Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 890
Filtrar
1.
Food Chem ; 361: 130173, 2021 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-34062455

RESUMO

Glutathione and its disulfide were determined in a single run using liquid chromatography with on-line post-column derivatization and fluorimetric detection (340 nm/425 nm). The analytes were separated using a reversed-phase column capable of operating at 100% aqueous mobile phase and detected following direct on-line reaction with o-phthalaldehyde (7.5 mmol L-1) in highly basic medium (0.37 mol L-1 NaOH). The instrumental and chemical variables were carefully investigated towards high sensitivity and throughput, while special attention was paid to validating potential matrix effects. Glutathione and its disulfide could be selectively determined with respective LODs of 0.10 and 0.30 µmol L-1 in the absence of matrix effect (<6%). The endogenous content of the analytes was accurately determined in various food samples with recoveries ranging between 80 and 120% in all cases. The proposed method is reliable and promising as a generic analytical tool for the convenient estimation of the redox status of glutathione in various food matrices.


Assuntos
Cromatografia Líquida/métodos , Análise de Alimentos/métodos , Dissulfeto de Glutationa/análise , Glutationa/análise , Cromatografia Líquida de Alta Pressão/métodos , Limite de Detecção , Oxirredução , Verduras/química , Vinho/análise , o-Ftalaldeído/química
2.
Chem Res Toxicol ; 34(3): 754-766, 2021 03 15.
Artigo em Inglês | MEDLINE | ID: mdl-33556243

RESUMO

Ortho-phthalaldehyde (OPA) is a chemical disinfectant used for the high-level sterilization of heat-sensitive medical instruments. Although OPA is considered a safer alternative to glutaraldehyde, no exposure limits have been established for respiratory exposures to ensure the safety of OPA sterilization and the safe use of OPA-treated medical instruments. In order to address data gaps in the toxicological profile of OPA, we treated human in vitro air-liquid-interface (ALI) airway cultures at the air interface with various concentrations of OPA aerosols for 10 consecutive days. Temporal tissue responses were evaluated at multiple time points during the treatment phase as well as 10 days following the last exposure. The disturbance of glutathione (GSH) homeostasis occurred as early as 20 min following the first exposure, while oxidative stress persisted throughout the treatment phase, as indicated by the sustained induction of heme oxygenase-1 (HMOX-1) expression. Repeated exposures to OPA aerosols resulted in both functional and structural changes, including the inhibition of ciliary beating frequency, aberrant mucin production, decreases in airway secretory cells, and tissue morphological changes. While OPA-induced oxidative stress recovered to control levels after a 10 day recovery period, functional and structural alterations caused by the high concentration of OPA aerosols failed to fully recover over the observation period. These findings indicate that aerosolized OPA induces both transient and relatively persistent functional and structural abnormalities in ALI cultures under the conditions of the current study.


Assuntos
Sistema Respiratório/efeitos dos fármacos , o-Ftalaldeído/efeitos adversos , Aerossóis/efeitos adversos , Aerossóis/química , Células Cultivadas , Humanos , Estrutura Molecular , Estresse Oxidativo/efeitos dos fármacos , Sistema Respiratório/metabolismo , o-Ftalaldeído/química
3.
Artigo em Inglês | MEDLINE | ID: mdl-33429128

RESUMO

A novel analytical method was developed for the quantification of glutathione hydropersulfide (G-SSH) in biological samples by high-performance liquid chromatography (HPLC) with post-column derivatization. G-SSH was treated with iodoacetamide as an alkylating agent for 5 min at 37 °C, and the resultant acetamide-labeled G-SSH (G-SS-acetamide) was subjected to HPLC. After separation on a reversed-phase column, G-SS-acetamide was quantified by detection using a post-column reaction with orthophthalaldehyde under alkaline conditions. The standard G-SS-acetamide was synthesized through the S-S exchange reaction between oxidized glutathione and 2-mercaptoacetamide. It should be noted that some types of alkylating agents, including N-ethylmaleimide and monobromobimane, cleave the polysulfide chains of polysulfides that consist of glutathione, resulting in the production of alkylated G-SSHs. We confirmed that iodoacetamide did not enhance the cleavage of acetamide-labeled glutathione trihydropersulfide (G-SSS-acetamide). The lowest quantification limit was estimated to be 25 nM for G-SS-acetamide. This method can be useful for studying the dynamics of sulfane sulfur in glutathione-containing matrices.


Assuntos
Alquilantes/química , Cromatografia Líquida de Alta Pressão/métodos , Dissulfetos , Glutationa/análogos & derivados , Iodoacetamida/química , Linhagem Celular Tumoral , Dissulfetos/análise , Dissulfetos/química , Dissulfetos/metabolismo , Glutationa/análise , Glutationa/química , Glutationa/metabolismo , Humanos , o-Ftalaldeído/química
4.
Molecules ; 25(18)2020 Sep 13.
Artigo em Inglês | MEDLINE | ID: mdl-32933160

RESUMO

BACKGROUND: Maintenance of the ratio of glutathione in the reduced (GSH) and oxidised (GSSG) state in cells is important in redox control, signal transduction and gene regulation, factors that are altered in many diseases. The accurate and reliable determination of GSH and GSSG simultaneously is a useful tool for oxidative stress determination. Measurement is limited primarily to the underestimation of GSH and overestimation GSSG as a result of auto-oxidation of GSH. The aim of this study was to overcome this limitation and develop, optimise and validate a reverse-phase high performance liquid chromatographic (HPLC) assay of GSH and GSSG for the determination of oxidant status in cardiac and chronic kidney diseases. METHODS: Fluorescence detection of the derivative, glutathione-O-pthaldialdehyde (OPA) adduct was used. The assay was validated by measuring the stability of glutathione and glutathione-OPA adduct under conditions that could affect the reproducibility including reaction time and temperature. Linearity, concentration range, limit of detection (LOD), limit of quantification (LOQ), recovery and extraction efficiency and selectivity of the method were assessed. RESULTS: There was excellent linearity for GSH (r2 = 0.998) and GSSG (r2 = 0.996) over concentration ranges of 0.1 µM-4 mM and 0.2 µM-0.4 mM respectively. The extraction of GSH from tissues was consistent and precise. The limit of detection for GSH and GSSG were 0.34 µM and 0.26 µM respectively whilst their limits of quantification were 1.14 µM and 0.88 µM respectively. CONCLUSION: These data validate a method for the simultaneous measurement of GSH and GSSG in samples extracted from biological tissues and offer a simple determination of redox status in clinical samples.


Assuntos
Glutationa/análise , Glutationa/metabolismo , Estresse Oxidativo , Extratos de Tecidos/análise , Extratos de Tecidos/metabolismo , Animais , Arginina/química , Osso e Ossos , Cromatografia Líquida de Alta Pressão/métodos , Coração , Peróxido de Hidrogênio/química , Rim , Limite de Detecção , Fígado , Masculino , Oxirredução , Ratos Sprague-Dawley , Espécies Reativas de Oxigênio/química , Reprodutibilidade dos Testes , o-Ftalaldeído/química
5.
Fitoterapia ; 146: 104698, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32745508

RESUMO

Three new flavipin-derived alkaloids, azacoccones F-H (1-3), along with six known compounds (4-9) were isolated from the endophytic fungus Epicoccum nigrum MK214079 associated with leaves of Salix sp. The structures of the new compounds were established by analysis of their 1D/2D nuclear magnetic resonance (NMR) and high-resolution electrospray ionization mass spectroscopy (HRESIMS) data. The absolute configuration of azacoccones F-H (1-3) was determined by comparison of experimental electronic circular dichroism (ECD) data with reported ones and biogenetic considerations. Epicocconigrone A (4), epipyrone A (5), and epicoccolide B (6) exhibited moderate antibacterial activity against Staphylococcus aureus ATCC 29213 with minimal inhibitory concentration (MIC) values ranging from 25 to 50 µM. Furthermore, epipyrone A (5) and epicoccamide A (7) displayed mild antifungal activity against Ustilago maydis AB33 with MIC values of 1.6 and 1.8 mM, respectively. Epicorazine A (8) showed pronounced cytotoxicity against the L5178Y mouse lymphoma cell line with an IC50 value of 1.3 µM.


Assuntos
Alcaloides/farmacologia , Ascomicetos/química , Produtos Biológicos/farmacologia , o-Ftalaldeído/análogos & derivados , Alcaloides/isolamento & purificação , Animais , Antibacterianos/isolamento & purificação , Antibacterianos/farmacologia , Antifúngicos/isolamento & purificação , Antifúngicos/farmacologia , Antineoplásicos/isolamento & purificação , Antineoplásicos/farmacologia , Basidiomycota , Produtos Biológicos/isolamento & purificação , Linhagem Celular Tumoral , Endófitos/química , Camundongos , Testes de Sensibilidade Microbiana , Estrutura Molecular , Folhas de Planta/microbiologia , Federação Russa , Salix/microbiologia , Staphylococcus aureus/efeitos dos fármacos , o-Ftalaldeído/isolamento & purificação , o-Ftalaldeído/farmacologia
6.
J Occup Health ; 62(1): e12139, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-32713059

RESUMO

OBJECTIVES: The present study aimed to develop a method for measuring the ceiling level of ortho-phthalaldehyde (OPA) exposure and evaluate the ceiling levels of OPA exposure among health care workers who handle disinfectant solutions containing OPA for the disinfection of endoscopes. METHODS: The study consisted of a preliminary survey and main survey. In the preliminary survey, processes involving high-concentration exposure to OPA were identified by video-exposure monitoring (VEM). In the main survey, the ceiling levels of OPA exposure for high-concentration exposure processes identified from the results of the preliminary survey were determined using a measuring method combining sampling using a 2,4-dinitrophenylhydrazine-silica cartridge and analysis by high-performance liquid chromatography tandem mass spectrometry. RESULTS: In the preliminary survey, seven processes involving high-concentration exposure to OPA were identified by VEM. The duration of each process was short, lasting from 20 seconds to a few minutes. In the main survey, the OPA concentrations for the identified high-concentration exposure processes ranged from 1.18 to 4.49 ppb, which markedly exceeded the threshold limit value ceiling (TLV-C) of 0.1 ppb recommended by the American Conference of Governmental Industrial Hygienists. CONCLUSIONS: The method for measuring the ceiling level of OPA exposure was established using VEM and the highly sensitive method of chemical analysis; and we successfully evaluated the ceiling levels of OPA exposure among health care workers engaged in endoscope disinfection. This approach can also be applied to other chemical substances with recommended TLV-Cs, and important information for reducing exposure can thus be obtained.


Assuntos
Desinfetantes/análise , Endoscópios , Monitoramento Ambiental/métodos , Pessoal de Saúde , Exposição Ocupacional/análise , o-Ftalaldeído/análise , Desinfetantes/efeitos adversos , Contaminação de Equipamentos/prevenção & controle , Humanos , Exposição por Inalação , Inquéritos e Questionários , Gravação em Vídeo , o-Ftalaldeído/efeitos adversos
7.
Toxicol Sci ; 178(1): 127-137, 2020 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-32647894

RESUMO

Health-care workers have an increased incidence of allergic disease compared with the general public and are exposed to a variety of high-level disinfectants. Although exposure to these agents has been associated with allergic disease, findings between epidemiology and animal studies often conflict respecting immunological mechanisms. Therefore, we hypothesized that previous exposure to a representative IgE-mediated sensitizer (ortho-phthalaldehyde [OPA]) alters immune responses to a representative T-cell-mediated sensitizer (didecyldimethlyammonium chloride [DDAC]). Here, BALB/c mice were topically exposed to OPA (0.5%) for 3 days, rested, then topically exposed to DDAC (0.0625%, 0.125%, and 0.25%) for 14 days. Coexposure resulted in phenotypic changes in draining lymph node (dLN) cells, including a decreased frequency of CD8+ T cells and increased frequency and number of B cells compared with DDAC-only treated mice. The coexposed mice also had enhanced Th2 responses, including significant alterations in: dLN Il4 (increased), B-cell activation (increased), CD8+ T-cell activation (decreased), and local and systemic IgE production (increased). These changes were not observed if mice were exposed to DDAC prior to OPA. Exposure to OPA alone shows Th2 skewing, indicated by increased activation of skin type 2 innate lymphoid cells, increased frequency and activation of draining lymph node B cells, and increased levels of type 2 cytokines. These findings suggest that the OPA-induced immune environment may alter the response to DDAC, resulting in increased IgE-mediated immune responses. This data may partially explain the discordance between epidemiological and laboratory studies regarding disinfectants and provide insight into the potential immunological implications of mixed chemical exposures.


Assuntos
Desinfetantes/toxicidade , Imunoglobulina E/imunologia , Compostos de Amônio Quaternário/toxicidade , o-Ftalaldeído/toxicidade , Animais , Linfócitos B/efeitos dos fármacos , Linfócitos T CD8-Positivos/efeitos dos fármacos , Citocinas , Imunidade Inata , Camundongos , Camundongos Endogâmicos BALB C
8.
Methods Enzymol ; 639: 237-261, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32475404

RESUMO

Ortho-Phthalaldehyde (OPA)-amine reaction and OPA-amine-thiol reaction have been developed to effectively modify native peptides and proteins under the physiological conditions. First, OPA and its derivatives can rapidly and smoothly react with primary amine moieties in peptides and proteins to achieve native protein biconjugations. Furthermore, OPA-alkyne bifunctional linkers can be used for proteome profiling. Second, OPA-amine-thiol three-component reaction has been developed for chemoselective peptide cyclization, directly on unprotected peptides in the aqueous buffer. Moreover, this OPA-guided cyclic peptide can be further modified with the N-maleimide moiety in one pot to introduce additional functionalities. The development of this OPA based chemoselective bioconjugation and peptide cyclization extends the toolbox for protein chemical modification and construction of cyclic peptides.


Assuntos
Proteínas , o-Ftalaldeído , Alcinos , Ciclização , Peptídeos
9.
Methods Enzymol ; 639: 313-332, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32475407

RESUMO

The rigidification of peptide secondary structure via stapling is an important and enduring goal in the development of functional peptides for biochemical and pharmaceutical applications. In addition, the incorporation of fluorophores and chromophores has been a sought-after application for creating peptidic probes of cellular function and localization. The combined application of peptide stapling and fluorescent-readout is featured by the reaction of ortho-phthalaldehydes to create isoindole staples, thus transforming inactive linear and monocyclic precursors into fluorescent or visibly colored monocyclic and bicyclic products with noted biological activity. Given its user-friendliness, we have termed this approach FlICk (fluorescent isoindole crosslink) chemistry and we have featured this application on an array of high-affinity macrocyclic α-MSH derivatives as well as for late-stage intra-annular isoindole stapling furnished a bicyclic peptide mimic of α-amanitin that is cytotoxic to CHO cells. The synthetic methods for preparing substituted ortho-phthalaldehydes along with subsequent applications to FlICk stapling are detailed herein.


Assuntos
Isoindóis , Peptídeos , Animais , Cricetinae , Cricetulus , Corantes Fluorescentes , o-Ftalaldeído
10.
Electrophoresis ; 41(21-22): 1851-1869, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-32530051

RESUMO

Amino acids are essential compounds for living organisms, and their determination in biological fluids is crucial for the clinical analysis and diagnosis of many diseases. However, the detection of most amino acids is hindered by the lack of a strong chromophore/fluorophore or electrochemically active group in their chemical structures. The highly sensitive determination of amino acids often requires derivatization. Capillary electrophoresis is a separation technique with excellent characteristics for the analysis of amino acids in biological fluids. Moreover, it offers the possibility of precapillary, on-capillary, or postcapillary derivatization. Each derivatization approach has specific demands in terms of the chemistry involved in the derivatization, which is discussed in this review. The family of homocyclic o-dicarboxaldehyde compounds, namely o-phthalaldehyde, naphthalene-2,3-dicarboxaldehyde, and anthracene-2,3-dicarboxaldehyde, are powerful derivatization reagents for the determination of amino acids and related compounds. In the presence of suitable nucleophiles they react with the primary amino group to form both fluorescent and electroactive derivatives. Moreover, the reaction rate enables all of the derivatization approaches mentioned above. This review focuses on articles that deal with using these reagents for the derivatization of amino acids and related compounds for ultraviolet-visible spectrometry, fluorescence, or electrochemical detection. Applications in capillary and microchip electrophoresis are summarized and discussed.


Assuntos
Aldeídos/química , Aminoácidos , Eletroforese Capilar/métodos , Aminoácidos/análise , Aminoácidos/química , Aminoácidos/isolamento & purificação , Eletroforese em Microchip , Naftalenos/química , Estereoisomerismo , o-Ftalaldeído/química
11.
Luminescence ; 35(8): 1402-1407, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32592606

RESUMO

In the present study we report the reaction between homocysteine and o-phthalaldehyde under flow conditions. Homocysteine reacts on-line with the derivatization reagent in a strong alkaline medium and in the absence of nucleophilic reagents to yield a fluorescent derivative (λex /λem = 370/480 nm). The reaction variables were investigated using the concept of zone fluidics. Selectivity factors against other compounds were calculated at 10-fold excess. The findings formed the basis of an automated proposed method that was found to be linear in the range 0.1-1.5 µmol L-1 , with a limit of detection of 20 nmol L-1 and relative standard deviation < 0.5% (within-day) and 3.2% (between-day). The method proved to be rapid, offering a practical sampling rate of 24 h-1 and accurate following application to an artificial urine matrix with minimum dilution.


Assuntos
Homocisteína , o-Ftalaldeído , Cromatografia Líquida de Alta Pressão , Fluorometria , Indicadores e Reagentes
12.
Am J Obstet Gynecol ; 223(3): B2-B6, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32470457

RESUMO

Recent surveys have shown widespread lapses in the procedures used to reduce the risk of transmitting infection via medical devices. Transvaginal ultrasound examination has the potential to transmit vaginal infections, including human papillomavirus. Areas of particular concern are the use of probe covers with high rates of leakage, disinfectants that are not effective against human papillomavirus, and coupling gel from multiple-use containers. We reviewed these issues, and we recommend 4 steps to reduce the risk of transmitting infection. First, during every transvaginal ultrasound exam, the probe should be covered with a sterile, single-use "viral barrier" cover or a condom. Second, sterile, single-use ultrasound gel packets should be used. Third, after every examination, the probe should be cleaned to remove any visible gel or debris. Finally, after cleaning, the probe should undergo high-level disinfection using an agent with proven efficacy against the human papillomavirus, including hydrogen peroxide, hypochlorite, or peracetic acid. Glutaraldehyde, orthophthalaldehyde, phenols, and isopropyl alcohol have virtually no efficacy against the human papillomavirus.


Assuntos
Transmissão de Doença Infecciosa/prevenção & controle , Contaminação de Equipamentos/prevenção & controle , Ultrassonografia Pré-Natal/instrumentação , Doenças Vaginais/microbiologia , Doenças Vaginais/prevenção & controle , Desinfetantes , Desinfecção/métodos , Equipamentos Descartáveis , Feminino , Glutaral , Humanos , Controle de Infecções/métodos , Infecções por Papillomavirus/prevenção & controle , Gravidez , Esterilização/métodos , Ultrassonografia Pré-Natal/efeitos adversos , Doenças Vaginais/virologia , o-Ftalaldeído
13.
Workplace Health Saf ; 68(10): 491-500, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32364022

RESUMO

Background: Although nurses are well described as being at risk of work-related asthma, certified nurse aides (CNAs) are understudied. Using a statewide registry in Texas, we measured prevalence and risk factors for work-related asthma and bronchial hyperresponsiveness (BHR) symptoms among CNAs. Methods: For this cross-sectional study, a questionnaire was mailed to a random sample of CNAs (n = 2,114) identified through the Texas Department of Aging and Disability Services registry, working in health care during 2016-2017, to collect data on job history, asthma symptoms, and sociodemographics. Two outcomes were defined: (a) new-onset asthma (NOA) after entry into the health care field and (b) BHR-related symptoms. Job exposures to cleaning compounds and tasks were assigned using an externally coded CNA-specific job-exposure matrix. Logistic regression modeling was used to measure associations between cleaning exposures and the two asthma outcomes. Findings: The final sample consisted of 413 CNAs (response rate 21.6%). The prevalence of NOA and BHR symptoms were 3.6% and 26.9%, respectively. In adjusted models, elevated odds for BHR symptoms were observed for patient care cleaning (odds ratio [OR] = 1.71, 95% confidence interval [CI] = [0.45, 6.51]), instrument cleaning (OR = 1.33, 95% CI = [0.66, 2.68]), building-surface cleaning (OR = 1.39, 95% CI = [0.35, 5.60]), exposure to glutaraldehyde/orthophthalaldehyde (OR = 1.33, 95% CI = [0.66, 2.68]), and latex glove use during 1992-2000 (OR = 1.62, 95% CI = [0.84, 3.12]). There were too few NOA cases to warrant meaningful regression analysis. Conclusion/Application to Practice: Although not statistically significant, we observed elevated odds of BHR symptoms among nurse aides, associated with cleaning exposures, suggesting this is an at-risk group of health care professionals for work-related respiratory disease, meriting further study.


Assuntos
Asma Ocupacional/epidemiologia , Hiper-Reatividade Brônquica/epidemiologia , Assistentes de Enfermagem/estatística & dados numéricos , Exposição Ocupacional/estatística & dados numéricos , Adulto , Asma Ocupacional/etiologia , Hiper-Reatividade Brônquica/etiologia , Estudos Transversais , Desinfetantes/efeitos adversos , Feminino , Glutaral/efeitos adversos , Humanos , Látex/efeitos adversos , Masculino , Pessoa de Meia-Idade , Exposição Ocupacional/efeitos adversos , Prevalência , Fatores de Risco , Inquéritos e Questionários , Texas/epidemiologia , o-Ftalaldeído/efeitos adversos
14.
Molecules ; 25(7)2020 Apr 04.
Artigo em Inglês | MEDLINE | ID: mdl-32260350

RESUMO

In the present study, the determination of histidine (HIS) by an on-line flow method based on the concept of zone fluidics is reported. HIS reacts fast with o-phthalaldehyde at a mildly basic medium (pH 7.5) and in the absence of additional nucleophilic compounds to yield a highly fluorescent derivative (λex/λem = 360/440 nm). The flow procedure was optimized and validated, paying special attention to its selectivity and sensitivity. The LOD was 31 nmol·L-1, while the within-day and day-to-day precisions were better than 1.0% and 5.0%, respectively (n = 6). Random urine samples from adult volunteers (n = 7) were successfully analyzed without matrix effect (<1%). Endogenous HIS content ranged between 116 and 1527 µmol·L-1 with percentage recoveries in the range of 87.6%-95.4%.


Assuntos
Histidina/urina , Urina/química , Adulto , Cromatografia Líquida de Alta Pressão , Feminino , Fluorometria , Humanos , Limite de Detecção , Masculino , Voluntários , o-Ftalaldeído/química
16.
J Occup Health ; 62(1): e12105, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31883172

RESUMO

OBJECTIVES: The purpose of this research was to develop and validate an analytical method for rapid determination of the exposure of workers to ortho-phthalaldehyde (OPA) at the ceiling threshold concentration. METHODS: A 2,4-dinitrophenylhydrazine (DNPH)-silica cartridge was chosen as a sampler. OPA collected by the DNPH-silica cartridge was subsequently extracted with 5 mL of acetonitrile. A 50-µL aliquot of phosphoric acid/acetonitrile solution (2%, v/v) was added to 950 µL of the extraction solution and allowed to stand for 30 minutes at room temperature. This solution was then analyzed by high-performance liquid chromatography tandem mass spectrometry. The basic characteristics of the proposed method, such as recovery, repeatability, limit of quantification, and storage stability of the samples, were examined. RESULTS: The overall recoveries of OPA from OPA-spiked DNPH-silica cartridges were 93.6%-100.1% with relative standard deviations, representing the repeatability, of 1.5%-10.8%. The limit of quantification was 0.165 ng/sample. The recovery of OPA from DNPH-silica cartridges after 5 days of storage in a refrigerator exceeded 95%. CONCLUSIONS: The proposed method enabled the determination of the OPA concentration corresponding to the Threshold Limit Value-Ceiling of 0.1 ppb recommended by the American Conference of Governmental Industrial Hygienists, with a minimum sampling time of 18 seconds (corresponding to a sampling volume of 300 mL at 25°C and 1 atm). Thus, this method will be useful for estimating worker exposures to OPA.


Assuntos
Poluentes Ocupacionais do Ar/análise , Monitoramento Ambiental/métodos , Exposição Ocupacional/análise , Níveis Máximos Permitidos , o-Ftalaldeído/análise , Cromatografia Líquida de Alta Pressão , Humanos , Espectrometria de Massas , Estrutura Molecular , Fenil-Hidrazinas , Dióxido de Silício
17.
Spectrochim Acta A Mol Biomol Spectrosc ; 229: 117963, 2020 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-31884397

RESUMO

A zone-fluidics (ZF) based automated fluorimetric sensor for the determination of glutathione (GSH) is reported. Discrete zones of GSH and o-phthalaldehyde (OPA) mix and react on-line under mild basic pH without the need of additional nucleophillic reagents, to yield a fluorescent isoindole derivative (λex/λem = 340/425 nm). The proposed ZF sensor was optimized (pH, c(OPA), time, instrumental variables) and validated. Cysteine, glutamate, glycine and ammonium were representatively examined in terms of selectivity and were found not to react in 10-fold excess. Linearity was proved in the range of 5-100 µmol L-1 GSH, with an LOD of 1 µmol L-1 at a practical sampling rate of 20 h-1 and RSD < 0.5% (within-day) and 4.2% (day-to-day). The dosage uniformity of commercially available GSH - containing nutraceuticals was evaluated.


Assuntos
Técnicas Biossensoriais/métodos , Suplementos Nutricionais/análise , Fluorometria/métodos , Glutationa/análise , Microfluídica/métodos , Água/química , o-Ftalaldeído/química
18.
Anal Chem ; 92(2): 1669-1673, 2020 01 21.
Artigo em Inglês | MEDLINE | ID: mdl-31886647

RESUMO

To provide alternative methods of analyzing amino acids without liquid chromatography, 19F NMR-based simultaneous and individual detection methods for amino acids using o-phthalaldehyde (OPA)-based 19F labeling have been developed. Since the chemical shifts of almost all 19F-labeled amino acids differ from each other, and they can be discriminated on the 19F NMR spectrum, simultaneous detection of amino acids has been successfully demonstrated. The discrimination pattern of the peak identical to that of the 19F-labeled amino acids was largely dependent on the chemical structure of the thiols having 19F nuclei, strongly suggesting that there is a large potential for clearer discrimination of amino acids by optimizing the thiol structure and/or combined use of thiols.


Assuntos
Aminoácidos/análise , Ressonância Magnética Nuclear Biomolecular , o-Ftalaldeído/química , Flúor/química , Humanos , Estrutura Molecular , Compostos de Sulfidrila/química
19.
Biochemistry ; 59(2): 175-178, 2020 01 21.
Artigo em Inglês | MEDLINE | ID: mdl-31657212

RESUMO

Lysine residues have been considered as a routine conjugating site for protein chemical labeling and modification. The commercially available lysine-labeling agents have several limitations in labeling efficiency, stability, and cost. To pursue alternative protein lysine-labeling strategies, herein, we report the development of an ortho-phthalaldehyde (OPA)-based bifunctional linker suitable for protein chemical labeling and profiling. Among three designed OPA-based bifunctional linkers, OPA-NH-alkyne 5 was proved to be optimal for protein labeling with minimal protein turbidity. We further demonstrated OPA-NH-alkyne 5 was applicable for immediate capture of protein or proteome chemical labeling.


Assuntos
Alcinos/química , Lisina/química , Sondas Moleculares/química , Proteínas/química , o-Ftalaldeído/análogos & derivados , Alcinos/síntese química , Animais , Bactérias/química , Galinhas , Sondas Moleculares/síntese química , o-Ftalaldeído/síntese química
20.
Se Pu ; 38(8): 923-928, 2020 Aug 08.
Artigo em Chinês | MEDLINE | ID: mdl-34213184

RESUMO

Using o-phthalaldehyde (OPA) as the derivatization reagent, a precolumn derivatized -high performance liquid chromatography (HPLC) method was developed for the simultaneous determination of amino acid neurotransmitters taurine (Tau), glutamic acid (Glu), glycine(Gly), and γ -aminobutyric acid (γ-GABA), as well as the monoamine neurotransmitter dopamine (DA), in serum samples. The samples and ethanol were mixed at a volume ratio of 1:2 (v/v) for protein precipitation. After centrifugation, the supernatant was withdrawn and blown to dryness using nitrogen. The residue was pre-column derivatized with OPA, and the derivatized product was isolated by gradient elution ona Luna 5u C18 column (250 mm×4.6 mm, 5 µm). Under the optimal experimental conditions, the five neurotransmitters showed good linearities (r2 ≥ 0.9866). The limits of detection were between 0.10 and 0.40 µmol/L. The spiked recoveries at different spiked levels were 87.57%-115.31%, and the RSDs were below 7.80%. This method is simple, sensitive, and it can be promised for the simultaneous detection of amino acid and monoamine neurotransmitters.


Assuntos
Aminoácidos , Neurotransmissores , Aminoácidos/sangue , Cromatografia Líquida de Alta Pressão , Humanos , Neurotransmissores/sangue , o-Ftalaldeído
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...