RESUMO
Therapeutic peptides have an important effect on physiological function and human health, so it is momentous to quantify and detect low levels of these biomolecules in biological samples for treatment and diagnostic purposes. In the present study, an efficient magnetic solid-phase extraction (MSPE) method was developed based on stearic acid-functionalized magnetic hydroxyapatite nanocomposite (MHAP/SA) as a novel and cost-effective adsorbent for extraction of five hypothalamic-related peptides (goserelin, octreotide, triptorelin, somatostatin, and cetrorelix) from biological samples. To characterize the morphology and physicochemical properties of MHAP/SA, Fourier transform infrared spectroscopy (FT-IR), energy-dispersive X-ray spectroscopy (EDS), field emission scanning microscopy (FE-SEM), CHNS elemental analysis, Brunauer-Emmett-Teller (BET), and vibrating sample magnetometry (VSM) were applied. Under optimum conditions, the proposed method (MSPE-HPLC-UV) represented favorable linearity with R2 ≥ 0.9987, suitable intra- and inter-day precisions (RSD ≤ 6.9% and RSD ≤ 8.1%, respectively, n = 3), and limits of detection and quantification in the range of 0.75-1.12 ng mL-1 and 2.50-3.75 ng mL-1, respectively. Eventually, the proposed method was used for the extraction and quantification of target therapeutic peptides in plasma and urine samples, and satisfactory relative recoveries were achieved in the range of 90.6-110.3%.
Assuntos
Durapatita/química , Hipotálamo/química , Nanocompostos/química , Peptídeos/análise , Extração em Fase Sólida/métodos , Ácidos Esteáricos/química , Cromatografia Líquida de Alta Pressão , Humanos , Limite de Detecção , Microscopia Eletrônica de Varredura , Peso Molecular , Peptídeos/sangue , Peptídeos/urina , Reprodutibilidade dos Testes , Análise Espectral/métodosRESUMO
Maltodextrin- and ß-cyclodextrin-functionalized magnetic graphene oxide (mGO/ß-CD/MD), a novel hydrophilic-lipophilic composite, was successfully fabricated and used for the co-extraction of triazines and triazoles from vegetable samples before HPLC-UV analysis. mGO/ß-CD/MD was synthesized by chemical bonding of ß-CD and MD to the surface of mGO, using epichlorohydrin (ECH) as a linker. The successful synthesis of mGO/ß-CD/MD was confirmed by characterization tests, including attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR), X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), vibrating sample magnetometry (VSM), thermogravimetric analysis (TGA), energy-dispersive X-ray spectroscopy (EDX), Brunauer-Emmett-Teller (BET), and Barrett-Joyner-Halenda (BJH) analyses. The hydrophobic cavity of ß-CD and a large number of hydroxyl groups on the MD structure contributed to the co-extraction of mentioned pesticides with a wide range of polarity. Under the optimized condition (sorbent amount, 30 mg; desorption time, 10 min; desorption solvent volume, 300 µL; desorption solvent, methanol/acetonitrile (1:1) containing 5% (v/v) acetic acid; extraction time, 20 min; and pH of sample solution, 7.0), good linearity within the range 1.0-1000 µg L-1 (r2 ≥ 0.992) was achieved. Extraction efficiencies were in the range 66.4-95.3%, and the limits of detection were 0.01-0.08 µg L-1. Relative recoveries for spiked samples were obtained in the range 88.4-112.0%, indicating that the matrix effect was insignificant, and good precisions (intra- and inter-day) were also achieved (RSDs < 9.0%, n = 3). The results confirmed that the developed method was efficient for the determination of trace amounts of pesticides in potato, tomato, and corn samples.
Assuntos
Grafite/química , Polissacarídeos/metabolismo , Extração em Fase Sólida/métodos , Triazinas/metabolismo , Triazóis/metabolismo , Verduras/química , beta-Ciclodextrinas/metabolismoRESUMO
In this study, the application of a mixture of organic solvents as a supported liquid membrane for improving the efficiency of the electromembrane extraction procedure was investigated. The extraction process was followed by high-performance liquid chromatography analysis of two model drugs (verapamil and riluzole). In this research, four organic solvents, including 1-heptanol, 1-octanol, 2-nitrophenyl octyl ether, and 2-ethyl hexanol, were selected as model solvents and different binary mixtures (v/v 2:1, 1:1 and 1:2) were used as the supported liquid membrane. The mixture of 2-ethyl hexanol and 1-otanol (v/v, 2:1) improved the extraction efficiency of model drugs by 1.5 to 12 times. It was found that extraction efficiency is greatly influenced by the level of electric current. In this study, for various mixtures of organic solvents, the electric current fluctuated between 50 and 2500 µA, and the highest extraction efficiencies were obtained with low and stable electric currents. Finally, the optimized extraction condition was validated and applied for the determination of model drugs in urine and wastewater samples.
Assuntos
Técnicas Eletroquímicas , Riluzol/isolamento & purificação , Verapamil/isolamento & purificação , Águas Residuárias/química , Poluentes Químicos da Água/isolamento & purificação , 1-Octanol/química , Éteres/química , Heptanol/química , Hexanóis/química , Riluzol/química , Riluzol/urina , Solventes/química , Verapamil/química , Verapamil/urina , Poluentes Químicos da Água/química , Poluentes Químicos da Água/urinaRESUMO
Herein, electromembrane extraction was combined with ultraviolet spectrophotometry using a customized manifold for preconcentration and simultaneous determination of morphine, codeine, and papaverine in water and human urine samples. Absorption spectra of the extracts were recorded inside the lumen of the hollow fiber using two fiber optics connected to a miniature spectrophotometer. Partial least squares regression was applied to resolve the overlapped spectra of the analytes. Performance of the model was validated by an independent test set. Central composite design was applied to optimize the extraction parameters. The optimized extraction conditions are as follows; supporting liquid membrane: 2-nitrophenyl octyl ether containing 15% v/v bis(2-ethylhexyl) phosphate, applied voltage: 80 V, donor pH: 3.0, acceptor pH: 1.0, extraction time: 20 min. Finally, the optimized extraction method was validated for determination of the mentioned alkaloids in human urine samples. The method showed good linearity (R2 > 0.995) for all of the mentioned alkaloids. The limits of detection for morphine, codeine, and papaverine in diluted human urine were found to be 0.6, 1.1, and 0.6 ng/mL, respectively with acceptable relative standard deviations. Enrichment factors of 104, 108, and 102 were achieved for morphine, codeine, and papaverine, respectively.
Assuntos
Codeína/análise , Morfina/análise , Papaverina/análise , Poluentes Químicos da Água/química , Técnicas Eletroquímicas , Humanos , Espectrofotometria UltravioletaRESUMO
The synergistic effect of two acidic amino acids, aspartic and glutamic acid, on the electrophoretic enantioseparation of four basic drugs was evaluated in the BGE containing a CD and at different pHs. Chlorpheniramine, hydroxyzine, propranolol and tramadol were used as the basic model drugs. However, no enantioseparations were achieved with a BGE containing sole amino acid, but the combined use of an acidic amino acid and a CD showed improved enantioseparations (synergistic effect) compared with the single CD system. The results demonstrated that at optimized pH, the electrostatic interactions of the anionic amino acids with the positively charged basic drugs could result in a decrease of the analyte migration velocity and it consequently improved the enantioseparation. The effective parameters such as the amino acid and chiral selector type and concentration, buffer pH, applied voltage, and capillary temperature were optimized. Favorable enantiomeric resolution and migration times of the model drugs were achieved with a 100 mM phosphate buffer solution (pH 3.0) containing 5.0 mM HP-α-CD/HP-ß-CD and 20 mM aspartic acid with an 18 kV applied voltage at 25°C. 1 H NMR experiments were also carried out in a mixture of an analyte and CD in the absence and presence of aspartic acid. The NMR results were consistent with the results obtained by CE which showed the synergistic effect of amino acid.
Assuntos
Aminoácidos/química , Eletroforese Capilar/métodos , Preparações Farmacêuticas/análise , Preparações Farmacêuticas/química , Concentração de Íons de Hidrogênio , EstereoisomerismoRESUMO
In this study, electromembrane extraction from a flowing sample solution, termed as continuous-flow electromembrane extraction, was developed and compared with conventional procedures for the determination of four basic drugs in real samples. Experimental parameters affecting the extraction efficiency were further studied and optimized. Under optimum conditions, linearity of continuous-flow procedure was within 8.0-500 ng/mL, while it was wider for conventional procedures (2.0-500 ng/mL). Moreover, repeatability (percentage relative standard deviation) was found to range between 5.6 and 10.4% (n = 3) for the continuous-flow procedure, with a better repeatability than that of conventional procedures (2.3-5.5% (n = 3)). Also, for the continuous-flow procedure, the estimated detection limit (signal-to-noise ratio = 3) was less than 2.4 ng/mL and extraction recoveries were within 8-10%, while the corresponding figures for conventional procedures were less than 0.6 ng/mL and 42-60%, respectively. Thus, the results showed that both continuous flow and conventional procedures were applicable for the extraction of model compounds. However, the conventional procedure was more convenient to use, and thus it was applied to determine sample drugs in real urine and wastewater samples.
Assuntos
Membranas Artificiais , Preparações Farmacêuticas/isolamento & purificação , Urina/química , Águas Residuárias/análise , Humanos , Limite de DetecçãoRESUMO
Simultaneous extraction of acidic and basic analytes from a sample is seen to be a challenging task. In this work, a novel and efficient electromembrane extraction (EME) method based on two separate cells was applied to simultaneously extract and preconcentrate two acidic drugs (naproxen and ibuprofen) along with a basic drug (ketamine). Once both cells were filled with the sample solution, basic drug was extracted from one cell with the other cell used to extract acidic drugs. The employed supported liquid membranes for the extraction of acidic and basic drugs were 2-ethyl hexanol and 1-octanol, respectively. Under an applied potential of 250 V in the course of the extraction process, acidic, and basic drugs were extracted from a 3.0 mL aqueous sample solution into 25 µL acceptor solutions. The pH values of the donor and acceptor solutions in the cathodic cell were 5.0 and 1.5, respectively, the corresponding values in the anodic cell were, however, 8.0 and 12.5, respectively. The rates of recovery obtained within 20 min of extraction time at a stirring rate of 750 rpm ranged from 45 to 54%. With correlation coefficients ranging from 0.990 to 0.996, the proposed EME technique provided good linearity over a concentration range of 20-1000 ng/mL. The LOD for all drugs was found to be 6.7 ng/mL, while reproducibility ranged from 7 to 12% (n = 5). Finally, applying the proposed method to determine and quantify the drugs in urine and wastewater samples, satisfactory results were achieved.
Assuntos
Fracionamento Químico/instrumentação , Técnicas Eletroquímicas/instrumentação , Membranas Artificiais , Preparações Farmacêuticas/isolamento & purificação , Fracionamento Químico/métodos , Técnicas Eletroquímicas/métodos , Concentração de Íons de Hidrogênio , Limite de Detecção , Preparações Farmacêuticas/química , Fatores de TempoRESUMO
In the present study, for the first time electromembrane extraction followed by high performance liquid chromatography coupled with ultraviolet detection was optimized and validated for quantification of four gonadotropin-releasing hormone agonist anticancer peptides (alarelin, leuprolide, buserelin and triptorelin) in biological and aqueous samples. The parameters influencing electromigration were investigated and optimized. The membrane consists 95% of 1-octanol and 5% di-(2-ethylhexyl)-phosphate immobilized in the pores of a hollow fiber. A 20 V electrical field was applied to make the analytes migrate from sample solution with pH 7.0, through the supported liquid membrane into an acidic acceptor solution with pH 1.0 which was located inside the lumen of hollow fiber. Extraction recoveries in the range of 49 and 71% within 15 min extraction time were obtained in different biological matrices which resulted in preconcentration factors in the range of 82-118 and satisfactory repeatability (7.1 < RSD% < 19.8). The method offers good linearity (2.0-1000 ng/mL) with estimation of regression coefficient higher than 0.998. The procedure allows very low detection and quantitation limits of 0.2 and 0.6 ng/mL, respectively. Finally, it was applied to determination and quantification of peptides in human plasma and wastewater samples and satisfactory results were yielded.
Assuntos
Antineoplásicos Hormonais/isolamento & purificação , Técnicas Eletroquímicas/instrumentação , Hormônio Liberador de Gonadotropina/agonistas , Membranas Artificiais , Águas Residuárias/química , Poluentes Químicos da Água/isolamento & purificação , Antineoplásicos Hormonais/análise , Antineoplásicos Hormonais/sangue , Antineoplásicos Hormonais/química , Técnicas Eletroquímicas/métodos , Humanos , Modelos Lineares , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/sangue , Poluentes Químicos da Água/químicaRESUMO
Electromembrane extraction (EME) of model analytes was carried out using a virtually rotating supported liquid membrane (SLM). The virtual (nonmechanical) rotating of the SLM was achieved using a novel electrode assembly including a central electrode immersed inside the lumen of the SLM and five counter electrodes surrounding the SLM. A particular electronic circuit was designed to distribute the potential among five counter electrodes in a rotating pattern. The effect of the experimental parameters on the recovery of the extraction was investigated for verapamil (VPL), trimipramine (TRP), and clomipramine (CLP) as the model analytes and 2-ethyl hexanol as the SLM solvent. The results showed that the recovery of the extraction is a function of the angular velocity of the virtual rotation. The best results were obtained at an angular velocity of 1.83 RadS(-1) (or a rotation frequency of 0.29 Hz).The optimization of the parameters gave higher recoveries up to 50% greater than those of a conventional EME method. The rotating also allowed the extraction to be carried out at shorter time (15 min) and lower voltage (200 V) with respect to the conventional extraction. The model analytes were successfully extracted from wastewater and human urine samples with recoveries ranging from 38 to 85%. The RSD of the determinations was in the range of 12.6 to 14.8%.
Assuntos
Fracionamento Químico/instrumentação , Clomipramina/isolamento & purificação , Técnicas Eletroquímicas/instrumentação , Membranas Artificiais , Trimipramina/isolamento & purificação , Verapamil/isolamento & purificação , Antiarrítmicos/isolamento & purificação , Antiarrítmicos/urina , Antidepressivos Tricíclicos/isolamento & purificação , Antidepressivos Tricíclicos/urina , Clomipramina/urina , Eletrodos , Desenho de Equipamento , Humanos , Limite de Detecção , Rotação , Trimipramina/urina , Urinálise/instrumentação , Verapamil/urina , Águas Residuárias/análise , Poluentes Químicos da Água/isolamento & purificação , Poluentes Químicos da Água/urina , Purificação da Água/instrumentaçãoRESUMO
In the present study, for the first time electromembrane extraction followed by high-performance liquid chromatography coupled with ultraviolet detection was developed and validated for the determination of tartrazine in some food samples. The parameters influencing electromembrane extraction were evaluated and optimized. The membrane consists of 1-octanol immobilized in the pores of a hollow fiber. As a driving force, a 30 V electrical field was applied to make the analyte migrate from sample solution with pH 3, through the supported liquid membrane into an acceptor solution with pH 10. Best preconcentration (enrichment factor >21) was obtained in extraction duration of 15 min. Effects of some solid nano-sorbents like carbon nanotubes and molecularly imprinted polymers on membrane performance and electromembrane extraction efficiency were evaluated. The method provided the linearity in the range 25-1000 ng/mL for tartrazine (R(2) > 0.9996) with repeatability range (RSD) between 3.8 and 8.5% (n = 3). The limits of detection and quantitation were 7.5 and 25 ng/mL, respectively. Finally, the method was applied to the determination and quantification of tartrazine from some food samples with relative recoveries in the range between 90 and 98%.
Assuntos
Técnicas Eletroquímicas , Análise de Alimentos , Contaminação de Alimentos/análise , Nanoestruturas/química , Tartrazina/análise , 1-Octanol/química , Adsorção , Cromatografia Líquida de Alta Pressão , Estrutura Molecular , Propriedades de Superfície , Raios UltravioletaRESUMO
A simple electromembrane extraction (EME) procedure combined with ion chromatography (IC) was developed to quantify inorganic anions in different pure water samples and water miscible organic solvents. The parameters affecting extraction performance, such as supported liquid membrane (SLM) solvent, extraction time, pH of donor and acceptor solutions, and extraction voltage were optimized. The optimized EME conditions were as follows: 1-heptanol was used as the SLM solvent, the extraction time was 10 min, pHs of the acceptor and donor solutions were 10 and 7, respectively, and the extraction voltage was 15 V. The mobile phase used for IC was a combination of 1.8 mM sodium carbonate and 1.7 mM sodium bicarbonate. Under these optimized conditions, all anions had enrichment factors ranging from 67 to 117 with RSDs between 7.3 and 13.5% (n = 5). Good linearity values ranging from 2 to 1200 ng/mL with coefficients of determination (R(2) ) between 0.987 and 0.999 were obtained. The LODs of the EME-IC method ranged from 0.6 to 7.5 ng/mL. The developed method was applied to different samples to evaluate the feasibility of the method for real applications.
Assuntos
Ânions/análise , Cromatografia por Troca Iônica/métodos , Técnicas Eletroquímicas/métodos , Solventes/química , Água/química , Concentração de Íons de Hidrogênio , Membranas Artificiais , Compostos Orgânicos/químicaRESUMO
Prediction of chiral separation for a compound using a chiral selector is an interesting and debatable work. For this purpose, in this study 23 chiral basic drugs with different chemical structures were selected as model solutes and the influence of their chemical structures on the enantioseparation in the presence of maltodextrin (MD) as chiral selector was investigated. For chiral separation, a 100-mM phosphate buffer solution (pH 3.0) containing 10% (w/v) MD with dextrose equivalent (DE) of 4-7 as chiral selector at the temperature of 25°C and voltage of 20 kV was used. Under this condition, baseline separation was achieved for nine chiral compounds and partial separation was obtained for another six chiral compounds while no enantioseparation was obtained for the remaining eight compounds. The results showed that the existence of at least two aromatic rings or cycloalkanes and an oxygen or nitrogen atom or -CN group directly bonded to the chiral center are necessary for baseline separation. With the obtained results in this study, chiral separation of a chiral compound can be estimated with MD-modified capillary electrophoresis before analysis. This prediction will minimize the number of preliminary experiments required to resolve enantiomers and will save time and cost.
RESUMO
Maltodextrin was investigated as a chiral selector in capillary electrophoresis (CE) analysis of amlodipine (AM) enantiomers. For development of a stereoselective CE method, various effective parameters on the enantioseparation were optimized. The best results were achieved on an uncoated fused silica capillary at 20 °C using phosphate buffer (100 mM, pH 4) containing 10% w/v maltodextrin (dextrose equivalent value 4-7). The UV detector was set at 214 nm and a constant voltage of 20 kV was applied. The range of quantitation was 2.5-250 µg/mL (R(2) > 0.999) for both enantiomers. Intra- (n = 5) and interday (n = 3) relative standard deviation (RSD) values were less than 7%. The limits of quantitation and detection were 1.7 µg/mL and 0.52 µg/mL, respectively. Recoveries of R(+) and S(-) enantiomers from tablet matrix were 97.2% and 97.8%, respectively. The method was applied for the quantification of AM enantiomers in commercial tablets. Also, the enantioseparation capability of heparin was evaluated and the results showed that heparin did not have any chiral selector activity in this study.
Assuntos
Anlodipino/análise , Anlodipino/química , Eletroforese Capilar/métodos , Polissacarídeos/química , Anlodipino/isolamento & purificação , Eletrólitos/química , Eletroforese Capilar/economia , Glucose/química , Concentração de Íons de Hidrogênio , Estereoisomerismo , ComprimidosRESUMO
For the first time, a magnetic carbon nanocomposite was synthesized using one-step hydrothermal procedure, employing bovine serum albumin, curcumin, and ferric ammonium citrate. Additionally, the application of this novel composite as an adsorbent for magnetic dispersive solid phase extraction of fungicides and pesticides from water and food samples is a unique aspect of this study. Under optimum conditions (salt concentration: 5.0% w/v, pH: 7.0, desorption solvent: ethanol, sorbent amount: 20 mg, extraction time: 20 min, desorption time: 3 min, stirring rate: 500 rpm, sample volume: 30 mL, extraction temperature: room temperature, and desorption solvent volume: 150 µL) linearity (2.5 to 1400 ng mL-1), coefficients of determination (R2 ≥ 0.997), limits of detection (0.75 to 1.5 ng mL-1), and limits of quantification (2.5 to 5.0 ng mL-1) were achieved. The method validation results showed extraction recovery ranging from 71.2% to 93.4%, and preconcentration factors ranging from 142.5 to 186.1.
Assuntos
Curcumina , Contaminação de Alimentos , Praguicidas , Soroalbumina Bovina , Extração em Fase Sólida , Extração em Fase Sólida/métodos , Curcumina/química , Curcumina/isolamento & purificação , Contaminação de Alimentos/análise , Soroalbumina Bovina/química , Soroalbumina Bovina/isolamento & purificação , Adsorção , Praguicidas/isolamento & purificação , Praguicidas/química , Química Verde , Animais , BovinosRESUMO
The separation of enantiomers using chiral membranes has garnered much research interest. In this study, the enantioseparation of amino acids using chiral membranes, namely graphene oxide-ethylenediamine-maltodextrin (GO-EDA-MD) and GO-EDA-hydroxypropyl-MD (GO-EDA-HP-MD), was evaluated. HP-MD and MD were investigated as chiral selectors due to their inherent chirality. Various characterization techniques, including atomic force microscopy, Fourier transform infrared spectrometry, field emission scanning electron microscopy, water contact angle analysis, tensile properties, and thermal gravimetric analysis were employed to analyze the membrane structures. The evaluation of enantioseparation performance was conducted by employing tryptophan, phenylalanine, and tyrosine enantiomers. Optimal conditions for enantiomer separation were achived using a GO-EDA-HP-MD chiral composite (1.75 wt%), a feed concentration of 10 mg/L for each enantiomer, a separation time of 15 min, and a membrane effective surface area of 1.0 cm2. Also, the bovine serum albumin rejection was 90.0 %, and the water flux reached 37.1 L m-2 h-1. The highest enantiomeric excess (ee.%) values were 46.33 %, 76.97 %, and 73.04 % for tryptophan, phenylalanine, and tyrosine, respectively. The impact of voltage on ee.% and substance flux was also explored. This membrane was able to separate enantiomers successfully.
Assuntos
Aminoácidos , Grafite , Membranas Artificiais , Polissacarídeos , Grafite/química , Estereoisomerismo , Polissacarídeos/química , Polissacarídeos/isolamento & purificação , Aminoácidos/química , Aminoácidos/isolamento & purificação , Etilenodiaminas/químicaRESUMO
The present study investigates the use of dextrins (maltodextrin, ß-cyclodextrin, and hydroxypropyl-ß-cyclodextrin) to improve the efficiency of the agarose-based gel electromembrane extraction technique for extracting chiral basic drugs (citalopram, hydroxyzine, and cetirizine). Additionally, it examines the enantioselectivity of the extraction process for these drugs. To achieve these, dextrins were incorporated into either the sample solution, the membrane, or the acceptor solution, and then the extraction procedure was performed. Enantiomers were separated and analyzed using a capillary electrophoresis device equipped with a UV detector. The results obtained under the optimal extraction conditions (sample solution pH: 4.0, acceptor solution pH: 2.0, gel membrane pH: 3.0, agarose concentration: 3 % w/v, stirring rate: 1000 rpm, gel thickness: 4.4 mm, extraction voltage: 62.3 V, and extraction time: 32.1 min) indicated that incorporating dextrins into either the sample solution, membrane or the acceptor solution enhances extraction efficiency by 17.3-23.1 %. The most significant increase was observed when hydroxypropyl-ß-cyclodextrin was added to the acceptor solution. The findings indicated that the inclusion of hydroxypropyl-ß-cyclodextrin in the sample solution resulted in an enantioselective extraction, yielding an enantiomeric excess of 6.42-7.14 %. The proposed method showed a linear range of 5.0-2000 ng/mL for enantiomers of model drugs. The limit of detection and limit of quantification for all enantiomers were found to be < 4.5 ng/mL and <15.0 ng/mL, respectively. Intra- and inter-day RSDs (n = 4) were less than 10.8 %, and the relative errors were less than 3.2 % for all the enantiomers. Finally, the developed method was successfully applied to determine concentrations of enantiomers in a urine sample with relative recoveries of 96.8-99.2 %, indicating good reliability of the developed method.
Assuntos
Dextrinas , Géis , Membranas Artificiais , Estereoisomerismo , Dextrinas/química , Géis/química , Eletroforese Capilar/métodos , Hidroxizina/análise , Hidroxizina/isolamento & purificação , Hidroxizina/química , Hidroxizina/urina , beta-Ciclodextrinas/química , 2-Hidroxipropil-beta-Ciclodextrina/química , Cetirizina/química , Cetirizina/urina , Cetirizina/análise , Cetirizina/isolamento & purificação , Concentração de Íons de Hidrogênio , Preparações Farmacêuticas/análise , Preparações Farmacêuticas/química , Preparações Farmacêuticas/isolamento & purificação , Preparações Farmacêuticas/urina , Sefarose/químicaRESUMO
In this study, a coating of electrospun polyvinyl alcohol/modified chitosan/hydroxy-containing porous organic framework (PVA/MCS/HC-POF) was fabricated and applied as a novel sorbent for thin-film solid-phase microextraction of pesticides from cereal samples, followed by HPLC-UV. The successful fabrication of PVA/MCS/HC-POF was confirmed through characterization tests. The functional group of MCS and a large number of hydroxyl groups on the HC-POF structure contributed to the co-extraction of pesticides. Under the optimum conditions, the calibration plots were linear within the range of 5.0-800 ng mL-1 (r2 ≥ 0.978), and the limits of detection were obtained below 4.0 ng mL-1. The method's precision was investigated through intra-day, inter-day, and film-to-film RSD (%) measurements, all of which were less than 6.5 %, 8.2 %, and 10.0 %, respectively. Furthermore, satisfactory recoveries ranging from 63.3 % to 79.0 % were obtained. Accordingly, the proposed method can be considered a suitable alternative for measuring trace amounts of pesticides in cereal samples.
Assuntos
Quitosana , Nanofibras , Praguicidas , Álcool de Polivinil , Grão Comestível , Nanofibras/química , Porosidade , Microextração em Fase Sólida/métodos , Limite de DetecçãoRESUMO
In this study, a platinum wire coated with poly(3,4-ethylenedioxythiophen) was used as an electro-assisted solid-phase microextraction fiber for the quantification of tricyclic antidepressant drugs in biological samples by coupling to GC employing a flame ionization detector. In this study, an electric field increased the extraction rate and recovery. The fiber used as a solid phase was synthesized by the electropolymerization of 3,4-ethylenedioxythiophen monomers onto a platinum wire. The ability of this fiber to extract imipramine, desipramine, and clomipramine by using the electro-assisted solid-phase microextraction technique was evaluated. The effect of various parameters that influence the extraction efficiency, which include solution temperature, extraction time, stirring rate, ionic strength, time and temperature of desorption, and thickness of the fiber, was optimized. Under optimized conditions, the linear ranges and regression coefficients of calibration curves were in the range of 0.5-250 and 0.990-0.998 ng/mL, respectively. Detection limits were in the range of 0.15-0.45 ng/mL. Finally, this method was applied to the determination of drugs in urine and wastewater samples and recoveries were 4.8-108.9%.
Assuntos
Antidepressivos Tricíclicos/isolamento & purificação , Antidepressivos Tricíclicos/urina , Cromatografia Gasosa/métodos , Microextração em Fase Sólida/métodos , Compostos Bicíclicos Heterocíclicos com Pontes/química , Humanos , Concentração de Íons de Hidrogênio , Limite de Detecção , Polímeros/química , Microextração em Fase Sólida/instrumentaçãoRESUMO
A two-phase electromembrane extraction (EME) was developed and directly coupled with gas chromatography mass spectrometry (GC-MS) analysis. The proposed method was successfully applied to the simultaneous determination of imipramine, desipramine, citalopram and sertraline. The model compounds were extracted from neutral aqueous sample solutions into the organic phase filled in the lumen of the hollow fiber. This method was accomplished with 1-heptanol as organic phase, by means of 60 V applied voltage and with the extraction time of 15 min. Experiments reported recoveries in the range of 69-87% from 1.2 mL neutral sample solution. The compounds were quantified by GC-MS instrument, with acceptable linearity ranging from 1 to 500 ng mL(-1) (R(2) in the range of 0.989 to 0.998), and repeatability (RSD) ranging between 7.5 and 11.5% (n = 5). The estimated detection limits (S/N ratio of 3:1) were less than 0.25 ng mL(-1). This novel approach based on two-phase EME brought advantages such as simplicity, low-costing, low detection limit and fast extraction with a total analysis time less than 25 min. These experimental findings were highly interesting and demonstrated the possibility of solving ionic species in the organic phase at the presence of electrical potential.
Assuntos
Cromatografia Gasosa-Espectrometria de Massas/métodos , Preparações Farmacêuticas/química , Preparações Farmacêuticas/isolamento & purificação , Extração em Fase Sólida/métodos , Membranas , Estrutura Molecular , Extração em Fase Sólida/instrumentaçãoRESUMO
An electromembrane extraction procedure coupled with HPLC and visible detection was applied for the extraction of three textile azo dyes as organic salts. The extraction parameters such as extraction time, applied voltage, pH range, and concentration of salt added were optimized. A driving force of 60 V was applied to extract the analytes through 2-nitrophenyl octyl ether, used as the supported liquid membrane, into a neutral aqueous solution. This method required 20 min extraction time from a neutral sample solution. The proposed microextraction technique provided good linearity with correlation coefficients from 0.996 to 0.998 over a concentration range of 1.0-1000.0 ng/mL. The LODs of dyes were 0.30-0.75 ng/mL, while the reproducibility ranged from 6.7 to 12.9% (n = 6). Also, enrichment factors of 96-162 that corresponded to the recoveries ranging from 48 to 81% were achieved. Finally, the application of this new method was demonstrated on wastewater samples and some plants grown in contaminated environments. Excellent selectivity was obtained as no interfering peaks were detected.