UV Vis NIR Spectrum Research Articles

Rapid determination of egg yolk contamination in egg white by VIS spectroscopy

In this study, a non-invasive method utilizing VIS spectroscopy for rapid and quantitative determination of yolk contamination in egg white was developed. Fresh eggs were obtained from Iowa egg production facilities and were used to prepare 210 egg white samples with various levels of yolk contamination. The simulated yolk contamination levels ranged from 0.001 to 0.1wt% in egg white (as-is basis), and the samples were subjected to spectroscopic analysis. UV–Vis–NIR spectra (200–860nm) were acquired for each sample with a spectral resolution of 2nm. The absorption bands at 430nm and 378nm were identified as the most sensitive to the yolk contamination. A quantitative predictive model was developed to correlate the two absorptions to the concentration of yolk contamination. The correlation coefficient of calibration set and validation set are 0.9830 and 0.9769, respectively. The MSE (mean squares error) of calibration set and validation set are 0.0066 and 0.0044%, respectively. The UV–VIS spectroscopy method was demonstrated to be sensitive at as low as 0.001% yolk content. It can potentially become a simple, noninvasive, and rapid and yet highly sensitive routine test as a quality control means for egg processing industry.

Concentration dependent structural and spectroscopic properties of Sm3+/Yb3+ co-doped sodium tellurite glass

Tuning the optical and structural behaviors of tellurite glasses with controlled dopants is the key issue in solid state lasers and amplifiers. Sm3+/Yb3+ co-doped sodium tellurite glasses are prepared by the melt quenching technique and characterized using XRD, FTIR and DTA, optical absorption and luminescence techniques. The XRD spectra reveals the amorphous nature of glasses and the presence of functional groups such as Te–O bond in trigonal bipyramids (TeO4), Te–O bending vibration of the trigonal pyramids (TeO3) and non-hygroscopic nature of the glasses are confirmed from FTIR spectra. The DTA measurement shows the thermal stability lies in the range of 106–123. The UV–vis–NIR spectra exhibit eight absorption bands corresponding to the transition from ground level 6H5/2 to the various excited state of Sm3+ ions and the broad absorption band in the range of ~825–1100nm is ascribed to the large contribution of the absorption from 2F7/2→2F5/2 transition of Yb3+ ion. The experimental oscillator strengths calculated from the absorption spectra are used to evaluate three phenomenological Judd–Ofelt (J–O) intensity parameters Ωλ (λ=2, 4 and 6). Emission spectra consist of four bands 4G5/2→6H7/2 (moderate green) 4G5/2→6H5/2 (intense orange), 4G5/2→6H7/2 (moderate orange-yellow) and 4G5/2→6H11/2 (feeble red). The J–O parameters are employed to calculate radiative parameters such as transition probability (AR), branching ratio (BR), effective bandwidth (λeff) and stimulated emission cross-section σ(λp) of these emission transition of trivalent samarium ion. The optical band gap energy value (Eopt) and Urbach energy values (ΔE) are calculated and compared. The concentration dependent spectroscopic behavior of Sm3+-doped and Sm3+/Yb3+co-doped glasses is understood. Our systematic study may contribute towards the development of optical device fabrication.

Growth and physical properties of an organic crystal for NLO applications: Guanidinium phenyl arsonate (GPA)

Single crystals of organic material guanidinium phenyl arsonate (GPA) of size 28×14×10mm3 were grown from propanol–water mixed solvent by slow solvent evaporation technique. The crystal belongs to monoclinic system with noncentrosymmetric space group Cc. The lattice parameter values of GPA crystals are a=18.453Å, b=7.609Å, c=12.592Å and β=121.856°. The grown crystal was subjected to X-ray diffraction (XRD) study to identify its morphology and structure. Chemical etching study using propanol–water as etchant reveals the mechanism of growth. The formation of synthesized compound was confirmed by Fourier transform infrared (FT-IR) spectroscopy analysis. Optical transmittance and second harmonic generation (SHG) of the grown crystals were studied by UV–vis–NIR spectrum and Kurtz powder technique respectively. The transmittance of GPA has been used to calculate the refractive index ‘n’ and the extinction coefficient ‘k’. The laser induced surface damage threshold for the grown crystal was determined using Nd:YAG laser. The mechanical behavior of GPA was analyzed using Vickers microhardness test.

A phase matchable nonlinear optical crystal salicylideneaniline: Synthesis, growth and characterization

A new NLO organic crystal of salicylideneaniline (SAN) was synthesized and SAN bulk crystal was grown along <412> plane using uniaxial crystal growth method of Sankaranarayanan–Ramasamy with a new modification in the growth assembly. The crystal was grown with a growth rate of 2mm/day upto a dimension of 4cm in length and 6cm in diameter having a cylindrical morphology within 30 days. The powder XRD analysis confirmed the crystalline perfection. The presence of CN bond with intramolecular hydrogen bonding on the protonation of ions were confirmed by FTIR analysis. The range of optical absorbance was ascertained by recording UV–vis–NIR spectrum. The 1H1 and C13 NMR spectrum confirms the molecular structure. Dielectric studies were carried out to estimate the dielectric parameters of the grown crystal in the frequency range from 100Hz to 100KHz. The existence of second harmonic generation (SHG) signal was observed using Nd:YAG laser with the fundamental wavelength of 1064nm. Phase matching parameters of the grown crystal confirms that salicylideneaniline is a promising candidate for LASER applications.

Crystal growth, structural, optical, thermal and NLO studies of γ-glycine single crystals

In the present work, single crystals of γ-glycine possessing nonlinear optical properties were successfully grown at ambient temperature in the presence of sodium sulphate for the first time by using the slow evaporation method. Bulk growths of α-glycine and γ-glycine single crystal were grown by slow evaporation method and top-seeded solution growth method. The grown crystal was subjected to powder X-ray diffraction analysis to determine the characteristic peak of γ-glycine and lattice parameters. The chemical composition of the γ-glycine crystal was determined by elemental analysis. The results of the Inductively Coupled Plasma Optical Emission Spectrometry (ICPOES) study show the presence of a small amount of sodium species in the grown γ-glycine crystal. The presence of functional groups was confirmed by FTIR spectroscopic analysis. The UV–vis–NIR spectrum indicates that the crystal has 75 percentage of transmittance in the entire visible and near IR region spectrum suggesting the suitability of the material for NLO applications. Differential scanning calorimetry (DSC) technique was employed to find the possible phase transition and to determine the thermal stability of γ-glycine. The second-order nonlinear optical property of the powdered sample of γ-glycine crystal was investigated by Kurtz and Perry powder technique and the relative second harmonic generation efficiency was found to be higher than that of standard inorganic material potassium dihydrogen phosphate (KDP).

Spinel Indium Sulfide Precursor for the Phase-Selective Synthesis of Cu–In–S Nanocrystals with Zinc-Blende, Wurtzite, and Spinel Structures

Group I–III–VI ternary chalcogenides have attracted extensive attention as important functional semiconductors. Among them, Cu–In–S compounds have seen strong research interest due to their potential applications in high-efficiency solar cells. However, the controllable synthesis of Cu–In–S nanostructures with different phases is always difficult. In this research, zinc-blende CuInS2, wurtzite CuInS2, and spinel CuIn5S8 could be selectively synthesized using spinel In3–xS4 as the precursor by a simple solvothermal method. X-ray powder diffraction was used to determine the phase and crystal structure, and transmission electron microscopy was employed to characterize the morphologies of the as-prepared samples. Experiments showed that the acidity–basicity of the reaction system and the coordination and reducibility of the capping ligands were crucial to the final phases of the products. The UV–vis–NIR spectra of the three phases all exhibited a broad-band absorption over the entire visible light and extendi...

Growth and Characterisation of Thiourea Doped Sulphamic Acid Single Crystals

Thiourea doped Sulphamic acid (Th : SA) single crystals were grown successfully by slow-evaporation technique. To identify the morphology and structure, the as grown crystals were subjected to characterization like powder and single XRD analysis. UVVis-NIR spectrum and FTIR studies are performed to identify the cut-off wavelength and the various functional groups present in the grown crystal. Second harmonic generation were investigated to study the linear and nonlinear optical properties. In order to ascertain the thermal stability of the crystal, thermo-gravimetric analysis (TGA), differential thermo-gravimetric analysis (DTA) and differential scanning calorimetry (DSC) were also carried out.

Synthesis and microstructural properties of α-Fe1−xGaxOOH solid solutions

Isostructural iron oxyhydroxide α-FeOOH (goethite) and gallium oxyhydroxide α-GaOOH, as well as their solid solutions α-Fe1−xGaxOOH in a whole concentration range (x=0.00, 0.05, 0.10, 0.15, 0.20, 0.30, 0.50, 0.80 or 1.00) were synthesized by precipitation in a weakly alkaline medium using an organic alkali tetramethylammonium hydroxide (TMAH) for pH adjustment. Lath-shaped α-Fe1−xGaxOOH particles common for goethite formed in alkaline media were observed in all samples containing more Fe than Ga, whereas fairly uniform ellipsoidal α-Fe1−xGaxOOH particles characteristic of α-GaOOH formed in alkaline media were observed in samples containing more Ga than Fe. An increased content of Ga3+ ions in α-Fe1−xGaxOOH led to a decrease in the unit-cell size (in line with the smaller radius of Ga3+ ions). A reduction in the hyperfine magnetic field and a collapse of the room temperature magnetic order in α-Fe1−xGaxOOH with x>0.2 were found (due to the dilution of the magnetic lattice brought about by the replacement of the magnetic Fe3+ ions by the diamagnetic Ga3+ ions). A shift in the position of (Fe,Ga)–O–H bending bands and Fe–O and Fe–OH stretching (lattice vibration) bands towards higher wave numbers (due to increased strength of the O–H⋯O hydrogen bond), a decrease in intensity of all absorption bands in UV–Vis–NIR spectra and a shift of Fe3+ ligand field transition bands to lower energies (due to an increase in the ligand field splitting energy), and an increase in dehydroxilation temperature (due to the higher stability of the Ga–OH bond in comparison with the Fe–OH bond) with the increased Ga3+ content were also found.

Coupling of graphene oxide into titania for purification of gaseous toluene under different operational conditions

Graphene oxide (GO)–titania (TiO2) composite was synthesized using a chemical mixing process and its photocatalytic activity for the degradation of a toxic organic vapor (toluene) under different operational conditions was examined. The as-prepared GO–TiO2 and undoped TiO2 photocatalysts were characterized using SEM, XRD, and UV–VIS–NIR spectra. Moreover, the photocatalytic degradation efficiency of the GO–TiO2 composite was much higher than that of the P25 TiO2, with an average efficiency of the GO–TiO2 composite of 84% and an average efficiency of the TiO2 powder of just 13%. As the air flow rate increased from 1 to 4 L min−1, the average degradation efficiencies of toluene decreased from 86 to 32%. In addition, as the initial concentration increased from 0.1 to 1.0 ppm, the average degradation efficiencies of toluene decreased from 86 to 8%. Overall, the GO–TiO2 composite could be applied effectively for purification of gaseous toluene under optimal operational conditions.

Oxidation States of [5]Radialene with Five 1,3-Dithiol-2-ylidenes and Its Oxygen Adduct

Abstract Spectroelectrochemistry of [5]radialenes with five 1,3-dithiol-2-ylidenes (DTs) (1) was carried out. The UV–vis–NIR spectra of 12+ suggest delocalization of two positive charges over three DT units. X-ray structure analysis of an oxygen adduct (2)2+(AsF6−)2(PhCl)1.5 reveals that 22+ has a cyclopentadienide structure in the central five-membered ring.

Studies on the growth, structural, optical, SHG and thermal properties of γ-glycine single crystal: An organic nonlinear optical crystal

Single crystals of the organic nonlinear optical material γ-glycine have been grown in the presence of Zinc sulphate by slow evaporation technique at ambient temperature for the first time. Bulk growth of γ-glycine single crystals was grown by Top-seeded solution growth method. The γ-phase of glycine was confirmed by powder X-ray diffraction and the FTIR analysis. Elemental analysis CHN was performed to confirm the non-inclusion of zinc sulphate species into the solution. Inductively coupled plasma optical emission spectrometry study (ICP-OES) was employed to quantify the concentration of Zinc element in the grown γ-glycine single crystals. The optical transmission was ascertained from UV–Vis–NIR spectrum. The optical band gap was estimated for γ-glycine single crystal using UV–Vis–NIR study. Differential scanning calorimetry analysis was employed to explore information about thermal stability, phase transition and melting point of the grown crystal. The second harmonic generation relative efficiency was measured by Kurtz and Perry powder technique.

Nonprecious-Metal-Assisted Photochemical Hydrogen Production from ortho-Phenylenediamine

The combination of o-phenylenediamine (opda), which possesses two proton- and electron-pooling capability, with Fe(II) leads to the photochemical hydrogen-evolution reaction (HER) in THF at room temperature without addition of photosensitizers. From the THF solution, the tris(o-phenylenediamine) iron(II) complex, [Fe(II)(opda)3](ClO4)2 (1), was isolated as a photoactive species, while the deprotonated oxidized species was characterized by X-ray crystallographic analysis, electrospray ionization mass spectrometry, and UV-vis NIR spectra. Furthermore, the HER is photocatalyzed by hydroquinone, which serves as a H(+)/e(-) donor. The present work demonstrates that the use of a metal-bound aromatic amine as a H(+)/e(-) pooler opens an alternative strategy for designing nonprecious-metal-based molecular photochemical H2 production/storage materials.

Growth and characterization of semi-organic nonlinear optical crystal: Sodium 2,4-dinitrophenolate monohydrate

Sodium 2,4-dinitrophenolate monohydrate salt has been synthesized and the crystals have been grown in aqueous solution by slow evaporation solution growth technique. Grown crystal was confirmed by powder XRD studies. Functional groups presented in the grown crystal were identified and their vibrational properties were studied by recording FTIR spectrum. Thermal stability of the grown crystal was deliberated by recording TGA/DTA. Existence of the ionic form in the crystal was confirmed and the energy gap of the crystal was also calculated by analyzing UV–VIS–NIR spectrum. Second harmonic frequency generation was examined by Kurtz and Perry powder test and it reveals that the relative conversion efficiency was 2.5 times greater than the urea. Theoretical first order hyperpolarizability value was calculated for the optimized structure.

Solid-State and Solution-State Coordination Chemistry of Lanthanide(III) Complexes with (Pyrazol-1-yl)acetic Acid

As a precursor of carboxyl-functionalized task-specific ionic liquids (TSILs) for f-element separations, (pyrazol-1-yl)acetic acid (L) can be deprotonated as a functionalized pyrazolate anion to coordinate with hard metal cations. However, the coordination chemistry of L with f-elements remains unexplored. We reacted L with lanthanides in aqueous solution at pH = 5 and synthesized four lanthanide complexes of general formula [Ln(L)3(H2O)2]·nH2O (1, Ln = La, n = 2; 2, Ln = Ce, n = 2; 3, Ln = Pr, n = 2; 4, Ln = Nd, n = 1). All complexes were characterized by single crystal X-ray diffraction analysis revealing one-dimensional chain formations. Two distinct crystallographic structures are governed by the different coordination modes of carboxylate groups in L: terminal bidentate and bridging tridentate (1-3); terminal bidentate, bridging bidentate, and tridentate coordination in 4. Comparison of the solid state UV-vis-NIR diffuse reflectance spectra with solution state UV-vis-NIR spectra suggests a different species in solution and solid state. The different coordination in solid state and solution was verified by distinctive (13)C NMR signals of the carboxylate groups in the solid state NMR.

Growth, spectroscopy properties and DFT based PCM calculations of guanidinium chlorochromate

Nonlinear optical single crystals of guanidinium chlorochromate [GCC] are grown by slow evaporation solution growth technique using water as the solvent. Purity of crystals is increased by the method of recrystallization. The solubility of the material is measured at various temperatures in de-ionized water. The grown crystals are characterized by single crystal XRD for obtaining unit cell parameters. The presence of functional groups and modes of vibrations are identified by FT-IR spectroscopy. The chemical structure of crystal is established by FT-NMR techniques. The UV–vis–NIR spectrum of GCC shows less absorption and good transmittance in the entire visible region enabling its use in optical application. Also, the Kurtz powder second harmonic generation test shows that the compound is a potential material for optical second harmonic generation. The theoretical vibration frequency of HC(NH2)3 and [C(NH2)3]2 are analyzed in different solvent media.

Pink ceramic pigments based on chromium doped M(Al 2−x Cr x )O 4 , M=Mg, Zn, normal spinel

In this paper M(Al 2− x Cr x )O 4 , M=Mg, Zn and x from 0.05 to 2 compositions, have been prepared by solid state reaction in order to analyse their reactivity, structure, limit of solid solution, stability and pigmenting properties in conventional ceramic glazes. Solid solutions are obtained at 1200 °C in the Zn case (gahnite) and at 1400 °C in the Mg case (magnesium spinel). In both cases powders become pink coloured up to x =0.4 and then progressively greenish. Likewise powders glazed in a conventional ceramic glaze matrix of the CaO-ZnO-SiO 2 system for double firing stoneware (1050 °C) produce glazes firstly orange coloured up to x =0.4, pink up to x =1.2 and finally green at higher x . The colour evolution is associated to the entrance at low doping levels of relatively big Cr 3+ (0.755 Å) substituting Al 3+ (0.675 Å) in VI coordinated sites of both spinel lattices; this produces an enhancement of the crystal field strength under the VI coordinated Cr 3+ that shifts the light absorbances to higher energy and an orange-pink colour can be observed. But when the entrance of Cr 3+ progresses, the crystal field strength under the ion relaxes and absorption bands shift to higher wavelength when x increases, producing green colours. The UV–vis–NIR spectra of low x pink M(Al 2− x Cr x )O 4 compositions are similar to those of ruby (Cr 0.1 Al 1.9 )O 3 , indicating analogous mechanism of colour.

Linear and nonlinear optical properties of a new organic NLO l-asparaginium l-tartarate (AST) single crystal

A new organic NLO material l-asparaginium l-tartarate (AST) was synthesized and good quality crystals were grown from aqueous solution. The solubility and metastable zone width for AST solution were determined. Single crystal X-ray diffraction and powder X-ray diffraction analyses were carried out to confirm structure and crystalline nature of AST crystal. Optical transmittance and second harmonic generation efficiency (SHG) of the grown crystal were studied by UV⿿vis⿿NIR spectrum and Kurtz powder technique respectively. The transmittance of AST crystal was used to calculate the refractive index (n), the extinction coefficient (k) and reflectance (R). The laser induced surface damage threshold for the grown crystal was measured using Nd:YAG laser.

Structural, spectral, thermal, dielectric, mechanical and optical properties of L-threonine cadmium acetate dihydrate a semiorganic nonlinear optical crystals

Semiorganic nonlinear optical crystal of L-threonine cadmium acetate dihydrate (LTCA) has been grown from aqueous solution by slow evaporation technique at room temperature. The grown crystal was subjected to single-crystal X-ray diffraction and powder X-ray diffraction analysis to find the lattice parameter and the structure of the crystal. The vibrational frequencies of various functional groups in LTCA were confirmed by Fourier transform infrared spectroscopy (FTIR) analysis. The UV–vis–NIR spectrum of the crystal shows the lower cut-off wavelength at 289nm. The fluorescence spectrum confirms the crystal has blue fluorescence emission. The thermal stability of the grown crystal was confirmed by TG/DTA study. The Hardness value was measured by using Vickers microhardness test. The dielectric properties were studied at room temperature. The grown crystal belongs to negative photoconductivity nature. The NLO study was carried out and compared with KDP. The optical behavior, including second harmonic generation (SHG), was investigated to study its NLO property.

Self-assembled flower-like antimony trioxide microstructures with high infrared reflectance performance

A simple hydrothermal process was adopted to self-assembly prepare high infrared reflective antimony trioxide with three-dimensional flower-like microstructures. The morphologies of antimony trioxide microstructures were characterized by X-ray diffractometry (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and high resolution transmission electron microscopy (HRTEM) respectively. It is also found that experimental parameters, such as NaOH concentration, surfactant concentration and volume ratio of ethanol–water played crucial roles in controlling the morphologies of Sb2O3 microstructures. A possible growth mechanism of flower-like Sb2O3 microstructure was proposed based on the experimental data. UV–vis–NIR spectra verified that the near infrared reflectivity of the obtained flower-like microstructures could averagely achieve as 92% with maximum reflectivity of 98%, obviously higher than that of other different morphologies of antimony trioxide microstructures. It is expected that the flower-like Sb2O3 nanostructures have some applications in optical materials and heat insulation coatings.

Optical reflectance, optical refractive index and optical band gap measurements of nonlinear optics for photonic applications

Single crystals of Pyrrolidinomethylpthalamide (PMP) were grown by the slow evaporation solution growth at room temperature. The grown crystals were subjected to powder X-ray diffraction studies to confirm the crystal structure. The modes of vibration of different molecular groups present in PMP have been identified by FTIR spectral analysis. Optical transference of the grown crystal was investigated by UV–vis-NIR spectrum. The lower optical cut off wavelength for this crystal is observed at 300nm and energy band gap 5.167eV. The optical reflectance and optical refractive index studies have been carried out in this crystal. The optical conductivity and electrical conductivity studies have been carried out on PMP single crystal. Finally Second Harmonic Generation (SHG) for the materials of this work was confirmed using Nd:YAG laser.