Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 11 de 11
Filtrar
1.
Nanomaterials (Basel) ; 14(2)2024 Jan 12.
Artigo em Inglês | MEDLINE | ID: mdl-38251148

RESUMO

This study aimed to characterize and investigate the potential of the oils from Gryllus bimaculatus, Teleogryllus mitratus, and Acheta domesticus to be used in nanoemulsions. The oils were extracted by a cold press method and characterized for their fatty acid profiles. Their irritation effects on the chorioallantoic membrane (CAM) were evaluated, along with investigations of solubility and the required hydrophilic-lipophilic balance (RHLB). Various parameters impacting nanoemulsion generation using high-pressure homogenization were investigated. The findings revealed that G. bimaculatus yielded the highest oil content (24.58% w/w), followed by T. mitratus (20.96% w/w) and A. domesticus (15.46% w/w). Their major fatty acids were palmitic, oleic, and linoleic acids. All oils showed no irritation, suggesting safety for topical use. The RHLB values of each oil were around six-seven. However, they could be successfully developed into nanoemulsions using various surfactants. All cricket oils could be used for the nanoemulsion preparation, but T. mitratus yielded the smallest internal droplet size with acceptable PDI and zeta potential. Nanoemulsion was found to significantly enhance the antioxidant and anti-skin wrinkle of the T. mitratus oil. These findings pointed to the possible use of cricket oils in nanoemulsions, which could be used in various applications, including topical and cosmetic formulations.

2.
Molecules ; 25(7)2020 Apr 04.
Artigo em Inglês | MEDLINE | ID: mdl-32260353

RESUMO

A mono-segmented sequential injection lab-at-valve (SI-LAV) system for the determination of albumin, glucose, and creatinine, three key biomarkers in diabetes screening and diagnosis, was developed as a single system for multi-analyte analysis. The mono-segmentation technique was employed for in-line dilution, in-line single-standard calibration, and in-line standard addition. This made adjustments to the sample preparation step easy unlike the batch-wise method. The results showed that the system could be used for both fast reaction (albumin) and slow reaction (glucose with enzymatic reaction and creatinine). In the case of slow reaction, the analysis time could be shortened by using the reaction rate obtained with the SI-LAV system. This proposed system is for cost-effective and downscaling analysis, which would be applicable for small hospitals and clinics in remote places with a small number of samples but relatively fast screening would be needed.


Assuntos
Técnicas de Laboratório Clínico/instrumentação , Creatinina/análise , Glucose/análise , Albumina Sérica Humana/análise , Técnicas de Química Analítica/instrumentação , Técnicas de Química Analítica/métodos , Técnicas de Laboratório Clínico/métodos , Humanos
3.
Talanta ; 201: 226-229, 2019 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-31122415

RESUMO

A simple cost-effective device for downscaling chemical analysis with microliter-scale dropwise handing and smartphone detection is proposed. The platform was made from easily available materials. Drops of constant volume of analyte and reagent were placed onto a channel then moved by gravity force to mix and react with each other. The color change due to reaction was monitored with a smartphone. Assays of iron, copper and phosphate employing the platform were demonstrated with 1,10-phenanthroline, bicinchoninic acid and molybdate reagents, respectively. Kinetic study was also demonstrated for this simple device.

4.
Anal Sci ; 35(3): 347-350, 2019 Mar 10.
Artigo em Inglês | MEDLINE | ID: mdl-30344207

RESUMO

We propose the creation of reusable indicator-sorbed-solids, using anion-exchange resins or kaolin as supports, with the aim to reduce chemical use towards green analytical chemistry. Indicators (phenolphthalein, thymol blue and butterfly pea flower extract as a natural indicator) sorbed on a solid support, were employed in acid-base titration, in both homogenous aqueous and heterogenous aqueous organic phases. Applications of the developed techniques to some real samples, such as vinegar, colored fruit juice and vegetable oil, have been demonstrated.


Assuntos
Resinas de Troca Aniônica/química , Análise de Alimentos/métodos , Química Verde/métodos , Indicadores e Reagentes/química , Caulim/química , Titulometria/métodos , Ácido Acético/análise , Adsorção , Sucos de Frutas e Vegetais/análise , Óleos de Plantas/análise
5.
Anal Sci ; 35(2): 219-221, 2019 Feb 10.
Artigo em Inglês | MEDLINE | ID: mdl-30249929

RESUMO

A downscaling in true titration based on a simple sequential injection analysis-lab-at-valve (SIA-LAV) has been proposed. A titrant solution was stepwise aspirated into a titration LAV chamber and a titration curve was obtained by monitoring the change in the solution color spectroscopically. This fully-automated SIA-LAV system required less volume of the sample/reagents, only a micro-liter scale, compared to the conventional method. The system was investigated with complexometric titration and acid-base titration. Application of the developed technique to some real samples has been demonstrated.

6.
Talanta ; 190: 85-88, 2018 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-30172545

RESUMO

Anionic surfactant as sodium dodecyl sulfate (SDS) can be assayed by using methylene blue (MB). The ion-association of SDS-MB can be extracted solventless but sorbed on a specified polyurethane foam (PUF) monolithic rod, prepared in the lab by mixing polyether with methylene diphenyl diisocyanate (MDI). The blue product (the ion-association of SDS-MB) on the rod can be followed by a smartphone (iPhone 6S). With a set of conditions, a single standard calibration can be applied. The proposed green analytical procedure can be employed for on-site assay. Application to real water samples was demonstrated.

7.
Talanta ; 185: 160-165, 2018 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-29759184

RESUMO

A webcam camera as an alternative cost-effective colorimetric sensor for the simple dual electrochemical - colorimetric detection system is proposed. Performance test of the system was investigated through electrochemical and colorimetric behaviors of redox reactions of potassium ferrocyanide complex. Image processing with two color systems, RGB and HSV, was applied together with various electrochemical techniques. Color responses obtained from the webcam correlated with electrochemical signals in various electrochemical techniques. The results from the proposed dual detection system agreed well with those obtained using conventional UV-vis spectroelectrochemical system reported previously. The application of proposed system was demonstrated for studying the redox reaction of catechin and electrochemical - colorimetric behaviors of Fe(II) and Fe(III) mixture.

8.
Talanta ; 181: 1-5, 2018 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-29426486

RESUMO

Noodle based analytical devices are proposed for cost effective green chemical analysis. Two noodle based analytical platforms have been examined. Conditions for flow with laminar behaviors could be established. Detection may be via a webcam camera or a flatbed scanner. Acid-base reactions were chosen as a model study. The assays of acetic acid and sodium hydroxide were investigated. Apart from bromothymol blue, simple aqueous extract of butterfly pea flower was used as a natural reagent. Another model was the assay of copper (Cu2+) which was based on the redox reaction of copper (Cu2+) with iodide to produce tri-iodide forming brown/black product with starch which already exists in the noodle platform. Demonstration to apply the noodle platforms for real samples was made.

9.
Talanta ; 136: 84-94, 2015 May.
Artigo em Inglês | MEDLINE | ID: mdl-25702989

RESUMO

This paper reviews the development and recent use of everyday communications and IT equipment (mobile phones, digital cameras, scanners, webcams, etc) as detection devices for colorimetric chemistries. Such devices can readily be applied for visible detection using reaction formats such as microfluidic paper based analytical devices (µPADs), indicator papers, and well plate reaction vessels. Their use is highly advantageous with respect to cost, simplicity and portability, and offers many opportunities in the areas of point of care diagnosis, and at-site monitoring of environmental, agricultural, food and beverage parameters.

10.
Talanta ; 84(5): 1396-400, 2011 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-21641458

RESUMO

Green analytical methods employing flow analysis with simple natural reagent extracts have been exploited. Various formats of flow based analysis systems including a single line FIA, a simple lab on chip with webcam camera detector, and a newly developed simple lab on chip system with reflective absorption detection and the simple extracts from some available local plants including butterfly pea flower, orchid flower, and beet root were investigated and shown to be useful as alternative self indicator reagents for acidity assay. Various tea drinks were explored to be used for chromogenic reagents in iron determination. The benefit of a flow based system, which allows standards and samples to go through the analysis process in exactly the same conditions, makes it possible to employ simple natural extracts with minimal or no pretreatment or purification. The combinations of non-synthetic natural reagents with minimal processed extracts and the low volume requirement flow based systems create some unique green chemical analyses.


Assuntos
Produtos Biológicos/química , Análise de Injeção de Fluxo/instrumentação , Química Verde/instrumentação , Ferro/análise , Absorção , Concentração de Íons de Hidrogênio , Indicadores e Reagentes/química , Internet , Dispositivos Lab-On-A-Chip , Fibras Ópticas
11.
Talanta ; 81(3): 1137-41, 2010 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-20298905

RESUMO

A modification of a webcam camera for use as a small and low cost detector was demonstrated with a simple lab-on-chip reactor. Real time continuous monitoring of the reaction zone could be done. Acid-base neutralization with phenolphthalein indicator was used as a model reaction. The fading of pink color of the indicator when the acidic solution diffused into the basic solution zone was recorded as the change of red, blue and green colors (%RBG.) The change was related to acid concentration. A low cost portable semi-automation analysis system was achieved.


Assuntos
Técnicas de Química Analítica , Internet , Procedimentos Analíticos em Microchip/métodos , Ácido Acético/química , Automação , Calibragem , Colorimetria/métodos , Dispositivos Lab-On-A-Chip , Procedimentos Analíticos em Microchip/economia , Fenolftaleína/química , Reprodutibilidade dos Testes , Fatores de Tempo , Gravação em Vídeo
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA