Beer's Law Research Articles

Estimation of differential pathlength factor from NIRS measurement in skeletal muscle

The utilization of continuous wave (CW) near-infrared spectroscopy (NIRS) device to measure non-invasively muscle oxygenation in healthy and disease states is limited by the uncertainties related to the differential path length factor (DPF). DPF value is required to quantify oxygenated and deoxygenated heme groups’ concentration changes from measurement of optical densities by NIRS. An integrated approach that combines animal and computational models of oxygen transport and utilization was used to estimate the DPF value in situ. The canine model of muscle oxidative metabolism allowed measurement of both venous oxygen content and tissue oxygenation by CW NIRS under different oxygen delivery conditions. The experimental data obtained from the animal model were integrated in a computational model of O2 transport and utilization and combined with Beer-Lambert law to estimate DPF value in contracting skeletal muscle. A 2.1 value was found for DPF by fitting the mathematical model to the experimental data obtained in contracting muscle (T3) (Med.Sci.Sports.Exerc.48(10):2013–2020,2016). With the estimated value of DPF, model simulations well predicted the optical density measured by NIRS on the same animal model but with different blood flow, arterial oxygen contents and contraction rate (J.Appl.Physiol.108:1169–1176, 2010 and 112:9–19,2013) and demonstrated the robustness of the approach proposed in estimating DPF value. The approach used can overcome the semi-quantitative nature of the NIRS and estimate non-invasively DPF to obtain an accurate concentration change of oxygenated and deoxygenated hemo groups by CW NIRS measurements in contracting skeletal muscle under different oxygen delivery and contraction rate.

Performance and optimization study of selected 4-terminal tandem solar cells

Tandem solar cells owing to their layered structure in which each sub-cell utilizes a certain part of the solar spectrum with reduced thermal losses, are promising applicants to promote the power conversion efficiency beyond the Shockley–Queisser limit of single-junction solar cells. This study delves into the performance and optimization of 4-terminal organic/silicon tandem solar cells through numerical simulations using SCAPS-1D software. The tandem architecture combining organic, perovskite, and silicon materials, shows potential in enhancing light absorption across the solar spectrum with complementary absorption spectra. Through innovative material exploration, optimization techniques are explored to advance the performance boundaries of organic/silicon tandem solar cells. The study employs the Beer–Lambert law to assess the impact of varied physical parameters on tandem solar cell efficiency, aiming to propose optimal configurations. Results indicate a maximum efficiency of 25.86% with P3HT:PC70BM organic active layer (150 nm thickness) and 36.8% with Cs2AgBi0.75Sb0.25Br6 active layer (400 nm thickness) in the studied 4-terminal tandem structures. These findings offer valuable insights into the complex physics of these tandem solar cells, for developing high-performance and commercially practical photovoltaic devices.

Bouguer–Lambert–Beer Law of Absorption: Spectrophotometry in Electrolyte Solutions

Bouguer–Lambert–Beer Law of Absorption: Spectrophotometry in Electrolyte Solutions

A kind of multi-dot ensemble regression AI detector for lubricating oil additive content based on lambert-beer law

In this work, we propose a Multi-dot Ensemble Regression AI detector (MER) based on the Lambert-Beer law. We pre-trained a model using the infrared spectral data of target additives collected in advance to detect the target additives in unknown oil samples. The algorithm's feasibility was validated by assessing the content of additives in a series of simulated commercial oil samples that were not part of the training set. We established models for three common lubricating oil additives (anti-friction, anti-wear, and antioxidant agents), demonstrating their effectiveness in oil sample detection. Additionally, by comparing with other algorithms, we established the superiority of MER in small-sample learning scenarios.

The structural, optical, electrical and radiation shielding properties of Co-doped ZnO thin films

Co:ZnO thin films are promising due to the similar ionic radii of cobalt and ZnO, and their potential for carrier spin injection, transfer, and detection. This study aims to investigate the structural, optical, electrical, and radiation shielding properties of Co-doped zinc oxide (Co:ZnO) thin films for potential applications in various fields such as semiconductors, solar cells, spintronics, and radiation shielding. The effect of commercially available Cobalt acetate tetrahydrate and Cobalt complex (Co with conjugated NN ligand) as cobalt additives on the synthesis of ZnO thin films is compared, aiming to discern their respective impacts. The dopants are incorporated in 2, 4, and 6 wt%, employing the sol-gel spin coating method.Applying cobalt complex additive as Co precursor resulted in ZnO:Co films with a superior enhancement of the electronic band gap of 2.84–3.00 eV compared to cobalt acetate precursor (2.62–2.84 eV). With the introduction of Cobalt, there is a notable change in the electrical conductivity, showcasing a decrease from 1.5x10−7 to 2.11x10−10 (S/cm). Also, radiation shielding parameters were experimentally measured in the energy range of 186.1–1764.5 keV within the scope of gamma ray spectral analysis. Exposure buildup factors (EBF) in the energy range of 15–15,000 keV were calculated up to 1–40 mean free path (mfp). Mass stopping power (MSP) and projected range values (PR) for nuclear safety applications were calculated for protons and alpha particles using the SRIM code. Thin film thicknesses were determined by using Lambert-Beer law. It was observed that the thin film thicknesses obtained from gamma spectrometry (2.090–2.628 μm) and SEM (2.157–2.725 μm) were compatible with each other.

Non-Destructive Prediction of the Mixed Mineral Pigment Content of Ancient Chinese Wall Paintings Based on Multiple Spectroscopic Techniques.

This study first developed non-destructive and accurate methods to predict the relative contents of mixed mineral pigments in ancient Chinese wall paintings using multiple spectroscopic techniques. The colorimetry, attenuated total reflection Fourier transform infrared spectroscopy (ATR FT-IR), ultraviolet-visible-near-infrared (UV-Vis-NIR) spectroscopy, and Raman spectroscopy were employed. Analyses were conducted including color difference, spectral reflection, ATR FT-IR spectra, and Raman mapping for simulated samples (malachite-lazurite mixed with rabbit glue samples) before and after aging. Models were then established for predicting the relative pigment contents of samples using UV-Vis-NIR and ATR FT-IR spectral data with Beer-Lambert law, and mathematical methods comprising principal component analysis (PCA) and nonlinear curve fitting. In particular, PCA and empty modeling methods combined with non-negative partial least squares were developed to predict the relative pigment contents based on Raman mapping data. The results demonstrated that approaches comprising PCA, mathematical model, and empty modeling based on the spectral data were effective at predicting the relative pigment contents. The predicted results obtained using the mathematical model based on UV-Vis-NIR spectra had an error of about 2%, and the best prediction based on ATR FT-IR spectra had an error of <3.6% at 1041 cm-1. The errors for the predictions using PCA and empty modeling based on Raman mapping data were 0.01-9.30% and 0.28-7.15%, respectively. However, the predicted relative pigment contents obtained based on ATR FT-IR data combined with the Beer-Lambert law had higher errors. The findings of this study confirm the strong feasibility of using spectroscopic techniques for quantitatively analyzing mixed mineral pigments.

Influence of Polymer Surface Roughness on the Fractions of Transmitted, Reflected and Absorbed Energy in Operation of Laser Transmission Welding

The study of energy fractions plays a fundamental role in laser joining operations: from their knowledge, it is possible to calculate the amount of laser beam energy that is effectively available during the formation of chemical and physical bonds, and how much energy is dissipated. This study examines semi-crystalline polymers of polyamide 6.6 (PA), polyethylene terephthalate (PET), polytetrafluoroethylene (PTFE), and polypropylene (PP), semitransparent to light radiation, with the aim of studying the influence of surface roughness on the distribution of energy fractions, and in particular on the reflection portion. For this purpose, polymeric samples with different surface finishing were prepared and characterized by profilometric analysis. Subsequently, an experimental setup was implemented to directly measure the transmitted ratio, obtaining the reflected energy fraction from the Beer-Lambert law, and the absorbed ratio by energy balance. The results showed a decrease in the power transmitted by polymers subjected to surface treatment, due to an increase in the reflection fraction, a phenomenon particularly evident for PET, for which the reflection share increased from ~ 0.5% to ~ 15.3%, following P240 treatment. A lower influence was verified for PA and especially PTFE, due to a lower influence of the treatment on surface morphology. On the basis of the experimental results, it is hypothesised that roughening the lower section of the irradiated polymer could allow an increase in the total internal reflection fraction, favouring the joint at the interface point.Graphical

Towards in-situ water quantification via neutron imaging: insights from NeXT-Grenoble

Neutron imaging has gained increasing attention in recent years. A notable domain is the in-situ study of flow and concentration of hydrogen-rich materials. This demands precise quantification of the evolving concentrations. Several implementations deviate from the ideal conditions that allow the direct applicability of the Beer–Lambert law to assess this concentration. The objective of this work is to address these deviations by applying both calibration and correction procedures to ensure and validate accurate quantitative measurements during 2D and 3D neutron imaging conducted at the cold neutron source at the NeXT instrument of the Institute Laue–Langevin, Grenoble, France. Linear attenuation coefficients and non-linear correlations have been proposed to measure the water concentration based on the sample-to-detector distance. Furthermore, the effectiveness of the black body grid correction method, introduced by Boillat et al (2018 Opt. Express 26 15769), is evaluated which accounts for spurious deviations arising from the scattering of neutrons from the sample and the surrounding environment. The applicability of the Beer–Lambert law without any data correction is found to be reasonable within limited equivalent thickness (e.g. below 4 mm of water) beyond which the correction algorithm proves highly effective in eliminating spurious effects. Notably, this correction method maintains its effectiveness even with transmissions below 1%. We examine here the impact of grid location and resolution with respect to sample heterogeneity.

UV Spectrophotometric Method Development and Validation of Butorphanol Tartrate in Bulk Drug and Pharmaceutical Formulation

The present research work discusses the development and validation of a UV spectrophotometric method for butorphanol tartrate. Simple, accurate and cost efficient spectrophotometric method has been developed for the estimation of butorphanol tartrate in tablet dosage form. The optimum conditions for the analysis of the drug were established. The maximum wavelength (λ max) was found to be 278nm. The percentage recovery of butorphanol tartrate was in the 100.016±0.68. Beers law was obeyed in the concentration range of 2-12μg/ml. Calibration curves shows a linear relationship between the absorbance and concentration. The line equation y = 0.0674x - 0.0057 with r2 of 0.9998was obtained. Validation was performed according to ICH guidelines for linearity, accuracy, precision, LOD and LOQ. The sample solution was stable up to 36 hours. The proposed method may be suitable for the analysis of butorphanol tartrate in tablet formulation for quality control purposes.&#x0D; Keywords: Butorphanol tartrate, Validation, Precision, Accuracy, LOQ, LOD, ICH guidelines.

Visual pigment concentration and photoreceptor outer segment length in the human retina.

The Beer-Lambert law suggests that visual pigment optical density (OD) should be linearly related to the length of photoreceptor outer segments (POSs). Mammalian studies indicate that visual pigment concentration increases with POS length, but the nature of this relationship may vary due to factors such as visual pigment packing density or retinal eccentricity, and may not necessarily be linearly related. The purpose of this study was to establish the relationship between OD and POS length in humans. Spectral domain optical coherence tomography (OCT) was used to image POS, and imaging retinal densitometry (IRD) was used to measure OD at corresponding locations in 19 healthy participants (age range 25-82 years). POS length and OD measurements were extracted from OCT and IRD images at 23 discrete locations spanning the central 9° of the retina. The averaged data from all participants were fitted with models based on the Beer-Lambert law to establish the relationship between OD and POS length. Visual pigment OD increased monotonically with POS length, but the relationship was non-linear, and a straight-line fit, based on a simple interpretation of the Beer-Lambert law, provided a poor description. A model allowing for different rod and cone visual pigment concentrations provided a superior fit. Specifically, the data were well described by a model where the molar concentration of visual pigment in cones and rods were 3.8 × 10-3 mol/L and 1.8 × 10-3mol/L, respectively. In accordance with the Beer-Lambert law, the results indicate that OD increases monotonically with POS length in humans, but the precise relationship is dependent on photoreceptor type. These results suggest that visual pigment concentration in rods is only about 48% of that found in cones. This may be due to the ubiquitous nature of artificial light that works to reduce the concentration of rhodopsin in rod photoreceptors.

Investigating Skin Cancer Diagnosis Using a Webcam-based Microcontroller System

Skin cancer can spread fast to nearby tissue and other parts of the human body if it's not diagnosed early. Most are curable only if skin cancer is found and treated in the early stages. Therefore, it's essential to seek a casual way of early diagnosis. This paper assesses a prototype system for skin cancer detection using an Arduino with an ArduCam Mega 5MP, benchmarked against smartphone diagnosis. Bandpass filters capture skin images at red (650 nm), green (532 nm), and blue (450 nm) wavelengths, measuring reflectance values. The approach aims to quantitatively determine skin melanin, oxyhemoglobin, and deoxyhemoglobin levels, aiding in various skin lesions' diagnosis. Evaluation involves comparing pixel reflectance values of images taken by smartphones and the prototype using a 3D mesh grid. Applying the modified Lambert-Beer law to reflectance values of moles, pimples, scars, scabs, and traces predicts relative levels of skin components. The system shows an 87% match with the smartphone standard, demonstrating high reliability. Further study might be needed to clarify the confirmation with clinical cases.

Characterization of Flower Based Organic Dyes and Titanium Dioxide Thin Film for Dye Sensitized Solar Cell

In the present study, we described the organic dye extraction process from local flowers employing different methods and solvents (a mixture of acetic acid and ethanol, another is only acetic acid); especially we completed our research by exploring dye from red gerbera flower as it showed higher absorbance. Both dry and fresh petals of the flower were used for extracting dyes. The results revealed that the mixture-based dye extraction from dry red gerbera yielded a higher absorbance value of 4.579 a.u., whereas the acetic acid-based extraction from the same source exhibited a lower absorbance value of 2.778 a.u. The choice of solvent for dye extraction was found to significantly influence the absorption spectrum. Additionally, the Beer-Lambert law was employed to analyze the relationship between the absorbance and the concentration of the extracted dyes. For the electrode, a TiO2 film was created using the spin coating technique. From the XRD graph, we found the band gap energy of TiO2 which is 2.81eV (annealed at 450°C), the type of nanoparticle of the thin film. Also found a Crystallite size of 32.95nm and a specific Surface Area (SSA) of 43.048 m2.g−1, Microstrain (ε) of 5e-3 and Dislocation Density (δ) of 9.2e-4cm−2.

Loading Determination of DMTr-substituted Resins for Large-scale Oligonucleotide Synthesis.

The loading (i.e., substitution) of solid supports for oligonucleotide synthesis is an important parameter in large-scale manufacturing of oligonucleotides. Several key process parameters are dependent on the substitution of the solid support, including the number of phosphoramidite nucleoside equivalents used in the coupling step. For dimethoxytrityl (DMTr)-loaded solid supports, the substitution of the resin is determined by quantitatively cleaving the DMTr protecting group from the resin under acidic conditions and then analyzing the DMTr cation extinction by UV/vis spectroscopy. The spectrometric measurement can be performed at 409 nm or the global extinction maximum of 510 nm. The substitution is then calculated based on the Lambert-Beer law analogously to the substitution determination of Fmoc-substituted resins. Below, the determination of the molar extinction coefficient at 510 nm in a solution of 10% dichloroacetic acid in toluene and subsequent determination of the DMTr loading of DMTr-substituted resins is reported. © 2024 The Authors. Current Protocols published by Wiley Periodicals LLC. Basic Protocol 1: Determination of the molar extinction coefficient at 510 nm in DCA Deblock solution Basic Protocol 2: Substitution determination of DMTr-substituted resins by cleavage of the DMTr cation.

Comparison and evaluation of the methods for measuring hemolytic activity of &lt;i&gt;Stomolophus meleagris&lt;/i&gt; jellyfish tentacle extract

Hemolytic activity assessment is a widely used method to evaluate the toxicity of marine organisms, including jellyfish. However, there are some challenges associated with testing hemolytic activity. In this study, four methods were employed to compare the hemolytic activity of jellyfish tentacle extract (TE). Firstly, a microplate reader was used to compare the mouse hemoglobin solution at three different wavelengths (415 nm, 541 nm, and 576 nm), and the most sensitive wavelength was selected for further experiments. Secondly, photomicrograph counting was used to determine the number of complete red blood cells in the field of view. Thirdly, a microplate reader was used to test hemolytic activity in a 96-well plate at 415 nm. Fourthly, a Bicinchoninic Acid (BCA) kit was used to test the concentration of hemoglobin in the solution. Finally, a UV-Vis Spectrophotometer was used to test hemolytic activity at 415 nm. Among the three wavelengths tested, the absorption value was most sensitive at 415 nm. The photomicrograph counting method was able to reflect changes in the shape of Red Blood Cells (RBCs). The microplate reader method may exhibit deviations when the solution concentration is high, while external factors could influence the BCA kit when the toxin concentration in the experimental group is low. The spectrophotometer method was found to be relatively accurate and sensitive to changes. When optimizing the method, it is important to consider the applicability of the Beer-Lambert law and the concentration of solutions.

Application of UV-vis spectroscopy in the detection and analysis of substances

Ultraviolet-visible (UV-vis) spectroscopy is a spectral measurement technique that relies on Lambert-Beer's law. Due to its user-friendly nature, rapid analytical capabilities, broad applicability, and non-destructive properties, it has gained significant prominence across various scientific disciplines. In the realm of environmental science, UV-vis spectroscopy can be employed for effectively detecting water quality by determining the concentration of heavy metals and related chemicals in water sources. Within the field of clinical medicine, UV-vis spectroscopy plays an indispensable role in disease diagnosis and patient health monitoring. Agriculture and plantation industries greatly benefit from UV-vis spectroscopy due to its capability in facilitating precise analysis of soil and plant nutrients. The field of materials science heavily relies on ultraviolet-visible spectroscopy for the examination of optical properties pertaining to various materials. Moreover, UV-vis spectroscopy finds extensive application in organic chemistry for compound identification and purity evaluation. This research aims to provide a comprehensive overview of multiple applications of UV-vis spectroscopy while exploring its potential synergies with specific technologies across different fields.

NeBLa: Neural Beer-Lambert for 3D Reconstruction of Oral Structures from Panoramic Radiographs

Panoramic radiography (Panoramic X-ray, PX) is a widely used imaging modality for dental examination. However, PX only provides a flattened 2D image, lacking in a 3D view of the oral structure. In this paper, we propose NeBLa (Neural Beer-Lambert) to estimate 3D oral structures from real-world PX. NeBLa tackles full 3D reconstruction for varying subjects (patients) where each reconstruction is based only on a single panoramic image. We create an intermediate representation called simulated PX (SimPX) from 3D Cone-beam computed tomography (CBCT) data based on the Beer-Lambert law of X-ray rendering and rotational principles of PX imaging. SimPX aims at not only truthfully simulating PX, but also facilitates the reverting process back to 3D data. We propose a novel neural model based on ray tracing which exploits both global and local input features to convert SimPX to 3D output. At inference, a real PX image is translated to a SimPX-style image with semantic regularization, and the translated image is processed by generation module to produce high-quality outputs. Experiments show that NeBLa outperforms prior state-of-the-art in reconstruction tasks both quantitatively and qualitatively. Unlike prior methods, NeBLa does not require any prior information such as the shape of dental arches, nor the matched PX-CBCT dataset for training, which is difficult to obtain in clinical practice. Our code is available at https://github.com/sihwa-park/nebla.

Development of Green and High-Throughput Microwell Spectrophotometric Methods for Determination of Galidesivir in Bulk Drug and Dosage Forms Based on Simple Oxidimetric Reactions With Inorganic Agents.

Galidesivir hydrochloride (GDV) is a new potent and safe antiviral drug used for the treatment of a broad spectrum of viral diseases, including COVID-19. In the literature, no analytical method exists for the determination of GDV in bulk or dosage form. The objective of this study was the investigation of oxidation reactions of GDV with five inorganic oxidizing reagents and the employment of the reactions in the development of five green microwell spectrophotometric methods (MW-SPMs) with simple procedure and high throughputs for determination of GDV in its bulk and dosage forms (capsules). The reactions were carried out in 96-well plates, and the absorbances of reaction solutions were measured by an absorbance microplate reader. Variables influencing the reactions were carefully investigated and optimized. Under the refined optimum conditions, Beer's law with excellent correlation coefficients (0.9992-0.9997) was followed in GDV concentrations in a general range of 5-700 µg/mL, and the limits of detection were ≥1.8 µg/mL. All validation parameters of all methods were acceptable. The methods were successfully applied to the analysis of GDV in bulk drug and capsules with high accuracy and precision; the recovery percentages were 98.6-101.2 ± 0.58-1.14%. The greenness of MW-SPMs was evaluated by three comprehensive metric tools, which demonstrated the adherence of MW-SPMs to the principles of the green analytical chemistry (GAC) approach. The proposed MW-SPMs combined the advantages of microwell-based practice and the use of common laboratory reagents for the analysis. The advantages of microwell analysis were the high throughput, readily available for semi-automation, reduced samples/reagents volume, precise measurements, and versatility. The advantages of using common laboratory reagents were the availability, consistency, compatibility, safety, and cost-effectiveness. Overall, the proposed MW-SPMs are versatile, valuable tools for the quantitation of GDV during its pharmaceutical manufacturing.

Development and Validation of a Viable and User-Friendly Spectrophotometric Analytical Method for Estimation of Assay of Formoterol and Beclomethasone in Metered Dose Inhaler Formulation

The primary aim of this research endeavor is to innovate a viable and user-friendly UV spectroscopic approach for quantifying formoterol and beclomethasone within metered dose inhalers (MDIs). These formulations, amalgamating Beclomethasone Dipropionate (BDP) and Formoterol Fumarate (FF), are extensively employed in managing bronchial asthma and chronic obstructive pulmonary diseases. Although analytical techniques already exist for assessing formoterol and beclomethasone in combination dry powder inhalers, this study concentrates on devising and validating a UV spectrophotometric method for simultaneously quantifying formoterol fumarate and Anhydrous Beclomethasone Dipropionate in Pressurized Metered Dose Inhalers (pMDIs). The estimation is performed at a wavelength of 240 nm for Beclomethasone Dipropionate and 216 nm for Formoterol Fumarate. Both drugs demonstrate satisfactory linearity within the concentration range of 10-30 μg/ml for BDP and 0.3 to 0.9 μg/ml for FF at wavelengths of 240 nm (r^2=0.999) and 216 nm (r^2=0.999), respectively. The Beer-Lambert law is adhered to within the concentration range of 10-30 μg/ml for BDP and 0.3-0.9 μg/ml for FF. The proposed methods are subjected to validation following ICH guidelines to assess accuracy, method precision, specificity, among other parameters. As a result, the proposed method can be effectively employed for the simultaneous determination of Beclomethasone Dipropionate and Formoterol Fumarate in routine analytical applications, offering a rapid and reliable solution for pharmaceutical analysis in the field.

Extending UWOC System Applications through Photon Transmission Dynamics Study in Harbor Waters

Underwater wireless optical communication (UWOC) in harbor waters can facilitate real-time monitoring underwater instruments for environmental monitoring, underwater inspection, and maintenance tasks. This study delves into the complex dynamics of UWOC in four distinct harbor waters. The research employs Monte Carlo method incorporated with Fournier–Forand scattering phase function for simulating photon transmission. Key parameters such as the Transmitted full divergence angle, received aperture, and Field of View (FOV) are meticulously evaluated for their impact on power loss and time delay spread. Notably, the normalized power loss and time delay spread are found to be more significantly affected by communication distance than water quality, and the traditional Beer–Lambert law is ineffective in harbor water. The power loss of Harbor II, III, and IV are found to be 14.00 dB, 31.59 dB, and 41.59 dB lower than that of Harbor I, and the time delay spread of Harbor II, III, and IV is 30.56%, 9.67%, and 0.49% times that of the Harbor I under certain conditions. In addition, increasing the received aperture and FOV, particularly over longer distance, make little contribution to reduce the power loss and mitigate the time delay spread. Based on the fixed transmitted full divergence angle, the most applicable received FOV range is 1–3.2 rad, and the most ideal received aperture is 0.15–0.4 m. Under these conditions, the variation in normalized power loss is less than 2 dB. Additionally, the time delay spread remains within the same order of magnitude with the attenuation length (AL) held constant. These conclusions hold substantial technical relevance for the engineering design of UWOC systems in harbor waters.

Ensemble Extreme Learning Machine Method for Hemoglobin Estimation Based on PhotoPlethysmoGraphic Signals.

Non-invasive detection of hemoglobin (Hb) concentration is of great clinical value for health screening and intraoperative blood transfusion. However, the accuracy and stability of non-invasive detection still need to be improved to meet clinical requirement. This paper proposes a non-invasive Hb detection method using ensemble extreme learning machine (EELM) regression based on eight-wavelength PhotoPlethysmoGraphic (PPG) signals. Firstly, a mathematical model for non-invasive Hb detection based on the Beer-Lambert law is established. Secondly, the captured eight-channel PPG signals are denoised and fifty-six feature values are extracted according to the derived mathematical model. Thirdly, a recursive feature elimination (RFE) algorithm is used to select the features that contribute most to the Hb prediction. Finally, a regression model is built by integrating several independent ELM models to improve prediction stability and accuracy. Experiments conducted on 249 clinical data points (199 cases as the training dataset and 50 cases as the test dataset) evaluate the proposed method, achieving a root mean square error (RMSE) of 1.72 g/dL and a Pearson correlation coefficient (PCC) of 0.76 (p < 0.01) between predicted and reference values. The results demonstrate that the proposed non-invasive Hb detection method exhibits a strong correlation with traditional invasive methods, suggesting its potential for non-invasive detection of Hb concentration.