Beer's Law Research Articles

EXTRACTION-FREE SPECTROPHOTOMETRIC DETERMINATION OF MELOXICAM USING BROMOTHYMOL BLUE

Objective: The purpose of the present work was to develop and validate a fast, simple and sensitive extraction-free spectrophotometric technique for the quantitative determination of meloxicam based on the reaction with bromothymol blue. Material and Method: The reference standard of meloxicam, bromothymol blue and finished dosage forms of meloxicam were used in the study. Absorption measurements were performed on the Analytic Jena UV-visible spectrophotometer model Specord 200. Result and Discussion: The developed method is based on the formation of the colored reaction product between meloxicam and bromothymol blue in acetone medium with absorption maximum at 348 nm. The method meets the requirements of the State Pharmacopoeia of Ukraine for such validation characteristics as specificity, linearity, precision, accuracy, robustness and range of application. The obedience to Beer's law is observed in the range of meloxicam concentrations 0.80-2.40 mg/100 ml, the correlation coefficient is 0.9998. The range of application of the method is 60-140%.

Enhancement of the radiation shielding, physical and mechanical qualities of the Nd-glass series

The current study examines the physical, structural, mechanical, and radiation shielding properties of a series of (75-x) TeO2 -15 MgO -10Na2O -x Nd2O3: 0.0 <x < 2.0 mol% glasses. Nine distinct glasses coded as Nd-0.0 to Nd-2.0 are simulated via MCNPX Monte Carlo code by the varying composition of Nd2O3 (Neodymium oxide) and the related characteristics are evaluated between 0.015 and 10 MeV. The Beer-Lambert Law and Makishima–Mackenize theory are used to assess the preferred glass samples' radiation shielding and mechanical characteristics. Acquired results show that the Nd-2.0 glass sample gives the best gamma photon shielding performance. In addition, the computed physical features reveal that increasing the Nd2O3 contents from Nd-0.0 to Nd-2.0 leads to a tightly packed glass structure. Finally, it can be concluded that the candidate glass samples can be used as shielding substances against gamma photons and are able to enhance the structural and mechanical qualities.

Numerical Modeling and Simulation of Non-Invasive Acupuncture Therapy Utilizing Near-Infrared Light-Emitting Diode.

Acupuncture is one of the most extensively used complementary and alternative medicine therapies worldwide. In this study, we explore the use of near-infrared light-emitting diodes (LEDs) to provide acupuncture-like physical stimulus to the skin tissue, but in a completely non-invasive way. A computational modeling framework has been developed to investigate the light-tissue interaction within a three-dimensional multi-layer model of skin tissue. Finite element-based analysis has been conducted, to obtain the spatiotemporal temperature distribution within the skin tissue, by solving Pennes' bioheat transfer equation, coupled with the Beer-Lambert law. The irradiation profile of the LED has been experimentally characterized and imposed in the numerical model. The experimental validation of the developed model has been conducted through comparing the numerical model predictions with those obtained experimentally on the agar phantom. The effects of the LED power, treatment duration, LED distance from the skin surface, and usage of multiple LEDs on the temperature distribution attained within the skin tissue have been systematically investigated, highlighting the safe operating power of the selected LEDs. The presented information about the spatiotemporal temperature distribution, and critical factors affecting it, would assist in better optimizing the desired thermal dosage, thereby enabling a safe and effective LED-based photothermal therapy.

Quantitative analysis of organic additives in acid copper plating solution

Due to the decomposition, condensation, and invalidation of organic additives in acid copper plating solution, it is hard to identify the effective concentration of additives, which causes difficulties in the prediction and grasping of the electroplating effect. To solve this problem, this paper established the linear relationship between absorbency and the concentration of organic additives based on the principle of ultraviolet spectrophotometry and the luminescence mechanism of the chromogenic agent and three organic additives after eliminating the interference of copper and hydrogen ions in the plating solution. The concentrations of polyethylene glycol (PEG), bis-(sodium sulfopropyl)-disulfide(SPS), and gelatin in the solution were analyzed quantitatively according to Law of Lambert-Beer. According to the results, the linear relationship between PEG’s mass concentration and absorbency can be described as y = 0.01057 + 0.01372x, with a linear correlation of 0.9982, a relative error of about 0.56%-3.7%, and a minimum detection limit of 1 mg/L. The method adopted for detecting the SPS content records a relative error of around 0.817%-4.202% with the minimum detection limit of 2 μmol/L. The linear relationship between gelatin concentration and absorbancy is expressed as y = 0.02165x + 0.00932, in which the linear correlation r = 0.9906.

Measuring liquid film thickness based on the brightness level of the fluorescence: Methodical overview

Thin layers of liquid (liquid films) appear in a variety of industrial applications. The main parameter of a liquid film is its local instantaneous thickness, which can be measured using a great number of methods. One of such methods is based on the phenomenon of Laser-Induced Fluorescence: the fluorescence intensity is integrated along the optical ray and recalculated into film thickness using Lambert-Beer law. An overview of previous applications of this technique is presented here together with a detailed description of this method, including its working principle, factors affecting the fluorescence, calibration procedure, and spatial configurations. The advantages and shortcomings of the technique are discussed. The advantages include high spatial resolution, large area of measurement without coarsening the measurement accuracy, three-dimensional measurements of film thickness, and studying droplets and bubbles simultaneously with the waves. The shortcomings are mainly related to optical distortions appearing locally due to steep slope and high curvature of the interface. These distortions are analyzed in frames of a simple ray-tracing model, showing the limits of applicability of the technique.

Origin of high optical contrast in zinc-zinc oxide electrodeposits for dynamic windows

The control of solar light and heat emission through windows is an important strategy for increasing the energy efficiency of buildings. Reversible Zn electrodeposition has recently emerged as a promising method for constructing electronically tintable robust dynamic windows. In Zn electrodeposits formed from dimethyl sulfoxide (DMSO) electrolytes during device tinting, we observe extraordinary absorption that is in excess of what is predicted by the Beer-Lambert law for a uniform Zn thin film. The charge required to electroplate these films is abnormally low, significantly less than previously reported dynamic windows based on reversible metal electrodeposition, which facilitates the construction of large-area devices that switch uniformly. Finite-difference time-domain (FDTD) simulations are used to investigate the origin of this enhanced absorption, which arises from plasmonic effects among the Zn nanoparticles and ZnO dendrites in the film. The dielectric ZnO dendrites promote absorption via slit-like Zn-dielectric-Zn structures that from hybrid surface plasmon resonance at metal walls. Through these investigations, we provide design principles to construct low-charge and high-contrast metal and metal oxide-based dynamic windows.

Process-structure-property effects of ultraviolet curing in multi-material jetting additive manufacturing

Material jetting (MJT) is an additive manufacturing process that involves selective jetting of a liquid material that is subsequently solidified, often via ultraviolet (UV) irradiation. The process presents designers with the opportunity to tune material properties on a voxel-by-voxel basis to fabricate high-resolution, multi-material parts. However, MJT is mainly constrained to prototyping and modeling applications, due to a limited selection of functional materials and challenges in attaining repeatable and reproducible part quality. Specifically, MJT’s indiscriminate UV dosing poses the risk of providing inconsistent dosing to parts, which could cause unintended variations in mechanical properties that are dependent on part design and build layout. To enable relating MJT processing conditions to final part properties, an MJT process model is presented that predicts accumulated exposure in parts of different materials, surface finishings, and build layouts by accounting for inputs relating to surface exposure, part design, and build plate configuration. Fundamentally guided by the Beer-Lambert law, the model leverages physical measurements of an MJT system, including UV spectral intensity distribution and toolpathing, to quantify cumulative exposure in batch-printed parts. Experimental characterization of parts printed in different configurations enabled correlation of parts’ total received exposure to their mechanical properties (tensile, three-point bend, Shore hardness, and dynamic mechanical analysis). It is observed that, especially in build layouts featuring multiple parts with dissimilar heights, the indiscriminate application of UV irradiation in MJT can lead to overexposure of parts, which results in changes in mechanical properties, including increased modulus and hardness. The effects of overexposure are largely dependent on material, toolpathing, and build layout. Connecting accumulated exposure to mechanical performance enables improved strategies for part design, build plate configuration, and process modification to better ensure consistency of UV dosage and reliable mechanical performance for batch-printed end-use parts.

Synthesis, characterization, and application of hydroxyapatite grafted over pristine charcoal /activated charcoal for removal of pb2+ ions from aqueous solution

Hydroxyapatite (HAP) is one of the major components found in bones and teeth and has outstanding biocompatibility. Hydroxyapatite is a possible sorbent for heavy metals in contaminated water attributable to its high adsorption capabilities and solubility of water very low. However, pure hydroxyapatite is very difficult to use because it exists in the form of white power and also is too much costly. The above difficulties were overcome by the synthesis and characterization of hydroxyapatite grafted over Pristine charcoal/ activated charcoal for the expulsion of lead ions from aqueous solutions by the simple hydrothermal process at different temperatures like 120 °C and 150 °C. The result reveals that rod-like HAP nanocrystals with a range of 22––62 nm, are impregnated over charcoal. Characterization of synthesized hydroxyapatite samples by using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), Field emission scanning electron microscopy (FESEM), and Energy-dispersive X-ray spectroscopy (EDX) methods. To investigate adsorbent for removal of Pb2+ from an aqueous solution of Pb (NO3)2, and to vary the adsorbent dosage to evaluate its influence on the adsorption efficiency. The observed that synthesis of HT-CH at 120 °C gives the best result, UV Analysis for the calculation of equilibrium sorption capacity of HT-CH120 and HT-ACH120 on the adsorption of Pb2+ ion is carried out by Lambert-Beer law. The equilibrium sorption capacity of HT-CH120 is 76.13 mg/gm while the equilibrium sorption capacity of HT-ACH120 is 15.8 mg/gm.

Development and Validation of Simultaneous Spectroscopic Method for Tetracycline Hydrochloride and Clotrimazole

Abstract: A simple and accurate simultaneous method was developed for tetracycline hydrochloride (TH) and clotrimazole with a mixture of solvents. the combination is used to Validate the developed UV-spectrophotometric method as per ICH guidelines, The concentration of Tetracycline hydrochloride &amp; clotrimazole in the sample solution was determined by solving the respective simultaneous equations generated by using absorptivity coefficients and absorbance values of TH &amp; Clotrimazole at these wavelengths 361 nm and 259 nm respectively. and both satisfy Beer's law in concentration ranges of 4-20 µg/ml for TH and 10- 30 µg/ml for Clotrimazole. The method was effectively used to estimate TH and clotrimazole in Buccal film without the interference of common excipients.

Development and Validation by UV Spectrophotometric Method for Simultaneous Estimation of Gliclazide and Quercetin in Formulation

Abstract: A simple, quick, accurate, precise, and cost-effective spectrophotometric approach for simultaneous estimation of Gliclazide and Quercetin has been developed by Simultaneous equation method. Gliclazide and Quercetin shows absorbance maximum at 226 and 255 nm respectively, as a result absorbance was measured at these wavelengths for the estimation of Gliclazide and Quercetin. In concentration ranges from 2-18 g/ml, and 2-22 g/ml for Gliclazide and Quercetin respectively followed Beer-Lambert's law. The method has been developed and validated in accordance with ICH recommendations and can be used for estimation of Gliclazide and Quercetin in formulations.

Study of the pedological quality of an overexploited soil and the operating constraints: Case of market gardening sites from Kimuenza to Kinshasa

The study aims at assessing the quality of the market garden soil of Kimuenza and the constraints faced with its productivity. The analysis was carried out on the one hand, by Hach UV-visible spectroscopy based on the beer-Lambert law, for the physicochemical parameters, by X-ray fluorescence for the saturation elements and on the other hand, by ICP- MS for metallic trace elements. The detection limit and the reproducibility of these methods have been confirmed. The obtained indicated that the soil is poor in nutrients necessary for plants, low water retention and a sandy texture and has a high rate of Cd varying between 9.6 to 12.1 mg/Kg in all sites.

UV Spectrophotometric and UPLC assay methods for the determination of Palbociclib in bulk and Tablet Dosage Form

The goal of this study was to create a sensitive and reliable UV-spectrophotometric and reverse phase liquid chromatographic method for determining Palbociclib in bulk and pharmaceutical dosage forms. The current UV approach uses methanol and phosphate buffer as a solvent to evaluate absorption at a maximum wavelength of 220nm. Waters Acquity BEH C18 (2.1 x 50mm, 1.7µm) UPLC column with Empower 2 was used in the UPLC procedure. The mobile phase was made up of 50:50 (v/v) methanol and phosphate buffer.The drug obeyed Beer Lambert's law in the UV technique in the concentration range of 1-70µg/ml with a regression coefficient of 0.999. The linearity level in the UPLC technique was 1-100µg/ml. In the validation investigation, the developed UV and UPLC procedures were successful. For the UPLC and UV methods, the percentage purity of the marketed dosage form of Palbociclib was found to be 98.76 percent and 98.84 percent, respectively. The percent RSD of all validation parameters investigated, as suggested by the ICH recommendations, was determined to be less than 2 in both techniques. The two methods established for determining Palbociclib in bulk and tablet doses were found to be accurate, simple, and validated.

Deviation of photoelectron intensity from Beer-Lambert law in near-ambient pressure hard x-ray photoelectron spectroscopy

In near-ambient-pressure photoelectron spectroscopy, the photoelectron intensity is assumed to follow the Beer-Lambert law, that is, the intensity decreases exponentially with distance d between the sample and the aperture cone. In this study, the gas pressure dependence of photoelectron intensity is systematically studied in a wide range of d values from 0.3 up to 5 mm. The experimental results were reproduced by replacing d with d + do (do is a constant) in the Beer-Lambert law. The do value was evaluated as ∼1 mm, which is considerably larger than the normal d value of 0.3 mm. Fluid dynamics simulation results obtained using a structural model with a size close to that of the actual differential pumping system suggested that the residual gas in the long pumping path caused a large do value.

Study of Particle Size Measurement by the Extinction Method in Flame

The laser extinction method (LEM) is particularly suitable for measuring particle sizes in flames because this method, which is based on the Beer–Lambert law, is non-intrusive and easy to implement. In the LEM, the interpretation of the extinction data is usually developed under the assumption that light extinction due to scattering is a result of the superposition of single scattering by individual particles; however, this could be violated for flames with dense concentrations of particles in which multiple scattering could occur. Quantifying the effect of multiple scattering under general conditions is still a formidable problem. In this work, we carried out a series of careful measurements of the laser extinction using standard particles of various known sizes, number densities and optical path lengths, all under the condition that the acceptance angle of the detector was limited to nearly zero. Combined with a four-flux model, we quantitatively analyzed the effect of multiple scattering on the size measurement using the LEM. The results show that the effect of multiple scattering could be ignored when the optical thickness is less than two under strict restrictions on the detector acceptance angle. Guided by this, the size distribution of an alumina (Al2O3) particle sample was measured by the LEM with dual wavelengths. Parameterized distributions were solved with the help of graph plotting, and the results compared well with the measurement from the Malvern particle size analyzer. The same method was then used to measure the particle size distribution in the plume of a solid rocket motor (SRM). The use of an off-axis parabolic mirror in the experimental setup could suppress the jitter of light passing through the SRM plume, and the particle size in the plume of the measured SRM was in the order of microns.

STUDY OF COMPLEX FORMATION OF Ni (II) WITH AZODERIVATIVES PIROHALLOLA IN THE PRESENCE OF CATIONIC SURFACE ACTIVE SUBSTANCES

The effect of the third components of cationic surfactants – chloridecetylpyridinium (CPCl), cetylpyridinium bromide (CPBr), cetyltrimethylammonium bromide (CPMABr) for complexation of nickel (II) with 4- (2´, 3´, 4´-trihydroxyphenyl) -3-sulfo-5-chlorophenylazo benzene (R). Same- (NiR) and mixed-ligand complex compounds (Ni (II) -RCPCl, Ni (II) -RCPBr and Ni (II) -RCPMABr) are formed at pH 6, 4, 4 and 4, respectively. All complexes are formed immediately after mixing the solutions of the components and differ in stability. The ratio of the reacting components in the composition of same- (1: 1) and mixed-ligand (1: 1: 1) complexes are established. The interval of obedience to Beer's law is determined. The coefficients of the calibration curve equation are determined by the method of least squares. Complexation of nickel (II) is expressed by linear dependence of A = f (c) is. Stability constants of same- (NiR) and mixed-ligand complexes (Ni (II) -RCPCl, Ni (II) -RCPBr and Ni (II) -RCPMABr) are calculated. Under optimal conditions of complexation, Ni-R was titrated with a solution of third components (CPCl, CPBr and CPMABr) by conductometric method. The influence of foreign ions on complexation of nickel (II) with R in the absence and in the presence of third components was studied. A technique has been developed for the spectrophotometric determination of microquantities of nickel in the waters of the Akstafa and Jogaz rivers of the Kazakh region of the Republic of Azerbaijan

A novel salt-assisted liquid-phase ultrasound exfoliation method in the preparation of GaSe nanosheets via Lambert-Beer obtaining rational design

In this study, a novel Salt-assisted Liquid-phase ultrasound exfoliation (LPUE) method was proposed for the large-scale and high-efficiency preparation of GaSe nanosheets in Isopropyl alcohol (IPA). The LPUE can significantly improve the exfoliation efficiency and concentration with the assistance of salts including Sodium chloride (Nacl), Hexaammonium heptamolybdate tetrahydrate ((NH4)6Mo7O24·4H2O) and Calcium acetate (Ca(CH3COO)2·H2O). Remarkably, the Lambert-Beer law is applied for the first time in this study to obtain the concentration of GaSe by ultraviolet–visible (UV–Vis). The characterizations show that the nanoflake has been successfully exfoliated, with ∼95% of GaSe nanosheets containing 1–5 layers and 90% of the as-made GaSe nanosheets larger than 0.5 μm. The proposed LPUE method via Lambert-Beer law for precisely rational design has great potential for mass-producing GaSe nanosheets with a wide range of applications.

Neutral red dye as a novel reagent in spectrophotometric determination of Doxycycline via oxidation and bleaching color of the dye

A simple and accrued spectrophotometric method was developed to estimate Doxycycline as pure and in its formulation. The method included using a novel reagent neutral red dye the present method. The method was based on the oxidation of Doxycycline with an excess amount of N-bromosucinimide in an acid medium, then the residual amount of N-bromosucinimide oxidized the neutral red dye and caused bleaching of the color of the dye. The absorbance of the dye's color did not bleach measured at wavelength 525 nm. The absorbance is proportional to the concentration of Doxycycline in the solution. The linearity was from 1 to 15 µg/ ml, and the higher concentration above 15 µg/ ml gave deviation from Beer's law. The important analytical parameter included molar absorptivity and Sandell's sensitivity index, which were calculated and equal to 3.67 x104 l/mol.cm, 0.01261µg/cm2, respectively. An application part included estimating Doxycycline in its dosage form (capsule) from different manufacturers with satisfactory results. Keywords: Doxycycline, Neutral red, Bleaching Color, Oxidation,

AI-Assisted Disease Monitoring Using Stretchable Polymer-Based Sensors.

Flexible sensors have attracted significant attention for medical applications. Herein, an AI-assisted stretchable polymer-based (AISP) sensor has been developed based on the Beer-Lambert law for disease monitoring and telenursing. Benefiting from the use of superior polymer materials, the AISP sensor features a high tensile strain of up to 100%, durability of >10,000 tests, excellent waterproofness, and no effect of temperature (1.6-60.9 °C). Such advantages support the capability that the AISP can be flexibly pasted on the skin surface as a wearable device for real-time monitoring of multiple physiological parameters. An AISP sensor-based swallowing recognition technique has been proposed with a high accuracy of up to 88.89%. Likewise, it has been expanded to a remote nursing assistance system to meet critical patients' physiological requirements and daily care. The hands-free communication experiment and robot control applications have also been successfully conducted based on the constructed system. Such merits demonstrate its potential as a medical toolkit and indicate promise for intelligent healthcare.

AM–GM Algorithm for Evaluating, Analyzing, and Correcting the Spatial Scaling Bias of the Leaf Area Index

The leaf area index (LAI) is a crucial variable in climate, ecological, and land surface modeling. However, the estimation of the LAI from coarse-resolution remote sensing data can be affected by the spatial scaling bias, which arises from the nonlinearity of retrieval models and the heterogeneity of the land surface. This study provides an algorithm named Arithmetic Mean and Geometric Mean (AM–GM) to correct the spatial scaling bias. It is established based on negative logarithmic functions and avoids second-order stationarity. In this algorithm, relationships are derived between the scaling bias of LAI and the arithmetic and geometric means of directional gap probability for two commonly used remote sensing models, the Beer–Lambert law and a semi-empirical transfer function, respectively. According to the AM–GM algorithm, the expression representing the model nonlinearity is derived and utilized for the analysis of LAI scaling bias. Furthermore, the AM–GM algorithm is simplified by a linear relationship, which is constructed between two quantities related to the directional gap probability between two specific resolutions. Two scenes simulated by the LargE-Scale remote sensing data and image Simulation framework (LESS) model and three sites are used to evaluate the proposed algorithm and analyze the scaling bias of LAI. The validation results show that the AM–GM algorithm provides accurate correction of LAI scaling bias. The analyses based on the AM–GM algorithm demonstrate that the scaling bias of LAI increases with the increase in the LAI value, with stronger surface heterogeneity and coarser spatial resolution. The validation results of the simplified AM–GM algorithm demonstrate that at the Sud-Ouest site, the absolute value of the bias for the estimated LAI decreases from 0.10, 0.22, 0.29, and 0.31 to 0.04, 0.01, 0.04, and 0.05 at 200 m, 500 m, 1000 m, and 1500 m resolutions, respectively. In conclusion, the proposed algorithm is effective in the analysis and correction of the scaling bias for coarse-resolution LAI.

A modified Beer–Lambert–Bouguer law for nonrandom distributions and its application in gap probability calculations for heterogeneous canopies

A modified Beer–Lambert–Bouguer law for nonrandom distributions and its application in gap probability calculations for heterogeneous canopies