detection, calculated from a blank test based on 3σ, was 2·10-9 mol L-1.


Assuntos
Contaminação de Alimentos/análise , Microextração em Fase Líquida , Carne/análise , Ofloxacino/análise , Animais , Galinhas , Cromatografia Líquida de Alta Pressão , Solventes
19.
Talanta ; 167: 761-767, 2017 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-28340790

RESUMO

A fully automated method for the determination of pesticides (malathion, diazinon, imidacloprid and triadimefon) in fruit and berry juices has been developed. In the current study, the on-line in-syringe sugaring-out liquid-liquid extraction was successfully combined with a HPLC-MS/MS system for the first time. The procedure assumes the liquid-liquid extraction of analytes in water-miscible organic solvent acetonitrile followed by phase separation using glucose as sugaring-out reagent. After the phase separation in a syringe of a flow system, the extract containing pesticides was injected into the HPLC-MS/MS system. The proposed automated sample preparation procedure is rapid, simple, relatively inexpensive, and allows to avoid shortcomings of conventional liquid-liquid extraction, such as necessity to use nonpolar organic solvents, which are not always suitable for the HPLC-MS/MS detection. The conditions of pesticides' extraction such as ratio of acetonitrile/water, type and concentration of sugaring-out reagent, volume of sample and effect of pH have been studied and optimized. Under optimal experimental conditions the linear detection ranges were found to be 10-2-10mgL-1 for malathion and triadimefon, 10-3-10mgL-1 for diazinon, and 10-1-10mgL-1 for imidacloprid. The LODs, calculated from a blank test, based on 3σ, found to be 3·10-3mg L-1 for malathion and triadimefon, 3·10-4mg L-1 for diazinon and 3·10-2mgL-1 for imidacloprid. The application of the method has been demonstrated in the determination of these four pesticides in commercial samples of five fruit and berry juices. As an outcome, the analytical results agreed fairly well with the results obtained by a reference GC-FID method.


Assuntos
Automação , Cromatografia Líquida de Alta Pressão/métodos , Sucos de Frutas e Vegetais/análise , Glucose/química , Extração Líquido-Líquido/métodos , Praguicidas/análise , Espectrometria de Massas em Tandem/métodos , Acetonitrilas/química , Limite de Detecção , Sistemas On-Line , Seringas , Água
20.
Crit Rev Anal Chem ; 46(5): 374-88, 2016 Sep 02.
Artigo em Inglês | MEDLINE | ID: mdl-26364745

RESUMO

We suggest a novel approach for classification of flow analysis methods according to the conditions under which the mass transfer processes and chemical reactions take place in the flow mode: dispersion-convection flow methods and forced-convection flow methods. The first group includes continuous flow analysis, flow injection analysis, all injection analysis, sequential injection analysis, sequential injection chromatography, cross injection analysis, multi-commutated flow analysis, multi-syringe flow injection analysis, multi-pumping flow systems, loop flow analysis, and simultaneous injection effective mixing flow analysis. The second group includes segmented flow analysis, zone fluidics, flow batch analysis, sequential injection analysis with a mixing chamber, stepwise injection analysis, and multi-commutated stepwise injection analysis. The offered classification allows systematizing a large number of flow analysis methods. Recent developments and applications of dispersion-convection flow methods and forced-convection flow methods are presented.


Assuntos
Análise de Injeção de Fluxo/classificação , Análise de Injeção de Fluxo/métodos , Análise de Injeção de Fluxo/instrumentação
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