scholarly journals Preparation of a reference material for microplastics in water—evaluation of homogeneity

2021 ◽  
Author(s):  
John Seghers ◽  
Elzbieta A. Stefaniak ◽  
Rita La Spina ◽  
Claudia Cella ◽  
Dora Mehn ◽  
...  
Keyword(s):  
Reference Materials ◽  
Large Scale ◽  
Average Mass ◽  
Good Potential ◽  
Ft Ir ◽  
Dynamic Image Analysis ◽  
The Stability ◽  
Particle Shapes ◽  
Specific Number ◽  
Ft Ir Spectroscopy

AbstractValidation of analytical methods for measurements of microplastics (MP) is severely hampered because of a general lack of reference materials, RM. There is a great need to develop such reference materials. This study presents a concept of three-component kit with immobilised MP in solid NaCl, a surfactant and clean water that can be applied for the production of many types of MP RMs. As proof of concept, an RM for polyethylene terephthalate (PET) particles in water was prepared and evaluated for its homogeneity. The particles ranged from 30 μm (Feretmin) to about 200 μm adapted by wet sieving. A specific number of PET particles were immobilized in about 0.29 g of solid NaCl by freeze-drying 1 mL of a NaCl suspension. By using manual and automated counting, twenty reconstituted 1-L water samples were evaluated for homogeneity with respect to number of PET particles from 30 μm to > 200 μm/L of water. The number of particles was 730 ± 120 (mean ± one standard deviation (SD); n = 10) and 865 ± 155 particles (n = 10) obtained by optical microscopy in two independent laboratories. This corresponded to relative SDs of 16.4 and 17.9% and a mean of 797 ± 151 particles (18.9% RSD, for n = 20). Homogeneity studies of the NaCl carrier without reconstitution resulted in 794 ± 60 particles (7.5% RSD). The homogeneity of PET in the salt carrier was also evaluated directly with respect to mass of PET per vial using an ultra-micro balance. An average mass of 293 ± 41 μg of PET was obtained (14, % RSD for n = 14). Micrographs were recorded to demonstrate the absence of major sources of contamination of the RM components. Information about the particle size distribution and particle shapes was obtained by laser diffraction (LD) and dynamic image analysis (DIA). In addition, the identity of the PET polymer was confirmed by Raman and FT-IR spectroscopy. The RM was developed for a large-scale inter-laboratory comparison of PET particles in water (ILC). Based on the homogeneity results, the material was found to be sufficiently homogeneous to be of meaningful use in the ILC. In a 3-day process, more than 500 samples of PET particles in the NaCl carrier were prepared with good potential for further upscaling with respect to the number of vials or with other kinds of polymers. The stability of PET was not evaluated but it was deemed to be stable for the duration of the ILC.

Study on Host-Guest Inclusion Complexation of a Drug in Cucurbit [6]uril

2018 ◽  
Vol 232 (2) ◽  
pp. 281-293 ◽  
Author(s):  
Kanak Roy ◽  
Subhadeep Saha ◽  
Biswajit Datta ◽  
Lovely Sarkar ◽  
Mahendra Nath Roy
Keyword(s):  
Surface Tension ◽  
Specific Conductivity ◽  
Inclusion Complexation ◽  
Conductivity Measurements ◽  
Saline Environment ◽  
H Nmr ◽  
Vis Spectroscopy ◽  
Ft Ir ◽  
The Stability ◽  
Ft Ir Spectroscopy

AbstractAssembly of pyridine-2-aldoxime drug with cucurbit [6]uril (CB[6]) has been investigated by1H-NMR and 2D-ROESY NMR, UV-Vis spectroscopy, FT-IR spectroscopy, surface tension and conductivity measurements in aqueous saline environment. The distinct cationic receptor feature and the cavity dimension of the CB[6] emphasize that the macro-cyclic host molecule remain as complex with the nerve stimulus drug molecule. The results obtained from surface tension and specific conductivity measurements suggest 1:1 inclusion complex formation between drug and CB[6]. The stability constant evaluated by UV-Vis spectroscopic approach is 2.21×105M−1at 298.15 K, which indicates that the complex is sufficiently stable at physiological temperature.

Effects of added phthalate plasticizers on photodegradation of irradiated poly (α-methylstyrene) films

2015 ◽  
Vol 35 (2) ◽  
pp. 159-167 ◽  
Author(s):  
Afrah E. Ramadhan
Keyword(s):  
Dibutyl Phthalate ◽  
Irradiation Time ◽  
Broad Band ◽  
Dioctyl Phthalate ◽  
Solid Films ◽  
Polymeric Chains ◽  
Ft Ir ◽  
The Stability ◽  
Monomer Fluorescence ◽  
Ft Ir Spectroscopy

Abstract The effects of UV irradiation and blending on the stability of poly (α-methylstyrene) (PαMS) in solid films were studied at different intervals of irradiation time in the presence of air, by absorption, emission and Fourier transform infrared (FT-IR) spectroscopy. The increase in irradiation time caused an increase in the intensity of the absorption band of the polymer, and an increase in the intensity of absorption of a new broad band at a longer wavelength, thus indicating the possibility of photodegradation of polymeric chains. The influence of added plasticizers, dimethyl terephthalate (DMT), diethyl terephthalate (DET), dibutyl phthalate (DBP), dioctyl phthalate (DOP) and dioctyl terephthalate (DOT) on photoquenching of the polymer fluorescence band was also investigated, and found to increase the photoquenching processes with increase in the amount of added plasticizers. By contrast, the intensity of excimer and monomer fluorescence bands was also found to decrease with increase in irradiation times. These changes may be attributed to the formation of new photoproducts which resulted from the photodegradation and photooxidation of irradiated polymeric chains. In addition, the observed increase in the intensities of the carbonyl and hydroxyl regions of the FT-IR spectra provides evidence for the photooxidation of polymeric chains. The increase in the intensity of some bands and the disappearance of new bands indicate the photodegradation of polymeric chains.

DLC-coated Substrate for Infrared Absorption Spectroscopy in Supercritical Water

2011 ◽  
Vol 1309 ◽  
Author(s):  
Takuji Ube ◽  
Takashi Ishiguro
Keyword(s):  
Ir Spectroscopy ◽  
Zinc Selenide ◽  
Supercritical Water ◽  
Fused Silica ◽  
Diamond Like Carbon ◽  
Infrared Absorption Spectroscopy ◽  
Coated Substrate ◽  
Ft Ir ◽  
The Stability ◽  
Ft Ir Spectroscopy

ABSTRACTThe stability of several kinds of substrates, such as Corning #1737 glass, fused silica, synthetic silica, water free synthetic silica, zinc selenide, silicon, and diamond like carbon (DLC) coated Si in supercritical water (663K and 25MPa) were examined. Their reaction with the water was evaluated by using Fourier transform infrared (FT-IR) spectroscopy. As a result of the present experiment, it was found that DLC-coated Si is one of the most stable and useful substrates for IR spectroscopy in supercritical water.

scholarly journals Simulink-Based Analysis for Coupled Metabolic Systems

2018 ◽  
Vol 2018 ◽  
pp. 1-10
Author(s):  
Shinq-Jen Wu ◽  
Cheng-Tao Wu
Keyword(s):  
Stability Analysis ◽  
Dynamic Simulation ◽  
Large Scale ◽  
Dynamic Behaviour ◽  
Canonical Systems ◽  
Metabolic Systems ◽  
Good Potential ◽  
Set Up ◽  
The Stability ◽  
Interactive Behaviour

Stability analysis and dynamic simulation are important for researchers to capture the performance and the properties of underling systems. S-systems have good potential for characterizing dynamic interactive behaviour of large scale metabolic and genetic systems. It is important to develop a platform to achieve timely dynamic behaviour of S-systems to various situations. In this study, we first set up the respective block diagrams of S-systems for module-based simulation. We then derive reasonable theorems to examine the stability of S-systems and find out what kinds of environmental situations will make systems stable. Three canonical systems are used to examine the results which are carried out in the Matlab/Simulink environments.

scholarly journals Biogeneration and physico-chemical properties of panchagavya fortified chicken feather vermicompost

2021 ◽  
Author(s):  
Mohan Arthanari ◽  
Dhanapalan Senthil Kumar ◽  
Ravikumar Jayachandran ◽  
Ananthanarayanan Yuvaraj ◽  
Ramasundaram Thangaraj
Keyword(s):  
Large Scale ◽  
Fourier Transforms ◽  
Chemical Properties ◽  
Cow Dung ◽  
Chicken Feather ◽  
Feather Waste ◽  
Physico Chemical ◽  
Ft Ir ◽  
Chicken Feather Waste ◽  
Ft Ir Spectroscopy

Abstract An enormous amount of chicken feather waste materials released by the poultry industry creates severe environmental pollution. Vermicomposting is an eco-friendly way to degrade chicken feather waste along with microbial mixture (Panchagavya). Chicken feather waste was pre-decomposed by mixing it with fresh cow dung (T1), dry cow dung (T2), and Panchagavya (T3). Among these, T3 exhibits rapid deterioration of chicken feather waste and seven combination T3 substrates (E0-E6), taken for the vermicomposting process by Eudrilus eugeniae in 60 days. Scanning Electron Microscopy/Energy Dispersive Spectroscopy (SEM-EDS) and Fourier Transforms Infrared (FT-IR) Spectroscopy are used to assess compost maturity. The result shows that E1 (0.050:1 ratio) shows various functional groups, rich nutrients, and necessary acids than other combinations. For large-scale commercial vermi-stabilization of chicken feather waste, the E1 combination is suitable for manure production and thereby enhances soil fertility, agricultural production.

scholarly journals A Novel Experimental Study on the Rheological Properties and Thermal Conductivity of Halloysite Nanofluids

Nanomaterials ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1834
Author(s):  
Thong Le Ba ◽  
Ahmed Qani Alkurdi ◽  
István Endre Lukács ◽  
János Molnár ◽  
Somchai Wongwises ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Halloysite Nanotubes ◽  
Visual Observation ◽  
X Ray ◽  
Conductivity Enhancement ◽  
Practical Applications ◽  
Zeta Potentials ◽  
Ft Ir ◽  
The Stability ◽  
Ft Ir Spectroscopy

Nanofluids obtained from halloysite and de-ionized water (DI) were prepared by using surfactants and changing pH for heat-transfer applications. The halloysite nanotubes (HNTs) nanofluids were studied for several volume fractions (0.5, 1.0, and 1.5 vol%) and temperatures (20, 30, 40, 50, and 60 °C). The properties of HNTs were studied with a scanning electron microscope (SEM), energy-dispersive X-ray analysis (EDX), Fourier-transform infrared (FT-IR) spectroscopy, X-ray powder diffraction (XRD), Raman spectroscopy and thermogravimetry/differential thermal analysis (TG/DTA). The stability of the nanofluids was proven by zeta potentials measurements and visual observation. With surfactants, the HNT nanofluids had the highest thermal conductivity increment of 18.30% for 1.5 vol% concentration in comparison with the base fluid. The thermal conductivity enhancement of nanofluids containing surfactant was slightly higher than nanofluids with pH = 12. The prepared nanofluids were Newtonian. The viscosity enhancements of the nanofluid were 11% and 12.8% at 30 °C for 0.5% volume concentration with surfactants and at pH = 12, respectively. Empirical correlations of viscosity and thermal conductivity for these nanofluids were proposed for practical applications.

scholarly journals Comparative Study of The Yield and Physicochemical Properties of Collagen from Sea Cucumber (Holothuria scabra), Obtained through Dialysis and the Ultrafiltration Membrane

Molecules ◽  
2021 ◽  
Vol 26 (9) ◽  
pp. 2564
Author(s):  
Suryani Saallah ◽  
Jumardi Roslan ◽  
Flavian Sheryl Julius ◽  
Sharinee Saallah ◽  
Umi Hartina Mohamad Razali ◽  
...  
Keyword(s):  
Physicochemical Properties ◽  
Sea Cucumber ◽  
Large Scale ◽  
Type I Collagen ◽  
Ultrafiltration Membrane ◽  
The Body ◽  
Type I ◽  
Holothuria Scabra ◽  
Ft Ir ◽  
Ft Ir Spectroscopy

Collagen was extracted from the body wall of sea cucumber (Holothuria scabra) using the pepsin-solubilized collagen method followed by isolation using dialysis and the ultrafiltration membrane. The yield and physicochemical properties of the collagen obtained from both isolation methods, denoted as D-PSC and UF-PSC, were compared. The ultrafiltration method affords a higher yield of collagen (11.39%) than that of the dialysis (5.15%). The isolated collagens have almost the same amino acid composition, while their functional groups, referred to as amide A, B, I, II, and III bands, were in accordance with commercial collagen, as verified by Fourier Transform Infrared (FT-IR) spectroscopy. The UV-Vis absorption peaks at 240 nm and 220 nm, respectively, indicated that the collagens produced are type-I collagen. The D-PSC showed interconnecting sheet-like fibrils, while the UF-PSC exhibited a flaky structure with flat-sheets arranged very close to each other. The higher yield and comparable physicochemical properties of the collagen obtained by ultrafiltration as compared with dialysis indicate that the membrane process has high potential to be used in large-scale collagen production for food and pharmaceutical applications.

scholarly journals Induced Smectic Phases from Supramolecular H-Bonded Complexes Based on Non-Mesomorphic Components

Crystals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 940
Author(s):  
Fowzia S. Alamro ◽  
Hoda A. Ahmed ◽  
Magdi M. Naoum ◽  
Ayman M. Mostafa ◽  
Asmaa A. Alserehi
Keyword(s):  
Fatty Acids ◽  
Differential Scanning Calorimetry ◽  
Scanning Calorimetry ◽  
Acid Component ◽  
Smectic Phases ◽  
Ft Ir ◽  
The Stability ◽  
Oleic And Linoleic Acids ◽  
Ft Ir Spectroscopy ◽  
Induced Smectic Phases

New non-symmetrical 1:1 supramolecular H-bonded (SMHB) interactions, Ix/II, were designed between the non-mesomorphic fatty acids (palmitic, oleic and linoleic acids) and 4-tetradecyloxyphenylazo pyridine. Mesophase behaviors of the formed complexes were examined via differential scanning calorimetry (DSC) and polarizing optical microscopy (POM). In order to confirm the H-bond interaction formations within the prepared SMHB complexes, FT-IR spectroscopy was established whereby Fermi bands confirm these interactions. Mesomorphic investigations for all complexes indicated that, independent of the terminal alkenyl chains of the natural acids, induced dimorphic smectic phases were observed. The stability of formed mesophases was found to depend on the degree of un-saturation of the terminal alkenyl group of acid component.

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