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1.
Anal Bioanal Chem ; 415(13): 2547-2560, 2023 May.
Artigo em Inglês | MEDLINE | ID: mdl-36629895

RESUMO

In this work, a solid-phase microextraction (SPME) Arrow method combined with comprehensive two-dimensional gas chromatography-mass spectrometry (GC × GC-MS) was developed for the elucidation of the volatile composition of honey samples. The sample preparation protocol was optimized to ensure high extraction efficiency of the volatile organic compounds (VOCs) which are directly associated with the organoleptic properties of honey and its acceptance by the consumers. Following its optimization, SPME Arrow was compared to conventional SPME in terms of sensitivity, precision, and number of extracted VOCs. The utilization of SPME Arrow fibers enabled the determination of 203, 147, and 149 compounds in honeydew honey, flower honey, and pine honey, respectively, while a significantly lower number of compounds (124, 94, and 111 for honeydew honey, flower honey, and pine honey, respectively) was determined using conventional SPME. At the same time, the utilization of SPME Arrow resulted in enhanced sensitivity and precision. All things considered, SPME Arrow and GC × GC-MS can be considered as highly suitable for the elucidation of the volatile composition of complex food samples resulting in high sensitivity and separation efficiency.


Assuntos
Mel , Compostos Orgânicos Voláteis , Cromatografia Gasosa-Espectrometria de Massas/métodos , Mel/análise , Microextração em Fase Sólida/métodos , Compostos Orgânicos Voláteis/análise
2.
Molecules ; 27(4)2022 Feb 21.
Artigo em Inglês | MEDLINE | ID: mdl-35209222

RESUMO

Two novel microwave-assisted extraction (MAE) methods were developed for the isolation of phenols and tocopherols from pistachio nuts. The extracts were analyzed by reversed-phase high-pressure liquid chromatography coupled with a UV detector (RP-HPLC-UV). In total, eighteen pistachio samples, originating from Greece and Turkey, were analyzed and thirteen phenolic compounds, as well as α-tocopherol, (ß + γ)-tocopherol, and δ-tocopherol, were identified. The analytical methods were validated and presented good linearity (r2 > 0.990) and a high recovery rate over the range of 82.4 to 95.3% for phenols, and 93.1 to 96.4% for tocopherols. Repeatablility was calculated over the range 1.8-5.8%RSD for intra-day experiments, and reproducibility over the range 3.2-9.4%RSD for inter-day experiments, respectively. Principal component analysis (PCA) was employed to analyze the differences between the concentrations of the bioactive compounds with respect to geographical origin, while agglomerative hierarchical clustering (AHC) was used to cluster the samples based on their similarity and according to the geographical origin.


Assuntos
Fracionamento Químico , Quimiometria/métodos , Cromatografia Líquida de Alta Pressão , Micro-Ondas , Nozes/química , Compostos Fitoquímicos/análise , Pistacia/química , Fracionamento Químico/métodos , Análise por Conglomerados , Grécia , Fenóis/análise , Pistacia/classificação , Tocoferóis/análise , Tocoferóis/química , Turquia
3.
J Sep Sci ; 44(8): 1633-1640, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33448130

RESUMO

Monitoring the residual toxicant concentrations in foods is the key step for minimizing potential hazards. The huge interest about food contamination and exposure to endocrine disruptors such as bisphenol A has emerged the development of sensitive analytical methodologies to guarantee the safety and quality of foods. In this work, a green molecularly imprinted solid-phase extraction protocol coupled with high-performance liquid chromatography with UV detection was optimized following the principles of green analytical chemistry. An imprinted sol-gel silica-based hybrid inorganic-organic polymeric sorbent was used to monitor the leaching of bisphenol A from different packaging materials (glass vessels, cans, and polypropylene containers) in walnuts stored within a period of 6 months at 25 and 4°C. Extraction parameters including loading time (5-20 min), solvent type (acetonitrile, ethanol, methanol, acetone, acetonitrile:methanol, 50:50, v/v), and elution flow rate (0.2-1 mL/min) were optimized with one-factor-at-a-time method. The selected extraction optimum parameters incorporated elution with acetonitrile at 0.2 mL/min flow rate, for 10 min sample holding time. The imprinting factor was equal to 4.55 ± 0.26 (n = 3). The optimized method presented high recovery (94.3 ± 4.2%, n = 3), good linearity (>0.999), intra-assay repeatability (90.2-95.6%, n = 3), and interassay precision (86.7-93.1%, n = 3).


Assuntos
Compostos Benzidrílicos/análise , Contaminação de Alimentos/análise , Armazenamento de Alimentos , Impressão Molecular , Nozes/química , Fenóis/análise , Extração em Fase Sólida , Cromatografia Líquida de Alta Pressão , Espectrofotometria Ultravioleta
4.
Molecules ; 26(21)2021 Oct 24.
Artigo em Inglês | MEDLINE | ID: mdl-34770827

RESUMO

Walnut byproducts have been shown to exert functional properties, but the literature on their bioactive content is still scarce. Among walnut byproducts, walnut septum is a dry ligneous diaphragm tissue that divides the two halves of the kernel, exhibiting nutritional and medicinal properties. These functional properties are owing to its flavonoid content, and in order to explore the flavonoid fraction, an ultrasound-assisted (UAE) protocol was combined with solid phase extraction (SPE) and coupled to high-performance liquid chromatography with diode array detection (HPLC-DAD) for the determination of flavonoids in Greek walnut septa membranes belonging to Chandler, Vina, and Franquette varieties. The proposed UAE-SPE-HPLC-DAD method was validated and the relative standard deviations (RSD%) of the within-day and between-day assays were lower than 6.2 and 8.5, respectively, showing good precision, and high accuracy ranging from 90.8 (apigenin) to 97.5% (catechin) for within-day assay, and from 88.5 (myricetin) to 96.2% (catechin) for between-day assay. Overall, seven flavonoids were determined (catechin, rutin, myricetin, luteolin, quercetin, apigenin, and kaempferol) suggesting that the walnut septum is a rich source of bioactive constituents. The quantification results were further processed using ANOVA analysis to examine if there are statistically significant differences between the concentration of each flavonoid and the variety of the walnut septum.


Assuntos
Membrana Celular/química , Flavonoides/análise , Nozes/química , Extração em Fase Sólida , Ondas Ultrassônicas , Cromatografia Líquida de Alta Pressão
5.
Molecules ; 26(18)2021 Sep 07.
Artigo em Inglês | MEDLINE | ID: mdl-34576903

RESUMO

Reversed phase-high-pressure liquid chromatographic methodologies equipped with UV detector (RP-HPLC-UV) were developed for the determination of phenolic compounds and tocopherols in almonds. Nineteen samples of Texas almonds originating from USA and Greece were analyzed and 7 phenolic acids, 7 flavonoids, and tocopherols (-α, -ß + γ) were determined. The analytical methodologies were validated and presented excellent linearity (r2 > 0.99), high recoveries over the range between 83.1 (syringic acid) to 95.5% (ferulic acid) for within-day assay (n = 6), and between 90.2 (diosmin) to 103.4% (rosmarinic acid) for between-day assay (n = 3 × 3), for phenolic compounds, and between 95.1 and 100.4% for within-day assay (n = 6), and between 93.2-96.2% for between-day assay (n = 3 × 3) for tocopherols. The analytes were further quantified, and the results were analyzed by principal component analysis (PCA), and agglomerative hierarchical clustering (AHC) to investigate potential differences between the bioactive content of almonds and the geographical origin. A decision tree (DT) was developed for the prediction of the geographical origin of almonds proposing a characteristic marker with a concentration threshold, proving to be a promising and reliable tool for the guarantee of the authenticity of the almonds.


Assuntos
Cromatografia Líquida de Alta Pressão , Tocoferóis , Análise de Componente Principal , Prunus dulcis
6.
Molecules ; 25(4)2020 Feb 20.
Artigo em Inglês | MEDLINE | ID: mdl-32093410

RESUMO

The concept of metal-organic frameworks (MOFs) was first introduced in 1990; nowadays they are among the most promising novel materials. MOFs belong to a new class of crystalline materials that consist of coordination bonds between metal clusters (e.g., metal-carboxylate clusters and metal-azolate clusters), metal atoms, or rod-shaped clusters and multidentate organic linkers that contain oxygen or nitrogen donors (like carboxylates, azoles, nitriles, etc.); thus, a three-dimensional structure is formed [...].


Assuntos
Estruturas Metalorgânicas/química , Estruturas Metalorgânicas/síntese química
7.
Molecules ; 24(11)2019 May 31.
Artigo em Inglês | MEDLINE | ID: mdl-31159316

RESUMO

In the present study, a novel, simple, and fast sample preparation technique is described for the determination of four sulfonamides (SAs), namely Sulfathiazole (STZ), sulfamethizole (SMT), sulfadiazine (SDZ), and sulfanilamide (SN) in cow milk prior to HPLC. This method takes advantage of a novel material that combines the extractive properties of graphene oxide (GO) and the known properties of common polyurethane sponge (PU) and that makes sample preparation easy, fast, cheap and efficient. The PU-GO sponge was prepared by an easy and fast procedure and was characterized with FTIR spectroscopy. After the preparation of the sorbent material, a specific extraction protocol was optimized and combined with HPLC-UV determination could be applied for the sensitive analysis of trace SAs in milk. The proposed method showed good linearity while the coefficients of determination (R2) were found to be high (0.991-0.998). Accuracy observed was within the range 90.2-112.1% and precision was less than 12.5%. Limit of quantification for all analytes in milk was 50 µg kg-1. Furthermore, the PU-GO sponge as sorbent material offered a very clean extract, since no matrix effect was observed.


Assuntos
Cromatografia Líquida de Alta Pressão , Grafite/química , Leite/química , Óxidos/química , Sulfonamidas/análise , Animais , Bovinos , Cromatografia , Grafite/síntese química , Concentração de Íons de Hidrogênio , Poliuretanos/química , Análise Espectral
8.
Molecules ; 24(6)2019 Mar 13.
Artigo em Inglês | MEDLINE | ID: mdl-30871257

RESUMO

Fabric phase sorptive extraction, an innovative integration of solid phase extraction and solid phase microextraction principles, has been combined with gas chromatography-mass spectrometry for the rapid extraction and determination of nineteen organochlorine pesticides in various fruit juices and water samples. FPSE consolidates the advanced features of sol-gel derived extraction sorbents with the rich surface chemistry of cellulose fabric substrate, which could extract the target analytes directly from the complex sample matrices, substantially simplifying the sample preparation operation. Important FPSE parameters, including sorbent chemistry, extraction time, stirring speed, type and volume of back-extraction solvent, and back-extraction time have been optimized. Calibration curves were obtained in a concentration range of 0.1⁻500 ng/mL. Under optimum conditions, limits of detection were obtained in a range of 0.007⁻0.032 ng/mL with satisfactory precision (RSD < 6%). The relative recoveries obtained by spiking organochlorine pesticides in water and selected juice samples were in the range of 91.56⁻99.83%. The sorbent sol-gel poly(ethylene glycol)-poly(propylene glycol)-poly(ethylene glycol) was applied for the extraction and preconcentration of organochlorine pesticides in aqueous and fruit juice samples prior to analysis with gas chromatography-mass spectrometry. The results demonstrated that the present method is simple, rapid, and precise for the determination of organochlorine pesticides in aqueous samples.


Assuntos
Sucos de Frutas e Vegetais/análise , Hidrocarbonetos Clorados/análise , Resíduos de Praguicidas/análise , Extração em Fase Sólida/métodos , Poluentes Químicos da Água/análise , Calibragem , Contaminação de Alimentos/análise , Cromatografia Gasosa-Espectrometria de Massas , Extração em Fase Sólida/normas , Microextração em Fase Sólida/métodos , Microextração em Fase Sólida/normas , Água/química
9.
Molecules ; 24(3)2019 Jan 22.
Artigo em Inglês | MEDLINE | ID: mdl-30678177

RESUMO

This paper reports the performance comparison between the exhaustive and equilibrium extraction using classical Avantor C18 solid phase extraction (SPE) sorbent, hydrophilic-lipophilic balance (HLB) SPE sorbent, Sep-Pak C18 SPE sorbent, novel sol-gel Carbowax 20M (sol-gel CW 20M) SPE sorbent, and sol-gel CW 20M coated fabric phase sorptive extraction (FPSE) media for the simultaneous extraction and analysis of three inflammatory bowel disease (IBD) drugs that possess logP values (polarity) ranging from 1.66 for cortisone, 2.30 for ciprofloxacin, and 2.92 for sulfasalazine. Both the commercial SPE phases and in-house synthesized sol-gel CW 20M SPE phases were loaded in SPE cartridges and the extractions were carried out under an exhaustive extraction mode. FPSE was carried out under an equilibrium extraction mode. The drug compounds were resolved using a Luna C18 column (250 mm × 4.6 mm; 5 m particle size) in gradient elution mode within 20 min and the method was validated in compliance with international guidelines for the bioanalytical method validation. Novel in-house synthesized and loaded sol-gel CW 20M SPE sorbent cartridges were characterized in terms of their extraction capability, breakthrough volume, retention volume, hold-up volume, number of the theoretical plate, and the retention factor.


Assuntos
Materiais Revestidos Biocompatíveis/química , Géis/química , Polietilenoglicóis/química , Extração em Fase Sólida , Microextração em Fase Sólida , Adsorção , Anti-Inflamatórios/química , Anti-Inflamatórios/isolamento & purificação , Fenômenos Químicos , Interações Hidrofóbicas e Hidrofílicas , Modelos Químicos , Estrutura Molecular , Extração em Fase Sólida/métodos , Microextração em Fase Sólida/métodos , Espectroscopia de Infravermelho com Transformada de Fourier , Termogravimetria
10.
Molecules ; 23(11)2018 Nov 06.
Artigo em Inglês | MEDLINE | ID: mdl-30404197

RESUMO

Food samples such as milk, beverages, meat and chicken products, fish, etc. are complex and demanding matrices. Various novel materials such as molecular imprinted polymers (MIPs), carbon-based nanomaterials carbon nanotubes, graphene oxide and metal-organic frameworks (MOFs) have been recently introduced in sample preparation to improve clean up as well as to achieve better recoveries, all complying with green analytical chemistry demands. Metal-organic frameworks are hybrid organic inorganic materials, which have been used for gas storage, separation, catalysis and drug delivery. The last few years MOFs have been used for sample preparation of pharmaceutical, environmental samples and food matrices. Due to their high surface area MOFs can be used as adsorbents for the development of sample preparation techniques of food matrices prior to their analysis with chromatographic and spectrometric techniques with great performance characteristics.


Assuntos
Análise de Alimentos/métodos , Estruturas Metalorgânicas , Compostos Orgânicos/análise , Animais , Bebidas/análise , Carne/análise
11.
J Sep Sci ; 39(24): 4805-4811, 2016 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-27781391

RESUMO

A high-performance liquid chromatographic method was developed for the determination of six quinolone residues (ciprofloxacin, enrofloxacin, sarafloxacin, oxolinic acid, nalidixic acid, and flumequine) in shrimp tissue samples. Separation was carried out by a LiChrospher® 100 RP-8e column, running at a 22 min gradient elution program, and the mobile phase consisted of citric acid (0.4 mol/L), acetonitrile and methanol. Detection was achieved by a diode array detector, monitoring at 255 and 275 nm. Sample preparation included initial extraction with citric acid solution and further clean-up by solid-phase extraction, employing Lichrolut RP-18 cartridges. Validation was performed according to the European Union Decision 2002/657/EC. The detection capability was 127.2 µg/kg for ciprofloxacin, 115.2 µg/kg for enrofloxacin, 126.2 µg/kg for sarafloxacin, 113.1 µg/kg for oxolinic acid, 125.2 µg/kg for nalidixic acid, and 239.0 µg/kg for flumequine. Recoveries ranged between 83.0 and 121.6%. The Youden test was applied to study the method ruggedness.


Assuntos
Resíduos de Drogas/análise , Contaminação de Alimentos/análise , Quinolonas/análise , Alimentos Marinhos/análise , Cromatografia Líquida de Alta Pressão , União Europeia , Extração em Fase Sólida
12.
Anal Chim Acta ; 1304: 342555, 2024 May 22.
Artigo em Inglês | MEDLINE | ID: mdl-38637039

RESUMO

BACKGROUND: Omics is used as an analytical tool to investigate wine authenticity issues. Aging authentication ensures that the wine has undergone the necessary maturation and developed its desired organoleptic characteristics. Considering that aged wines constitute valuable commodities, the development of advanced omics techniques that guarantee aging authenticity and prevent fraud is essential. RESULTS: Α solid phase microextraction Arrow method combined with comprehensive two-dimensional gas chromatography-mass spectrometry was developed to identify volatiles in red wines and investigate how aging affects their volatile fingerprint. The method was optimized by examining the critical parameters that affect the solid phase microextraction Arrow extraction (stirring rate, extraction time) process. Under optimized conditions, extraction took place within 45 min under stirring at 1000 rpm. In all, 24 monovarietal red wine samples belonging to the Xinomavro variety from Naoussa (Imathia regional unit of Macedonia, Greece) produced during four different vintage years (1998, 2005, 2008 and 2015) were analyzed. Overall, 237 volatile compounds were tentatively identified and were treated with chemometric tools. Four major groups, one for each vintage year were revealed using the Hierarchical Clustering Analysis. The first two Principal Components of Principal Component Analysis explained 86.1% of the total variance, showing appropriate grouping of the wine samples produced in the same crop year. A two-way orthogonal partial least square - discriminant analysis model was developed and successfully classified all the samples to the proper class according to the vintage age, establishing 17 volatile markers as the most important features responsible for the classification, with an explained total variance of 88.5%. The developed prediction model was validated and the analyzed samples were classified with 100% accuracy according to the vintage age, based on their volatile fingerprint. SIGNIFICANCE: The developed methodology in combination with chemometric techniques allows to trace back and confirm the vintage year, and is proposed as a novel authenticity tool which opens completely new and hitherto unexplored possibilities for wine authenticity testing and confirmation.


Assuntos
Compostos Orgânicos Voláteis , Vinho , Vinho/análise , Cromatografia Gasosa-Espectrometria de Massas/métodos , Microextração em Fase Sólida/métodos , Quimiometria , Análise por Conglomerados , Compostos Orgânicos Voláteis/análise
13.
Anal Chim Acta ; 1268: 341400, 2023 Aug 08.
Artigo em Inglês | MEDLINE | ID: mdl-37268341

RESUMO

The proof-of-concept of an integrated automatic foam microextraction lab-in-syringe (FME-LIS) platform coupled to high performance liquid chromatography is presented. Three different sol-gel coated foams were synthesized, characterized, and conveniently packed inside the glass barrel of the LIS syringe pump, as an alternative approach for sample preparation, preconcentration and separation. The proposed system efficiently combines the inherent benefits of lab-in-syringe technique, the good features of sol-gel sorbents, the versatile nature of foams/sponges, as well as the advantages of automatic systems. Bisphenol A (BPA) was used as model analyte, due to the increasing concern for the migration of this compound from household containers. The main parameters that affect the extraction performance of the system were optimized and the proposed method was validated. The limit of detection for BPA were 0.5 and 2.9 µg L-1, for a sample volume of 50 mL and 10 mL, respectively. The intra-day precision was <4.7% and the inter-day precision was <5.1% in all cases. The performance of the proposed methodology was evaluated for the migration studies of BPA using different food simulants, as well as for the analysis of drinking water. Good method applicability was observed based on the relative recovery studies (93-103%).

14.
J Chromatogr A ; 1708: 464366, 2023 Oct 11.
Artigo em Inglês | MEDLINE | ID: mdl-37716085

RESUMO

Fabric Phase Sorptive Extraction (FPSE) combined with high pressure liquid chromatography using to diode array detection (HPLC-DAD) was applied for the simultaneous determination of bisphenols (BPA, BPB, BPC, BPE, BPF, BPS) in juice pouches. The FPSE procedure was optimized with regards to the critical parameters that affect the performance of the method including the selection of the FPSE membrane type and size, adsorption time, extraction time, solvent volume desorption, magnetic stirring ratio, and salt addition. The FPSE membrane could be reused up to 14 times. The developed FPSE-HPLC-DAD method was validated in terms of linearity, sensitivity, accuracy andprecision. The limits of detection (LODs) were lower than 6.9 ng/mL, while the limits of quantification (LOQs) were lower than 21 ng/mL. The results obtained are satisfactory in terms of precision, accuracy and repeatability, with recoveries above 86% and CV values below 9.5%. The FPSE-HPLC-DAD method was successfully applied in the determination of six bisphenols in juice samples stored in pouches.


Assuntos
Alimentos , Cloreto de Sódio na Dieta , Cromatografia Líquida de Alta Pressão , Adsorção
15.
Food Chem ; 424: 136423, 2023 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-37247598

RESUMO

In this work, different sol-gel sorbent-coated second-generation fabric phase sorptive extraction (FPSE) membranes were synthesized using titania-based sol-gel precursors. The proposed membranes were tested for their efficiency to extract eleven selected organophosphorus pesticides (OPPs) from apple juice samples. Among the examined materials, sol-gel C18 coated titania-based FPSE membranes showed the highest extraction efficiency. These membranes were used for the optimization and validation of an FPSE method prior to analysis by gas chromatography-mass spectrometry. The detection limits for OPPs ranged between 0.03 and 0.08 ng mL-1. Moreover, the relative standard deviation was < 8.2% and 8.4% for intra-day and inter-day studies, respectively. The relative recoveries were 91-110% (intra-day study) and 90-106% (inter-day study) for all the target analytes, demonstrating good overall method accuracy. Moreover, the novel membranes were reusable at least 5 times. The titania-based membranes were compared to the conventional silica-based membranes and their utilization resulted in higher extraction recoveries.


Assuntos
Malus , Praguicidas , Cromatografia Gasosa-Espectrometria de Massas/métodos , Praguicidas/análise , Compostos Organofosforados/análise
16.
J Sep Sci ; 35(10-11): 1372-8, 2012 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-22733519

RESUMO

A confirmatory high-pressure liquid chromatographic method for the determination of nine tetracyclines in Sparus aurata (gilthead seabream) muscle tissue is developed and presented herein. Tetracycline, 4-epi-tetracycline, oxytetracycline, 4-epi-oxytetracycline, chlortetracycline, 4-epi-chlortetracycline, doxycycline, methacycline and demeclocycline were separated on a Kromasil, C18 (250 mm × 4 mm, 5 µm) analytical column by gradient elution with a mobile phase consisting of 0.001 M ethylenediaminetetraacetic acid/sodium salt and acetonitrile at 25°C. Diode array detection with monitoring at 280 nm (for the determination of chlortetracycline, 4-epi-chlortetracycline, methacycline and demeclocycline) and 355 nm (for tetracycline, 4-epi-tetracycline, oxytetracycline, 4-epi-oxytetracycline and demeclocycline) was applied for peak identification and quantification of analytes. Examined antibiotics were isolated from gilthead seabream tissue by leaching using a citrate buffer (pH 4.0) and purified by solid phase extraction using Oasis HLB(200 mg/6 mL) cartridges. The developed method was fully validated in terms of selectivity, linearity, accuracy, precision, stability and sensitivity according to the European Union Decision 2002/657/EC.


Assuntos
Antibacterianos/análise , Cromatografia Líquida de Alta Pressão/métodos , Músculos/química , Tetraciclinas/química , Animais , Cromatografia Líquida de Alta Pressão/instrumentação , Estrutura Molecular , Dourada
17.
J Sep Sci ; 35(19): 2599-607, 2012 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-22941669

RESUMO

The application of ultrasound-assisted matrix solid phase dispersive extraction for the confirmatory analysis of 12 ß-lactam antibiotics in milk by high performance liquid chromatography with photodiode array detection has been proposed herein. Four penicillins (cloxacillin, dicloxacillin, oxacillin, and amoxicillin) and eight cephalosporins (cefaclor, cefadroxil, ceftiofur, cefuroxime, cefoperazone, cefazolin, cephalexin, and cefotaxime) are effectively extracted using a mixed sorbent of Quick Easy Cheap Effective Rugged Safe technique and OASIS HLB providing a matrix free from any endogenous interference. Examined analytes were well resolved on an Inertsil ODS-3 analytical column with a mobile phase of CH(3)COONH(4) (0.05 M) and acetonitrile delivered under a gradient program. 1,7-Dimethyl-xanthine was used as internal standard. The method was validated meeting the European Legislation determining linearity, selectivity, stability, decision limit, detection capability, accuracy, precision, and ruggedness according to the Youden approach. Recoveries of all antibiotics rated from 85.0 to 115.7%, while RSD values were <12.7%. Finally, the method was successfully applied to milk samples purchased from local market.


Assuntos
Antibacterianos/química , Antibacterianos/isolamento & purificação , Cromatografia Líquida de Alta Pressão/métodos , Leite/química , Extração em Fase Sólida/métodos , beta-Lactamas/química , beta-Lactamas/isolamento & purificação , Animais , Bovinos , Resíduos de Drogas/química , Resíduos de Drogas/isolamento & purificação , Contaminação de Alimentos/análise , Extração em Fase Sólida/instrumentação
18.
J Sep Sci ; 35(13): 1603-11, 2012 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-22761138

RESUMO

An analytical method based on an optimized solid-phase extraction procedure and followed by high-performance liquid chromatography (HPLC) separation with diode array detection was developed and validated for the simultaneous determination of phenolic acids (gallic, protocatechuic, 4-hydroxy-benzoic, vanillic, caffeic, syringic, p-coumaric, ferulic, sinapic, and cinnamic acids), flavanols (catechin and epicatechin), flavonols (myricetin, quercetin, kaempferol, quercetin-3-O-glucoside, hyperoside, and rutin), flavones (luteolin and apigenin) and flavanones (naringenin and hesperidin) in rice flour (Oryza sativa L.). Chromatographic separation was carried out on a PerfectSil Target ODS-3 (250 mm × 4.6 mm, 3 µm) column at temperature 25°C using a mobile phase, consisting of 0.5% (v/v) acetic acid in water, methanol, and acetonitrile at a flow rate 1 mL min(-1) , under gradient elution conditions. Application of optimum extraction conditions, elaborated on both Lichrolut C(18) and Oasis HLB cartridges, have led to extraction of phenolic acids and flavonoids from rice flour with mean recoveries 84.3-113.0%. The developed method was validated in terms of linearity, accuracy, precision, stability, and sensitivity. Repeatability (n = 5) and inter-day precision (n = 4) revealed relative standard deviation (RSD) <13%. The optimized method was successfully applied to the analysis of phenolic acids and flavonoids in pigmented (red and black rice) and non-pigmented rice (brown rice) samples.


Assuntos
Cromatografia Líquida de Alta Pressão/métodos , Flavonoides/análise , Hidroxibenzoatos/análise , Oryza/química , Extratos Vegetais/análise , Extração em Fase Sólida/métodos , Cromatografia Líquida de Alta Pressão/instrumentação , Cromatografia de Fase Reversa/métodos , Flavonoides/isolamento & purificação , Hidroxibenzoatos/isolamento & purificação , Extratos Vegetais/isolamento & purificação
19.
Food Chem ; 134(3): 1624-32, 2012 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-25005991

RESUMO

Whole cereal grains are a good source of phenolic acids associated with reduced risk of chronic diseases. This paper reports the development and validation of a high-performance liquid chromatography-diode array detection (HPLC-DAD) method for the determination of phenolic acids in cereals in either free or bound form. Extraction of free phenolic acids and clean-up was performed by an optimised solid-phase extraction (SPE) protocol on Oasis HLB cartridges using aqueous methanol as eluant. The mean recovery of analytes ranged between 84% and 106%. Bound phenolic acids were extracted using alkaline hydrolysis with mean recoveries of 80-95%, except for gallic acid, caffeic acid and protocatechuic acid. Both free and bound phenolic extracts were separated on a Nucleosil 100 C18 column, 5 µm (250 mm × 4.6 mm) thermostated at 30 °C, using a linear gradient elution system consisting of 1% (v/v) acetic acid in methanol. Method validation was performed by means of linearity, accuracy, intra-day and inter-day precision and sensitivity. Detection limits ranged between 0.13 and 0.18 µg/g. The method was applied to the analysis of free and bound phenolic acids contents in durum wheat, bread wheat, barley, oat, rice, rye, corn and triticale.


Assuntos
Cromatografia Líquida de Alta Pressão/métodos , Grão Comestível/química , Hidroxibenzoatos/química , Extração em Fase Sólida/métodos
20.
Methods Protoc ; 5(3)2022 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-35645346

RESUMO

Aquaculture, a mass supplier of seafood, relies on plastic materials that may contain the endocrine disruptors bisphenol-A (BPA) and tert-octylphenol (t-OCT). These pollutants present toxicity to Artemia, the live aquaculture feed, and are transferred through it to the larval stages of the cultured organisms. The purpose of this work is the development and validation of an analytical method to determine BPA and t-OCT in Artemia and their culture medium, using n-octylphenol as the internal standard. Extraction of the samples was performed with H2O/TFA (0.08%)-methanol (3:1), followed by SPE. Analysis was performed in a Nucleosil column with mobile phases A (95:5, v/v, 0.1% TFA in H2O:CH3CN) and B (5:95, v/v, 0.08% TFA in H2O:CH3CN). Calibration curves were constructed in the range of concentrations expected following a 24 h administration of BPA (10 µg/mL) or t-OCT (0.5 µg/mL), below their respective LC50. At the end of exposure to the pollutants, their total levels appeared reduced by about 32% for BPA and 35% for t-OCT, and this reduction could not be accounted for by photodegradation (9-19%). The developed method was validated in terms of linearity, accuracy, and precision, demonstrating the uptake of BPA and t-OCT in Artemia.

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