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1.
Anal Bioanal Chem ; 412(6): 1317-1324, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31927600

RESUMO

Herein, a dual-emission metal-organic framework based ratiometric fluorescence nanoprobe was reported for detecting copper(II) ions. In particular, carbon dots (CDs) and gold nanoclusters (AuNCs) were embedded into ZIF-8 (one of the classical metal-organic frameworks) to form CDs/AuNCs@ZIF-8 nanocomposites, which exhibited dual-emission peaks at UV excitation. In the presence of Cu2+, the fluorescence attributed to AuNCs can be rapidly quenched, while the fluorescence of CDs serves as reference with undetectable changes. Therefore, the CDs/AuNCs@ZIF-8 nanocomposites were utilized as a ratiometric fluorescence nanoprobe for sensitive and selective detection of Cu2+. A good linear relationship between the ratiometric fluorescence signal of CDs/AuNCs@ZIF-8 and Cu2+ concentration was obtained in the range of 10-3-103 µM, and the detection limit was as low as 0.3324 nM. The current ratiometric fluorescence nanoprobe showed promising prospects in cost-effective and rapid determination of Cu2+ ions with good sensitivity and selectivity. Furthermore, this nanoprobe has been successfully applied for the quantitative detection of Cu2+ in serum samples, indicating its value of practical application. Graphical abstract Carbon dots (CDs) and gold nanoclusters (AuNCs) were embedded into metal-organic frameworks (ZIF-8) to form CDs/AuNCs@ZIF-8 nanocomposites, which exhibited dual-emission peaks at 365 nm excitation. In the presence of Cu2+, the fluorescence emission peak at 574 nm can rapidly respond by quenching, while the fluorescence at 462 nm serves as reference with undetectable changes.


Assuntos
Carbono/química , Cobre/análise , Ouro/química , Nanopartículas Metálicas/química , Estruturas Metalorgânicas/química , Pontos Quânticos/química , Espectroscopia de Infravermelho com Transformada de Fourier/métodos , Cobre/sangue , Humanos , Limite de Detecção
2.
Food Chem Toxicol ; 135: 110944, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31707031

RESUMO

Polysaccharides are known as one of the most important bioactive compounds in Flammulina velutipes. However, there is no accurate and comprehensive assessment method to evaluate and authenticate F. velutipes polysaccharides (FVPs) from different sources. In this study, a multiple fingerprint analysis method including scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FT-IR), and high-performance liquid chromatography (HPLC) was established. The inhibitory activities of FVPs against HepG2 were measured and introduced into multiple linear regression (MLR) analysis to investigate fingerprint-activity relationship. The principal component analysis (PCA) scores showed that the polysaccharides extracted from 20 batches of different F. velutipes were highly similar, and substandard samples could be distinguished from the authentic polysaccharides clearly. The glucuronic acid could be considered as a marker for discrimination of white and yellow F. velutipes polysaccharides in HPLC fingerprints. Moreover, the HPLC fingerprint-growth inhibitory activity relationship illuminated that monosaccharides composition played an important role on the HepG2 growth inhibitory activity, and activity-associated markers (mannose, rhamnose, xylose, and galactose) were chosen to assess FVPs from different sources. The suggested HPLC fingerprint-activity relationship method provides an integrated strategy for the quality control of F. velutipes and its related products.


Assuntos
Flammulina/química , Polissacarídeos/normas , Controle de Qualidade , Cromatografia Líquida de Alta Pressão/métodos , Células Hep G2 , Humanos , Microscopia Eletrônica de Varredura/métodos , Polissacarídeos/química , Análise de Componente Principal , Espectroscopia de Infravermelho com Transformada de Fourier/métodos
3.
Anal Bioanal Chem ; 412(1): 129-138, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31773230

RESUMO

A novel lab-on-chip integrated microfluidic device for solid-phase extraction (SPE) and spectrophotometric detection of morphine (MOR), codeine (COD), and papaverine (PAP) was developed. The extracted analytes were analyzed with a miniature UV-Vis spectrophotometer. The SPE adsorptive phase composed of polyurethane/polyaniline (PU/PANI) nanofibers was fabricated by electrospinning and in situ oxidative polymerization techniques. The sorbent was characterized by Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM). The main factors of extraction such as desorption conditions, pH, salt effect, and extraction time were investigated. The partial least square (PLS) regression was applied to improve the quantification of analytes. The linear dynamic ranges (LDRs) for MOR, COD, and PAP were 4-240, 4-210, and 1-150 ng mL-1, respectively. Finally, the proposed method was successfully applied for the determination of MOR, COD, and PAP in human urine samples and the extraction recoveries were obtained in the range of 66.7-85.0% with RSDs < 8.3%.


Assuntos
Codeína/urina , Dispositivos Lab-On-A-Chip , Morfina/urina , Papaverina/urina , Extração em Fase Sólida/instrumentação , Espectrofotometria Ultravioleta/métodos , Espectroscopia de Infravermelho com Transformada de Fourier/métodos , Humanos , Microscopia Eletrônica de Varredura , Reprodutibilidade dos Testes
4.
Food Chem ; 310: 125800, 2020 Apr 25.
Artigo em Inglês | MEDLINE | ID: mdl-31784070

RESUMO

Fourier-transform infrared (FTIR) spectroscopy was applied to predict the degree of hydrolysis (DH%) and weight-average molecular weight (Mw) in milk protein hydrolysates. Both DH% and Mw are important quality parameters of protein hydrolysates. Measuring these parameters and following their development during proteolytic reactions is therefore essential for process control and optimization in industry. In the present study the intercorrelation and the complimentary nature of these parameters were investigated and a partial least squares regression (PLSR) model was developed for the prediction of DH% from molecular weight distributions. Finally, we developed PLSR models based on dry-film FTIR spectroscopy for the prediction of both DH% and Mw. Here spectral changes in the amide region were found to be important for the two calibration models, underlining the advantage of dry-film FTIR measurement. This shows that dry-film infrared spectroscopy is a promising tool for dual prediction of DH% and Mw.


Assuntos
Proteínas do Leite/química , Leite/química , Hidrolisados de Proteína/química , Espectroscopia de Infravermelho com Transformada de Fourier/métodos , Animais , Biotecnologia/métodos , Calibragem , Hidrólise , Análise dos Mínimos Quadrados , Peso Molecular , Hidrolisados de Proteína/análise
5.
J Agric Food Chem ; 68(1): 390-401, 2020 Jan 08.
Artigo em Inglês | MEDLINE | ID: mdl-31820962

RESUMO

Infrared spectroscopy is often used as a simple, fast, and green method to screen for economically motivated adulteration in spices. However, conventional microscopy remains the reference method. In this research, the combination of microscopy and Fourier-transform infrared spectroscopy in mapping mode, namely, micro-FTIR imaging, along with Principle Component Analysis were used to develop a non-targeted method for detecting a broad range of organic and mineral bulking agents that could potentially be used to adulterate black pepper. This method, based on the spatial distribution of black pepper chemical composition, has been thoroughly validated as a one-class, non-targeted classification method. Results are categorized as Typical or Atypical, where an Atypical result indicates a high probability of adulteration. For an Atypical outcome, a multitool investigational approach is then used for the detection and identification of the potential adulterant.


Assuntos
Contaminação de Alimentos/análise , Piper nigrum/química , Espectrofotometria Infravermelho/métodos , Espectroscopia de Infravermelho com Transformada de Fourier/métodos , Análise de Componente Principal , Sementes/química , Especiarias/análise
6.
Anal Bioanal Chem ; 412(4): 805-810, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31858169

RESUMO

Recently, pre-analytical, analytical, and post-analytical issues have been addressed to implement biofluid FTIR spectroscopy as a novel diagnostic tool in the clinical setting. Although hemolysis, icterus, and hyperlipidemia are known to interfere with colorimetric and turbidimetric biochemical methods, there are no data on their impact on serum/plasma FTIR spectra. This study aimed at investigating the impact of hemoglobin, bilirubin, and triglycerides concentrations on plasma spectral analysis. Plasma samples with high concentrations of hemoglobin, conjugated bilirubin, or triglycerides were studied. To mimic the various concentrations observed in clinical setting, samples were diluted using normal plasma and analyzed using high-throughput FTIR spectroscopy. Hemolytic, icteric, and hyperlipidemic plasma spectra were compared with control plasma spectra. Unsupervised analysis of all spectra was performed using principal component analysis. The comparison between control and hemolytic plasmas did not show spectral differences in the range of hemoglobin concentrations observed in spurious or pathological hemolysis. By contrast, spectra from lipidemic plasmas had different spectral profiles compared with control plasma, exhibiting increased absorbance in lipid bands. Differences in the same spectral regions were observed in spectra from icteric plasma, which may be explained by the hyperlipidemia associated with cholestasis. PCA did not discriminate between control and hemolytic plasmas up to 1 g/L hemoglobin but confirmed the interference of bilirubin and triglycerides concentrations on spectral classification. Our results show that hemolysis does not have an impact on the plasma spectral profile except for high concentrations of hemoglobin rarely observed in clinical practice, whereas icterus and hyperlipidemia constitute significant confounding factors. Graphical abstract.


Assuntos
Plasma/química , Espectroscopia de Infravermelho com Transformada de Fourier/métodos , Bilirrubina/sangue , Hemoglobinas/análise , Hemólise , Humanos , Hiperlipidemias/sangue , Icterícia/sangue , Triglicerídeos/sangue
7.
Food Chem ; 302: 125349, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31442700

RESUMO

Knowledge about the critical interfacial concentration of a protein supports our understanding of the kinetic stability of an emulsion. Its determination is currently limited to either invasive or indirect methods. The aim of our study was the determination of the critical interfacial concentration of whey protein ß-lactoglobulin at oil/water-interfaces through fluorescence and pendant drop analysis and the comparison to an in situ Fourier-transform-infrared-spectroscopy (FTIR) method. Exponentially decreasing interfacial tension with increasing ß-lactoglobulin content (0.10-1.00 wt%) in pendant drop analysis could partly be confirmed by fluorescence spectra. A critical interfacial concentration of 0.20-0.31 wt% ß-lactoglobulin (1.80-2.69 mg/m2) in oil/water (5/95)-emulsions was determined via FTIR, analyzing the Amide I/Amide II peak intensity ratio. This was confirmed by the increasing formation of intermolecular ß-sheets, revealed by second derivative spectra. With this FTIR method we expand current options to investigate the interfacial behavior of food proteins by determination of secondary structure elements.


Assuntos
Lactoglobulinas/química , Óleos/química , Espectroscopia de Infravermelho com Transformada de Fourier/métodos , Emulsões/química , Cinética , Estrutura Secundária de Proteína , Dodecilsulfato de Sódio/química , Tensão Superficial , Água/química
8.
Food Chem ; 303: 125404, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31466033

RESUMO

Fourier transform infrared (FTIR) spectroscopy calibrations were developed to simultaneously determine the multianalytes of five artificial sweeteners, including sodium cyclamate, sucralose, sodium saccharin, acesulfame-K and aspartame. By combining the pretreatment of the spectrum and principal component analysis, 131 feature wavenumbers were extracted from the full spectral range for modelling to qualitative and quantitative analysis. Compared to random forest, k nearest neighbour and linear discriminant analysis, support vector machine model had better predictivity, indicating the most effective identification performance. Furthermore, multivariate calibration models based on partial least squares regression were constructed for quantifying any combinations of the five artificial sweeteners, and validated by prediction data sets. As shown by the good agreement between the proposed method and the reference HPLC for the determination of the sweeteners in beverage samples, a promising and rapid tool based on FTIR spectroscopy, coupled with chemometrics, has been performed to identify and objectively quantify artificial sweeteners.


Assuntos
Espectroscopia de Infravermelho com Transformada de Fourier/métodos , Edulcorantes/análise , Aspartame/análise , Bebidas/análise , Calibragem , Cromatografia Líquida de Alta Pressão/métodos , Ciclamatos/análise , Aprendizado de Máquina , Análise de Componente Principal , Sacarina/análise , Tiazinas/análise
9.
Equine Vet J ; 52(1): 46-51, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30900769

RESUMO

BACKGROUND: Reliable and validated biomarkers for osteoarthritis (OA) are currently lacking. OBJECTIVES: To develop an accurate and minimally invasive method to assess OA-affected horses and provide potential spectral markers indicative of disease. STUDY DESIGN: Observational, cross-sectional study. METHODS: Our cohort consisted of 15 horses with OA and 48 without clinical signs of the disease, which were used as controls. Attenuated total reflection Fourier-transform infrared (ATR-FTIR) spectroscopy was used to investigate serum samples (50 µL) collected from these horses. Spectral processing and multivariate analysis revealed differences and similarities, allowing for detection of spectral biomarkers that discriminated between the two cohorts. A supervised classification algorithm, namely principal component analysis coupled with quadratic discriminant analysis (PCA-QDA), was applied to evaluate the diagnostic accuracy. RESULTS: Segregation between the two different cohorts, OA-affected and controls, was achieved with 100% sensitivity and specificity. The six most discriminatory peaks were attributed to proteins and lipids. Four of the spectral peaks were elevated in OA horses, which could be potentially due to an increase in lipids, protein expression levels and collagen, all of which have been previously reported in OA. Two peaks were found decreased and were tentatively assigned to the reduction of proteoglycan content that is observed during OA. MAIN LIMITATIONS: The control group had a wide range of ages and breeds. Presymptomatic OA cases were not included. Therefore, it remains unknown whether this test could also be used as an early diagnostic tool. CONCLUSIONS: This spectrochemical approach could provide an accurate and cost-effective blood test, facilitating point-of-care diagnosis of equine OA.


Assuntos
Doenças dos Cavalos/diagnóstico , Osteoartrite/veterinária , Espectroscopia de Infravermelho com Transformada de Fourier/veterinária , Animais , Estudos Transversais , Doenças dos Cavalos/sangue , Cavalos , Osteoartrite/sangue , Osteoartrite/diagnóstico , Espectroscopia de Infravermelho com Transformada de Fourier/métodos
10.
J Sci Food Agric ; 100(2): 855-862, 2020 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-31646648

RESUMO

BACKGROUND: The starting point of this work is to propose a qualitative approach for authenticity confirmation of the composition of liquid egg products. To this end, it was aimed to detect the liquid egg authenticity and adulteration (with water) by using attenuated total reflectance Fourier-transform infrared (ATR-FTIR), near infrared (NIR) spectroscopy and chemometrics. RESULTS: Liquid (n = 50) and dry (n = 50) samples of whole egg, egg yolk, egg white, and whole egg containing extra egg white (BXEW) and water (BXW) were prepared. Principal component analysis (PCA) models were formed using the data obtained from ATR-FTIR and NIR measurements of liquid and dry samples. A better classification was achieved with PCA model of ATR-FTIR measurements formed by using dry samples (100%) instead of liquid ones (80%). The best separation was obtained between dry sample groups of BXEW and BXW (adulterated). The presence of water content in liquid samples showed a negative effect on classification of the samples, while a good classification (100%) was obtained for NIR measurements of both liquid and dry sample groups. The developed PCA models achieved classification regardless of the form of egg samples (liquid or dry). CONCLUSION: The results of the study revealed that adulterated egg samples (with water) could be qualitatively detected using ATR-FTIR and NIR spectroscopy techniques in combination with PCA. © 2019 Society of Chemical Industry.


Assuntos
Ovos/análise , Contaminação de Alimentos/análise , Análise de Componente Principal/métodos , Espectroscopia de Infravermelho com Transformada de Fourier/métodos , Espectroscopia de Luz Próxima ao Infravermelho/métodos , Animais , Galinhas , Água/análise
11.
Chemosphere ; 238: 124564, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31472348

RESUMO

Microplastics pose a worldwide risk for the environment. Microplastic fibers, which are released during the household washing of synthetic fabrics, are a substantial percentage of microplastics in rivers and in oceans. A novel quantification and simultaneous identification of fiber polymers via Micro-FTIR (Fourier Transform Infrared Spectroscopy) was developed. Washing simulations with commercially available household products were performed and effluents were filtered either on GF/F filters (0.7 µm) or on Anodisc filter (0.2 µm), to gather even the smallest fibers. Furthermore, a novel purification procedure of effluents was developed. Subsequently, filters were analyzed also with the scanning electronic microscope (SEM) to confirm the width and length of fibers. This novel method is robust and replicable and it allows better quantification of fibers released and identification of fiber polymers with optimal matches (averagely 80%).


Assuntos
Monitoramento Ambiental/métodos , Espectroscopia de Infravermelho com Transformada de Fourier/métodos , Poluentes Químicos da Água/análise , Filtração , Produtos Domésticos/análise , Microscopia , Têxteis/análise
12.
Food Chem ; 309: 125585, 2020 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-31708344

RESUMO

Seed samples from 117 genetically diverse pea breeding lines were used to determine the robustness of Fourier transform mid-infrared spectroscopy (FT-MIR) for the rapid nutritional profiling of seeds. The FT-MIR results were compared to wet chemistry methods for assessing the concentrations of total protein, starch, fiber, phytic acid, and carotenoids in pea seed samples. Of the five partial least square regression models (PLSR) developed, protein, fiber and phytic acid concentrations predicted by the models exhibited correlation coefficients greater than 0.83 when compared with data obtained using the wet chemistry methods for both the calibration and validation sets. The starch PLSR model had a correlation greater than 0.75, and carotenoids had correlation of 0.71 for the validation sets. The methods implemented in this research show the novelty and usefulness of FT-MIR as a simple, fast, and cost-effective technique to determine multiple seed constituents simultaneously.


Assuntos
Ervilhas/química , Sementes/química , Espectroscopia de Infravermelho com Transformada de Fourier/métodos , Carboidratos/análise , Carotenoides/análise , Análise de Alimentos , Ácido Fítico/análise , Proteínas de Plantas/análise , Amido/análise
13.
Spectrochim Acta A Mol Biomol Spectrosc ; 224: 117405, 2020 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-31351421

RESUMO

The objective of this work is to establish a spectral assignment of several communic acids. The most significant vibrational modes of three stereoisomers of communic acids [trans-, cis-, and iso- (or mirceo-)] are presented. They are showed throughout experimental Raman and IR spectra, and on the basis on calculations with Density Functional Theory (DFT) and the assignment of the spectral bands of different resins found in the literature. These three communic acids studied are the most important isomers present in the scaffold of the fossil resins Class I, as monomers or co-polymerized according to several authors. These kinds of terpenes are used as starting material, for example, for the synthesis of the fungicide and compounds bioactives. In a novel way, it is reported jointly the assignment of the experimental Infrared and Raman modes together with theoretical modes, since normally the authors tend to focus on one or another spectroscopic technique only. These results can be used as a reference for distinguishing amber from less matured resins as copal, determining the local origin of archaeological fossilized resins. Moreover, they will serve as help to differentiate between real and imitation ambers.


Assuntos
Diterpenos/análise , Fósseis , Espectroscopia de Infravermelho com Transformada de Fourier/métodos , Análise Espectral Raman/métodos , Teoria da Densidade Funcional
14.
Spectrochim Acta A Mol Biomol Spectrosc ; 224: 117460, 2020 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-31422338

RESUMO

Over the past decades, ATR-FTIR has emerged as promising tool for the identification of plants at the genus and (sub-) species level through surface measurements of intact leaves. Theoretical considerations regarding the penetration depth of the evanescent wave into the sample and the thickness of plant leaf cuticles suggest that the structure and composition of the cuticle represent universal taxonomic markers. However, experimental evidence for this hypothesis is scarce. In the current contribution, we present results of a series of simple experiments on epidermal monolayers derived from the bulbs of Allium cepa L. (Amaryllidaceae) as a model system to study the effect of an IR active probe located beyond the theoretical penetration depth of the evanescent wave. We found that this probe had a significant influence on the ATR-FTIR spectra for up to 4 epidermal layers stacked on top of each other corresponding to a total thickness of around 60 µm, exceeding the theoretical penetration depth of the evanescent wave by a factor of around 20. Altogether, our data indicate a major discrepancy between theory and practice in ATR-FTIR spectroscopy in general and provide strong evidence that in general plant leaf spectra cannot be fully explained by the structure and composition of the cuticle alone.


Assuntos
Cebolas , Epiderme Vegetal , Folhas de Planta , Espectroscopia de Infravermelho com Transformada de Fourier/métodos , Cebolas/química , Cebolas/citologia , Epiderme Vegetal/química , Epiderme Vegetal/citologia , Folhas de Planta/química , Folhas de Planta/citologia , Análise de Componente Principal , Microtomografia por Raio-X
15.
Spectrochim Acta A Mol Biomol Spectrosc ; 224: 117382, 2020 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-31357053

RESUMO

Fourier transform infrared (FTIR) and Raman spectroscopic techniques were employed to analyze the biomolecular transitions and lipid accumulation in three freshwater green microalgal species, Monoraphidium contortum (M. contortum), Pseudomuriella sp. and Chlamydomonas sp. during various phases of their growth. Biomolecular transitions and lipid [hydrocarbons, triacylglycerides (TAGs)] accumulation within the microalgal cells were identified using second derivatives of the FTIR absorption spectroscopy. Second derivative analysis normalized and resolved the original spectra and led to the identification of smaller, overlapping bands. Both relative and absolute content of lipids were determined using the integrated band area. M. contortum exhibited higher accumulation of lipids than the other two species. The integrated band area of the vibrations from saturated (SFA) and unsaturated lipids (UFA) enabled quantification of fatty acids. The percentage of SFA and UFA was determined using GC, FTIR and Raman spectroscopy. From the spectral data, the order of increasing concentration of SFA among the three microalgal species was M. contortum > Chlamydomonas sp. >Pseudomuriella sp. The spectral results on fatty acids were consistent with the separation of lipids by gas chromatography. The results emphasized the significance of FTIR and Raman spectroscopic methods in monitoring the biomolecular transitions and rapid quantification of lipids, without the need for extraction of lipids.


Assuntos
Clorófitas , Lipídeos , Microalgas , Espectroscopia de Infravermelho com Transformada de Fourier/métodos , Análise Espectral Raman/métodos , Biocombustíveis/análise , Clorófitas/química , Clorófitas/metabolismo , Ácidos Graxos/análise , Ácidos Graxos/química , Ácidos Graxos/metabolismo , Lipídeos/análise , Lipídeos/química , Microalgas/química , Microalgas/metabolismo
16.
Anal Bioanal Chem ; 412(5): 1077-1086, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31865413

RESUMO

Meningiomas are the commonest types of tumours in the central nervous system (CNS). It is a benign type of tumour divided into three WHO grades (I, II and III) associated with tumour growth rate and likelihood of recurrence, where surgical outcomes and patient treatments are dependent on the meningioma grade and histological subtype. The development of alternative approaches based on attenuated total reflection Fourier-transform infrared (ATR-FTIR) spectroscopy could aid meningioma grade determination and its biospectrochemical profiling in an automated fashion. Herein, ATR-FTIR in combination with chemometric techniques is employed to distinguish grade I, grade II and grade I meningiomas that re-occurred. Ninety-nine patients were investigated in this study where their formalin-fixed paraffin-embedded (FFPE) brain tissue samples were analysed by ATR-FTIR spectroscopy. Subsequent classification was performed via principal component analysis plus linear discriminant analysis (PCA-LDA) and partial least squares plus discriminant analysis (PLS-DA). PLS-DA gave the best results where grade I and grade II meningiomas were discriminated with 79% accuracy, 80% sensitivity and 73% specificity, while grade I versus grade I recurrence and grade II versus grade I recurrence were discriminated with 94% accuracy (94% sensitivity and specificity) and 97% accuracy (97% sensitivity and 100% specificity), respectively. Several wavenumbers were identified as possible biomarkers towards tumour differentiation. The majority of these were associated with lipids, protein, DNA/RNA and carbohydrate alterations. These findings demonstrate the potential of ATR-FTIR spectroscopy towards meningioma grade discrimination as a fast, low-cost, non-destructive and sensitive tool for clinical settings. Graphical abstract Attenuated total reflection Fourier-transform infrared (ATR-FTIR) spectroscopy was used to discriminate meningioma WHO grade I, grade II and grade I recurrence tumours.


Assuntos
Neoplasias Meníngeas/química , Meningioma/química , Espectroscopia de Infravermelho com Transformada de Fourier/métodos , Análise Discriminante , Humanos , Análise de Componente Principal , Sensibilidade e Especificidade
17.
Talanta ; 206: 120208, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31514827

RESUMO

Evaluating the possibility of extending shelf life of rice germ (a by-product of rice milling process) by reducing water activity in combination with storage atmosphere packaging, without any heat treatment, is the aim of the present study. Samples at different water activities (0.55, 0.45 and 0.36) were packed in air, argon or under vacuum, and stored at 27 °C for 150 days. To the aim, a non-targeted approach was applied by means of an FT-NIR spectrometer in reflectance with a rotating sample holder and a portable electronic nose, equipped with 10 non-specific sensors. For understanding the impact of the factors under study on the rice germ shelf life, a modified mid-level data fusion approach was applied to enhance the information most correlated with time. Moreover, Principal Component Analysis was applied on fused data to follow samples evolution during storage and identify different clusters according to the storage conditions. The rice germ case study allowed to better understand the information captured by the non-specific sensors: a 2D correlation map was developed combining the e-nose data with the NIR spectral information, highlighting relationships among NIR absorption bands and classes of chemical compounds inducing e-nose responses. A data fusion approach highlighted the importance of water activity on rice germ storage, while no interesting differences were ascribable to storage atmosphere packaging systems. In terms of correlation, the sensors could be divided in two groups, negatively inter-correlated: sensors ascribable to aromatic compounds (WC) and correlated with the NIR band around 4800-4900 cm-1 (N-H bending of primary amides, typical for peptides coming from protein hydrolysis); broad-range response sensors (WS), linked with the NIR band at 5128 cm-1 (second overtone of CO stretching of esters).


Assuntos
Grão Comestível/química , Armazenamento de Alimentos , Oryza/química , Espectroscopia de Infravermelho com Transformada de Fourier/estatística & dados numéricos , Espectroscopia de Luz Próxima ao Infravermelho/estatística & dados numéricos , Nariz Eletrônico/estatística & dados numéricos , Análise de Componente Principal , Espectroscopia de Infravermelho com Transformada de Fourier/métodos , Espectroscopia de Luz Próxima ao Infravermelho/métodos
18.
Eur J Pharm Biopharm ; 145: 98-112, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31698042

RESUMO

The present study evaluates the physical stability and intermolecular interactions of Rivaroxaban (RXB) amorphous solid dispersions (ASDs) in polymeric carriers via thermodynamic modelling and molecular simulations. Specifically, the Flory-Huggins (FH) lattice solution theory was used to construct thermodynamic phase diagrams of RXB ASDs in four commonly used polymeric carriers (i.e. copovidone, coPVP, povidone, PVP, Soluplus, SOL and hypromellose acetate succinate, HPMCAS), which were stored under 0%, 60% and 75% relative humidity (RH) conditions. In order to verify the phase boundaries predicted by FH modelling (i.e. truly amorphous zone, amorphous-amorphous demixing zones and amorphous-API recrystallization zones), samples of ASDs were examined via polarized light microscopy after storage for up to six months at various RH conditions. Results showed a good agreement between the theoretical and the experimental approaches (i.e. coPVP and PVP resulted in less physically-stable ASDs compared to SOL and HPMCAS) indicating that the proposed FH-based modelling may be a useful tool in predicting long-term physical stability in high humidity conditions. In addition, molecular dynamics (MD) simulations were employed in order to interpret the observed differences in physical stability. Results, which were verified via differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FTIR), suggested the formation of similar intermolecular interactions in all cases, indicating that the interaction with moisture water plays a more crucial role in ASD physical stability compared to the formation of intermolecular interactions between ASD components.


Assuntos
Polímeros/química , Rivaroxabana/química , Varredura Diferencial de Calorimetria/métodos , Cristalização/métodos , Portadores de Fármacos/química , Composição de Medicamentos/métodos , Estabilidade de Medicamentos , Umidade , Espectroscopia de Infravermelho com Transformada de Fourier/métodos , Termodinâmica
19.
AAPS PharmSciTech ; 20(8): 327, 2019 Oct 28.
Artigo em Inglês | MEDLINE | ID: mdl-31659590

RESUMO

Freeze-dried immunoglobulin G (IgG) incorporating trehalose and human serum albumin (HSA) was statistically evaluated regarding the existence of synergism between additives on the stability profile. The levels of HSA (X1) and trehalose (X2) were independent variables. Aggregation following the process (Y1), after 2 and 3 months at 40°C (Y2) and (Y3), respectively, along with the rate constant of aggregation (Y4) were dependent variables. Aggregation and beta-sheet conformation were quantified through size-exclusion chromatography (SEC-HPLC) and Fourier transform infrared spectroscopy (FTIR). Central composite design (CCD) suggested the best formulation. The integrity and thermodynamic stability of optimized formulation were investigated through sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and differential scanning calorimetry (DSC). The calculated responses were Y1, 0-0.90%; Y2, 0.4-4.3%; Y3, 2.10-13.46%; and Y4, 0.16-0.69 1/month. The optimized formulation had 10 mg IgG, 86 mg trehalose, and 1 mg HSA with observed responses of Y1, 0.01%; Y2, 0.51%; Y3, 3.08%; and Y4, 0.33 1/month. The models were statistically well-fitted. The optimized formulation was amorphous during freeze-drying (FD), and no fragmentation was observed. Trehalose and HSA demonstrated statistical synergism. CCD was successfully employed to recommend the best ratio of stabilizers and achieve the maximum stabilization of IgG as a model freeze-dried antibody.


Assuntos
Desenho de Drogas , Imunoglobulina G/química , Albumina Sérica Humana/síntese química , Trealose/síntese química , Varredura Diferencial de Calorimetria/métodos , Combinação de Medicamentos , Estabilidade de Medicamentos , Liofilização/métodos , Humanos , Imunoglobulina G/administração & dosagem , Albumina Sérica Humana/administração & dosagem , Espectroscopia de Infravermelho com Transformada de Fourier/métodos , Trealose/administração & dosagem
20.
J Oleo Sci ; 68(11): 1073-1084, 2019 Nov 07.
Artigo em Inglês | MEDLINE | ID: mdl-31611515

RESUMO

Eucommia ulmoides is a traditional Chinese herb whose seeds can be used to produce edible oils. Fourier transform infrared (FTIR) and synchronous fluorescence spectroscopic (SyFS) spectra of Eucommia ulmoides seed oil (EUSO) are lacking. The relevant functional and fluorescent groups were determined by FTIR and SyFS techniques for discriminating adulteration of EUSO, respectively. FTIR and SyFS spectra of EUSO and six common-used vegetable oils were recorded from 4000-400 cm-1 and 250-700 nm at wavelength interval of 60 nm, respectively. Principal component analysis (PCA), linear discriminant analysis (LDA), cluster analysis (CA) and partial least square (PLS) regression was used for qualitative and quantitative calibration of EUSO adulteration. The FTIR spectral regions of 1429-1377 cm-1 and 1128-1110 cm-1 based on PCA, LDA, and CA, and the PCA of SyFS spectral regions of 600-700 nm and 300-500 nm were evaluated for qualitative differentiation of EUSO adulteration. The recognition rate of PCA validation was found to be 100% by FTIR regions. PLS calibration was optimal by the spectral normalization vector treatment in the two FTIR spectral regions and SyFS spectra were combined with characteristic absorption peak area, which can achieve quantitative detection of EUSO adulteration. The two techniques are useful for EUSO adulteration detection at levels down to 1% and 0.48% (w/w), respectively. The results indicated that spectral information obtained by FTIR and SyFS of EUSO can be used for qualitative and quantitative analysis of EUSO adulteration with the advantages of high sensitivity, simplicity, and rapidness.


Assuntos
Gorduras Insaturadas na Dieta/análise , Eucommiaceae/química , Contaminação de Alimentos/prevenção & controle , Qualidade dos Alimentos , Óleos Vegetais/química , Sementes/química , Espectrometria de Fluorescência/métodos , Espectroscopia de Infravermelho com Transformada de Fourier/métodos , Calibragem , Sensibilidade e Especificidade
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