RESUMO
In the present study, an environmentally friendly magnetic dispersive micro-solid phase extraction was developed based on magnetic agarose nanoparticles and deep eutectic solvents for the isolation and pre-concentration of three flavonoids (morin, quercetin, and kaempferol) from dark tea, chocolate, vegetable, and fruit juice samples. In this method, deep eutectic solvents were synthesized from less toxic and low-cost substances under feasible conditions and used as eluents in the desorption process. These solvents can be considered as a green alternative to traditional organic reagents to increase the adsorption capacity and reduce the matrix interferences, dangerous waste generation and environmental pollution. A Plackett-Burman design was employed for screening the experimental variables. The effective variables were then optimized by Box-Behnken design (BBD). Under the optimial conditions, the presented method demonstrated wide linear ranges of 1-500 µg. L-1 for morin and quercetin, and 5-500 µg. L-1 for kaempferol with satisfactory recoveries above 91%. Limit of detections (LODs) and quantifications (LOQs) of flavonoids varied in 0.2-1.1 µg. L-1 and 0.66-3.63 µg. L-1, respectively. The precision of the proposed method was the range of 2.6-5.7%.
Assuntos
Nanopartículas , Extração em Fase Sólida , Cromatografia Líquida de Alta Pressão , Flavonoides/análise , Fenômenos Magnéticos , Sefarose , SolventesRESUMO
In this study, an environmentally friendly magnetic dispersive micro solid-phase extraction was developed based on a deep eutectic solvent as a carrier and disperser of ferrofluids for the isolation and pre-concentration of meloxicam from biological samples. The extracted analyte was then analyzed by high performance liquid chromatography with ultraviolet detection (HPLC-UV). The ferrofluid was prepared via a combination of silica-coated magnetic nanoparticles and an ethylene glycol/choline chloride deep eutectic solvent as a carrier. In this method, the rapid injection of the magnetic nanoparticles into the sample solution using a green carrier liquid increased the contact surface between the adsorbent and the target analyte which reduced the amount of the adsorbent and extraction time. A fractional factorial design was used for screening some effective parameters such as the amount of SiO2@Fe3O4, extraction time, pH of the sample solution, amount of the salt, volume of the desorption solvent, and desorption time. The effective parameters were then optimized by central composite design. Optimized extraction conditions were: amount of SiO2@Fe3O4 of 2 mg; extraction time of 1 min; pH of the sample solution of 4; volume of the desorption solvent of 200 µL; and desorption time of 2 min. Under the optimal conditions, wide linear ranges of 5-500 µg L-1 for water and 10-500 µg L-1 were obtained for urine and plasma samples with acceptable extraction recoveries above 89.2%. Limit of detections (LODs) were in the range of 1.5-3.0 µg L-1. The enrichment factors achieved were above 44.6 with relative standard deviations lower than 6.2%.
Assuntos
Análise Química do Sangue , Fenômenos Magnéticos , Meloxicam , Extração em Fase Sólida , Urinálise , Análise Química do Sangue/métodos , Meloxicam/análise , Dióxido de Silício , Solventes/química , Urinálise/métodosRESUMO
A polymer/layered silicate composite based on dimethyldioctadecylanimonium bentonite/chitosan magnetic nanoparticles was synthesized and characterized by field emission transmission electron microscopy, X-ray diffraction and Fourier transform infrared spectrometry. The prepared nanocomposite was used to isolate and preconcentrate celecoxib from human breast milk, urine and plasma samples. In this method, dimethyldioctadecylanimonium bentonite increases the accessibility of binding sites and adsorption capacity by high microporosity and large surface area, that has been realized for the first time in a magnetic chitosan nanoparticle support. A fractional factorial design was utilized for screening the experimental parameters. The effective parameters were then optimized by Box-Behnken design. Under the optimized conditions, the developed method exhibited wide linear ranges of 5-500 µg L-1 for plasma and urine and 10-500 µg L-1 for breast milk samples with satisfactory recoveries in the range of 96.7-99.0%. Limit of detection and quantification of celecoxib were in the ranges 0.3-3.2 and 0.99-10.56, respectively. The enrichment factors were obtained in the ranges 64.5-66.0, while precisions were <3.7%.
Assuntos
Bentonita/química , Celecoxib , Nanopartículas de Magnetita/química , Leite Humano/química , Extração em Fase Sólida/métodos , Adsorção , Adulto , Celecoxib/análise , Celecoxib/isolamento & purificação , Quitosana/química , Cromatografia Líquida de Alta Pressão , Feminino , Humanos , Limite de Detecção , Modelos Lineares , Compostos de Amônio Quaternário/química , Reprodutibilidade dos TestesRESUMO
In the present study, a new generation of water-immiscible natural deep eutectic solvents (DESs) was synthesized using borneol as a hydrogen-bonding acceptor and decanoic acid, oleic acid, and thymol as a hydrogen-bonding donor in different molar ratios. These green hydrophobic solvents which are chemically stable in aqueous solutions were used as extraction solvents for isolation and pre-concentration of warfarin in biological samples. In this method, fine droplets of DESs were dispersed into the sample solution by using the air-assisted liquid-liquid micro-extraction method to accelerate the cloudy emulsion system formation and increase the mass transfer of the analyte to the DES-rich phase. The borneol based deep eutectic solvent is a worthy generation of the extraction solvents in the ALLME method due to low-cost and less toxicity. A Plackett-Burman design was utilized for screening the experimental parameters. The effective parameters were then optimized by Box-Behnken design (BBD). Optimized extraction conditions were pH of sample solution of 3.9, number of aspiration/dispersion cycles of 15, the volume of DES of 60 µL, and rate and time of centrifuge of 6000 rpm and 10 min, respectively. Under the optimized conditions, the developed NADES-ALLME method exhibited a wide linear range of 5-500 µg L - 1 for plasma and urine samples with satisfactory recoveries above 88.80%. Limit of detections (LODs) and Limit of quantifications (LOQs) of warfarin were in the ranges of 0.5-2.7 and 1.65-8.91, respectively. The enrichment factors were obtained in the range of 148-164 and precisions were lower than 5.87%. Finally, the proposed method was successfully employed for the analysis of warfarin in human urine and plasma samples.
Assuntos
Canfanos/química , Microextração em Fase Líquida/métodos , Solventes/química , Varfarina/análise , Varfarina/isolamento & purificação , Adulto , Ar , Ácidos Decanoicos/química , Feminino , Química Verde , Humanos , Ligação de Hidrogênio , Interações Hidrofóbicas e Hidrofílicas , Limite de Detecção , Ácido Oleico/química , Solventes/síntese química , Timol/química , Varfarina/sangue , Varfarina/urina , Água/químicaRESUMO
In this study, a hydrophilic deep eutectic solvent was synthesized as a carrier and disperser of magnetic nanoparticles based on ferrofluid and used to develop the dispersive micro-solid-phase extraction method. Ethylene glycol/tetramethylammonium chloride deep eutectic solvent and SiO2 @Fe3 O4 were used to provide the highly stable ferrofluid with strong sorbing properties without any additional stabilizer, which was employed to extract and determine morin in apple and grape juices, diluted and acidic extract of dried onion, and green tea infusion samples. The dispersibility of SiO2 @Fe3 O4 and prevention of its aggregation in the sample solution were improved using the deep eutectic solvent-based ferrofluid. Also, it facilitated the fast injection of sorbent into the sample solution that led to an increase of the contact surface between the sorbent and analyte, and reduction of the extraction time and consumption of the sorbent. The important experimental parameters influencing the extraction efficiency of morin were examined. Under the optimal conditions, a linear calibration curve was obtained in the range of 3-500 µg/L with a determination coefficient of 0.9994. The limits of detection and quantification were of 0.91 and 2.98 µg/L, respectively. While an extraction recovery of 97.7% with relative standard deviation of 3.8% (interday) was obtained via three replicated measurements on a 30 µg/L of morin standard solution, the enrichment factor was 39.1. Finally, this method was successfully used to extract and preconcentrate morin in various samples, followed with their determination by high-performance liquid chromatography with ultraviolet detection.