Search results

This study aims to identify the bioactive compounds in the Onion (Allium burdickii [A.B]) bulb using Raman and Fourier transform infrared spectroscopy (FTIR) spectroscopy. It assessed the extraction conditions of bioactive compounds from A.B. while evaluating the best extraction conditions.

The research opted for an experimental qualitative approach. It examined the extraction conditions of A.B., namely, temperature (°C), time (min) and mass-to-liquor ratio (M:R) using ultraviolet-visible spectrophotometry. Identification of bioactive compounds present in the dye was performed using Raman spectroscopy and the validation of the results was done by FTIR spectroscopy.

The study determined the best extraction conditions (time, temperature, M:R) for A.B bulb. The study confirmed the presence of bioactive compounds.

The limitation was quantification of bioactive compounds in A.B bulb.

The findings prove that the A.B. bulb can provide a sustainable source of bioactive compounds (functionalized compounds). The study provides suitable extraction conditions for A.B. and further elaborates on the techniques for identifying bioactive compounds in A.B. bulb extracts.

The study provides A.B. as a source of bioactive compounds and a clean dye for textile coloration.

To the best of the authors’ knowledge, there is no documented study on the qualitative analysis of bioactive compounds in A.B using Raman and FTIR. Therefore, the study fulfils the identified need to ascertain alternative procedures for the analysis of bioactive compounds.

Applies Fourier transform infrared spectroscopy (FTIR) to the study of lac resin, a complex natural resin of insect origin, and some of its derivatives. Compares the result obtained by this method with those from earlier studies that used classical methods of chemical analysis (the so‐called wet methods). Finds that FTIR has several advantages over the classical methods but, as spectroscopic assignments are still only tentative because of the complex nature of the lac resin, the FTIR data requires supplementing by other instrumental techniques such as FT‐Raman spectroscopy and solid state nuclear magnetic resonance.

Consumption of game meat is growing when compared to other meats. It is susceptible to adulteration because of its cost and availability. Spectroscopy may lead to rapid methodologies for detecting adulteration. The purpose of this study is to detect the adulteration of wild fallow deer (Dama dama) meat with domestic goat (G) (Capra aegagrus hircus) meat, for samples stored for different periods of time using Fourier transform infrared (FTIR) spectroscopy coupled with chemometric.

Meat was cut and mixed in different percentages, transformed into mini-burgers and stored at 3°C from 12 to 432 h and periodically examined for FTIR, pH and microbial analysis. Principal component analysis (PCA) and partial least squares discriminant analysis (PLS-DA) were applied to detect adulteration.

The PCA model, applied to the spectral region from 1,138 to 1,180, 1,314 to 1,477, 1,535 to 1,556 and from 1,728 to 1,759 cm⁻¹, describes the adulteration using four principal components which explained 95 per cent of variance. For the levels of Adulteration A1 (pure meat), A2 (25 and 50 %w/wG) and A3 (75 and 100 %w/wG) for an external set of samples, the correlation coefficients for prediction were 0.979, 0.941 and 0.971, and the room mean square error were 8.58, 12.46 and 9.47 per cent, respectively.

The PLS-DA model predicted the adulteration for an external set of samples with high accuracy. The proposed method has the advantage of allowing rapid results, despite the storage time of the adulterated meat. It was shown that FTIR combined with chemometrics can be used to establish a methodology for the identification of adulteration of game meat, not only for fresh meat but also for meat stored for different periods of time.

The purpose of this paper is to discuss the chemical characterization of failures and process materials for microelectronics assembly.

The analytical techniques used for chemical structures and compositions including Fourier transform infrared spectrometer (FTIR), scanning electron microscopy, and energy‐dispersive X‐ray spectroscopy are conducted.

The residues on the golden finger are identified to be the flux used in the assembly processes. Besides, the contaminants on the processed and incoming connector pins are verified to be polyamides (–CONH functional groups) from housing material's residue. Three liquid fluxes used in wave soldering are analyzed by their chemical structure. One flux showing the OH groups at 3430 cm⁻¹ indicates higher acid contents. This consists with the acidic values specified by the supplier. Also, the solder mask under study has ever appeared peeled‐off issue. The FTIR spectra results indicated 62.2 percent degree of curing while vendor's spec is above 70 percent.

The establishment of the Infrared spectra database for fluxes and process materials help determine the root cause of the contaminants to reduce re‐occurrence of similar problems and thus enhance the manufacturing capability. The infrared spectrophotometry technique can be used by professional original design manufacturing and/or electronics manufacturing service, providers to investigate board/component defects during product pilot run stage and volume production.

The purpose of this paper is to explore the synthesis, preparation and investigation of micro structural, optical and mechanical studies of polyvinyl alcohol (PVA) doped with tungsten oxide (WO₃) nanocomposites films. These films were prepared by simple solvent casting method is further characterized using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), UV-visible spectroscopy, universal testing machine (UTM), scanning electron microscope (SEM), energy-dispersive analysis of X-rays (EDAX) and atomic force microscope (AFM) techniques to determine the enhancement in structural, optical and mechanical properties with increase in dopant concentration.

The present paper deals with the synthesis of WO₃ nanoparticles using precipitation method and doping into PVA matrix to prepare a polymer nanocomposite film using coagulation and solvent casting method. The FTIR explores the interaction of dopants with PVA matrix. The XRD spectra investigate the variation of crystallinity. The UV/Vis-spectra reveals the information of optical energy band gap and the Urbach Energy for different doping concentrations. The mechanical properties of the nanocomposites were exposed using UTM. The phase homogeneity, film topography, chemical composition of nanocomposites is analyzed using SEM, EDAX and AFM techniques supporting the above results.

The films characterized by FTIR spectroscopy explores the irregular shift in the bands of pure and doped PVA can be understood on the basis of intra/inter molecular hydrogen bonding with the adjacent OH group of PVA backbone. The XRD result reconnoiters that the particle size and crystallinity increases whereas microstructural strain and dislocation density decreases with increase in dopant concentration. Further the drastic decrease in optical energy band gap E _g =0.94 eV for doping concentration x=15 wt% and the increase in values of Urbach Energy (E _u ) with doping concentrations were investigated by UV/Vis spectra. Also the extinction coefficient was high in the wavelength range of 250-400 nm and low in the wavelength range of 400-1,200 nm. The mechanical studies indicates that the addition of the WO₃ with weight percentage concentration x=15 percent increases the tensile strength and Young’s modulus. The phase homogeneity, the particle size of the dopants and chemical composition of nanocomposites is analyzed using SEM and EDAX. The film topography of the nanocomposites is analyzed using AFM techniques supporting the above results.

The investigation of synthesis, preparation and investigation of micro structural, optical and mechanical studies of PVA doped with WO₃ nanocomposites films as been done. The results prove that these nanocomposites having good mechanical strength with crystalline nature and also very low optical energy gap value that could find possible applications in industries.

This paper aims to establish the acid concentration of finely dispersed droplets in hydrocarbon oils. Small quantities of aqueous sulphuric acid (H₂SO₄) were found to be trapped within hydrocarbon shells, making them inaccessible for concentration evaluation by titration.

Fourier transform infrared spectroscopy (FTIR) used in the attenuated total reflection mode (ATR; FTIR-ATR) was applied to study the reaction products of squalane, C₃₀H₆₂, and an API Group I base oil with various concentrations of aqueous H₂SO₄.

The absorbance comparison usually used for estimating acid concentrations was found to fail when small quantities of acid are trapped in the reaction product. It was found that the peak shift and changes in absorbance found for various pure aqueous acid concentrations were useful to establish the remaining concentration of the trapped H₂SO₄.

This paper fulfils the identified need to study acid dissociation-dependent peak shifts of H₂SO₄ to find the acid concentration of finely dispersed droplets in hydrocarbon oils.

Three common glob top encapsulant materials, two epoxy‐based, and one silicone‐based, were characterized prior to temperature cycling using differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), dynamic mechanical spectroscopy (DMS), gas chromatograph‐mass spectrometry (GC‐MS), and Fourier transform infrared spectroscopy (FTIR). After cycling between ‐55 to +125°C, for 1,000 cycles, the same samples were again analysed using DMS and FTIR. For the epoxy‐based samples, the DMS results indicated that temperature cycling in a humid environment can seriously affect the physical and mechanical properties of these samples. FTIR data also indicated that the molecular changes in the epoxy‐based samples appeared quite extensive after cycling, indicating a high level of degradation on the molecular scale. On the other hand, the silicon‐based glob top appeared to have survived the temperature cycling quite well.

The purpose of this paper is to develop a new water‐based coating system composed of poly(vinyl alcohol) and anthocyanin colourant extracted from Hibiscus sabdariffa L. and to characterise the system.

Anthocyanin from Hibiscus sabdariffa L. (roselle) calyxes was extracted by using distilled water and filtered to remove insoluble particle. Salts introduced into the extract were 5wt percent calcium nitrate, 5wt percent magnesium nitrate, and 5wt percent zinc nitrate. The solution was mixed with poly(vinyl alcohol) in ratio of 3:1. The mixtures were coated on glass substrate and allowed to cure for approximately one day. Colour of the extract systems was determined by CIELab colourimetry. FTIR spectroscopy was conducted on the samples to identify their functional groups and changes upon addition of salt. Thermal stability was assessed by thermogravimetric analysis (TGA). Differential scanning calorimetry (DSC) was employed to measure the glass transition temperature Tg of the samples. XRD was employed to determine the amorphous properties of the coating samples.

From FTIR spectroscopy, shifting in the OH stretching and CH2 bending bands was attributed to hydrogen bonds formation between PVA and nitrate salt. Shifting in the main decomposition step in samples with addition of nitrate salts in TGA was due to interaction of PVA and nitrate. Increase in glass transition temperature of samples with salts was attributed to the formation of hydrogen bonding. From XRD study, increase in the amorphous properties was due to the incorporation of nitrate salts into PVA coating.

Limitation of implementating poly(vinyl alcohol) as coating is caused by its weak water resistance and hydrophilic properties. This study could bring about research towards incorporation of different natural colourant with different binder materials to form coatings which are environmental‐friendly and low cost.

Mixture of PVA and anthocyanin colourant from roselle for use as coating has been developed. The coating can find usage in various applications such as coloured coating for furniture and wooden materials for decorative purposes, biodegradable design materials for interior purposes. It can be practically applied on a variety of substrates such as glass and wood.

Development of water‐based coating from PVA binder with anthocyanin colourant is introduced in this study.

The purpose of this paper is to develop a new water based coating system composed of poly(acrylamide‐co‐acrylic acid) and anthocyanin colourant extracted from Hibiscus sabdariffa L. and characterise the system.

Anthocyanin from Hibiscus sabdariffa L. (roselle) calyxes was extracted using optimised water extraction method with ratio of calyxes to water being 1:2. UV‐Vis absorption spectroscopy was conducted on the anthocyanin extract to monitor its degradation. Poly(acrylamide‐co‐acrylic acid) was mixed with the extracted anthocyanin solution in two different weight ratios. The mixtures were coated on glass substrate and let to cure for approximately one day. FTIR spectroscopy was conducted on the samples to determine their functional groups and identify the compounds in the samples. Cross hatch test was performed on the samples to determine the adhesion properties. Thermal degradation of the samples was determined through thermogravimetric analysis. Surface roughness of the samples was studied by atomic force microscopy. Colour stability was determined before and after UV irradiation.

Anthocyanin pigment from roselle extracted with water was found to be stable with 6.0 per cent drop in absorbance value over the 15 day period. The reaction rate was found to be 0.000181 h⁻¹, and the half life was calculated to be 3,850 hours. Better adhesion of the samples to the glass substrate was due to the higher concentration of poly(acrylamide‐co‐acrylic acid). Thermogravimetric analysis revealed similar thermal stability of the samples. Surface roughness study revealed that sample with higher anthocyanin content has higher surface roughness. Colour stability of the 20PBR was found to be better than 10PBR.

Usage of poly(acrylamide‐co‐acrylic acid) as coating is limited by its weak water resistance property. Improvement could be made in this direction for future applications.

Mixture of water‐based polymer and anthocyanin colourant from roselle has been developed into coating for the first time. Commercialisation is possible if more research is conducted towards water resistance property of poly(acrylamide‐co‐acrylic acid), storage condition for the pigment and coating, and mass production of the pigment.

Incorporation of anthocyanin pigment into water based coating is the first of its kind.

The purpose of this paper is a new thin-film based sensor proposed for sensitive and selective detection of mercury (Hg²⁺) ions in water. The thin-film platform is easy to use and quick for heavy metal ions (HMIs) detection in the picomolar range. Ion-selective self-assembled monolayer's (SAM) of thiol used for the detection of HMIs above the Au/Ti top surface.

A thin-film based platform is suitable for the on-field experiments and testing of water samples. HMIs (antigen) and thiol-based SAM (antibody) interaction results change in surface morphology and topography. In this study, the authors have used different characterization techniques to check the selectivity of the proposed method. This change in the morphology and topography of thin-film sensor checked with Fourier-transform infrared spectroscopy, surface-enhanced Raman scattering spectroscopy, atomic force microscopy and scanning electron microscopy with energy dispersive x-ray analysis used for high-resolution images.

This thin-film based platform is straightforward to use and suitable for real-time detection of HMIs at the picomolar range. This thin-film based sensor platform capable of achieving a lower limit of detection (LOD) 27.42 ng/mL (136.56 pM) using SAM of Homocysteine-Pyridinedicarboxylic acid to detect Hg²⁺ ions.

A thin-film based technology is perfect for real-time testing and removal of HMIs, but the LOD is higher as compared to microcantilever-based devices.

The excessive use and commercialization of nanoparticle (NPs) are quickly expanding their toxic impact on health and the environment. The proposed method used the combination of thin-film and NPs, to overcome the limitation of NPs-based technique and have picomolar (136.56 pM) range of HMIs detection. The proposed thin-film-based sensor shows excellent repeatability and the method is highly reliable for toxic Hg²⁺ ions detection. The main advantage of the proposed thin-film sensor is its ability to selectively remove the Hg²⁺ ions from water samples just like a filter and a sensor for detection at picomolar range makes this method best among the other current-state of the art techniques.