Applications In Analytical Chemistry Research Articles

Unveiling the ion sensing capabailities of 'click' derived chalcone-tailored 1,2,3-triazolic isomers for Pb(ii) and Cu(ii) ions: DFT analysis.

In this study, two novel chalcone-derived 1,2,3-triazole-appended positional isomers (probe 6 and probe 9) were synthesized via the 'CuAAC' (Cu(i) - catalysed alkyne azide cycloaddition) methodology for the purpose of metal ion detection. The synthesized probes underwent characterization utilizing standard spectroscopic methodologies including FTIR, NMR (1H and 13C), and mass spectrometry. Subsequently, the sensing capabilities of these probes were explored using UV-Vis and fluorescence spectroscopy, wherein their selective recognition potential was established for Pb(ii) and Cu(ii), both of which can pose serious health hazards when prevalent in the environment above permissible limits. Both the probes exhibited fairly low limits of detection (LoD), determined as 5.69 μM and 6.55 μM in the case of probe 6 for Pb(ii) and Cu(ii) respectively; whereas the probe 9 exhibited an LoD of 5.06 μM and 7.52 μM for Pb(ii) and Cu(ii), respectively. The job's plot for the probe demonstrates the formation of a 1 : 1 complex between the metal and ligand. Furthermore, the interaction of the free probes with the metal ions in the metal-ligand complex was elucidated through 1H NMR analysis and validated theoretically using Density Functional Theory (DFT) simulations with the B3LYP/6-311G++(d,p) and B3LYP/LANL2DZ basis sets for geometry optimization of the probes and their corresponding metal complexes. These findings offer a reliable approach to Cu(ii) and Pb(ii) ion detection and can be further used for the potential applications in environmental monitoring and analytical chemistry.

Application of Quantum Chemical Reactivity Index Analysis—Synthesis and Mechanism of Lithium Dimethyl Sulfide

Application of Quantum Chemical Reactivity Index Analysis—Synthesis and Mechanism of Lithium Dimethyl Sulfide

Microfluidic programmable strategies for channels and flow.

This review summarizes programmable microfluidics, an advanced method for precise fluid control in microfluidic technology through microchannel design or liquid properties, referring to microvalves, micropumps, digital microfluidics, multiplexers, micromixers, slip-, and block-based configurations. Different microvalve types, including electrokinetic, hydraulic/pneumatic, pinch, phase-change and check valves, cater to diverse experimental needs. Programmable micropumps, such as passive and active micropumps, play a crucial role in achieving precise fluid control and automation. Due to their small size and high integration, microvalves and micropumps are widely used in medical devices and biological analysis. In addition, this review provides an in-depth exploration of the applications of digital microfluidics, multiplexed microfluidics, and mixer-based microfluidics in the manipulation of liquid movement, mixing, and splitting. These methodologies leverage the physical properties of liquids, such as capillary forces and dielectric forces, to achieve precise control over fluid dynamics. SlipChip technology, which branches into rotational SlipChip and translational SlipChip, controls fluid through sliding motion of the microchannel. On the other hand, innovative designs in microfluidic systems pursue better modularity, reconfigurability and ease of assembly. Different assembly strategies, from one-dimensional assembly blocks and two-dimensional Lego®-style blocks to three-dimensional reconfigurable modules, aim to enhance flexibility and accessibility. These technologies enhance user-friendliness and accessibility by offering integrated control systems, making them potentially usable outside of specialized technical labs. Microfluidic programmable strategies for channels and flow hold promising applications in biomedical research, chemical analysis and drug screening, providing theoretical and practical guidance for broader utilization in scientific research and practical applications.

Investigating the Spectral Response of Fiber Bragg Grating for Strain Sensor Applications

Abstract: The optical fibre sensor (OFS) has become quite well-known and prominent in the sensor technology industry. It is often used to react to outputs from other systems, like those in industrial, monitoring, and chemical analysis applications, and to detect changes in the environment. A Bragg reflector starts to grow and transmit all other wavelengths while a short section of optical fibre with a specific wavelength is reflected with light in a device called a Fibre Bragg Grating. The current study focuses on the evolving characteristics and behaviours of strain and temperature sensors operating on Fibre Bragg Gratings (FBG) through software modelling. This work's primary goal is to investigate the characteristics and behaviour of strain sensor that are used with fibre bragg gratings. A strain sensor can be used to determine the strain in an object whose resistance changes when force is applied.

Investigating The Spectral Response of Fiber Bragg Grating (FBG) for Temperature Sensor Applications

Abstract: In the field of sensor technology, the optical fibre sensor (OFS) has gained a lot of notoriety and prominence. It is frequently utilised to detect changes in the environment and react to outputs from other systems, such as those used in chemical analysis, industrial, and monitoring applications. A Fibre Bragg Grating (FBG) is a type of device in which a brief segment of optical fibre with a particular wavelength is reflected with light, while the Bragg reflector begins to grow and transmit all other wavelengths. The developing features and behaviours of temperature and strain sensors working on Fibre Bragg Grating using computer modelling are the focus of the current project. The main objective of this work is to examine the behaviour and properties of temperature sensors operating on Fibre Bragg Grating. The temperature sensor is utilised to measure and identify any temperature anomalies operating on the Fibre Bragg Grating that may cause mishaps or fires. This will reveal how temperature sensors may be demonstrated using Fibre Bragg Grating.

The role played by sensors consisting of smartphone and black box in analytical chemistry: Increase the achievability

In recent years, smartphone-based rapid detection methods have emerged and gained popularity among a wide range of researchers. Smartphone are favoured due to their integration of diverse functions such as photography, positioning, internet connectivity, and high-performance operating systems. The presence of a black box ensures the stable and improved conversion and transmission of optical and electrical signals, which is crucial for detection tasks carried out in environments where the ideal laboratory environment may not be feasible or guaranteed. The objective of this review is to elaborate on the application of chemical analysis based on the combined effect of smartphone and black box. Initially, we analyzed the design factors and fundamental functions of the black box. Subsequently, we provided a detailed description of the process involving the black box's integration with cuvettes, paper bases, and microtiter plates (MTPs) for presenting and transmitting light signals, which are then processed and calculated by the smartphone. We also presented the conversion and application of light signals generated by special reaction vessels and the generation of electrical signals at electrodes through the black box. Finally, we discussed the challenges and prospects associated with the combination of smartphone and black box assay models.

Two all-biomass cellulose/amino acid spherical nanoadsorbents based on a tri-aldehyde spherical nanocellulose II amino acid premodification platform for the efficient removal of Cr(VI) and Cu(II)

Adsorbents consisting of spherical nanoparticles exhibit superior adsorption performance and hence, have immense potential for various applications. In this study, a tri-aldehyde spherical nanoadsorbent premodification platform (CTNAP), which can be grafted with various amino acids, was synthesized from corn stalk. Subsequently, two all-biomass spherical nanoadsorbents, namely, cellulose/l-lysine (CTNAP-Lys) and cellulose/L-cysteine (CTNAP-Cys), were prepared. The morphologies as well as chemical and crystal structures of the two adsorbents were studied in detail. Notably, the synthesized adsorbents exhibited two important characteristics, namely, a spherical nanoparticle morphology and cellulose II crystal structure, which significantly enhanced their adsorption performance. The mechanism of the adsorption of Cr(VI) onto CTNAP-Lys and that of Cu(II) onto CTNAP-Cys were studied in detail, and the adsorption capacities were determined to be as high as 361.69 (Cr(VI)) and 252.38 mg/g (Cu(II)). Using the proposed strategy, it should be possible to prepare other all-biomass cellulose/amino acid spherical nanomaterials with high functional group density for adsorption, medical, catalytic, analytical chemistry, corrosion, and photochromic applications.

PUFFIN: A path-unifying feed-forward interfaced network for vapor pressure prediction

Accurate vapor pressure prediction is crucial for various applications, but obtaining precise measurements for certain compounds is resource- and labor-intensive. This challenge is amplified when a temperature-dependent relationship is required. To address this, we introduce PUFFIN (Path-Unifying Feed-Forward Interfaced Network), a machine learning approach that combines transfer learning with a specialized inductive bias node (inspired by the Antoine equation) to enhance vapor pressure prediction. PUFFIN outperforms alternative strategies that lack inductive bias or use generic compound descriptors by leveraging inductive bias and transfer learning using graph embeddings. The framework's incorporation of domain-specific knowledge overcomes data limitations and shows promise for broader chemical compound analysis applications, including the prediction of other physicochemical properties. An important aspect of our proposed approach is its partial interpretability, as the inductive Antoine node yields network-derived Antoine equation coefficients.

Flow injection analysis system with smart phone for the determination of total phenolic compounds in wastewater using Folin Ciocalteu reagent

Smart phones are playing a big role in daily life and are being employed as supporting hardware in a variety of chemical analysis applications. flow injection analysis method for the rapid, simple, and straightforward determination of total phenols using Folin-Cioclteu reagent .The sample or standard solutions were injection into a carrier stream to react with reagent and detected by spectrophotometer at 765 nm . The experimental conditions such as flow rate of reagent and carrier ,reagent volume ,length of reaction coil and concentration of reagent were optimized .A good linear calibration curve in the range of (250-2000 mg L-1 ) was obtained with regression equation ( y=0.0123 x + 0.1857) ,( R= 0.999 ), the limit of detection was in the amount of ( 0.0102 mg L-1) .The method was successfully applied for the determination of the total phenols in wastewater .

Ferrocene-Based Electrochemical Sensors for Cations

This study investigates novel ferrocene-based electrochemical sensors for metal cation detection via the design, synthesis and characterisation of ferrocene derivatives. Specifically, this research determines the redox potentials of ferrocene versus decamethylferrocene to provide insight into the redox potential variations. The investigation also examines how electrochemical oxidation of the ferrocene moiety can modulate host affinity for transition metal cations via effects such as electrostatic interactions and changes to coordination chemistry. Metal ion coordination to receptors containing functional groups like imine and quinoline is explored to elucidate selectivity mechanisms. These findings advance the fundamental understanding of ferrocene electrochemistry and host–guest interactions, supporting the development of improved cation sensors with optimised recognition properties, sensitivity and selectivity. Overall, this work lays the necessary groundwork for applications in analytical chemistry and sensor technologies via customised ferrocene-derived materials.

Development of three UV-spectroscopic methods for simultaneous estimation of raloxifene and aspirin in pharmaceutical dosage form: Whiteness and greenness assessment with application of ComplexGAPI, AGREE, and RGB

This study evaluates three spectrophotometric techniques for quantifying a binary combination of raloxifene and aspirin in terms of whiteness and greenness. Application of green and white analytical chemistry has gained widespread acceptance in the analytical community. The whiteness and greenness of the assessment were evaluated using three approaches: Complex green analytical procedure index, Analytical GREEnness calculator and Red Green Blue additive model. The technique (I) uses the simultaneous equation methodology for raloxifene at 285 nm and aspirin at 222 nm, respectively. Method (II) includes the area under the curve operating at (280–290) nm and (217–227) nm for raloxifene and aspirin, respectively. Method (III) operates using the first derivative method for raloxifene at 269 nm and aspirin at 216 nm. The linearity range was 2–14 µg/ml for three methods. P-Values were found satisfactory at a 95 % level of confidence. These techniques were intended for the binary mixture analysis in investigational formulations with high recoveries. The developed methods were validated according to ICH guidelines. These developed methods have been utilized in routine analysis to simultaneously determine raloxifene and aspirin without pre-extraction.

TMB+-mediated etching of urchin-like gold nanostructures for colorimetric sensing

The morphology-dependent localized surface plasmon resonance of gold nanostructures has been widely utilized for designing sensors. One method relies on the color change of gold nanoparticles upon etching. In previous work, TMB2+ oxidized from 3,3′,5,5′-tetramethylbenzidine (TMB) was found to etch gold nanorods (AuNRs), leading to a spectrum of different colors. However, the preparation of TMB2+ needs the addition of a strong acid and other harsh conditions. Herein, a new colorimetric biosensing platform was developed using urchin-like gold nanoparticles (AuNUs). Compared with AuNRs, the etching of AuNUs can happen under mild conditions by TMB+ at pH 6, protecting enzymes and proteins from denaturation. The role of CTAB surfactant was dissected, and its bromide ions were found to be involved in the etching process. Based on these observations, a one-step colorimetric detection of H2O2 was realized by using horseradish peroxidase and H2O2 to oxidize TMB. Within 30 min, this system achieved a detection limit of 80 nM H2O2. This work offered fundamental insights into the etching of anisotropic gold nanostructures and optimized the etching conditions. These advancements hold promise for broader applications in biosensing and analytical chemistry.

Broadband and strength-switchable circular dichroism in a Ge2Sb2Te5-based metasurface.

Circular dichroism (CD) is highly required in the applications of biological detection and analytical chemistry. In this paper, we achieved a giant, broadband, and strength-switchable CD effect in a quadruple z-shaped G e 2 S b 2 T e 5 (GST) metasurface. At the amorphous state of GST (a-GST), the giant CD reaches 0.92 and the width of the absorption >0.80 is about 100nm. The giant and broadband CD originates from polarization selective excitations of Mie resonances and the coupling between subunit resonators. With the transition from a-GST to crystalline GST, CD could be dynamically switched from 0.92 to 0.05. The GST-based metasurfaces with giant and wide-range switching CD will promote the development of active chiral devices.

Modulating covalent organic frameworks with accessible carboxyl to boost superior extraction of polar nitrobenzene compounds from matrix-complicated beverages.

The wide use and high polarity of nitrobenzene compounds (NBCs) have caused a concern for their residues in daily beverages. Herein, the covalent organic frameworks (COFs) with abundant carboxyl were ingeniously designed by introducing a novel modulator, and further developed as solid phase microextraction (SPME) coatings. Due to the enhanced polar interaction, the extraction efficiencies of modified COF for NBCs were sharply increased. After coupling the high-performance SPME fiber with gas chromatograph-mass spectrometry (GC-MS), an ultrasensitive analytical method was developed, with a wide linear range (0.50-5000ng/L), and low limits of detection (0.15-3.0ng/L). More importantly, the method was highly feasible and practical, leading to the precise determinations of trace NBCs from variously matrix-complicated samples. This work provides a viable and efficacious approach for the extraction and analysis of polar pollutants form complicated matrices, and is of great significance for mild COF modification and its extended applications in analytical chemistry.

Special Issue on the Application of Analytical Chemistry in Pharmaceutical and Biomedicine

Pharmaceutical and biomedical products that are developed for therapeutic use are either synthesized in the laboratory or naturally derived from living sources [...]

EUREST-RISE: An innovative networking and training project on European Tobacco Control

Abstract Aim and objective The world's leading contributor to avoidable illness and premature death is thought to be smoking and other tobacco use. An integrated set of research projects are suggested as part of EUREST-RISE to aid in the training of researchers in the analysis of tobacco product systems, their processes and functions, and the relationships between important design elements and their evaluation in user populations. Methods Currently in its first phase of execution, EUREST-RISE is a Marie Sklodowska Curie Action (MSCA) funded under Grant Agreement (Number:101008139). In the framework of particular research objectives addressed within tasks of each WP, interdisciplinary knowledge transfer will be achieved through the intersectoral secondment of researchers and their reintegration to their home institution. Results By offering a special framework for collaboration on joint research and innovation projects in three areas, EUREST-RISE expects to achieve its goal of developing a cohort of scholars with cutting-edge practical training in European tobacco product regulatory science. A) Exchange of information about the use of big data bases to address tobacco control concerns from a product-level or population-level viewpoint, including EU Common Entry Gate product-level data and European secondary population-based databases B) offer research and training on the application of sensory and chemical analyses for the evaluation of flavors in heated tobacco products, e-cigarettes, and tobacco products C) train researchers in advocacy activities and policy integration, facilitate training in peer to peer communication, and training on communication to media and the general public. Conclusions A network of excellence in European tobacco product regulation science is anticipated to be created via the EUREST-RISE initiative. Key messages • Conflicts of Interest: None. • Funding: The EUREST-RISE Project takes place with the financial support of the European Union, under a Grant Agreement (Number:101008139, PI: Dr Vardavas).

Photo-responsive droplet manipulation slippery lubricant-infused porous surface with ultra-high durability

Photo-responsive slippery lubricant-infused porous surface (SLIPS) for droplet manipulation is flexible, non-contact and non-destructive in droplet manipulation, which has promising applications in flexible robotics, microfluidics, biomedicine, and chemical analysis. However, the repeated manipulations for droplets of SLIPSs are quite limited in the works reported so far, the poor durability of droplet manipulation severely limits the practical application of the surfaces. In this paper, an Fe3O4-doped polydimethylsiloxane (PDMS)-based SLIPS is proposed and implemented to achieve ultra-high repeated droplet manipulation numbers under near-infrared ray (NIR) laser irradiation. Firstly, a micron columnar array structure with micro-pits on the top side, as well as, a wall structure out of the array is designed on SLIPS to reserve the lubricant. Secondly, the prototype of the SLIPS is fabricated by a 3-step ultraviolet (UV) lithography, and subsequently immersed in silicone oil for more than 96 h to obtain the ultra-high durability slippery lubricant-infused porous surface (UD-SLIPS). With a power of 25 mW–85 mW NIR laser, the repeated manipulation of microdroplets (≤ 5 μL) in the scale of 1 cm can exceed more than 3000 times which is far beyond that in previous reports. Finally, the droplet manipulation performance of this photo-responsive UD-SLIPS and the influence of infusion time on durability are investigated. The mechanism of the PDMS swelling effect is found to be the key factor in improving the droplet manipulation durability of SLIPS. The findings of this work would be of great significance for the development of highly durable photo-responsive functional surfaces for droplet manipulation.

Hydration structure and dynamics, ultraviolet–visible and fluorescence spectra of caffeine in ambient liquid water. A combined classical molecular dynamics and quantum chemical study

The hydration structure and related dynamics of caffeine diluted in ambient liquid water have been extensively studied by performing classical molecular dynamics simulations, using our previously developed potential model of caffeine and the TIP4P/2005 water model. The results obtained have revealed that the first hydration shell of caffeine contains on average 56 water molecules. Hydrated caffeine forms in total 3 hydrogen bonds with its neighbor water molecules, with the Ocaffeine … Hwater hydrogen bonds exhibiting similar lifetimes with the ones corresponding to Owater … Hwater hydrogen bonds in liquid water. The self-diffusion coefficient of caffeine has been found to be four times lower than the corresponding value for water, being also in agreement with recent experimental measurements. The presence of water molecules inside the solvation shell of caffeine changes significantly their low-frequency intermolecular vibrations, as reflected on the calculated atomic velocity time correlation functions and corresponding spectral densities. Using the estimated average intermolecular structure of the first hydration shell of caffeine, the molecular cluster caffeine@W56 was optimized via quantum chemical calculations and subsequently the time-dependent density functional theory was used in order to predict the ultraviolet–visible and fluorescence spectra of hydrated caffeine. The results obtained are in agreement with recent experimental studies, which have proposed that such spectroscopic measurements can be used for the direct determination of alkaloids in aqueous extracts of natural products. In this framework, multi-scale molecular modelling providing accurate predictions of experimental data could also be a very useful tool, linking theoretical physical chemistry with analytical chemistry applications.

Resonance Light-Scattering Correlation Spectroscopy and Its Application in Analytical Chemistry for Life Science.

Resonance light-scattering correlation spectroscopy (RLSCS) is a new single-particle detection method with its working principle being like fluorescence correlation spectroscopy (FCS). RLSCS is obtained by autocorrelation function analysis on the measured fluctuation of the resonance light scattering (RLS) intensity occurring within a subfemtoliter volume when a single nanoparticle (such as gold nanoparticles (NPs) or silver (SNPs)) freely diffuses through the volume. The RLSCS technique can detect such parameters as concentration, diffusion coefficient (translation and rotation), etc. Compared with the FCS technique, the correlated fluorescence intensity signal in RLSCS is replaced with the RLS signal of the nanoparticles, overcoming some limits of the fluorescent probes such as photobleaching under high-intensity or long-term illumination. In this Account, we showcase RLSCS methods, theoretical models at different optical configurations, and some key applications. First, the RLSCS optical detection system was constructed based on the confocal optics, its theoretical model was proposed, and the diffusion behaviors of the nanoparticles in the solution were studied including the rotational and translational diffusion. And, methods were developed to measure the concentration, size, aspect ratio, and size distribution of the NPs. Second, based on the RLSCS methods, some detection strategies were developed for homogeneous DNA detection, immunoassay, apoptosis assay, self-thermophoresis of the nanomotor, and quantitative assay in single living cells. Meanwhile, a new fluorescence/scattering cross-correlation spectroscopy (FSCCS) method was proposed for monitoring the molecule-particle interaction. This method enriched the conventional fluorescence/fluorescence cross-correlation spectroscopy (FCCS) method. Third, using the EMCCD with high sensitivity and rapid response as an optical detector, two temporospatially resolved scattering correlation spectroscopy methods and their theoretical models were developed: total internal reflection (TIR) configuration-based spatially resolved scattering correlation spectroscopy (SRSCS) and dark-field illumination-based scattering correlation spectroscopy (DFSCS). These methods extended single-spot confocal RLSCS to imaging RLSCS, which makes RLSCS have the ability for multiple channel detection with temporospatial resolution. The method was successfully used for investigating the dynamic behaviors of gold NPs in live cells and obtained its temporospatial concentration distribution and diffusion behaviors. The final section of this Account outlines future directions in the development of RLSCS.

Preparation of Reactive Indicator Papers Based on Silver-Containing Nanocomposites for the Analysis of Chloride Ions.

In recent decades, metal-containing nanocomposites have attracted considerable attention from researchers. In this work, for the first time, a detailed analysis of the preparation of reactive indicator papers (RIPs) based on silver-containing nanocomposites derived from silver fumarate was carried out. Thermolysis products are silver-containing nanocomposites containing silver nanoparticles uniformly distributed in a stabilizing carbon matrix. The study of the optical properties of silver-containing nanocomposites made it possible to outline the prospects for their application in chemical analysis. RIPs were made by impregnating a cellulose carrier with synthesized silver fumarate-derived nanocomposites, which change their color when interacting with chlorine vapor. This made it possible to propose a method for the determination of chloride ions with preliminary oxidation to molecular chlorine, which is then separated from the solution by gas extraction. The subsequent detection of the active zone of RIPs using colorimetry makes it possible to identify mathematical dependences of color coordinates on the concentration of chloride ions. The red (R) color coordinate in the RGB (red-green-blue) system was chosen as the most sensitive and promising analytical signal. Calibration plots of exponential and linear form and their equations are presented. The limit of detection is 0.036 mg/L, the limits of quantification are 0.15-2.4 mg/L, and the time of a single determination is 25 min. The prospects of the developed technique have been successfully shown in the example of the analysis of the natural waters of the Don River, pharmaceuticals, and food products.