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1.
Anal Chem ; 2020 Sep 06.
Artigo em Inglês | MEDLINE | ID: mdl-32893620

RESUMO

An automated on-line isolation and fractionation system including controlling software was developed for selected nanosized biomacromolecules from human plasma by on-line coupled immunoaffinity chromatography - asymmetric flow field-flow fractionation (IAC - AsFlFFF). The on-line system was versatile, only different monoclonal antibodies, anti-apolipoprotein B-100, anti-CD9, or anti-CD61, were immobilized on monolithic disk columns for isolation of lipoproteins and extracellular vesicles (EVs). The platelet-derived CD61- positive EVs and CD9- positive EVs, isolated by IAC, were further fractionated by AsFlFFF to their size-based subpopulations (e.g. exomeres and exosomes) for further analysis. Field-emission scanning electron microscope elucidated the morphology of the subpopulations, and 20 free amino acids and glucose in EV subpopulations were identified and quantified in ng/mL range using hydrophilic interaction liquid chromatography - tandem mass spectrometry (HILIC-MS/MS). The study revealed that there were significant differences between EV origin and size based subpopulations. The on-line coupled IAC-AsFlFFF system was successfully programmed for reliable execution of 10 sequential isolation and fractionation cycles (37-80 min per cycle) with minimal operator involvement, minimal sample losses, and contamination. The relative standard deviations (RSD) between the cycles for human plasma samples were 0.84-6.6%.

2.
Anal Chim Acta ; 1128: 42-51, 2020 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-32825911

RESUMO

This work reports on the development of the first capillary electrophoresis methodology for the elucidation of extracellular vesicles' (EVs) electrokinetic distributions. The approach is based on capillary electrophoresis coupled with laser-induced fluorescent (LIF) detection for the identification and quantification of EVs after their isolation. Sensitive detection of these nanometric entities was possible thanks to an 'inorganic-species-free' background electrolyte. This electrolyte was made up of weakly charged molecules at very high concentrations to stabilize EVs, and an intra-membrane labelling approach was used to prevent EV morphology modification. The limit of detection for EVs achieved using the developed CE-LIF method reached 8 × 109 EV/mL, whereas the calibration curve was acquired from 1.22 × 1010 to 1.20 × 1011 EV/mL. The CE-LIF approach was applied to provide the electrokinetic distributions of various EVs of animal and human origins, and visualize different EV subpopulations from our recently developed high-yield EV isolation method.

3.
J Sep Sci ; 43(16): 3285-3293, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32506760

RESUMO

Today, wide variety of adsorbents have been developed for sample pretreatment to concentrate and separate harmful substances. However, only a few solid phase microextraction Arrow adsorbents are commercially available. In this study, we developed a new solid phase microextraction Arrow coating, in which nanosheets layered double hydroxides and poly(vinylpyrrolidone) were utilized as the extraction phase and poly(vinyl chloride) as the adhesive. This new coating entailed higher extraction capacity for several volatile organic compounds (allyl methyl sulfide, methyl propyl sulfide, 3-pentanone, 2-butanone, and methyl isobutyl ketone) compared to the commercial Carboxen 1000/polydimethylsiloxane coating. Fabrication parameters for the coating were optimized and extraction and desorption conditions were investigated. The validation of the new solid phase microextraction Arrow coating was accomplished using water sample spiked with volatile organic compounds. Under the optimal conditions, the limits of quantification for the five volatile organic compounds by the new solid phase microextraction Arrow coating and developed gas chromatography with mass spectrometry method were in the range of 0.2-4.6 ng/mL. The proposed method was briefly applied for enrichment of volatile organic compounds in sludge.

4.
J Chromatogr A ; 1619: 460992, 2020 May 24.
Artigo em Inglês | MEDLINE | ID: mdl-32151416
5.
J Chromatogr A ; 1616: 460825, 2020 Apr 12.
Artigo em Inglês | MEDLINE | ID: mdl-31924328

RESUMO

Several calibration approaches were evaluated for the quantitation of volatile organic compounds in air using miniaturized exhaustive and non-exhaustive sampling techniques, such as in-tube extraction (ITEX) and solid phase microextraction (SPME) Arrow. Eleven compounds, 2-ethyl-hexanol, hexanal, nonanal, toluene, ethyl-benzene, methyl isobutyl ketone, acetophenone, p-cymene, α-pinene, trimethylamine and triethylamine, all them found in the natural air samples, were selected as model analytes. Liquid injection, liquid standard addition to the sorbent bed and gas phase standards provided by an automatic permeation system, were evaluated in the case of ITEX packed with laboratory-made 10% polyacrylonitrile (PAN) material. Two different approaches, based on sampling of gas phase compounds from the permeation system and from sample vial containing gas phase standards, were evaluated for SPME Arrow with two different coatings, commercial divinylbenzene-poly(dimethylsiloxane) (DVB-PDMS) and laboratory-made mesoporous Mobil Composition of Matter No. 41 (MCM-41). In addition, interface model approach was used for the calculation of the real concentration of the target analytes in the sample from the total amount of analytes injected into the GC-MS in the case of SPME Arrow. Similar results were obtained with the different approaches used for the quantitation by ITEX and SPME Arrow. However, the use of gas phase standards with sample matrix similar to the natural samples, allowed the permeation system to provide the most reliable results for the quantitation of the target analytes. For this approach, linearity (expressed as r2 values) ranged between 0.991 and 0.999. The limit of detection ranged from 0.5 µg/m3 (trimethylamine, MCM-41) to 2.2 × 10-4 µg/m3 (methyl isobutyl ketone, MCM-41). In addition, the use of the fully automated permeation system provided good reproducibility values that were between 1.4% (acetophenone, MCM-41) and 7.8% (methyl isobutyl ketone, 10% PAN). The linear ranges were at least 3 order of magnitude for all the studied analytes with the exception of the calibration curve developed for trimethylamine with SPME Arrow (linear ranges between LOQ and 4.9 µg/m3 (DVB-PDMS) and LOQ and 9.8 µg/m3 (MCM-41)).


Assuntos
Ar/análise , Microextração em Fase Sólida/métodos , Compostos Orgânicos Voláteis/análise , Calibragem , Cinética , Reprodutibilidade dos Testes
6.
Anal Chim Acta ; 1091: 160-168, 2019 Dec 24.
Artigo em Inglês | MEDLINE | ID: mdl-31679569

RESUMO

A new, fast and selective immunoaffinity chromatographic method including a methacrylate-based convective interaction media (CIM®) disk monolithic column, immobilized with anti-human CD61 antibody, was developed for the isolation of CD61-containing platelet-derived extracellular vesicles (EVs) from plasma. The isolated EVs were detected and size characterized by asymmetrical flow field-flow fractionation (AsFlFFF) with multi-angle light-scattering (MALS) and dynamic light-scattering (DLS) detection, and further confirmed by nanoparticle tracking analysis (NTA) and transmission electron microscopy (TEM). The mean size of platelet-derived EV isolates from the anti-CD61 CIM® disk monolithic column were 174 nm (SD 60 nm) based on the NTA results. These results indicated a successful isolation of platelet-derived EVs, which was confirmed by Western blotting the isolates against the EV-specific markers CD9 and TSG101 together with transmission electron microscopy. Additional elucidation of MALS and DLS data provided detailed information of the size distribution of the isolated fractions, confirming the successful isolation of also small platelet-derived EVs ranging from 30 to 130 nm based on the hydrodynamic radii. The isolation procedure took only 19 min and the time can be even further decreased by increasing the flow rate. The same immunoaffinity chromatographic procedure, following AsFlFFF allowed also the isolation and characterization of platelet-derived EVs from plasma in under 60 min. Since it is possible to regenerate the anti-CD61 disk for multiple uses, the methodology developed in this study provides a viable substitution and addition to the conventional EV isolation procedures.


Assuntos
Plaquetas/citologia , Cromatografia de Afinidade/métodos , Vesículas Extracelulares , Animais , Anticorpos Imobilizados/imunologia , Difusão Dinâmica da Luz , Vesículas Extracelulares/química , Vesículas Extracelulares/imunologia , Fracionamento por Campo e Fluxo , Humanos , Integrina beta3/imunologia , Camundongos , Tamanho da Partícula , Ácidos Polimetacrílicos/química
7.
Sci Rep ; 9(1): 11235, 2019 08 02.
Artigo em Inglês | MEDLINE | ID: mdl-31375727

RESUMO

Low-density lipoprotein (LDL) is considered the major risk factor for the development of atherosclerotic cardiovascular diseases (ASCVDs). A novel and rapid method for the isolation of LDL from human plasma was developed utilising affinity chromatography with monolithic stationary supports. The isolation method consisted of two polymeric monolithic disk columns, one immobilized with chondroitin-6-sulfate (C6S) and the other with apolipoprotein B-100 monoclonal antibody (anti-apoB-100 mAb). The first disk with C6S was targeted to remove chylomicrons, very-low-density lipoprotein (VLDL) particles, and their remnants including intermediate-density lipoprotein (IDL) particles, thus allowing the remaining major lipoprotein species, i.e. LDL, lipoprotein(a) (Lp(a)), and high-density lipoprotein (HDL) to flow to the anti-apoB-100 disk. The second disk captured LDL particles via the anti-apoB-100 mAb attached on the disk surface in a highly specific manner, permitting the selective LDL isolation. The success of LDL isolation was confirmed by different techniques including quartz crystal microbalance. In addition, the method developed gave comparable results with ultracentrifugation, conventionally used as a standard method. The reliable results achieved together with a short isolation time (less than 30 min) suggest the method to be suitable for clinically relevant LDL functional assays.

8.
Anal Chem ; 91(13): 8507-8515, 2019 07 02.
Artigo em Inglês | MEDLINE | ID: mdl-31247721

RESUMO

Comprehensive and time-dependent information (e.g., chemical composition, concentration) of volatile organic compounds (VOCs) in atmospheric, indoor, and breath air is essential to understand the fundamental science of the atmosphere, air quality, and diseases diagnostic. Here, we introduced a fully automated online dynamic in-tube extraction (ITEX)-gas chromatography/mass spectrometry (GC/MS) method for continuous and quantitative monitoring of VOCs in air. In this approach, modified Cycle Composer software and a PAL autosampler controlled and operated the ITEX preconditioning, internal standard (ISTD) addition, air sampling, and ITEX desorption sequentially to enable full automation. Air flow passed through the ITEX with the help of an external pump, instead of plunger up-down strokes, to allow larger sampling volumes, exhaustive extraction, and consequently lower detection limits. Further, in order to evaluate the ITEX system stability and to develop the corresponding quantitative ITEX method, two laboratory-made permeation systems (for standard VOCs and ISTD) were constructed. The stability and suitability of the developed system was validated with a consecutive 19 day atmospheric air campaign under automation. By using an electrospun polyacrylonitrile nanofibers packed ITEX, selective extraction of some VOCs and durability of over 1500 extraction and desorption cycles were achieved. Especially, the latter step is critically important for on-site long-term application at remote regions. This ITEX method provided 2-3 magnitudes lower quantitation limits than the headspace dynamic ITEX method and other needle trap methods. Our results proved the excellence of the fully automated online dynamic ITEX-GC/MS system for tracking VOCs in the atmospheric air.

9.
Mikrochim Acta ; 186(7): 412, 2019 06 11.
Artigo em Inglês | MEDLINE | ID: mdl-31187285

RESUMO

Mesoporous silica-coated solid phase microextraction (SPME) Arrow systems were developed for capturing of low-molecular-weight aliphatic amines (LMWAAs) from complicated sample matrices. Specifically, silicas of type MCM-41, SBA-15 and KIT-6 were chosen as substrates to afford size-exclusion selectivity. They possess ordered multidimensional pore-channel structures and mesopore sizes between 3.8 and 8.2 nm. Their surface acidity was enhanced by grafting them with a layer of titanium hydrogenphosphate (-TP). This enhanced the chemical selectivity for basic LMWAAs. The siliceous coatings increased the extraction of ethylamine, diethylamine (DEA) and triethylamine (TEA) by factors of 18.6-102.5, 4.8-10.8 and 2.6-4.0, respectively, when compared to the commercial SPME Arrow with polydimethylsiloxane/divinylbenzene coating. Among them, the MCM-41 and MCM-41-TP coated SPME Arrows demonstrated exceptional selectivity towards LMWAAs that were quantified by gas chromatography-mass spectrometry (GC-MS). The total peak area ratios of LMWAAs/ten competing compounds were 25.4 and 36.3, respectively. The extraction equilibrium was reached within 20-30 min. The MCM-41 and MCM-41-TP derived SPME Arrows gave very similar results (18.4 ± 2.1-376 ± 12 ng g-1 to DEA and TEA) when applied to urban mushroom samples. SPME Arrow with MCM-41 coatings followed by GC-MS was applied also to the analysis of atmospheric air and urine samples resulting in high selectivity due to the size and mesoporous structure of the functionalized silica, and its chemical interactions with the LMWAAs. Graphical abstract Scheme of synthesis of the MCM-41 silicas, and the preparation of solid phase microextraction Arrow coatings. They were employed for selective capturing of aliphatic amines from complex sample matrices, followed by gas chromatography-mass spectrometry.

10.
J Chromatogr A ; 1597: 202-208, 2019 Jul 19.
Artigo em Inglês | MEDLINE | ID: mdl-31030954

RESUMO

The applicability of an aerial drone as a carrier for new passive and active miniaturized air sampling systems, including solid phase microextration Arrow (SPME Arrow) and in-tube extraction (ITEX), was studied in this research. Thermal desorption, gas chromatography and mass spectrometry were used for the determination of volatile organic compounds (VOCs) collected by the sampling systems. The direct comparison of the profiles of VOCs, simultaneously sampled in air by SPME Arrow system including four different coatings, allowed the elucidation of their adsorption selectivity. A more complex experimental design, involving 20 samples (10 flights) and non-supervised pattern recognition techniques, was needed for the clarification of the same sampling parameters in the case of five ITEX sorbent materials. In addition, ITEX sampling accessories, such as particle, water and ozone traps, were evaluated by comparing the results obtained for air samples simultaneously collected by two ITEX systems, packed with the same sorbent and furnished or not with sampling accessories. The effect of the aerial drone horizontal displacement (HD) on the sampling efficiency was clear in the case of SPME Arrow. The number of detected compounds and their relative peak area values (RPA) revealed a clear increase (4 and 43%, respectively) in comparison with samples collected without drone HD. However, just minor differences were observed in the case of ITEX (2 compounds and 9% of the ∑RPA). In addition, the system was able to provide almost simultaneous passive (SPME Arrow) and active (ITEX) samplings at different altitudes (5 and 50 m), being a good tool for low cost vertical profiling studies (∑RPA decreased over 35% for the samples collected at 50 m). Finally, the successful simultaneous air sampling by SPME Arrow and ITEX systems in two difficult access places, such as boreal forest and wetlands, was demonstrated, resulting in 21 and 31 detected compounds in forest and wetlands by SPME Arrow, and 27 and 39 compounds by ITEX.


Assuntos
Ar/análise , Monitoramento Ambiental/instrumentação , Monitoramento Ambiental/métodos , Compostos Orgânicos Voláteis/análise , Adsorção , Cromatografia Gasosa-Espectrometria de Massas , Miniaturização , Microextração em Fase Sólida
11.
J Chromatogr A ; 1559: 1, 2018 07 20.
Artigo em Inglês | MEDLINE | ID: mdl-29859548
12.
Anal Chim Acta ; 1024: 93-100, 2018 Sep 18.
Artigo em Inglês | MEDLINE | ID: mdl-29776551

RESUMO

New chemical vapor reaction (CVR) and atomic layer deposition (ALD)-conversion methods were utilized for preparation of metal organic frameworks (MOFs) coatings of solid phase microextraction (SPME) Arrow for the first time. With simple, easy and convenient one-step reaction or conversion, four MOF coatings were made by suspend ALD iron oxide (Fe2O3) film or aluminum oxide (Al2O3) film above terephthalic acid (H2BDC) or trimesic acid (H3BTC) vapor. UIO-66 coating was made by zirconium (Zr)-BDC film in acetic acid vapor. As the first documented instance of all-gas phase synthesis of SPME Arrow coatings, preparation parameters including CVR/conversion time and temperature, acetic acid volume, and metal oxide film/metal-ligand films thickness were investigated. The optimal coatings exhibited crystalline structures, excellent uniformity, satisfactory thickness (2-7.5 µm), and high robustness (>80 times usage). To study the practical usefulness of the coatings for the extraction, several analytes with different chemical properties were tested. The Fe-BDC coating was found to be the most selective and sensitive for the determination of benzene ring contained compounds due to its highly hydrophobic surface and unsaturated metal site. UIO-66 coating was best for small polar, aromatic, and long chain polar compounds owing to its high porosity. The usefulness of new coatings were evaluated for gas chromatography-mass spectrometer (GC-MS) determination of several analytes, present in wastewater samples at three levels of concentration, and satisfactory results were achieved.

13.
Anal Chem ; 90(8): 5366-5374, 2018 04 17.
Artigo em Inglês | MEDLINE | ID: mdl-29589451

RESUMO

When using biosensors, analyte biomolecules of several different concentrations are percolated over a chip with immobilized ligand molecules that form complexes with analytes. However, in many cases of biological interest, e.g., in antibody interactions, complex formation steady-state is not reached. The data measured are so-called sensorgram, one for each analyte concentration, with total complex concentration vs time. Here we present a new four-step strategy for more reliable processing of this complex kinetic binding data and compare it with the standard global fitting procedure. In our strategy, we first calculate a dissociation graph to reveal if there are any heterogeneous interactions. Thereafter, a new numerical algorithm, AIDA, is used to get the number of different complex formation reactions for each analyte concentration level. This information is then used to estimate the corresponding complex formation rate constants by fitting to the measured sensorgram one by one. Finally, all estimated rate constants are plotted and clustered, where each cluster represents a complex formation. Synthetic and experimental data obtained from three different QCM biosensor experimental systems having fast (close to steady-state), moderate, and slow kinetics (far from steady-state) were evaluated using the four-step strategy and standard global fitting. The new strategy allowed us to more reliably estimate the number of different complex formations, especially for cases of complex and slow dissociation kinetics. Moreover, the new strategy proved to be more robust as it enables one to handle system drift, i.e., data from biosensor chips that deteriorate over time.


Assuntos
Algoritmos , Técnicas Biossensoriais , Técnicas de Microbalança de Cristal de Quartzo , Cinética
14.
Environ Sci Technol ; 51(10): 5602-5610, 2017 May 16.
Artigo em Inglês | MEDLINE | ID: mdl-28422480

RESUMO

Amines are recognized as key compounds in new particle formation (NPF) and secondary organic aerosol (SOA) formation. In addition, ozonolysis of α-pinene contributes substantially to the formation of biogenic SOAs in the atmosphere. In the present study, ozonolysis of α-pinene in the presence of dimethylamine (DMA) was investigated in a flow tube reactor. Effects of amines on SOA formation and chemical composition were examined. Enhancement of NPF and SOA formation was observed in the presence of DMA. Chemical characterization of gas- and particle-phase products by high-resolution mass spectrometric techniques revealed the formation of nitrogen containing compounds. Reactions between ozonolysis reaction products of α-pinene, such as pinonaldehyde or pinonic acid, and DMA were observed. Possible reaction pathways are suggested for the formation of the reaction products. Some of the compounds identified in the laboratory study were also observed in aerosol samples (PM1) collected at the SMEAR II station (Hyytiälä, Finland) suggesting that DMA might affect the ozonolysis of α-pinene in ambient conditions.


Assuntos
Poluentes Atmosféricos , Dimetilaminas , Monoterpenos/química , Aerossóis , Monoterpenos Bicíclicos , Finlândia , Ozônio
17.
J Chromatogr A ; 1486: 76-85, 2017 Feb 24.
Artigo em Inglês | MEDLINE | ID: mdl-27847109

RESUMO

In this study, a novel solid phase microextration (SPME) Arrow was prepared for the sampling of volatile low molecular weight alkylamines (trimethylamine (TMA) and triethylamine (TEA)) in wastewater, salmon and mushroom samples before gas chromatographic separation with mass spectrometer as detector. Acidified zeolitic imidazolate framework-8 (A-ZIF-8) was utilized as adsorbent and poly(vinyl chloride) (PVC) as the adhesive. The custom SPME Arrow was fabricated via a physical adhesion: (1) ZIF-8 particles were suspended in a mixture of tetrahydrofuran (THF) and PVC to form a homogeneous suspension, (2) a non-coated stainless steel SPME Arrow was dipped in the ZIF-8/PVC suspension for several times to obtain a uniform and thick coating, (3) the pore size of ZIF-8 was modified by headspace exposure to hydrochloric acid in order to increase the extraction efficiency for amines. The effect of ZIF-8 concentration in PVC solution, dipping cycles and aging temperature on extraction efficiency was investigated. In addition, sampling parameters such as NaCl concentration, sample volume, extraction time, potassium hydroxide concentration, desorption temperature and desorption time were optimized. The Arrow-to-Arrow reproducibilities (RSDs) for five ZIF-8 coated Arrows were 15.6% and 13.3% for TMA and TEA, respectively. The extraction with A-ZIF-8/PVC Arrow was highly reproducible for at least 130 cycles without noticeable decrease of performance (RSD<12.5%). Headspace SPME of 7.5mL sample solution with the fabricated ZIF-8 coated Arrow achieved linear ranges of 1-200ngmL-1 for both TMA and TEA. The limit of quantitation (LOQ) was 1ngmL-1 for both TMA and TEA. The method was successfully applied to the determination of TMA and TEA in wastewater, salmon and mushroom samples giving satisfactory selectivity towards the studied amines.


Assuntos
Aminas/análise , Aminas/química , Análise de Alimentos/métodos , Cromatografia Gasosa-Espectrometria de Massas , Imidazóis/química , Microextração em Fase Sólida/métodos , Águas Residuárias/química , Zeolitas/química , Agaricales/química , Animais , Etilaminas/análise , Etilaminas/química , Metilaminas/análise , Metilaminas/química , Peso Molecular , Cloreto de Polivinila/química , Salmão , Alimentos Marinhos , Cloreto de Sódio/química , Microextração em Fase Sólida/instrumentação , Aço Inoxidável/química , Temperatura
18.
Anal Biochem ; 518: 25-34, 2017 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-27984014

RESUMO

Two complementary instrumental techniques were used, and the data generated was processed with advanced numerical tools to investigate the interactions between anti-human apoB-100 monoclonal antibody (anti-apoB-100 Mab) and apoB-100 containing lipoproteins. Partial Filling Affinity Capillary Electrophoresis (PF-ACE) combined with Adsorption Energy Distribution (AED) calculations provided information on the heterogeneity of the interactions without any a priori model assumptions. The AED calculations evidenced a homogenous binding site distribution for the interactions. Quartz Crystal Microbalance (QCM) studies were used to evaluate thermodynamics and kinetics of the Low-Density Lipoprotein (LDL) and anti-apoB-100 Mab interactions. High affinity and selectivity were observed, and the emerging data sets were analysed with so called Interaction Maps. In thermodynamic studies, the interaction between LDL and anti-apoB-100 Mab was found to be predominantly enthalpy driven. Both techniques were also used to study antibody interactions with Intermediate-Density (IDL) and Very Low-Density (VLDL) Lipoproteins. By screening affinity constants for IDL-VLDL sample in a single injection we were able to distinguish affinity constants for both subpopulations using the numerical Interaction Map tool.


Assuntos
Anticorpos Monoclonais Murinos/química , Apolipoproteína B-100/química , Modelos Químicos , Termodinâmica , Animais , Humanos , Cinética , Camundongos
19.
Anal Biochem ; 514: 12-23, 2016 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-27623434

RESUMO

Immunoaffinity procedure was developed for isolation of low density lipoprotein (LDL) from biological samples by using silica-derived immunoaffinity sorbent. Sorbent was prepared by immobilization of monoclonal anti-apoB-100 antibody onto macroporous silica particles, using carefully optimized binding chemistry. Binding capacity of the sorbent towards LDL was determined by batch extraction experiments with solutions of isolated LDL in phosphate-buffered saline, and found to be 8 mg LDL/g. The bound LDL fraction was readily released from the sorbent by elution with ammonia at pH 11.2. The total time needed for isolation procedure was less than 1 h, with LDL recoveries being essentially quantitative for samples containing less than 0.3 mg LDL/mL. With higher concentrations, recoveries were less favorable, most probably due to irreversible adsorption caused by LDL aggreggation. However, reusability studies with isolated LDL at concentration 0.2 mg/mL indicate that the developed immunoaffinity material may be used for multiple binding-release cycles, with minor losses in binding capacity. Finally, the sorbent was successfully applied to isolation of LDL from diluted plasma. Apart from its practical implications for LDL isolation, this study provides crucial insights into issues associated with LDL-sorbent interactions, and may be useful in future efforts directed to development of lipoprotein isolation approaches.


Assuntos
Apolipoproteína B-100 , Técnicas de Imunoadsorção , Lipoproteínas LDL/isolamento & purificação , Apolipoproteína B-100/imunologia , Calibragem , Eletroforese em Gel de Poliacrilamida , Ensaio de Imunoadsorção Enzimática , Humanos , Técnicas de Imunoadsorção/instrumentação , Lipoproteínas LDL/metabolismo , Compostos de Silício/química , Dióxido de Silício
20.
Environ Sci Pollut Res Int ; 23(17): 17008-17, 2016 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-27206750

RESUMO

Emerging organic contaminants in wastewater are usually analyzed by targeted approaches, and especially estrogens have been the focus of environmental research due to their high hormonal activity. The selection of specific target compounds means, however, that most of the sample components, including transformation products and potential new contaminants, are neglected. In this study, the fate of steroidal compounds in wastewater treatment processes was evaluated by a nontargeted approach based on comprehensive two-dimensional gas chromatography-time-of-flight mass spectrometry. The potential of the nontargeted approach to generate comprehensive information about sample constituents was demonstrated with use of statistical tools. Transformation pathways of the tentatively identified compounds with steroidal four-ring structure were proposed. The purification efficiency of the wastewater treatment plants was studied, and the distribution of the compounds of interest in the suspended solids, effluent water, and sludge was measured. The results showed that, owing to strong adsorption of hydrophobic compounds onto the solid matter, the steroids were mostly bound to the suspended solids of the effluent water and the sewage sludge at the end of the treatment process. The most abundant steroid class was androstanes in the aqueous phase and cholestanes in the solid phase. 17ß-estradiol was the most abundant estrogen in the aqueous phase, but it was only detected in the influent samples indicating efficient removal during the treatment process. In the sludge samples, however, high concentrations of an oxidation product of 17ß-estradiol, estrone, were measured.


Assuntos
Cromatografia Gasosa-Espectrometria de Massas/métodos , Esteroides/análise , Águas Residuárias/química , Poluentes Químicos da Água/análise , Purificação da Água/métodos
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