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1.
J Sci Food Agric ; 100(1): 301-307, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31525264

RESUMO

BACKGROUND: Cyromazine (CYR) and its main degradation product melamine (MEL) are attracting wide attention due to their potential hazards to the environment and humans. In this work, double surfactants-assisted electromembrane extraction (DS-EME) by Tween 20 and alkylated phosphate was firstly used for purification and extraction of CYR and MEL, and the extract was directly analyzed by capillary electrophoresis with capacitively coupled contactless conductivity detection. RESULTS: Under the optimum conditions, two targets could be well separated from the main interferences, including common biogenic amines and inorganic cations within 14 min. This developed method was successfully applied to the analyses of surface water, soil and cucumber samples, and the average recoveries were in the range 93.3-112%. DS-EME provided a synergistic purification and enrichment effect for CYR and MEL by adding Tween 20 and alkylated phosphate into donor phase and supporting liquid membrane, respectively. Satisfactory limits of detection [0.2-1.5 ng mL-1 , signal-to-noise ratio (S/N) = 3] could be obtained in the tested sample matrices, and the corresponding enrichment factors were up to 115∼123 times. CONCLUSION: This developed method provides an alternative for the simultaneous analysis of CYR and MEL in complex real-world samples. © 2019 Society of Chemical Industry.


Assuntos
Cucumis sativus/química , Poluentes do Solo/isolamento & purificação , Extração em Fase Sólida/métodos , Triazinas/isolamento & purificação , Poluentes da Água/isolamento & purificação , Condutividade Elétrica , Eletroforese Capilar , Membranas Artificiais , Poluentes do Solo/química , Extração em Fase Sólida/instrumentação , Tensoativos/química , Triazinas/química , Poluentes da Água/química
2.
J Sci Food Agric ; 100(2): 811-816, 2020 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-31617212

RESUMO

BACKGROUND: Natamycin is often added to pastries, cheeses, and beverages. The residual amount of natamycin should be less than 10 mg kg-1 . The current method for its determination in various foodstuffs is high-performance liquid chromatography (HPLC). Capillary electrophoresis (CE) is a simple, fast, and environmentally friendly method with low reagent consumption and comparable separation performance. However, no reports were found on the determination of natamycin in foods by CE. A CE method to determine natamycin is therefore sought. RESULTS: Natamycin in foods was determined by the capillary zone electrophoresis (CZE) method with ultraviolet-visible (UV) detection. Separation conditions were optimized as 20 mM Na2 HPO4 , pH 9.2, with 25 kV applied voltage, and UV detection at 306 nm. Under optimal conditions, electrophoretic analysis was completed in less than 4 min, with a limit of detection (LOD) of 0.065 µg mL-1 and limit of quantitation (LOQ) of 0.22 µg mL-1 . A good linear relationship (r2 = 0.999) was obtained at the range of 0.1-25 µg mL-1 . A comparison with the HPLC-UV method was also carried out according to the National Standards of the People's Republic of China. CONCLUSION: The results obtained by the CZE and HPLC methods are comparable but the proposed CZE method can help us obtain a shorter detection time at low cost. © 2019 Society of Chemical Industry.


Assuntos
Bebidas/análise , Queijo/análise , Cromatografia Líquida de Alta Pressão/métodos , Eletroforese Capilar/métodos , Conservantes de Alimentos/análise , Natamicina/análise , China , Limite de Detecção
3.
Food Chem ; 308: 125647, 2020 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-31648088

RESUMO

An analyser was constructed on the basis of on-line connection of capillary electrophoresis over a short separation path with continuous mini-dialysis sample collection. The developed instrument was employed for simultaneous determination of the majority minerals K+, Ca2+, Na+ and Mg2+ (and possibly NH4+ ions) in commercially available unflavoured yoghurts. The cations are released from the organic structures by digestion with boiling 6 mol/L HCl. They were separated from residues of the organic matrix by a dialysis probe and were transferred to a stream of water. From the continuous stream, the dialysate was injected into the separation capillary through a flow-gating interface. Within the reliability interval, the determined total mineral content was equal to their contents stated on the yoghurt labels and the content determined by flame atomic absorption spectrometry and complexometric titration. The relative standard deviation of the electrophoretic determination is mostly about 5%.


Assuntos
Iogurte/análise , Cátions/química , Diálise , Eletroforese Capilar/métodos , Reprodutibilidade dos Testes , Espectrofotometria Atômica , Fatores de Tempo , Água/análise
4.
Anal Bioanal Chem ; 411(27): 7197-7206, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31616969

RESUMO

Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) is the fundamental technique for protein separation by size. Applying this technology in capillary format, gaining high separation efficiency in a more automated way, is a key technology for size separation of proteins in the biopharmaceutical industry. However, unequivocal identification by online mass spectrometry (MS) is impossible so far, due to strong interference in the electrospray process by SDS and other components of the SDS-MW separation gel buffer. Here, a heart-cut two-dimensional electrophoretic separation system applying an electrically isolated valve with an internal loop of 20 nL is presented. The peak of interest in the CE (SDS) separation is transferred to the CZE-MS, where electrospray-interfering substances of the SDS-MW gel are separated prior to online electrospray ionization mass spectrometry. An online SDS removal strategy for decomplexing the protein-SDS complex is implemented in the second dimension, consisting of the co-injection of organic solvent and cationic surfactant. This online CE (SDS)-CZE-MS system allows MS characterization of proteoforms separated in generic CE (SDS), gaining additional separation in the CZE and detailed MS information. In general, the system can be applied to all kinds of proteins separated by CE (SDS). Here, we present results of the CE (SDS)-CZE-MS system on the analysis of several biopharmaceutically relevant antibody impurities and fragments. Additionally, the versatile application spectrum of the system is demonstrated by the analysis of extracted proteins from soybean flour. The online hyphenation of CE (SDS) resolving power and MS identification capabilities will be a powerful tool for protein and mAb characterization. Graphical abstract Two-dimensional capillary electrophoresis system hyphenated with mass spectrometry for the characterization of CE (SDS)-separated proteins. As first dimension, a generic and high MS-interfering CE (SDS) separation is performed for size separation. After heart-cut transfer of the unknown CE (SDS) protein peak, via a four-port nanoliter valve to a volatile electrolyte system as second dimension, interference-free mass spectrometric data of separated mAb fragments and soybean proteins are obtained.


Assuntos
Eletroforese Capilar/instrumentação , Proteínas de Soja/isolamento & purificação , Soja/química , Espectrometria de Massas por Ionização por Electrospray/instrumentação , Eletroforese em Gel de Poliacrilamida , Desenho de Equipamento , Dodecilsulfato de Sódio/química , Proteínas de Soja/análise
5.
Se Pu ; 37(8): 878-886, 2019 Aug 08.
Artigo em Chinês | MEDLINE | ID: mdl-31642259

RESUMO

One of the major shortcomings in top-down proteomics is the lack of efficient separations for intact proteins that can be effectively coupled to mass spectrometry. Capillary zone electrophoresis (CZE) and nanoflow reversed-phase liquid chromatography (nanoRPLC) are two methods that can be coupled to mass spectrometry directly and have been recently advanced in terms of their ability to separate intact proteins in complex biological mixtures. In this work, for the first time, we compared the state-of-the-art nanoRPLC-MS/MS and CZE-MS/MS platforms for top-down characterization of a standard protein mixture and an Escherichia coli (E. coli) proteome sample. CZE-MS produced comparable signals of standard proteins to RPLC-MS with 10-times less sample consumption. Interestingly, the proteins in RPLC-MS tended to have higher charge states than in CZE-MS, most likely due to the high acetonitrile concentration in RPLC mobile phase, leading to the more extensive unfolding of proteins in RPLC compared to in CZE. CZE-MS/MS identified 159 proteins and 513 proteoforms using 1-µg E. coli proteins in a single run and outperformed RPLC-MS/MS using 1-µg E. coli proteins in terms of protein and proteoform identifications (159 vs. 105 proteins and 513 vs. 277 proteoforms). The RPLC-MS/MS using 8-µg E. coli proteins identified 245 proteins and 1004 proteoforms in a single run, and the data was much better than that from CZE-MS/MS (1-µg E. coli proteins) regarding the number of identifications because of the 8-times higher sample loading amount and significantly wider separation window of RPLC-MS/MS compared to CZE-MS/MS.


Assuntos
Cromatografia de Fase Reversa , Eletroforese Capilar , Proteômica/métodos , Espectrometria de Massas em Tandem , Escherichia coli , Proteínas de Escherichia coli/análise
6.
Klin Lab Diagn ; 64(8): 453-458, 2019.
Artigo em Russo | MEDLINE | ID: mdl-31479598

RESUMO

The article contains the literature review on laboratory criteria of detection and monitoring of the progression of the disease in patients with the diagnosis of diabetes mellitus. It also covers the issues of methodical approaches to the identification of glycated hemoglobin (HbA1c). The findings of author's researches of glycated hemoglobin in 149 patients have been given within the framework of comparison of two methodical approaches and comparison of the results with the subsequent classification of the received data. A random laboratory finding of qualitative hemoglobinopathy has been demonstrated, and the results recognized as unqualifiable and the approach to classification of such values have been discussed.Comparison of the results of glycated hemoglobin identification performed by different methods. 149 patients underwent a one-stage identification of glycated hemoglobin from plasma stabilized with K2-EDTA on Bio-Rad D10 and Sebia Capillarys Flex Piercing 2. Comparative study of the results of glycated hemoglobin identification has shown a difference in absolute values. However, a statistically reliable (p < 0.05) correlation between the values of glycated hemoglobin, expressed as a percentage obtained by different methods, has been revealed. In this case, the choice of a method for identifying glycated hemoglobin is not a matter of principal but it is important to adhere to the same method in treatment and long-term monitoring.


Assuntos
Diabetes Mellitus/diagnóstico , Hemoglobina A Glicada/análise , Eletroforese Capilar , Humanos
7.
J Chromatogr A ; 1604: 460469, 2019 Oct 25.
Artigo em Inglês | MEDLINE | ID: mdl-31474465

RESUMO

While they are commonly used as ultraviolet (UV) filters in plastic food packaging materials, benzophenones (BPs) are reported as environmental endocrine disruptors, and some of them possess significant estrogenic activity. Therefore sensitive determination of the content of those UV filters in plastic polymers is of vital importance in safety assessment of food packaging materials. Here, the sheathless capillary electrophoresis-electrospray ionization-tandem mass spectrometry (CE-ESI-MS/MS) method is applied for the first time to sensitively detect BP-type UV filters in plastic food packaging materials. We investigate and optimize a variety of factors that may affect ESI-MS efficiency and CE separation. Sensitive detection of six BP-type UV filters is achieved using sheathless CE-ESI-MS/MS in conjunction with accelerated solvent extraction and solid phase extraction, with the limit-of-detection of 7 pg/mL-2.4 ng/mL. The method exhibits excellent inter/intra-day repeatability along with the advantages of efficient separation, rapid analysis, low sample consumption and high sensitivity. Six BP-type UV filters in eight different brands of plastic films obtained from supermarkets are successfully analyzed using the method. Good recoveries of 81.3-104.1% at three levels of spiked concentrations are achieved with low RSDs (n = 5) of 2.5-8.7%. Our study shows that the sheathless CE-ESI-MS/MS is a robust and reliable method for sensitive and rapid analysis of UV filters, which would be of potential application in safety assessment of plastic food packaging materials.


Assuntos
Benzofenonas/análise , Técnicas de Química Analítica/métodos , Eletroforese Capilar , Embalagem de Alimentos , Plásticos , Espectrometria de Massas por Ionização por Electrospray , Disruptores Endócrinos/análise , Plásticos/química
8.
Forensic Sci Int ; 302: 109905, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31394460

RESUMO

Fingerprint detection and Short Tandem Repeat (STR) typing are two approaches used for identification of individuals. The main goal of forensic laboratories is the development of a standardized protocol to obtain an STR profile from latent fingerprints, by typing the DNA transferred onto touched objects. The results obtained in this field derive from studies conducted under controlled laboratory conditions. Here, for the first time, we report two different profiles obtained by DNA purified by latent fingerprints enhanced with dactyloscopic powders at a crime scene, 14 years previously. DNA extraction phase was optimized to improve removal of powder and automatically conducted. Despite the low concentration of purified DNA, it was not degraded. Even if quality of the profile is influenced by several factors such as the method of acquisition and storage conditions of the fingerprint, results obtained are adequately informative and could be uploaded to the CODIS database.


Assuntos
Impressões Digitais de DNA/métodos , DNA/isolamento & purificação , Dermatoglifia , Repetições de Microssatélites , Eletroforese Capilar , Humanos , Pós , Reação em Cadeia da Polimerase em Tempo Real , Análise de Regressão , Manejo de Espécimes/métodos
9.
J Agric Food Chem ; 67(31): 8425-8430, 2019 Aug 07.
Artigo em Inglês | MEDLINE | ID: mdl-31322874

RESUMO

In recent years, non-targeted methods have been a popular "buzz" phrase in food fraud detection. Using analytical instrumentation techniques, non-targeted methods have been developed and applied in many food and agricultural situations. However, confusion and misstatements remain regarding how the methods are used. This perspective will discuss the definitions related to non-targeted testing, the procedure of developing and validating methods, the techniques and data analysis, and opportunities and challenges regarding the use of this class of analytical methods. The perspective seeks to provide readers with the latest information regarding recent advances in the use of non-targeted methods.


Assuntos
Análise de Alimentos/métodos , Contaminação de Alimentos/análise , Cromatografia Líquida/métodos , Eletroforese Capilar/métodos , Análise de Alimentos/instrumentação , Humanos , Espectroscopia de Ressonância Magnética/métodos , Espectrometria de Massas/métodos
10.
J Chromatogr A ; 1603: 361-370, 2019 Oct 11.
Artigo em Inglês | MEDLINE | ID: mdl-31257038

RESUMO

Separation efficiency is ideally controlled by molecular diffusion in capillary electrophoresis (CE). However, other adverse phenomena, such as solute adsorption on capillary surface, tend to increase the peak dispersion. An interesting alternative to limit the solute adsorption is to avoid as much as possible the contact of the solute with the capillary surface by elaborating superhydrophobic (SH) coatings on fused silica capillary surfaces. This work describes an optimized protocol to get non-wettable SH coating using hydrophobically modified silica nanoparticle suspensions (Glaco™), based on simple capillary flushes and thermal stabilization. In this protocol, the control of the air flushing after the introduction of the Glaco™ suspension in the capillary was found crucial to get optimized coating coverage and reproducibility. The SH coating was characterized by ellipsometry, atomic force microscopy, scanning electron microscopy, contact angle (about 159°) and the observation of the meniscus of water in the coated capillary. The hydrodynamic behavior of the SH coated capillary was investigated by plotting the Poiseuille law. Finally, electrophoretic separations of a peptide mixture in acidic conditions demonstrated the interest of this approach with an increase by a factor 2 of the separation efficiency compared to fused silica capillary.


Assuntos
Eletroforese Capilar/métodos , Interações Hidrofóbicas e Hidrofílicas , Adsorção , Vidro/química , Hidrodinâmica , Microscopia de Força Atômica , Peptídeos/análise , Reprodutibilidade dos Testes
11.
J Agric Food Chem ; 67(28): 8053-8060, 2019 Jul 17.
Artigo em Inglês | MEDLINE | ID: mdl-31276393

RESUMO

The development of analytical methods for acrylamide formed during food processing is of great significance for food safety, but limited by its inherent characteristics, the analysis of acrylamide is a continuing challenge. In this study, an efficient derivatization strategy for acrylamide based on thiol-ene click reaction with cysteine as derivatization reagent was proposed, and the resulting derivative was then analyzed by capillary electrophoresis with capacitively coupled contactless conductivity detection (CE-C4D). After systematic investigation including catalyst dosage (0-20 mM), reaction temperature (30-90 °C) and time (1-60 min), and cysteine concentration (0.2-3.6 mM), acrylamide could be efficiently labeled by 2.0 mM cysteine at 70 °C for 10 min using 4 mM n-butylamine as catalyst. Application of 10 mM triethylamine as separation buffer, the labeled acrylamide was analyzed within 2.0 min, and the relative standard deviations of migration time and peak area were less than 0.84% and 5.6%, indicating good precision. The C4D signal of acrylamide derivative showed a good linear relationship with acrylamide concentration in the range of 7-200 µM with the correlation coefficient of 0.9991. The limit of detection and limit of quantification were calculated to be 0.16 µM and 0.52 µM, respectively. Assisted further by the QuEChERS (quick, easy, cheap, effective, rugged, and safe) sample pretreatment, the developed derivatization strategy and subsequent CE-C4D method were successfully applied for the determination of acrylamide in potato products.


Assuntos
Acrilamida/análise , Química Click/métodos , Eletroforese Capilar/métodos , Solanum tuberosum/química , Culinária , Cisteína/química , Temperatura Alta , Limite de Detecção , Tubérculos/química
12.
Clin Biochem ; 71: 69-71, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31299317

RESUMO

We report two cases of hemoglobin Sendagi in a Romanian family residing in Spain: a four-year-old boy and his mother, who had been previously diagnosed with another type of congenital hemolytic anemia and had undergone splenectomy in her country during childhood. The unstable hemoglobin variant, hemoglobin Sendagi, is characterized by decreased oxygen affinity caused by replacement of one of the critical amino acid residues, phenylalanine beta 42 (CD1) of the beta-chain, with valine in the heme pocket, resulting in methemoglobin formation. As a result of migratory movements in Europe, new disease-causing hemoglobin variants are emerging in our country. Here, capillary electrophoresis enabled the identification of the variant and a molecular study was used to establish an accurate diagnosis.


Assuntos
Eletroforese Capilar/métodos , Hemoglobinas Anormais/metabolismo , Mutação , Adulto , Pré-Escolar , Feminino , Humanos , Masculino
13.
J Chromatogr A ; 1601: 365-374, 2019 Sep 13.
Artigo em Inglês | MEDLINE | ID: mdl-31176483

RESUMO

Capillary electrophoresis (CE) coupled with contactless conductivity detector (C4D) was applied to characterize the migration of micellar segments under BGE/segment/BGE system, where a segment is a micellar phase surrounded by BGE. The transformation (non-ionic, ionic) → mixed micelles under the system was explained in terms of the features of the micellar phase discussed already in the literature. In the second part of the work, based on established phenomena for BGE/segment/BGE system, the BGE/segment/segment/BGE system was used to analyze the re-equilibration of two micellar phases (SDS│(TX-100/SDS)) during a run. This aspect was deeper analyzed with the conclusion that re-equilibration in the present system induces decomposition of the phase of mixed micelles by the phase of ionic micelles and this is a mechanism able to generate the boundary conditions. Established features for BGE/segment/segment/BGE system were further implemented towards preconcentration of nanoparticles and systematic studies show that the system in the configuration (SDS│(TX-100/SDS)) generates a trap state for nanoparticles. Due to this the preconcentration of nanoparticles, expressed in the terms of an enhancement factor (SEFheight), was found to reach level ca. 60.


Assuntos
Técnicas de Química Analítica/métodos , Eletroforese Capilar , Micelas , Nanopartículas/química , Polietilenoglicóis/química
14.
Molecules ; 24(12)2019 Jun 12.
Artigo em Inglês | MEDLINE | ID: mdl-31212790

RESUMO

A solid phase membrane adsorbent-a nylon 6 nanofibers membrane coated by polypyrrole (PPy-PA6-NFsM)-was firstly synthesized and used for extraction of two ß-lactam antibiotics (oxacillin and cloxacillin) in urban river water. Then the analytes were detected by capillary electrophoresis with a diode array detector (CE-DAD). The synthesized nanofibers membrane was characterized by scanning electron microscopy and a Fourier transform infrared spectrometer. The experimental conditions were optimized, including the amount used of PPy-PA6-NFsM, pH of the sample solutions, adsorption volume, and desorption conditions. Under the optimal extraction and separation conditions, the detection limits were found to be 2.0 ng/mL for both oxacillin and cloxacillin. The proposed method was applied to the determination of the two ß-lactams in water samples of an urban river. The recoveries of these two ß-lactams were found to be in the range 84.2-96.4%, demonstrating that PPy-PA6-NFsM has a high extraction capability for these two antibiotics. The relative standard deviations, ranging from 2.26% to 5.29% for intraday measurements and from 2.38% to 7.02% for inter-day determinations, were derived respectively.


Assuntos
Caprolactama/análogos & derivados , Eletroforese Capilar , Nanofibras , Polímeros , Pirróis , Poluentes Químicos da Água , beta-Lactamas , Adsorção , Antibacterianos/análise , Antibacterianos/química , Caprolactama/química , Estrutura Molecular , Nanofibras/química , Nanofibras/ultraestrutura , Polímeros/química , Pirróis/química , Extração em Fase Sólida/métodos , Espectroscopia de Infravermelho com Transformada de Fourier , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/química , beta-Lactamas/química
15.
Anal Bioanal Chem ; 411(21): 5617-5629, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31214752

RESUMO

Positive identification of capillary electrophoresis-sodium dodecyl sulfate (CE-SDS) electropherogram peaks provides information to understand protein molecular characteristics at the structural level. It is critical in the design of a robust assay that can accurately resolve, differentiate, and quantify all therapeutic protein components including fragmented species, which are considered as product related impurities. However, direct identification of the impurity peaks observed in CE-SDS is a challenging and oftentimes an ambiguous task. This paper proposed a systematic workflow for characterizing CE-SDS fragmentation peaks. Forced degradation of monoclonal antibody (mAb) by multiple stress methods was utilized to induce fragmentation and species enrichment. The characteristics, such as size and the clipped region of sequence, were then evaluated based on multiple enzymatic treatment and particle reduction. The identified fragments were further confirmed using tryptic digestion and liquid chromatography coupled with mass spectrometry (LC-MS) analysis. Common fragment sizes and clipping locations are identified after evaluating multiple IgG molecules. The methodology and procedure described in this article are readily deployable and will provide necessary information for method, process, and product characterizations. Graphical abstract.


Assuntos
Anticorpos Monoclonais/química , Eletroforese Capilar/métodos , Dodecilsulfato de Sódio/química , Cromatografia Líquida/métodos , Imunoglobulina G/química , Espectrometria de Massas em Tandem/métodos
16.
Chem Commun (Camb) ; 55(53): 7595-7598, 2019 Jul 07.
Artigo em Inglês | MEDLINE | ID: mdl-31180413

RESUMO

A label-free ultrasensitive determination of eight RNA modified nucleotides simultaneously was first established based on a sheathless capillary electrophoresis-tandem mass spectrometry system. This system performed well using only 500 pg-5 ng practical RNA samples, and a downward trend of most target nucleotides in HCT 116 cells was observed with the increase of nickel concentration.


Assuntos
Nucleotídeos/análise , RNA/química , Eletroforese Capilar , Células HCT116 , Humanos , Espectrometria de Massas em Tandem
17.
J Chromatogr B Analyt Technol Biomed Life Sci ; 1122-1123: 73-77, 2019 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-31158650

RESUMO

Phenol is commonly used as an antimicrobial agent with an initial concentration of 0.35% (w/v) in injectable diluted tuberculin purified protein derivative (TPPD) solution. The anti-microbial action of phenol in TPPD is directly concentration dependent. Furthermore, high phenol content (>0.5%) may have a negative effect on the stability and clinical effectiveness of TPPD solution. Therefore, simple, rapid and reliable reversed phase liquid chromatographic (RPLC) and capillary zone electrophoretic (CZE) methods were firstly developed and validated for phenol quantification in Connaught tuberculin (CT68) PPD diluted preparations at 5 TU per test dose of 0.1 mL. In RPLC, the elution was carried out by 80% (v/v) ACN mixed with 20% (v/v) phosphate buffer containing 0.05% (v/v) triflouroacetic acid (pH 3.2) at 0.2 mL min-1 flow rate and 20.0 °C column temperature. In addition, phenol was separated from tuberculin (CT68) protein with a resolution of (R = 2.81) and was quantified within 3 min. In CZE, the migration of phenol was performed by 50 mmol L-1 borate buffer (pH 9.8) at -20 kV applied voltage and 25.0 °C capillary temperature. Furthermore, excellent linearity was achieved within 0.17-0.53% (w/v) for the phenol content with coefficients of determination (r2) higher than 0.9995. Moreover, the detection and quantification limits were found to be 0.046 & 0.153% and 0.051 & 0.171% (w/v) with RPLC and CZE respectively. Additionally, the intraday precision (RSD%, n = 9) was ranged between 0.18 and 0.39 and 0.33-54 with RPLC and CZE respectively. Moreover, the interday precision (RSD%, n = 27) was varied between 2.06 and 2.99 and 2.25-3.40 by RPLC and CZE, respectively. Furthermore, the obtained mean recoveries were ranged between 91.32 and 107.51% with RPLC and 90.71-108.92% with CZE. In addition, the effect of different storage temperatures at 4, 25 and 37 °C over storage periods of 2, 7, 14, 21 and 30 days was also studied on the TPPD product. The obtained results have revealed that the phenol content was effectively decreased about 37% of its original content after 30 days at storage temperatures of 25 and 37 °C. However, the phenol content did not change and was stable up to 21 days at storage temperature of 4 °C. Therefore, the simple and rapid proposed analytical methods could be used for a rapid expiry investigation of TPPD products based on phenol quantification, as a marker.


Assuntos
Cromatografia Líquida/métodos , Eletroforese Capilar/métodos , Fenóis/análise , Fenóis/química , Tuberculina/análise , Tuberculina/química , Limite de Detecção , Modelos Lineares , Estabilidade Proteica , Reprodutibilidade dos Testes
18.
J Chromatogr A ; 1601: 375-384, 2019 Sep 13.
Artigo em Inglês | MEDLINE | ID: mdl-31160095

RESUMO

Therapeutic monoclonal antibodies (mAbs) are complex glycoproteins and ensuring their safety, efficacy and quality is still challenging. Indeed, during their manufacturing process, they are exposed to several stresses that can lead to their denaturation, misfolding or dimerization. We report here a new method based on capillary electrophoresis coupled to native mass spectrometry (MS) with a sheath liquid interface to analyze an intact therapeutic mAb, Infliximab, under non-denaturing conditions that preserve its conformational heterogeneity as well as self-association without inducing further unfolding / denaturation. For capillary zone electrophoresis (CZE) separation, a triple layer coating using polybrene-dextran sulfate-polybrene was employed. A sheath liquid composed of isopropanol - water - acetic acid with a flow rate of 10 µL min-1 and mild MS conditions allowed optimal signal intensities. A specific mass spectrum was obtained for each Infliximab conformation in a "stressed" formulated preparation. This is the first time that within a single analysis different conformational states, i.e. native and unfolded monomers as well as dimers are simultaneously detected. The results and the lack of analytical bias arising from the CZE-MS conditions were confirmed by using atomic force microscopy (AFM) as an orthogonal technique. A middle-up approach combined to CZE-MS analysis of the stressed samples suggested that the dimer formation involved mostly Fab-Fab interactions.


Assuntos
Anticorpos Monoclonais/análise , Eletroforese Capilar , Espectrometria de Massas , Controle de Qualidade , Sulfato de Dextrana/química , Brometo de Hexadimetrina/química , Infliximab/análise
19.
Anal Chim Acta ; 1075: 1-26, 2019 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-31196414

RESUMO

In recent years, advances in sensitive analytical techniques have encouraged the analysis of various compounds in biological fluids. While blood serum, blood plasma and urine still remain the golden standards in clinical, toxicological and forensic science, analyses of other body fluids, such as breast milk, exhaled breath condensate, sweat, saliva, amniotic fluid, cerebrospinal fluid, or capillary blood in form of dried blood spots are becoming more popular. This review article focuses on capillary electrophoresis and microchip electrophoresis of small ions and molecules (e.g. inorganic cations/anions, basic/acidic drugs, small acids/bases, amino acids, peptides and other low molecular weight analytes) in various less conventional human body fluids and hopes to stimulate further interest in the field.


Assuntos
Secreções Corporais/química , Líquidos Corporais/química , Íons/análise , Compostos Orgânicos/análise , Líquido Amniótico/química , Eletroforese Capilar/métodos , Eletroforese em Microchip/métodos , Humanos , Íons/líquido cefalorraquidiano , Compostos Orgânicos/líquido cefalorraquidiano
20.
Se Pu ; 37(6): 661-665, 2019 Jun 08.
Artigo em Chinês | MEDLINE | ID: mdl-31152518

RESUMO

A high performance quantitative capillary electrophoresis method was developed for the simultaneous determination of vitamins B1, B2, B6, nicotinamide, and calcium pantothenate in vitamin B tablets using a quantitative capillary electrophoresis instrument. The samples were extracted ultrasonically with acetonitrile-water (20:80, v/v). The automatic high precision quantitative capillary electrophoresis instrument was used to realize quantitative injection through a 10 nL injection valve. The background electrolyte was selected as 40 mmol/L sodium borate buffer (pH 9.0), which was continuously supplied by a microfluidic injection pump. The working voltage was -10 kV. The detection wavelength of vitamins B1, B2, B6, and nicotinamide was selected as 280 nm, which was then changed to 210 nm to detect calcium pantothenate. The result showed good linearities between the peak area and the concentration of vitamins B1, B2, B6, nicotinamide, and calcium pantothenate in the correlation coefficients (r) range of 0.9968-0.9998. The limits of detection (LODs) were in the range of 2.5-36.0 mg/L. The average recoveries were 94.1%-98.9% with relative standard deviations (RSDs) as 1.3%-1.9%. The method is precise, reliable, and suitable for the simultaneous determination of vitamins B1, B2, B6, nicotinamide, and calcium pantothenate in a real compound vitamin B tablet.


Assuntos
Complexo Vitamínico B/análise , Eletroforese Capilar , Niacinamida/análise , Ácido Pantotênico/análise , Riboflavina/análise , Comprimidos , Tiamina/análise , Vitamina B 6/análise
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