Solvent Controlled Colorimetric And Fluorometric Detection of Fe2+ and Cu2+ Ions By Naphthaldimine-Glucofuranose Conjugate

The sensing properties of naphthaldimine-glucofuranose conjugates 1 and 2 towards metal ions were investigated by 1H NMR titration, FTIR, absorbance, and fluorescence spectroscopic methods. The absorbance and fluorescence studies indicated that compound 1 formed coordination with Fe2+ and Cu2+ ions in DMSO through color changes yellow to brown and colorless, respectively. The Job's plots using absorbance data showed metal-ligand binding ratio is 1:1 for both cases. The formation of 1-Fe2+ and 1-Cu2+ complexes have been analyzed by absorption and emission spectroscopy, high-resolution mass spectrometry (HRMS) data, FTIR, 1H NMR titration experiment, and DFT calculations. The detection limits of naphthaldimine sugar conjugate 1 towards Fe2+/Cu2+ were calculated from UV-vis and fluorescence data according to the standard method. The sugar-naphthaldimine conjugate 2 has been used to establish the binding mode of 1 with Fe2+ or Cu2+ ions in DMSO.

Feasibility of UV-Vis Spectral Fingerprinting Combined with Chemometrics for Rapid Detection of Phyllanthus niruri Adulteration with Leucaena leucocephala

Phyllanthus niruri is widely used in Indonesia as immunostimulant. The morphology of Leucaena leucocephala leaves is similar to that of P. niruri leaves. L. leucocephala is easy to find and collect because it is widely distributed in the world. Therefore, it is likely P. niruri could be adulterated with L. leucocephala. Therefore, identification and authentication of P. niruri is important to ensure the raw materials used are original without any substitution or mixture with other similar plants causing inconsistencies in their efficacy. In this paper, we described feasibility used of UV-Vis spectral fingerprinting and chemometrics for rapid method for the identification and detection of P. niruri leaves adulterated with L. leucocephala leaves. UV-Vis spectra of samples measured in the interval of 200-800 nm and signal smoothing followed by standard normal variate were used for pre-processing the spectral data. Principal component analysis (PCA)with the absorbance data from the pre-processed UV-Vis spectra in the range of 250-700 nm as variables could distinguish P. niruri from L. leucocephala. PCA followed by discriminant analysis (DA) could successfully classified P. niruri mixed with 5, 25, and 50% L. luecocephala into their respective groups (96.81%). We also employed soft independent modelling of class analogy (SIMCA) for authentication of P. niruri and found that 88.3% of the samples were also correctly classified into their respective groups. A combination of UV-Vis spectroscopy with chemometrics, such as PCA-DA and SIMCA, were used for the first time for the identification and detection of P. niruri adulterated with L. leucocephala.

Comparison of theoretical and experimental investigation of protonation process of some thiones in acid media

PM3 semiempirical method was used for quantum chemical investigation in order to investigate the electronic properties and to determine the protonation centre in 1,2,4-triazoline-3-thione molecule. Confirmation of protonation center in acid media of investigated compounds was made using the values of atomic charges, as well as, proton affinity values. The results from semiempirical calculations indicated that the protonation center in the thione molecule was the sulphur atom. The behavior of thiones was investigated in mineral acid media using UV spectroscopy. The influence of the strength of the acid and its anion on the protonation process was discussed using three different mineral acids (perchloric, hydrochloric and phosphoric acid) for protonation. The protonation process in perchloric and hydrochloric acid took place in one step, while in phosphoric acid was not finished even when its concentration was to the highest degree. The dissociation constants of protonated forms (pKBH + ) and the solvation parameter m* values were calculated in accordance with "excess acidity" function method (Cox and Yates) using the absorbance data from the experimental and reconstructed spectra (Characteristic Vector Analysis (CVA)). The determined pKBH + values in hydrochloric acid had more negative value than those obtained in perchloric acid media. The pKBH + values were in agreement with the literature data for this class of compounds.

Water Treatment using Chemically Activated Charcoal

Water scarcity is a widely experienced problem in several countries in the world like Qatar, Israel, Lebanon and many others. Critical steps have to be taken before this becomes a worldwide phenomenon. The current study focuses on cleaning the greywater, which is about 65% of total wastewater from households, using activated charcoal powder prepared from coconut husk. The material is chemically activated. The shell based activated carbon is used for decolorization of three solution samples: Potassium Permanganate (Purple), Potassium Dichromate (Orange) and Copper Sulphate (Blue) as well as treating the sullage water. Change in normality of above-mentioned samples is calculated before and after treatment by activated charcoal using maximum absorbance data for before treatment as standard. Also, sullage water is treated with activated charcoal and comparison of physical and chemical properties is done before and after the treatment.

Application of Spectrophotometric Fingerprint in Cluster Analysis for Starch Origin Determination

The botanical origin of starch is of importance in industrial applications and food processing because it may influence the properties of the final product. Current microscopic methods are time-consuming. Starch consists of an origin-dependent amylose/amylopectin ratio. Triiodide ions bind characteristically to the amylose and amylopectin depending on the botanical origin of the starch. The absorbance of the starch-triiodide complex was measured for wheat, potato, corn, rye, barley, rice, tapioca and unknown origin starch, and within the different cultivars. Each starch sample had specific parameters: starch-triiodide complex peak wavelength maximum (λmax/nm), maximum absorbance change at λmax (ΔA) and λmax shift towards the unknown origin starch sample values. The visible absorption spectra (500-800 nm) for each starch sample were used as a unique fingerprint, and then elaborated by cluster analysis. The cluster analysis managed to distinguish data of two clusters, a cereal type cluster and a potato/tapioca/rice starch cluster. The cereal subclusters extensively distinguished wheat/barley/rye starches from corn starches. Data for cultivars were mostly in good agreement within the same subclaster. The proposed method that combines cluster analysis and visible absorbance data for starch-triiodide complex was able to distinguish starch of different botanical origins and cultivars within the same species. This method is simpler and more convenient than standard time-consuming methods.

Method Transfer Evaluation for Digital Derivative Spectrophotometry Through its Resolution Parameter Comparison of Different Computer Programs

The application assessment of different programs was performed with equivalence tests for method transfer pro second-order derivative spectrophotometry. The digital second-order derivative spectra were calculated on different instruments; GBC Scientific Equipment Cintra 20 (Cintral v.2.6 and Spectral v.1.70 software programs) and Thermo Scientific Evolution 300 (VISIONPro software) were analyzed using the amplitude A/B ratio (A = 2D265,263; B = 2D263,261). Amplitude A/B ratio is the resolution parameter for derivative spectrophotometry prescribed in European Pharmacopoeia. The obtained values for A/B ratio were either very similar or significantly different among programs: 0.669 (Cintral v.2.6), 0.549 (Spectral v.1.70), 0.556 (medium indirect VISIONPro), 0.557 (one-step Savitzky–Golay 7 VISIONPro), 0.689 (two-step Savitzky–Golay 7 VISIONPro). Method transfer was possible between Spectral v.1.70 and VISIONPro (medium indirect and one-step Savitzky–Golay 7), but the values obtained in Cintral v.2.6 were not comparable to the other programs. The absorbance data exported from both instruments were additionally calculated in OriginPro8 which provided almost the same mean A/B values (0.627 Cintral v.2.6; 0.624 VISIONPro), confirming that the two instruments recorded the same zero-order spectra. The calculation of resolution parameter could be used for verification of program comparison, which would enable transfer between sender and receiver laboratory. The accordance between program algorithms was confirmed when acceptable differences for values of resolution parameter (A/B ratios) were achieved.

Tramadol, Methadone and Buprenorphine-AuNPs Kit Based on Chemometrics Tools and Software

The SPR of the AuNPs, synthesized by the reduction of gold ion with citrate and modified with L-cysteine was used as a novel analytical method for the detection and determination of drugs and species based on aggregation of Au-nanoparticles. However, multivariate calibration modeling of the SPR absorbance data by chemometrics method resulted in more accurate results out-comes so that the relative prediction errors were almost lower than 5%. In comparison with the available analytical methods for highly selective and sensitive ternary determination of tramadol, methadone and buprenorphine the proposed method is in need of lower amounts of reagents. Through increasing the concentration of the Opiate and Fluent material, a visible color change of AuNPs from wine red to blue was observed so the obvious color change was easily noticeable by naked eyes. However, multivariate calibration modelling and 3-d way methods that used for the SPR absorbance data by PARAFAC resulted in more accurate outcomes so that the software, as well as the chemometrics and the solvent kit, with great assurance our kit is unique. PARAFAC is a multi-way method originating from psychometrics. Due to various reasons such as high computational power, awareness of the method and its possibilities, the increased complexity complication of the data dealt with in science and industry, is gaining more attention in chemometrics and associated areas.

Compatibility Determination of Drug-Polymer, Drug-Excipient & Drug-Intravenous Admixtures Using Chemometric-assisted UVspectrophotometry

Purpose: A new multivariate chemometric approach was developed for fast and economic compatibility determinations of ranitidine hydrochloride (as model drug) with certain pharmaceutical; polymers (Alginate & Chitosan), excipient (Lactose) and intravenous fluids (Dextrose, Ringer & Dextrose/ Ringer). Binary mixtures of the drug and each item were prepared and investigated by chemometric- assisted UV- spectrophotometry as well as by HPLC reference method. Methods: Five drug concentration levels (0.004-0.025mg/ml) of test-mixtures were used and the average drug recovery percent after two and seven days of storage from initial concentration was determined. Physico-chemical techniques including DSC, XRD, & FTIR were also performed to investigate the nature of the observed drug-additive interactions. Results: UV-chemometric and HPLC results showed that ranitidine stability in mixture aqueous solutions appears to be concentration dependent. The ranitidine content remained greater than 90% in alginate & chitosan test mixtures at all used drug concentrations (0.004-0.025mg/ml), while in lactose, dextrose, ringer & dextrose/ringer test mixtures fell below 90% at low drug concentrations (0.004- 0.009mg/ml), which suggests more ranitidine compatibility with alginate & chitosan rather than the other additives. Conclusion: The developed chemometric method, employing UV absorbance data successfully used as simple, rapid, and economic alternative tool in drug-additive compatibility determinations.

Modeling Hyperspectral Response of Water-Stress Induced Lettuce Plants Using Artificial Neural Networks

Modeling the hyperspectral response of vegetables is important for estimating water stress through a noninvasive approach. This article evaluates the hyperspectral response of water-stress induced lettuce (Lactuca sativa L.) using artificial neural networks (ANN). We evenly split 36 lettuce pots into three groups: control, stress, and bacteria. Hyperspectral response was measured four times, during 14 days of stress induction, with an ASD Fieldspec HandHeld spectroradiometer (325–1075 nm). Both reflectance and absorbance measurements were calculated. Different biophysical parameters were also evaluated. The performance of the ANN approach was compared against other machine learning algorithms. Our results show that the ANN approach could separate the water-stressed lettuce from the non-stressed group with up to 80% accuracy at the beginning of the experiment. Additionally, this accuracy improved at the end of the experiment, reaching an accuracy of up to 93%. Absorbance data offered better accuracy than reflectance data to model it. This study demonstrated that it is possible to detect early stages of water stress in lettuce plants with high accuracy based on an ANN approach applied to hyperspectral data. The methodology has the potential to be applied to other species and cultivars in agricultural fields.

Structural and Electronic Characterization Through Spectroscopy Analysis of Gd-Gd2O3 Nanoparticles

Based on the new necessity of residual dispensing of heavy metals (or even more, rare earths) that are part of the composition of multiple electronic components as the cellular phones or computers; this work reports the use of physical processes for taking advantage of elements from the electronic residues. Recycling and processing to generate nanomaterials is an attractive option, because the economic and ecologic perspectives. In this work, Gd–Gd2O3 nanoparticles (through a sonic-chemical method at room temperature assisted with Tannic acid as reduction agent), is reported. The structure characterization was performed over the samples using complementary techniques such as transmission electron microscopy, X-ray diffraction, Raman and infrared spectroscopies. The obtained results are related to self-assembling mechanisms. As a complement, Ultraviolet-visible absorbance data was used to determine some electronic properties such as band structure. Therefore, this work has demonstrated the possibility of synthesizing lanthanide nanoparticles without burning the samples.