scholarly journals Facile and versatile ligand analysis method of colloidal quantum dot

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jin Hae Kim ◽  
Hyokeun Park ◽  
Tae-Gon Kim ◽  
Hyunmi Lee ◽  
Shinae Jun ◽  
...  

AbstractColloidal quantum-dots (QDs) are highly attractive materials for various optoelectronic applications owing to their easy maneuverability, high functionality, wide applicability, and low cost of mass-production. QDs usually consist of two components: the inorganic nano-crystalline particle and organic ligands that passivate the surface of the inorganic particle. The organic component is also critical for tuning electronic properties of QDs as well as solubilizing QDs in various solvents. However, despite extensive effort to understand the chemistry of ligands, it has been challenging to develop an efficient and reliable method for identifying and quantifying ligands on the QD surface. Herein, we developed a novel method of analyzing ligands in a mild yet accurate fashion. We found that oxidizing agents, as a heterogeneous catalyst in a different phase from QDs, can efficiently disrupt the interaction between the inorganic particle and organic ligands, and the subsequent simple phase fractionation step can isolate the ligand-containing phase from the oxidizer-containing phase and the insoluble precipitates. Our novel analysis procedure ensures to minimize the exposure of ligand molecules to oxidizing agents as well as to prepare homogeneous samples that can be readily analyzed by diverse analytical techniques, such as nuclear magnetic resonance spectroscopy and gas-chromatography mass-spectrometry.

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Hewen Hu ◽  
Xu Teng ◽  
Shanshan Zhang ◽  
Tingting Liu ◽  
Xiao Li ◽  
...  

The polysaccharide was extracted by water extraction and alcohol precipitation method from “deer tripe mushroom,” which was domesticated and bred from wild Auricularia delicata in Zambia. The structure of the deer tripe mushroom polysaccharide (DTMP) was characterized by gas chromatography-mass spectrometry (GC-MS), Fourier transform infrared spectroscopy (FT-IR), nuclear magnetic resonance spectroscopy (NMR), scanning electron microscope (SEM), and other analytical techniques. And the rheological and gel properties and antioxidant capacities of the polysaccharide were studied. The results showed that DTMP was mainly composed of mannose, fructose, glucose, and galacturonic acid, of which the galacturonic acid was the main component. By calculation, the molar ratio of mannose : fructose : glucose : galactoacid in DTMP is 0.8 : 14.8 : 1.0 : 26.32. The polysaccharide was mainly composed by α-1,4-glycosidic bond. DTMP solution showed a shear-thinning (pseudoplastic) behaviour, and its pseudoplasticity was more obvious at a concentration of 2%. The power law model was used to evaluate the viscosity curves of DTMP, and its viscosity and consistency indices both increased as the concentration increased, whereas both indices decreased as the concentration decreased. The viscosity of the polysaccharide solution changed as the pH changed: the polysaccharide solutions had a higher viscosity at pH = 10. DTMP showed gel-like behaviour (G′ > G″), and the gel strength enhanced with the increase of concentration (2%–10%). In addition, the antioxidant experiment of DTMP showed that it had good antioxidant activity, and there was a significant dose-effect relationship between its activity and concentration in the low concentration range.


2021 ◽  
Vol 11 (4) ◽  
pp. 1410
Author(s):  
Martina Daute ◽  
Frances Jack ◽  
Irene Baxter ◽  
Barry Harrison ◽  
John Grigor ◽  
...  

This study compared the use of three sensory and analytical techniques: Quantitative Descriptive Analysis (QDA), Napping, and Gas Chromatography-Mass Spectrometry (GC-MS) for the assessment of flavour in nine unmatured whisky spirits produced using different yeasts. Hierarchical Multiple Factor Analysis (HMFA) showed a similar pattern of sample discrimination (RV scores: 0.895–0.927) across the techniques: spirits were mostly separated by their Alcohol by Volume (ABV). Low ABV spirits tended to have heavier flavour characteristics (feinty, cereal, sour, oily, sulphury) than high ABV spirits, which were lighter in character (fruity, sweet, floral, solventy, soapy). QDA differentiated best between low ABV spirits and GC-MS between high ABV spirits, with Napping having the lowest resolution. QDA was time-consuming but provided quantitative flavour profiles of each spirit that could be readily compared. Napping, although quicker, gave an overview of the flavour differences of the spirits, while GC-MS provided semi-quantitative ratios of 96 flavour compounds for differentiating between spirits. Ester, arenes and certain alcohols were found in higher concentrations in high ABV spirits and other alcohols and aldehydes in low ABV spirits. The most comprehensive insights on spirit flavour differences produced by different yeast strains are obtained through the application of a combination of approaches.


2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Kooliyankal Naseema ◽  
Kaniyamkandy Ribin ◽  
Nidiyanga Navya ◽  
Prasoon Prasannan

AbstractNano crystalline zinc sulfide thin films were deposited onto glass substrates by chemical bath deposition method. One of the samples was annealed at 300 °C for 2 h in air using a muffle furnace. The prepared thin films were investigated by X-ray diffraction (XRD), UV–visible spectroscopy (UV–vis), photoluminescence spectroscopy (PL), scanning electron microscopy (SEM) and Raman spectroscopy (FT-R) studies before and after annealing. The analysis confirmed the thermal-induced anion substitution and conversion of ZnS crystal to ZnO wurtzite crystal. XRD pattern showed that these films were phase pure and polycrystalline in nature. Optical band gap was found to be 3.86 eV for ZnS and 3.21 eV for ZnO. The films prepared by this simple, low-cost technique are suitable for photovoltaic and optoelectronic applications.


Author(s):  
João Marcos Pereira Galúcio ◽  
Sorrel Godinho Barbosa de Souza ◽  
Arthur Abinader Vasconcelos ◽  
Alan Kelbis Oliveira Lima ◽  
Kauê Santana da Costa ◽  
...  

: Nanotechnology is a cutting-edge area with numerous industrial applications. Nanoparticles are structures that have dimensions ranging from 1–100 nm which exhibit significantly different mechanical, optical, electrical, and chemical properties when compared with their larger counterparts. Synthetic routes that use natural sources, such as plant extracts, honey, and microorganisms are environmentally friendly and low-cost methods that can be used to obtain nanoparticles. These methods of synthesis generate products that are more stable and less toxic than those obtained using conventional methods. Nanoparticles formed by titanium dioxide, zinc oxide, silver, gold, and copper, as well as cellulose nanocrystals are among the nanostructures obtained by green synthesis that have shown interesting applications in several technological industries. Several analytical techniques have also been used to analyze the size, morphology, hydrodynamics, diameter, and chemical functional groups involved in the stabilization of the nanoparticles as well as to quantify and evaluate their formation. Despite their pharmaceutical, biotechnological, cosmetic, and food applications, studies have detected their harmful effects on human health and the environment; and thus, caution must be taken in uses involving living organisms. The present review aims to present an overview of the applications, the structural properties, and the green synthesis methods that are used to obtain nanoparticles, and special attention is given to those obtained from metal ions. The review also presents the analytical methods used to analyze, quantify, and characterize these nanostructures.


1977 ◽  
Vol 5 (6) ◽  
pp. 665-667
Author(s):  
C W Moss ◽  
M A Lambert ◽  
G L Lombard

Cellular fatty acids of Peptococcus variables and Peptostreptococcus anaerobius were identified by gas chromatography, mass spectrometry, and associated analytical techniques. Iso- and anteiso-branched-chain acids were major components in both species.


2019 ◽  
Vol 3 (2) ◽  
pp. 35 ◽  
Author(s):  
Heman Smail ◽  
Mohammad Rehan ◽  
Kafia Shareef ◽  
Zainab Ramli ◽  
Abdul-Sattar Nizami ◽  
...  

This work highlights how the treatment of ZSM-5 (parent Zeolite Socony Mobil–5, Si/Al = 23) with different surfactant templates and alkaline solution, improved the catalytic performance in the Friedel-Crafts acylation of anisole with a propionic anhydride to obtain p-methoxypropiophenone. The modified microporous to mesoporous zeolite catalysts were characterized using different analytical techniques, including X-ray diffraction (XRD), nitrogen porosimetry, Fourier-transform infrared spectroscopy (FT-IR), temperature-programmed desorption (ammonia-TPD) and field emission scanning electron microscopy (FE-SEM) to analyze the crystallographic structure, surface acidity, surface area, porosity, morphology, and particle size. The results showed that the formed mesoporous zeolite by NaOH solution had smaller mesopores (ca. 3.7 nm) as compared to the mesoporous zeolites obtained by surfactant templates, such as, CTAB (ca. 14.9 nm), TPAOH (ca. 11.1 nm) and mixture of CTAB/TPAOH (ca. 15.2 nm). The catalytic acylation reaction was conducted in a batch glass reactor at various temperatures and the products were analyzed using off-line gas chromatography–mass spectrometry (GC-MS). It was found that the activity of treated ZSM-5 with mixed surfactant templates (CTAB/TPAOH) exhibited enhanced selectivity towards the main product (p-methoxypropiophenone) by a factor 1.7 or higher than unmodified ZSM-5 due to its increased surface area by 1.5 times and enhanced acid sites.


Revista Vitae ◽  
2021 ◽  
Vol 28 (3) ◽  
Author(s):  
Laura Carvajal Barbosa ◽  
Diego Insuasty Cepeda ◽  
Andrés Felipe León Torres ◽  
Maria Mercedes Arias Cortes ◽  
Zuly Jenny Rivera Monroy ◽  
...  

BACKGROUND : Biosensing techniques have been the subject of exponentially increasing interest due to their performance advantages such as high selectivity and sensitivity, easy operation, low cost, short analysis time, simple sample preparation, and real-time detection. Biosensors have been developed by integrating the unique specificity of biological reactions and the high sensitivity of physical sensors. Therefore, there has been a broad scope of applications for biosensing techniques, and nowadays, they are ubiquitous in different areas of environmental, healthcare, and food safety. Biosensors have been used for environmental studies, detecting and quantifying pollutants in water, air, and soil. Biosensors also showed great potential for developing analytical tools with countless applications in diagnosing, preventing, and treating diseases, mainly by detecting biomarkers. Biosensors as a medical device can identify nucleic acids, proteins, peptides, metabolites, etc.; these analytes may be biomarkers associated with the disease status. Bacterial food contamination is considered a worldwide public health issue; biosensor-based analytical techniques can identify the presence or absence of pathogenic agents in food. OBJECTIVES: The present review aims to establish state-of-the-art, comprising the recent advances in the use of nucleic acid-based biosensors and their novel application for the detection of nucleic acids. Emphasis will be given to the performance characteristics, advantages, and challenges. Additionally, food safety applications of nucleic acid-based biosensors will be discussed. METHODS: Recent research articles related to nucleic acid-based biosensors, biosensors for detecting nucleic acids, biosensors and food safety, and biosensors in environmental monitoring were reviewed. Also, biosensing platforms associated with the clinical diagnosis and food industry were included. RESULTS: It is possible to appreciate that multiple applications of nucleic acid-based biosensors have been reported in the diagnosis, prevention, and treatment of diseases, as well as to identify foodborne pathogenic bacteria. The use of PNA and aptamers opens the possibility of developing new biometric tools with better analytical properties. CONCLUSIONS: Biosensors could be considered the most important tool for preventing, treating, and monitoring diseases that significantly impact human health. The aptamers have advantages as biorecognition elements due to the structural conformation, hybridization capacity, robustness, stability, and lower costs. It is necessary to implement biosensors in situ to identify analytes with high selectivity and lower detection limits.


Author(s):  
Salman Mau ◽  
Shakir Saleem ◽  
Vishwadeepak Kimothi ◽  
Vineet Joshi ◽  
Sanjay Singh

Diabetes mellitus is one of the most common metabolic disorders associated with disturbed hormonal secretion. Diabetes is characterized by high blood glucose levels over a prolonged period of time. High sugar levels are due to abnormal metabolism of carbohydrates and lipids which is caused by absolute or relative insulin deficiency. Herbal medicines have been the highly esteemed source of medicine throughout the human history. Herbs are becoming more popular today because of their least side effects, holistic beliefs, easy availability and low cost. Individual herbal products and formulations are gaining popularity because of their quality manufacturing using modern analytical techniques and standardized raw materials. Herbal drugs are widely used for the treatment of diabetes worldwide in various dosage forms. India has a long list of native herbal drugs with scientifically proven blood sugar lowering properties. The seeds of Nigella sativa, Olea europaea, fruits of Aegle marmelos, Momordica charantia, Coccinia indica, Nigella sativa,Gymnema sylvestre leaves,whole plant of Pterocarpus marsupium, Syzygium cumini fruits, Swertia punicea, Urtica dioica, gum of Ferula assa-foetida and seeds of Trigonella foenum graecum were discussed along with their reported mechanisms of action. In this review paper an attempt has been made to give an overview of certain Indian plants which have shown their anti-diabetic activity in various pre-clinical studies.


2012 ◽  
Author(s):  
Ethan J. D. Klem ◽  
Jay Lewis ◽  
Christopher Gregory ◽  
Garry Cunningham ◽  
Dorota Temple

Author(s):  
Aditya Manivannan Iyer ◽  
Vedika Dadlani ◽  
Harshal Ashok Pawar

Abstract: Acrylamide is classified as a hazard whose formation in carbohydrate-rich food cooked at a high temperature has created much interest in the scientific community. The review attempts to comprehend the chemistry and mechanisms of formation of acrylamide and its levels in popular foods. A detailed study of the toxicokinetic and biochemistry, carcinogenicity, neurotoxicity, genotoxicity, interaction with biomolecules, and its effects on reproductive health has been presented. The review outlines the various novel and low-cost conventional as well as newer analytical techniques for the detection of acrylamide in foods with the maximum permissible limits. Various effective approaches that can be undertaken in industries and households for the mitigation of levels of acrylamide in foods have also been discussed. This review will assist to provide in depth understanding about acrylamide that will make it simpler to assess the risk to human health from the consumption of foods containing low amounts of acrylamide.


Sign in / Sign up

Export Citation Format

Share Document