Analytical Chemistry
A Typology and Lead Isotope and Cultural Exchange Study on Bronze Knives from Shuangyuan Cemetery, Chengdu City, Southwest China
Background: Bronze knives which have been excavated in large quantities and acquired hierarchical significance are essential artifacts in Shu State in Southwest China. Building upon previous typological analyses of bronze knives it is hypothesized that Shu culture may have imported foreign-style bronze knives. However further demonstration of the provenance of metal materials the types of knives and the cultural exchange necessitates a comprehensive examination through the lens of scientific analysis. The purpose of this study is to investigate the differences in the manufacturing processes and metal resources of Shu bronze knives with various cultural styles and whether bronze knives in the foreign styles were imported or locally imitated. Methods: In this study the typology portable X-ray fluorescence spectrometry and multi-collector inductively coupled plasma mass spectrometry were used to analyze twenty-four bronze knives unearthed from Shuangyuan Cemetery a cemetery of the Eastern Zhou Dynasty in Chengdu City Sichuan Province Southwest China. Results: The results of the study show that the knives of Shuangyuan Cemetery can be classified typologically into five types encompassing both local and foreign styles. The predominant alloy composition of these knives is lead-tin bronze characterized by a notably high tin content. Lead isotope ratios indicate that metal materials from the South China geochemical province and the Yangtze geochemical province were mainly used to manufacture the bronze knives unearthed from the Shu state. Conclusion: While the majority of foreign-style knives with ring-shaped heads were likely imported from neighboring regions like Chu state distinctively styled type D and type E bronze knives appear to have been locally imitated by the Shu showcasing a blend of external influences and indigenous innovation. The combination of typology and scientific analysis of the bronze knife may shed new light on the study of the Shu culture of the Eastern Zhou period.
Studies on Quantitative Determination of Polyphenols in Seven Harvesting Times of Salvia deserta Schang Leaves and its Stability Evaluation
Introduction: Leaves of Salvia deserta Schang at seven harvesting times in the same year were collected as the materials. Method: The polyphenols were determined by the Folin–Ciocaileu method and High-Performance Liquid Chromatography (HPLC) to compare the quality of samples. The stability of polyphenols was studied under different conditions (light temperature pH common additives). Results: The results showed that the established method is fast simple and reliable which is fully validated in terms of outstanding validation data. High Performance Liquid Chromatography (HPLC) for the determination of total polyphenol content can be quickly and accurately detected reducing the error of manual determination of the content. The study of polyphenol stability was carried out using a UV spectrophotometer (UV) in order to explore the potential factors affecting polyphenol stability as much as possible and to make the study as scientific and rigorous as possible. The results of quantitative determination showed that there are obvious differences in the content of polyphenols in seven samples. The contents of total polyphenols rosmarinic acid (RA) and caffeic acid (CA) in the samples harvested in July reached the highest level of 41.37 26.73 and 1.05 mg/g. Conclusion: The results of the stability assay found that light could damage the stability of polyphenols in samples especially UV light. Polyphenols are quite sensitive to high temperatures. While polyphenols are less stable when exposed to high alkali conditions and salt treatment they are much more stable when subjected to low concentrations of redox agents carbohydrates and preservatives. The developed methods and stability evaluation provide valuable basis information for quality evaluation and the following use of polyphenols in S. deserta Schang leaves.
A New Modified Carbon Paste Electrode for Selective Determination of Chromium(III) in Pharmaceutical Drugs and Food Samples
Background and Objective: This study presents a novel potentiometric method for the precise accurate selective and rapid determination of Cr(III) ion concentration in different samples. Methods: A new ionophore namely macrocyclic tetramide ionophore (MCTA) was synthesized through an inexpensive and straightforward approach yielding a high-quality product. The (MCTA) ionophore was utilized as the active center in the preparation of modified carbon paste electrodes (MCPEs) to quantify the Cr(III) ion. The paste was made by adding graphite MCTA and plasticizer and mixing them in varying weight percent ratios. Results: The proposed electrodes I and II exhibited a trivalent Nernstian response of 20.029 ±0.57 and 20.3±0.56 mV decade-1 respectively with linearity of 1.0x10-7 – 1.0x10-2 and 1.0x10-5 – 1.0x10-2 mol L-1. Electrodes I and II were examined for their pH response time and thermal stability. In comparison to other mono- bi- and trivalent cations starch and sugars the electrodes demonstrated a high degree of selectivity for Cr(III). The modified electrodes were used to determine the concentration of Cr(III) in various real samples including drug tablets juice extractions and tap water with acceptable recovery values. Conclusion: The results were compared with those obtained using the previously reported method with no significant difference observed between them as indicated by the F and t-test values. The data showed good accuracy and precision as well as a high percentage of recovery. The adsorption capacity of the MCTA ionophore towards Cr(III) ions was also examined.
Study on 13C MultiCP/MAS ssNMR Analysis of Tobacco Pectin
Background: As one of the most important economic crops tobacco products have a long history and dominate the development of the world economy. Pectin as a complex colloidal substance widely present in plant cell walls its content is an important factor affecting the safety of tobacco smoking. Objective: This study aimed to analyze the content and structure of pectin in tobacco samples. Methods: In this study tobacco pectin was extracted by ultrasonic-assisted ionic liquid extraction and the 13C MultiCP/MAS NMR spectral analysis of pectin was conducted. Results: The type of extractant duration of ultrasonication extraction temperature and solid-liquid ratio were optimized. Under the conditions of using 1-Butyl-3-methylimidazolium tetrafluoroborate ([Bmim]BF4) as the extractant the solid-liquid ratio of 1:20 g/mL and the ultrasonic power of 600 w for 30 min at 30°C the yield of 23.7% of tobacco stem pectin and the purity of 54.2% could be obtained. The optimized MultiCP sequence parameters with 10 CP cycles of 1.0 ms and the repolarization time of 50 ms could obtain high-resolution spectra within a time of 1.0 h. The C-6 peaks of the pectin in spectra were fitted using the spectral deconvolution technique and calculated the methylesterification (DM) of the tobacco pectin which was generally less than 50% and belonged to the low methyl esterification pectin. The pectin content of the tobacco sample was calculated using the standard curve method with the addition of dimethyl sulfone (DMS) as an internal reference. The results of this method were consistent with the colorimetric method. Conclusion: The 13C MultiCP/MAS NMR method has the advantages of being green fast and accurate and provides a new technical tool for quantitative and qualitative studies of cell wall substances in tobacco samples.
Development and Validation of 1H Nuclear Magnetic Resonance Quantitative Method for Efavirenz API Quality Control
Background: The pharmaceutical industry is constantly looking for a better way to ensure and improve its products' safety quality and effectiveness. Since there are many attributes of the drug substance and excipients that could potentially affect the Critical Quality Attributes (CQAs) of the intermediates and the final product the evaluation of the raw material's physicochemical characteristics is crucial as they directly affect the quality safety efficacy and lot-to-lot consistency. Scientists rely on methods like HPLC HPTLC LC-MS GC-MS and NMR to analyze these substances. The advantage of NMR is that it is considered a primary analytical method compared to other analytical techniques. Objective: This work aimed to present a simple rapid specific and accurate method by proton Nuclear Magnetic Resonance spectroscopy (1H-NMR) developed to determine the activity of the antiretroviral Efavirenz’s (EFZ) Active Pharmaceutical Ingredient (API). The method was based on quantitative NMR spectroscopy (qNMR). Methods: A Bruker Avance spectrometer (11.7 Tesla 500 MHz for 1H) with a 5mm probe was used. The 1H-NMR signal at 7.54 ppm corresponding to the analyte of interest was employed to quantify the drug. The method was validated for specificity selectivity intermediate precision linearity range of work accuracy and robustness. Results: The method developed was specific and linear (r2 = 0.9998) with a value between 4.30 mg/mL and 12.40 mg/mL. The relative standard deviation for accuracy and precision was 0.4% or less. The method's robustness was demonstrated by changing four different parameters and the difference among each was 1.2% or less. The results of this work have been found to be in agreement with those obtained from High-performance Liquid Chromatography (HPLC) analysis. Conclusion: The proposed method has been found to be a valuable and practical tool for quality control. Its applicability to determining many APIs and saving solvent use and time is highlighted.
Layer-by-layer Fabrication of Gold Nanoparticles/Polyaniline Modified Gold Electrodes for Direct Non-enzymatic Oxidation of Glucose
Background: Non-enzymatic direct glucose biofuel cell is a promising technology to harness sustainable renewable energy. Furthermore monitoring glucose levels is essential for human lives with age. Thus there is an increasing need to develop highly efficient and stable modified electrodes. Methods: This study reported the manufacture of gold nanoparticles/polyaniline/modified gold electrodes (Au NPs/PANI/Au electrode) based on the electrochemical polymerization method followed by the deposition of gold nanoparticles. The shapes and chemical constitution of the electrodes were examined by using different techniques including SEM FTIR XRD EDS and Raman spectroscopy techniques. The electrocatalytic efficiency of the present electrodes toward direct glucose oxidation was evaluated by applying cyclic voltammetry linear sweep voltammetry and square wave voltammetry techniques. Results: The results exhibited high electrocatalytic performance for direct glucose electrooxidation in alkaline media. The modified electrodes show the ability to electrooxidation of various glucose concentrations (1 μM 100 μM) with a limit of detection and limit of quantitation of 140 nM and 424 nM respectively. Furthermore the Au NPs/PANI/Au electrode showed higher durability sensitivity and selectivity toward glucose oxidation than the Au NPs/ Au electrode which confirmed the role of the PANI layer in enhancing the stability of the modified electrode. Conclusion: Moreover the molar fraction of glucose to KOH has a crucial role in the output current. Hence the modified electrodes are great candidates for direct glucose biofuel cell application.
Deep Learning-enhanced Hyperspectral Imaging for the Rapid Identification and Classification of Foodborne Pathogens
Background: Bacterial cellulose (BC) is a versatile biomaterial with numerous applications and the identification of bacterial strains that produce it is of great importance. This study explores the effectiveness of a Stacked Autoencoder (SAE)-based deep learning method for the classification of bacterial cellulose-producing bacteria. Objective: The primary objective of this research is to assess the potential of SAE-based classification models in accurately identifying and classifying bacterial cellulose-producing bacteria with a particular focus on strain GZ-01. Methods: Strain GZ-01 was isolated and subjected to a comprehensive characterization process including morphological observations physiological and biochemical analysis and 16S rDNA sequencing. These methods were employed to determine the identity of strain GZ-01 ultimately recognized as Acetobacter Okinawa. The study compares the performance of SAE-based classification models to traditional methods like Principal Component Analysis (PCA). Results: The SAE-based classifier exhibits outstanding performance achieving an impressive accuracy of 94.9% in the recognition and classification of bacterial cellulose-producing bacteria. This approach surpasses the efficacy of conventional PCA in handling the complexities of this classification task. Conclusion: The findings from this research highlight the immense potential of utilizing nanotechnology- driven data analysis methods such as Stacked Autoencoders in the realm of bacterial cellulose research. These advanced techniques offer a promising avenue for enhancing the efficiency and accuracy of bacterial cellulose-producing bacteria classification which has significant implications for various applications in biotechnology and materials science.
Analysis of Seven Terpenoids by HS-SPME Coupled with GC-MS for the Identification and Classification of Different Teas
Background: Terpenoids are essential aroma substances in teas and their concentration brings various characteristics to different teas. Therefore developing a simple and stable method is necessary for distinguishing tea categories. Objective: In previous studies more attention was paid to non-chiral isomers of terpenes due to the challenges of separating chiral isomers. So this paper aims to present a method for effectively separating seven terpenoid substances including chiral isomers and non-chiral isomers to facilitate the classification and identification of teas. Methods: A method utilizing headspace solid-phase microextraction coupled with gas chromatography- mass spectrometry was used to isolate and analyze 7 terpenoid compounds. After optimized conditions the BGB-176 chiral column and the PDMS/DVB fiber were selected for subsequent analysis. Results: This method has a good linear range of 0.1-200 mg/L and its linear correlation coefficients are between 0.9974 and 0.9994 and the limit of detection and the limit of quantification is 0.02–0.03 and 0.06–0.09 mg/L respectively. Only five terpenoid substances were detected in a total of 15 tea samples. Furthermore In the detection of carvon and α-ionone optical isomers the S isomer was mainly detected. Conclusions: An effective approach was developed to separate and analyze 7 terpenoid compounds in natural and synthetic teas. Meanwhile 15 tea samples can be identified and classified using principal component analysis.
Camptothecin and its Analogs: High-Yielding Ophiorrhiza Species from Sri Lanka for Sustainable Anticancer Compound Production
Introduction: Camptothecin (CPT) is pivotal in cancer treatment derived from various CPT-producing plant species and is a fundamental component in synthesizing valuable cancer drugs like Irinotecan and Topotecan. Sourcing from nature poses conservation issues fostering interest in the herbaceous Ophiorrhiza plant as a more sustainable alternative. Ophiorrhiza species in Sri Lanka lack comprehensive study warranting exploration for echo-friendly anticancer compound production. Objectives: This study examines CPT and analog content in Ophiorrhiza mungos O. pectinata and O. rugosa across diverse Sri Lankan regions. Methods: The study employs Thin Layer Chromatography (TLC) High-Performance Liquid Chromatography- DAD (HPLC-DAD) and Liquid Chromatography-Mass Spectrometry (LC-MS) to quantify and confirm CPT and its analogs. Results: Significant variations in the content of CPT and its analogs were observed among plant parts and regions. O. mungos from Deraniyagala and Bibile regions notably exhibited elevated CPT levels in fruits and roots. O. rugosa var. Angustifolia and O. pectinata also exhibited a considerable content of CPT in their roots though it was significantly lower (p < 0.005) than O. mungos. Conclusion: The study validates analytical methods for specificity linearity precision accuracy and sensitivity per ICH guidelines. The results indicate that Ophiorrhiza species especially O. mungos and O. rugosa var. Angustifolia holds the potential to be a sustainable source of CPT. Optimizing cultivation practices offers an eco-friendly solution for anticancer compound production alleviating species threats and conserving biodiversity.
Applicability of QbD-assisted Analytical Method for Simultaneous Detection of Tetrahydrocurcumin and Folic Acid in Developed Nanostructured Lipid Carriers
Aims: Applicability of QbD-assisted analytical method for simultaneous detection of tetrahydrocurcumin and folic acid in developed nanostructured lipid carriers. Background: Diabetic foot ulcer (DFU) is a multifactorial disorder that involves chronic inflammation oxidative stress and neuropathy. Current treatment therapies involving the use of growth factors and skin substitutes being costly are out of reach for the majority of patients. The present research explored the usefulness of a combination of tetrahydrocurcumin and folic acid-loaded nanostructured lipidic carriers in DFU. Objectives: To develop and validate a QbD-assisted method for simultaneous analysis of tetrahydrocurcumin (THC) and folic acid (FA). Applicability of the above method to determine total drug content (TDC) and entrapment efficiency (EE) of nanostructured lipid carriers (NLCs) loaded with THC and FA. Methods: A high-performance liquid chromatographic (HPLC) method was developed optimized and validated using Box-Behnken design for improved method performance. Chromatographic separation was conducted on a Supelco 250 x 4.6 mm (5 μm) column with optimized mobile phase composition containing tetrahydrofuran: citric acid buffer pH 3.5 (50:50) at a flow rate of 0.4 mL.min-1 and diode array detection between 210 and 360 nm. Results: The method developed in a concentration range of 1 to 100 μg.mL-1 was found to be linear (R2 0.999 p≤0.001) accurate (99.10-101.70%) and precise with high recovery values in intra and inter-day results. The system adaptability and robustness evaluation revealed that the percent recovery ranged from 96.90 to 102.80% and the percent relative standard deviation (%RSD) values were less than 2%. Moreover the method was further applied for the determination of TDC (86±6% and 96±8%) and drug EE (81±21% and 73±13%) for THC and FA respectively. Conclusion: The investigation indicated the applicability of the developed and validated method for the estimation of THC and FA in the developed nanostructured lipidic carriers.
Sintering Driven Void Formation in PS@WO3 Core-Shell Composites: A Photodegradation Enhancement Strategy
Background: Polystyrene nanospheres are used as a substrate for the hydrothermal coating of tungsten trioxide (WO3 ) to form a core-shell composite of PS@WO3 . The core-shell structure is used for the next sintering step. This produces porous WO3 . The focus of this study is on the role of porous WO3 in enhancing photocatalytic performance. Methods: The hydrothermal method was employed for coating and the surface morphology as well as the structural properties of WO3 -coated PS spheres were systematically investigated using SEM and XRD analyses. Additionally the sintering process was introduced to enhance the material by inducing rupture in the PS sphere core creating voids that significantly increased the material's surface area. Results: The evaluation of the effect of sintering temperature on photodegradation efficiency highlighted the crucial role of sintering temperature. Un-sintered and 300°C sintered WO3 both having a hexagonal crystalline structure exhibited superior degradation efficiencies compared to samples sintered at higher temperatures (400°C and 500°C). In particular the 300°C sintered WO3 outperformed its un-sintered counterpart despite identical crystalline structures. The performance of the PS@WO3 composite was assessed to determine the enhanced role of porous WO3 . The porous WO3 obtained in particular by the sintering of the core-shell PS@WO3 composites at 300°C showed a remarkable improvement in the degradation efficiency. These composite demonstrated over 95% efficiency within 10 minutes and achieved near complete (100%) degradation for a further 10 minutes surpassing the performance of pure WO3 . It is important to clarify that while the final product was predominantly WO3 after the sintering process the inclusion of PS served a critical purpose in creating voids during sintering. The PS@WO3 composite structure used as a resource for the preparation of porous WO3 even with a potentially reduced PS composition has been found to play a significant role in influencing the surface area of the material and consequently the photocatalytic performance. Conclusion: The study has highlighted the importance of crystalline structure and sintering conditions in optimizing the efficiency of photocatalytic materials. The porous WO3 obtained in particular by the sintering of the core-shell PS@WO3 composites at 300°C showed promising potential for applications under UV and visible LED light irradiation. These results provide valuable insights for the development of advanced photocatalytic materials with improved performance highlighting WO3 as the key contributor to the observed improvements.
Local Structure and Optical Studies of Mn2+ Doped L-histidine-4- nitrophenolate 4-nitrophenol Single Crystal
Background: The zero-field splitting parameters of Mn2+gt; doped L-histidine-4- nitrophenolate 4-nitrophenol single crystals are evaluated. Methods: The superposition model and perturbation theory are used to obtain zero-field splitting parameters for Mn2+ ion-doped LHPP single crystals. The optical spectra of the system are computed using the crystal field parameters from the superposition model as input into the crystal field analysis program. Results: The evaluated zero field splitting parameters are in good match with the experimental values when local distortion is taken into account. The experimental finding that the Mn2+ ion enters the L-histidine-4-nitrophenolate 4-nitrophenol lattice at the interstitial position is supported by the theoretical result. Conclusion: It is found that the calculated and experimental band positions agree fairly well. Thus the theoretical study supports the experimental observation.
A Fluorescent Probe for Hydrazine Based on 4-hydroxycoumarin with High Selectivity and Sensitivity
Background: Hydrazine may induce gene abnormalities cancer and severe damage to the liver lungs kidneys and central nervous system. Therefore the development of reliable analytical techniques with high selectivity and sensitivity to detect hydrazine is required for the protection of human health and safety. Objectives: Traditional methods for detecting N2H4 are frequently time-consuming less accurate and unsuitable for the analysis of living systems. Numerous fluorescent probes for hydrazine have been produced and gained some valuable results recently. The creation of a simple fluorescent probe for hydrazine detection is the goal of this project. Method: In this study 300 μL of probe 3-methyl-2-oxo-2H-chromen-7-yl propionate (MOCP) was mixed with an equivalent amount of the solution of each analyte to obtain the measurement solution. Following a 10-minute room temperature incubation period the fluorescence spectra of the resultant solution were recorded. Results: The fluorescence intensity of the probe was noticeably enhanced when N2H4 was added to the probe but almost no fluorescence enhancement was observed when other competitive ions were added. Conclusion: A hydrazine fluorescent probe based on 4-hydroxycoumarin fluorophore was developed. The probe MOCP displayed high sensitivity and selectivity for hydrazine with a color change from colourless to blue for detection by the naked eye. Moreover it demonstrated a low detection limit of 20 nM and a fast reaction time of 30 s.
In vitro Antioxidant Activity of 5-caffeoylquinic Acid and Ester Analogues
Background: Chlorogenic acid an ester of caffeic acid with quinic acid also known as 5- O-caffeoylquinic acid (5-CQA) is a ubiquitous plant constituent that is an important intermediate in lignin biosynthesis. In some cases it occurs at surprisingly high levels in the leaves and fruits of certain higher plants such as coffee beans. Due to its catechol moiety and an extended side chain conjugation it easily forms a resonance-stabilised phenoxy radical accounting for its powerful antioxidant potential. Objective: The objective of this work was to determine if the esterification and methylation of 5- CQA would enhance its antioxidant activity. Methods: Two 5-CQA derivatives were prepared for this study. Chlorogenic acid was esterified with methanol over Amberlite IR120-H to obtain methyl chlorogenate while methyl 3'4´-dimethyl chlorogenate was prepared from 5-CQA by treatment with diazomethane. Spectroscopic methods confirmed the structure of these derivatives. Their antioxidant properties were tested to establish a relationship between structure and antioxidant activity. Results: Antioxidant activity results were generated for 5-CQA and its ester analogues using eight different methods. Depending on the method applied results were expressed as IC50/MCE50 values or as equivalents of the applied standard (ascorbic acid and Trolox). Conclusion: In most of these tests 5-CQA showed the highest antioxidant activity compared to its derivatives. Nevertheless due to their hydrophobic characteristics their ester analogues remain promising antioxidant candidates in emulsifying systems.
A Polyacrylate Cotton-based Pipette Tip Micro-solid-phase Extraction Technique Coupled with High-performance Liquid Chromatography for Carvedilol Determination in Aqueous Media
gt;Introduction: In this work a polyacrylate polymer was synthesized into a pipette tip containing cotton fibers and used to extract carvedilol from water and urine samples. Methods: A high-performance liquid chromatography-ultraviolet detection method was developed which demonstrated the suitability of the purposed pipette tip micro-solid-phase extraction device. Factors affecting the fabrication procedure and polymer quality were studied and optimized. In the next step the sample preparation process (including extraction and desorption) was fully optimized and the optimized method was validated. Results: A coating with suitable mechanical and chemical stability was achieved. Its structure was successfully characterized by Fourier transform infrared spectroscopy and scanning electron microscopy. Within-batch and between-batch fabrication reproducibility were obtained at 3.0 and 9.0% respectively. The developed method displayed a limit of detection of 1.1 μg L-1 when 1.5 mL of sample was processed and it was linear in the concentration range of 3.3-350 μg L-1 with LLOQ of 5 μg L-1. The polyacrylate cotton-based pipette tip was finally used to extract carvedilol from aqueous media with acceptable recoveries of 92-106%. Conclusion: The proposed method is simple and fast and requires low sample volumes. In addition this method has been evaluated in terms of greenness with three different tools and the evaluation results with all three tools have shown that this method is one of the green and environmentally friendly methods.
An Efficient and Cost-effective Modified Carbon Paste Electrodes for Diltiazem Hydrochloride Determination in Tablets
This study presented new sensitive and selective modified carbon paste (MCPE) potentiometric sensors modified with different ion pairs for the determination of the antihypertensive drug diltiazem hydrochloride (DTM-HCl) in biological fluids pharmaceutical preparations and in its pure form.
Plasticizers ion pair type ion pair content response time temperature and pH were just a few of the experimental factors evaluated that were found to affect electrode efficiency. The two electrodes that show the best sensitivity were prepared by mixing diltiazem-tetraphenyl borate (DTM-TPB) ion pair graphite and TCP or o-NPOE as a plasticizer.
Over the concentration ranges of 1.0x10-5–1.0x10-2 the produced electrodes I and II demonstrated monovalent Nernstian responses of 55.7±0.902 and 57.6±0.451 mV decade-1. The selectivity property of the suggested electrodes was used to study the interference ions. The concentration of DTM-HCl in pharmaceutical formulations and biological fluids was measured using these modified electrodes. During the validation procedure metrics like linearity accuracy precision limit of detection limit of quantification and specificity were used.
The obtained results showed good agreement with the HPLC technique as indicated by the F and t-test values and can conclude the possibility of using this potentiometric method in the routine analysis of DTM-HCl.
Progress in the Development of Antifouling Electrochemical Biosensors
Electrochemical biosensors a subclass of biosensors consisting of a biosensing element and an electrochemical transducer have been widely used in various fields due to their excellent performance and portable device. However in complex actual samples non-specific adsorption of proteins and solid particles and adhesion of cells and bacteria will lead to problems such as reduced sensor sensitivity prolonged response time and expanded detection errors. Therefore constructing antifouling sensing platforms to effectively resist the bioadhesion of non-targets is crucial for the performance of biosensors. This study first introduces the commonly used classifications of electrochemical biosensors and their main contaminants. It also provides a comprehensive overview of the construction methods and application research of electrochemical antifouling sensors using different strategies including the construction of physical chemical and biological modification interfaces. In addition the research progress on antifouling and antibacterial dual-action coatings for electrochemical detection is also reviewed. Finally the challenges and future development trends of various methods are summarized providing clues for better practical applications of electrochemical biosensors.
Silica-Based 1,3-Diphenyl-1,3-Propanedione Composites: Efficient Uranium Capture for Environmental Remediation
Introduction: This study synthesizes and characterizes a novel hybrid composite SGdpm to capture UO22+ ions from water. The composite has successfully formed by hosting covalently diphenylmethane-13-dione (dpm) within an inorganic silica gel matrix showing promising potential for environmental remediation and nuclear waste management. Methods: The preparation involved the reaction of tetraethylorthosilicate (TEOS) with diphenylmethane- 13-dione (dpm) under acidic conditions resulting in white solids. The doped composite was characterized by Fourier Transform Infrared Spectroscopy (FTIR) revealing the presence of siloxane and Si-O-C bonds. The application of SG-dpm for capturing UO22+ ions from water was investigated showing a shift in FTIR peaks and confirming the formation of SG-dpm-UO22+ as inner-sphere complexes. Scanning Electron Microscopy (SEM) revealed a non-uniform distribution of particles essential for consistent behavior in applications such as adsorption. Results and Discussion: Batch sorption experiments demonstrated temperature-dependent sorption behavior with increased efficiency at higher temperatures (T = 55°C). The study also explored the influence of pH and initial concentration on UO22+ sorption revealing optimal conditions at pH 5 and lower initial concentrations (1.0 mg L-1). Kinetic studies using pseudo-second-order models indicated a high efficiency of UO22+ ion removal (99%) as a chemisorption process. Intraparticle diffusion models highlighted three distinct sorption stages. Sorption isotherm studies favored the Langmuir model emphasizing monolayer adsorption. The thermodynamic analysis suggested an endothermic (ΔH = + 16.120 kJ mol-1) and spontaneous (ΔG = −25.113 to − 29.2449 kJ mol-1) sorption process. Selectivity studies demonstrated high efficiency in capturing Cu2+ Co2+ and Cr3+ ions high degree selectivity of UO22+ ions (74%) moderate efficiency for Fe3+ and Zn2+ and lower efficiency for Pb2+ Ni2+ and Cd2+ and poor efficiency for Mn2+ ions. Conclusion: SG-dpm exhibits promising potential for selective UO22+ ion removal demonstrating favorable characteristics for various applications including environmental remediation and nuclear waste management.
Biosensor Based on Zif-8-905% Metal-organic Nanocomposite and Carbon Nanotubes Associated with Concanavalin a for Detection of Alpha-fetoprotein
Introduction: Lung carcinoma presents an aggressive evolution with its carriers having reduced survival. Late diagnosis is one of the main factors of death. In the neoplasia in question there is an established correlation with increases in Alpha-Fetoprotein (AFP) serum concentrations. Methods: Commonly used diagnostic methods are invasive or inaccessible. Therefore a low-cost non-invasive method would be extremely promising and biomarkers can be used to achieve this goal. Electrochemical biosensors are a promising approach for detecting analytes of clinical interest using innovative bioreceptors. In this work we obtained an electrochemical biosensor based on a hybrid ligand metal-organic structure (ZIF-8-905%) and functionalized carbon nanotubes (MWCNTs- COOH) in association with the lectin Concanavalin A (ConA) as a biorecognition element for detecting AFP in human serum from patients with lung carcinoma. Cyclic Voltammetry (CV) Square Wave Voltammetry (SWV) and Electrochemical Impedance Spectroscopy (EIS) were used to characterize the development of this biosensor. Microscopic analysis through Atomic Force Microscopy (AFM) revealed the formation of ConA-AFP complexes pointing out the sensor's ability to identify the target analyte. Results: The blocking electron transfer effect in the electrode-redox pair interface assessed AFP detection. The ZIF-8-905%/MWCNTs-COOH/ConA platform exhibited a limit of detection (LOD) of 7.98 ng/mL and a limit of quantification (LOQ) of 23.78ng/mL was also estimated. In addition the biosensor showed excellent selectivity towards interfering biomolecules. Conclusion: Therefore the biosensor represents an efficient form of detection contributing to research that aims to detect tumor biomarkers and ensure better prognoses.