RESUMO
An ultrafast, efficient, and eco-friendly method combining magnetic solid phase extraction and capillary electrophoresis with diode array detection have been developed to determine ractopamine residues in food samples. A restricted access material based on magnetic and mesoporous molecularly imprinted polymer has been properly synthesized and characterized, demonstrating excellent selectivity and high adsorbent capacity. Short-end injection capillary electrophoresis method was optimized: 75 mM triethylamine pH 7 as BGE, -20 kV, 50 mbar by hydrodynamic injection during 8 s, and capillary temperature at 25 °C; reaching ultrafast ractopamine analysis (â¼0.6 min) with good peak asymmetry, and free from interfering and/or baseline noise. After sample preparation optimization, the conditions were: 1000 µL of sample at pH 6, 20 mg of adsorbent, stirring time of 120 s, 250 µL of ultrapure water as washing solvent, 1000 µL of methanol: acetic acid (7: 3, v/v) as eluent, and the adsorbent can be reused four times. In these conditions, the analytical method showed recoveries around to 100 %, linearity ranged from 9.74 to 974.0 µg kg-1, correlation coefficient (r) ≥ 0,99 in addition to adequate precision, accuracy, and robustness. After proper validation, the method was successfully applied in the analysis ractopamine residues in bovine milk and bovine and porcine muscle.
Assuntos
Impressão Molecular , Polímeros Molecularmente Impressos , Fenetilaminas , Animais , Suínos , Extração em Fase Sólida/métodos , Eletroforese Capilar/métodos , Fenômenos Magnéticos , Impressão Molecular/métodos , Cromatografia Líquida de Alta Pressão/métodosRESUMO
A novel lab-made alginate-based hydrogel device was successfully prepared and applied as a sorption material for the solid-phase microextraction of drugs (fluoxetine and its metabolite, norfluoxetine) in human plasma, with subsequent determination by high performance liquid chromatography-fluorescence detection (HPLC-FD). When supported in a polypropylene hollow fiber, the alginate was able to extract the analytes and functioned as a restricted access material, excluding >95 % of proteins from the biological matrix. The results indicate the potential use of this phase/device for quantitative drugs extraction from biological matrices at concentrations compatible with those typical in the literature (0.5 µg mL-1), and with satisfactory precision (13.4 % for fluoxetine and 6.2 % for norfluoxetine). Such outcomes, promoted by a simple and inexpensive material, open a new perspective of exploration of hydrogels as the sorption phase in biological matrices, a concept previously unexplored in the literature.
Assuntos
Fluoxetina , Hidrogéis , Alginatos , Cromatografia Líquida de Alta Pressão/métodos , Humanos , Microextração em Fase Sólida/métodosRESUMO
In this study, two sample preparation techniques were evaluated in the simultaneous determination of three compounds with different physicochemical properties, progesterone, pyriproxyfen, and deltamethrin that may be present in the chicken egg. In this procedure, firstly the restricted double access mesoporous polypyrrole was synthesized, which was evaluated as adsorbent in pipette-tip solid phase extraction and dispersive solid phase extraction. After optimizing the extraction parameters, it was found that pipette-tip solid phase extraction was more efficient and, therefore, it was used in the validation and application of the method. The analytical method showed good recoveries, acceptable linearity (r > 0.99), limits of quantification, precision and accuracy, robustness and stability within the limits of the literature. Finally, the developed method was successfully applied in simultaneous determination of analytes in different chicken egg samples. Therefore, this work provided a promising strategy for the extraction of different organic compounds from egg products.
Assuntos
Polímeros , Pirróis , Animais , Galinhas , Cromatografia Líquida de Alta Pressão , Nitrilas , Progesterona , Piretrinas , Piridinas , Extração em Fase SólidaRESUMO
Restricted-access nanoparticles (RANPs) were prepared from bovine serum albumin by coacervation. They have an average sized of 311 nm. They were characterized and used to capture the ß-blockers atenolol, metoprolol and propranolol from untreated biological samples. It is shown that both high protein affinity drugs (propranolol) and low protein affinity drugs (atenolol) could be rapidly extracted from plasma. This is revealed by kinetic and isothermal adsorption studies. On the other hand, almost all proteins from the sample were excluded. This demonstrates the efficiency of RANPs as restricted-access material. Sample preparation was carried out by solid phase microextraction using a probe obtained by the fixation of the RANPs at the end of a glass capillary. Atenolol (in concentrations from 100 to 1200 µg L-1), metoprolol (from 80 to 1000 µg L-1) and propranolol (from 15 to 200 µg L-1) were extracted from spiked plasma samples and analyzed by LC MS/MS without using a separation column. Correlation coefficients >0.99, good precision, accuracy, robustness, and lack of memory effects were observed for all of the analytes. The detection limits (at an S/N of 3) are 25.6, 14.6, and 3.8 µg L-1 for atenolol, metoprolol and propranolol, respectively. Ten samples can be simultaneously extracted within â¼15 min. Plasma samples of patients undergoing medical treatment were successfully analyzed with the method. Graphical abstract Schematic representation of a bovine serum albumin-based restricted access nanoparticle that exclude proteins from a human plasma sample but capture the small analytes.
Assuntos
Antagonistas Adrenérgicos beta/sangue , Nanopartículas/química , Soroalbumina Bovina/química , Animais , Bovinos , Cromatografia Líquida , Humanos , Tamanho da Partícula , Propriedades de Superfície , Espectrometria de Massas em TandemRESUMO
A novel analytical method was developed to determine 5 antihypertensive drugs of different pharmacological classes (angiotensin-converting enzyme inhibitors, calcium channel blockers, α-2 adrenergic receptor agonists, angiotensin II receptor blockers, and aldosterone receptor antagonists) and some of their metabolites in human serum. The untreated samples were directly analyzed in a column switching system using an extraction column packed with restricted access carbon nanotubes (RACNTs) in an ultra-high performance liquid chromatography coupled to a mass spectrometer (UHPLC-MS/MS). The RACNTs column was able to exclude approximately 100% of proteins from the samples in 2.0min, maintaining the same performance for about 300 analytical cycles. The method was validated in accordance with Food and Drug Administration (FDA) guidelines, being linear for all the determined analytes in their respective analytical ranges (coefficients of determination higher than 0.99) with limits of detection (LODs) and quantification (LOQs) ranging from 0.09 to 10.85µgL-1 and from 0.30 to 36.17µgL-1, respectively. High recovery values (88-112%) were obtained as well as suitable results for inter and intra-assay accuracy and precision. The method provided an analytical frequency of 5 samples per hour, including the sample preparation and separation/detection steps. The validated method was successfully used to analyze human serum samples of patients undergoing treatment with antihypertensive drugs, being useful for pharmacometabolomic, pharmacogenomic, and pharmacokinetic studies.
Assuntos
Anti-Hipertensivos/sangue , Anti-Hipertensivos/isolamento & purificação , Análise Química do Sangue/métodos , Cromatografia Líquida de Alta Pressão/instrumentação , Nanotubos de Carbono/química , Análise Química do Sangue/instrumentação , Humanos , Limite de Detecção , Reprodutibilidade dos Testes , Espectrometria de Massas em TandemRESUMO
This work describes restricted access material (RAM) constituted of porous octadecylsilane particles with the outer surface covered with bovine serum albumin (C18-BSA) as a stationary phase to extract drugs from plasma samples by disposable pipette extraction (DPX) for further analysis by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The C18-BSA phase simultaneously excluded macromolecules by chemical diffusion barrier (BSA network) and enrichment of the interior phase (C18) with drug traces by sorption. The hydrophilic barrier of the C18-BSA allows small molecules (drugs) to permeate through the hydrophobic part (C18), while at the same time it excludes the macromolecules by chemical diffusion barrier (BSA network). Optimization of the DPX variables (sorption equilibration time, exclusion of endogenous compounds, and elution step) improved the sensitivity and selectivity of the method, which presented a linear range from the lower limit of quantification (0.5-20.0ngmL-1) to the upper limit of quantification (32.5-10,500ngmL-1), inter- and intra-assay precision with coefficients of variation (CV) lower than 15%, and relative standard error (RSE) of the accuracy ranging from -12% to 11%. The developed method was successfully used to determine five antipsychotics (olanzapine, quetiapine, clozapine, haloperidol, and chlorpromazine) in combination with seven antidepressants (mirtazapine, paroxetine, citalopram, sertraline, imipramine, clomipramine, and fluoxetine), two anticonvulsants (carbamazepine and lamotrigine), and two anxiolytics (diazepam and clonazepam) in plasma samples from schizophrenic patients for therapeutic drug monitoring.
Assuntos
Fármacos do Sistema Nervoso Central/sangue , Equipamentos Descartáveis , Soroalbumina Bovina/química , Espectrometria de Massas em Tandem/métodos , Animais , Ansiolíticos/sangue , Anticonvulsivantes/sangue , Antidepressivos/sangue , Antipsicóticos/sangue , Bovinos , Cromatografia Líquida/métodos , HumanosRESUMO
The analysis of biological samples is a complex and difficult task owing to two basic and complementary issues: the high complexity of most biological matrices and the need to determine minute quantities of active substances and contaminants in such complex sample. To succeed in this endeavor samples are usually subject to three steps of a comprehensive analytical methodological approach: sample preparation, analytes isolation (usually utilizing a chromatographic technique) and qualitative/quantitative analysis (usually with the aid of mass spectrometric tools). Owing to the complex nature of bio-samples, and the very low concentration of the target analytes to be determined, selective sample preparation techniques is mandatory in order to overcome the difficulties imposed by these two constraints. During the last decade new chemical synthesis approaches has been developed and optimized, such as sol-gel and molecularly imprinting technologies, allowing the preparation of novel materials for sample preparation including graphene and derivatives, magnetic materials, ionic liquids, molecularly imprinted polymers, and much more. In this contribution we will review these novel techniques and materials, as well as their application to the bioanalysis niche.
Assuntos
Fracionamento Químico , Grafite , Líquidos Iônicos , Imãs , Impressão Molecular , Transição de FaseRESUMO
A new molecularly imprinted polymer modified with restricted access material (a hydrophilic external layer), (MIP-RAM) was synthesized via polymerization in situ in an open fused silica capillary. This stationary phase was used as sorbent for in-tube solid phase microextraction (in-tube SPME) to determine parabens in breast milk samples by ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). Scanning electron micrographs (SEM) illustrate MIP surface modification after glycerol dimethacrylate (hydrophilic monomer) incorporation. The interaction between parabens and MIP-RAM was investigated by Fourier-transform infrared (FTIR) spectroscopy. The Scatchard plot for MIP-RAM presented two linear parts with different slopes, illustrating binding sites with high- and low-affinity. Endogenous compounds exclusion from the MIP-RAM capillary was demonstrated by in-tube SPME/LC-UV assays carried out with blank milk samples. The in-tube SPME/UHPLC-MS/MS method presented linear range from 10 ng mL(-1) (LLOQ) to 400 ng mL(-1) with coefficients of determination higher than 0.99, inter-assay precision with coefficient of variation (CV) values ranging from 2 to 15%, and inter-assay accuracy with relative standard deviation (RSD) values ranging from -1% to 19%. Analytical validation parameters attested that in-tube SPME/UHPLC-MS/MS is an appropriate method to determine parabens in human milk samples to assess human exposure to these compounds. Analysis of breast milk samples from lactating women demonstrated that the proposed method is effective.
Assuntos
Cromatografia Líquida de Alta Pressão/métodos , Leite Humano/química , Parabenos/análise , Parabenos/isolamento & purificação , Polímeros/síntese química , Microextração em Fase Sólida/métodos , Espectrometria de Massas em Tandem/métodos , Adsorção , Cromatografia Líquida de Alta Pressão/instrumentação , Feminino , Humanos , Interações Hidrofóbicas e Hidrofílicas , Lactação , Impressão Molecular , Parabenos/química , Polimerização , Polímeros/química , Dióxido de Silício/química , Microextração em Fase Sólida/instrumentação , Espectrometria de Massas em Tandem/instrumentaçãoRESUMO
Oxidized carbon nanotubes were covered with layers of bovine serum albumin to result in so-called restricted-access carbon nanotubes (RACNTs). This material can extract Pb(2+) ions directly from untreated human blood serum while excluding all the serum proteins. The RACNTs have a protein exclusion capacity of almost 100% and a maximum Pb(2+) adsorption capacity of 34.5mg g(-1). High resolution transmission electron microscopy, scanning transmission electron microscopy and energy dispersive spectroscopy were used to confirm the BSA layer and Pb(2+) adsorption sites. A mini-column filled with RACNTs was used in an on-line solid phase extraction system coupled to a thermospray flame furnace atomic absorption spectrometry. At optimized experimental conditions, the method has a detection limit as low as 2.1µg L(-1), an enrichment factor of 5.5, and inter- and intra-day precisions (expressed as relative standard deviation) of <8.1%. Recoveries of the Pb(2+) spiked samples ranged from 89.4% to 107.3% for the extraction from untreated human blood serum.
Assuntos
Poluentes Ambientais/sangue , Chumbo/sangue , Nanotubos de Carbono/química , Adsorção , Poluentes Ambientais/química , Humanos , Cinética , Chumbo/química , Microscopia Eletrônica de Transmissão/métodos , Nanotubos de Carbono/ultraestrutura , Espectrofotometria AtômicaRESUMO
In this paper, we propose a new sorbent that is able to extract metal ions directly from untreated biological fluids, simultaneously excluding all proteins from these samples. The sorbent was obtained through the modification of carbon nanotubes (CNTs) with an external bovine serum albumin (BSA) layer, resulting in restricted access carbon nanotubes (RACNTs). The BSA layer was fixed through the interconnection between the amine groups of the BSA using glutaraldehyde as cross-linker. When a protein sample is percolated through a cartridge containing RACNTs and the sample pH is higher than the isoelectric point of the proteins, both proteins from the sample and the BSA layer are negatively ionized. Thus, an electrostatic repulsion prevents the interaction between the proteins from the sample on the RACNTs surface. At the same time, metal ions are adsorbed in the CNTs (core) after their passage through the chains of proteins. The Cd(2+) ion was selected for a proof-of-principle case to test the suitability of the RACNTs due to its toxicological relevance. RACNTs were able to extract Cd(2+) and exclude almost 100% of the proteins from the human serum samples in an online solid-phase extraction system coupled with thermospray flame furnace atomic absorption spectrometry. The limits of detection and quantification were 0.24 and 0.80 µg L(-1), respectively. The sampling frequency was 8.6h(-1), and the intra- and inter-day precisions at the 0.80, 15.0, and 30.0 µg L(-1) Cd(2+) levels were all lower than 10.1% (RSD). The recoveries obtained for human blood serum samples fortified with Cd(2+) ranged from 85.0% to 112.0%. The method was successfully applied to analyze Cd(2+) directly from six human blood serum samples without any pretreatment, and the observed concentrations ranged from Assuntos
Cádmio/sangue
, Nanotubos de Carbono/química
, Extração em Fase Sólida/métodos
, Espectrofotometria Atômica/métodos
, Animais
, Bovinos
, Análise de Injeção de Fluxo/métodos
, Humanos
, Concentração de Íons de Hidrogênio
, Soroalbumina Bovina/química
RESUMO
This study presents the development of a column-switching liquid chromatographic method with direct injection of human plasma for simultaneous determination of four statins (lovastatin, pravastatin, rosuvastatin and simvastatin), the main class of drugs used in the treatment of hyperlipidemia. By using a C18 (30 mm × 4.6 mm, 15 µm) a lab made bovine serum albumin restricted access material (RAM) column was prepared and compared with a commercial alquil-diol silica RAM column (C18, 25 mm × 4.0 mm, 25 µm) in terms of their protein exclusion capacity and micromolecules retention. Foreflush and backflush modes were compared for both RAM columns to the number of theoretical plates, asymmetry, resolution and chromatographic run time. The developed method was validated in the range from 125 to 876 ng mL(-1) for lovastatin, rosuvastatin and simvastatin, and from 500 to 2000 ng mL(-1) for pravastatin, presenting selectivity, precision and accuracy intra and inter-run. Total analysis time (sample preparation and chromatographic separation) was only 16 min when the backflush mode was employed in the column-switching system.