Field Of Analytical Chemistry Research Articles

Evaluating the greenness, blueness, and whiteness of spectroscopic and UPLC techniques for the simultaneous measurement of anti-glaucoma drugs and the preservation agent

The pursuit of sustainable solutions is increasingly crucial in contemporary times. We propose inventive research that fulfills the criteria of whiteness and greenness in analytical chemistry. The endeavor aims to advance environmentally conscious techniques for the simultaneous detection of timolol maleate (TIM), dorzolamide HCl (DOR), and benzalkonium Cl (BNZ). The first method employed a sustainable mobile phase consisting of 0.02 M phosphate buffer: ethanol (68:32, v/v), and a flow rate of 0.6 mL/min with retention times 1.274, 1.798, and 2.483 min for DOR, TIM, and BNZ, respectively, with a UV detector at 210 nm. This methodology was easy, fast, and accurate. The approach showed low processing times, peak symmetry, and satisfactory resolution, with correlation values of 0.999. The linearity was between 0.001–0.064, 0.001–0.060 µg mL-1, and 0.001–0.050 µg mL-1for DOR, TIM, and BNZ, respectively. Furthermore, employing water as the solvent, complementary spectrophotometric methods such as Mean Centering of Ratio Spectra (MCR) and Successive Derivative Ratio Spectra (SRDS) were investigated as economical and environmentally friendly substitutes. All procedures demonstrated good linearity (r² > 0.9990), acceptable accuracy, and precision (RSD ≤ 2 %). Furthermore, by proving the superiority of the current work over previously published methods regarding sustainability, analytical performance, economics, and practicality, the real-world implementation of four greenness and whiteness algorithms boosts the approval and overall sustainable development of the proposed methods. The suggested techniques offer low-cost, environmentally friendly substitutes for traditional methods, advancing the field of analytical chemistry towards more sustainable practices and fostering a less destructive future for quality control.

Facile and Sustainable Electrostatic Integration of Eosin Y Dye for the Assay of the Atomoxetine Drug Through the Enhancement of the RRS Phenomenon.

The suggested study follows specific protocols to guarantee that the atomoxetine drug analysis approach is environmentally friendly and sustainable. A number of recently created methods were used as prospective evidence for environmental sustainability and applicability, which is an essential point to emphasize. The current study introduces a new and very unique technology using ultrasensitive spectrofluorimetry to identify the atomoxetine (AXT) medication. A one-step, one-pot, direct spectrofluorimetric technique was used in this study's methodology, which was determined to be effective and environmentally sustainable for the drug's evaluation and validation. When AXT and EY reagent were mixed in an acidic setting, a highly resonant Rayleigh scattering product was promptly generated. The application of fluorimetric analysis was built on a novel theory that the augmentation in dye response subsequent to the addition of AXT was directly correlated to the resultant complex's molecular mass, as determined at a wavelength of 365nm. The complexation progression caused a considerable rise in the molecular mass, from 292.82 (AXT+) to 983.68 (AXT-EY) g mol-1. The quantum yield for the coupled product was measured. The linearity was determined to be between 30 and 1500 ng mL-1, while the sensitivity values were found to be between 9.2 and 28.1 ng mL-1. Analyzing AXT-EY complexes allowed us to determine the best values for all of the system's adjustable parameters. The system showed adherence to International Council for Harmonization (ICH) criteria without difficulties. The recommended procedure was then evaluated for environmental friendliness using many current environmental safety metrics. Fortunately, the current analytical technique is also recognized as a white one by the WAC standards, which integrate functional and ecological features using the Green/Red/Blue (RGB 12) design. A novel instrument called BAGI was used to assess the feasibility of the proposed approach in the field of analytical chemistry.

Cyano-modified molecular cage silica gel stationary phase: Multi-functional chromatographic performance by high-performance liquid chromatography

This study successfully prepared different loading levels of cyano-functionalized RCC3 molecular cage silica gel stationary phase (RCC3-CN@SiO2) through aldehyde-amine condensation reaction and subsequent modification strategies. Fourier transform infrared spectroscopy, thermogravimetric analysis, nitrogen adsorption-desorption, and scanning electron microscopy confirmed the successful synthesis of RCC3-CN@SiO2 chromatographic stationary phase. The research demonstrates that due to hydrophobic/hydrophilic interactions, π-π interactions, hydrogen bonding, and size-selective porous structure, the stationary phase effectively separates moderately polar and weakly polar compounds in reversed-phase liquid chromatography (RPLC) mode, exhibiting hydrophobic selectivity comparable to the commercial DaisoC18-RP columns. Additionally, the tertiary amine and cyanogen groups on the molecular cage surface enhance the interaction with polar compounds, successfully separating nucleosides, sulfonamides, amino acids, and sugars in hydrophilic interaction chromatography (HILIC) mode. Further applications in the separation analysis of acidic drugs, alkaline drugs, cinnamic acid natural products, and chiral compounds demonstrate the multifunctional chromatographic capabilities for diverse compound types. Compared to Unitary Diol commercial columns, the prepared stationary phase showed significant advantages in wide polarity range separation performance. Moreover, through nucleoside compound separation mode switching analysis, RCC3-CN@SiO2 stationary phase further validates its favorable performance in both RPLC and HILIC modes, demonstrating extensive potential applications in the field of analytical chemistry. Importantly, the stationary phase exhibits efficient separation of nucleoside compounds in pure water systems, aligning with the principles of green analysis.

Saponin is Essential for the Isolation of Proteins and RNA from Biological Nanoparticles.

Extracellular vesicles (EVs), biomimetics, and other biological nanoparticles (BNs) produced from human cells are gaining increasing attention in the fields of molecular diagnostics and nanomedicine for the delivery of therapeutic cargo. In particular, BNs are considered prospective delivery vehicles for different biologics, including protein and RNA therapeutics. Moreover, EVs are widely used in molecular diagnostics for early detection of disease-associated proteins and RNA. Technical approaches for measuring biologics mostly originated from the field of EVs and were later adopted for other BNs, such as extracellular vesicle-mimetic nanovesicles, membrane nanoparticles (nanoghosts), and hybrid nanoparticles, with minimal modifications. Here, we demonstrate that BNs are highly resistant to protocols that severely underestimate the protein and RNA content of BNs, and provide the relevance of these data both for general BNs characterization and practical applications of CRISPR/Cas-based therapies. We demonstrate that the addition of saponin leads to an ∼2- to 7-fold enhancement in protein isolation and an ∼2- to 242-fold improvement in RNA recovery rates and detection efficiency. Differences in the proteolipid contents of BNs, measured by Raman and surface-enhanced Raman spectroscopy, correlate with their susceptibility to saponin treatment for cargo extraction. Finally, we develop a unified protocol using saponin to efficiently isolate proteins and RNA from the BNs. These data demonstrate that previously utilized protocols underestimate BN cargo contents and offer gold standard protocols that can be broadly adopted into the field of nanobiologics, molecular diagnostics, and analytical chemistry.

Eco-friendly solvents in liquid-liquid microextraction techniques for biological and environmental analysis: a critical review.

In recent years, green solvents have emerged as promising alternatives in the field of analytical chemistry, replacing conventional organic solvents known for their toxicity, volatility, and flammability. The combination of these solvents with liquid-liquid microextraction techniques has facilitated the development of simpler, faster, more economical, and environment-friendly methodologies for the analysis of samples of varying complexity. This review discusses the fundamental physicochemical properties and advantages of using deep eutectic solvents, ionic liquids, switchable-hydrophilicity solvents, supramolecular solvents, and surfactants as extractants. Furthermore, analytical methods based on liquid-liquid microextraction techniques developed in the last 5years for the determination of organic compounds and metals in biological and environmental samples are presented and discussed, highlighting their applications and benefits to improve analytical performance and sustainability.

Cardiovascular Drugs as Water Contaminants and Analytical Challenges in the Evaluation of Their Degradation

Cardiovascular drugs have been a burning topic in the field of environmental analytical chemistry in the last few decades. Growing modern healthcare has led to the widespread use of pharmaceuticals. Among these, antihypertensives (sartans, angiotensin-converting enzyme inhibitors) and lipid-regulating drugs (fibrates and statins) are the most frequently consumed and, thus, excreted into wastewater. Their chemical fate during conventional and advanced wastewater treatment, such as ozonation, remains unclear. Analytical chemistry, providing sample pretreatment followed by instrumental analysis, has a tremendous role in water treatment evaluation, mostly from the perspective of parent contaminants’ removals and also assessment of transformation pathways. Ultrasensitive liquid chromatography–mass spectrometry (LC-MS) systems provide many opportunities. By carefully using planned workflows for chromatographic and mass-spectrometric data processing, i.e., suspect and non-target screening approaches, LC-MS allows for the identification and structural elucidation of unknown, predicted, suspected or selected transformation products. Accordingly, some examples and case studies on selected cardiovascular drugs in this review are presented to show the applicability of the used analytical approaches and workflows.

Application of deep eutectic solvent based dispersive liquid–liquid microextraction method followed by HPLC-DAD for quantification of selected neonicotinoid pesticides in vegetable oils

The use of deep eutectic solvents (DES) as alternative green solvents in various analytical chemistry fields has garnered attention of researchers globally. Therefore, this study presents environmentally friendly DES for extraction of selected neonicotinoids (acetamiprid, imidacloprid, thiacloprid and thiamethoxam) prior to their determination using high-performance liquid chromatography- diode array detector (HPLC-DAD). The DES mixture that resulted in the highest extraction recoveries of neonicotinoids (NEOs) was choline chloride with ethylene glycol (CCl:EG) and nuclear magnetic resonance and Fourier transform infrared confirmed the successful synthesized CCl:EG. Thereafter, the CCl:EG was applied in dispersive liquid–liquid microextraction (DLLME) for the preconcentration and extraction of acetamiprid, imidacloprid, thiacloprid and thiamethoxam. The optimum factors affecting extraction efficiency of the DES-DLLME procedure were 0.8 mL (DES volume), 4.5 min (extraction time), 0.5 mL (eluent volume), 7 pH and 75 s (eluent time). The optimized DES-DLLME achieved limit of detection (LOD) and quantification (LOD) range of 0.4–4.95 ng.µL−1 and 1.43–9.70 ng.µL−1 respectively. Additionally, the extraction method achieved good accuracy (79.0–119.6 %), preconcentration factors (39.3–118), interday (0.61–1.62 %) and intraday (0.1–0.98 %) precisions. The greenness assessment of the proposed DES-DLLME method using AGREE, NEMI and AES tools revealed that the method was green. Finally, the developed DES-DLLME method was applied to real vegetable oils and the concentrations were below detection limits.

Advances in Anion Sensing Using Dipyrromethane‐Based Compounds

AbstractAnion sensing plays a crucial role in areas ranging from medical diagnostics to environmental monitoring. Dipyrromethane‐based compounds offer a versatile platform for developing colorimetric and fluorescent chemosensors, owing to their structural tunability and favorable optical properties. This review provides a concise overview of current advancements in anion sensing using dipyrromethane molecular framework. We examined the diverse strategies employed in designing dipyrromethane‐based anion sensors. Emphasis is placed on the structure‐function relationships that dictate anion affinity and selectivity. Key sensing mechanisms, including visual detection, UV‐vis studies, NMR studies, and fluorescence modulation, are explored. Finally, the synthetic routes for the synthesis of chemosensors are mentioned in detail. Given the efficiency and flexibility of dipyrromethane‐based sensor, we believe that major developments are to be expected in the field of both sensor and analytical chemistry.

Highly sensitive intensity-type polarization chiral sensor with reference light.

Optical rotation is a special phenomenon in which the plane of polarization of polarized light is rotated after passing through a chiral medium. This work first, to our knowledge, presents and optimizes a polarization chiral sensor with a reference light on the basis of a weak measurement light path. The influences of phase shift and polarization angle difference on sensitivity were theoretically optimized and verified experimentally. The introduction of a reference light further reduced the impact of light source fluctuations on the detection signal, improving the signal-to-noise ratio and reducing the optical rotation resolution to 2 × 10-5 rad. This method has the characteristics of low cost, high sensitivity, and real-time rapid detection, making it potentially applicable in the field of chemical analysis, such as chiral molecule detection.

Evaluation of an automatic sample preparer in the development and validation of an analytical method for vial wall sorptive extraction

Automation has transformed the field of analytical chemistry by enhancing efficiency and precision in laboratory processes. A crucial step in analytical workflows, sample preparation, has traditionally relied on manual techniques, leading to variability and inefficiency. Vial wall sorptive extraction (VWSE) is a promising alternative for automating and enhancing sample preparation in analytical processes. This study aims to evaluate the performance of automated VWSE in the analysis of alkanes (C10-C18) in aqueous phases and to explore its potential use in routine laboratory settings for analyzing contaminants in environmental analysis, quality control, and forensics. VWSE devices were developed and characterized, a chromatographic method was established, and the sample preparation process was automated using an automated liquid handling system. The devices manufactured exhibit the best overall response and low standard deviation. Statistical tests confirm the equivalence of the vials prepared. The developed method achieved good results in analytical validation, a wide linear range with a high coefficient of determination (R2 > 0.90), low limits of detection (0.01–1.02 ng mL−1), and low limits of quantification (0.05–1.05 ng mL−1) were achieved. The parameters repeatability (<26.91 %), recovery (91 to 116 %), and intermediate precision (<22.29 %) also achieved a good analytical performance. The developed automated VWSE method proves effective in quantifying alkanes and meets analytical method validation criteria. This research highlights the potential of automated VWSE for sample preparation in various analytical applications.

Validation of two LC[sbnd]HRMS methods for large-scale untargeted metabolomics of serum samples: Strategy to establish method fitness-for-purpose

Untargeted metabolomics by LCHRMS is a powerful tool to enhance our knowledge of pathophysiological processes. Whereas validation of a bioanalytical method is customary in most analytical chemistry fields, it is rarely performed for untargeted metabolomics. This study aimed to establish and validate an analytical platform for a long-term, clinical metabolomics study. Sample preparation was performed with an automated liquid handler and four analytical methods were developed and evaluated. The validation study spanned three batches with twelve runs using individual serum samples and various quality control samples. Data was acquired with untargeted acquisition and only metabolites identified at level 1 were evaluated. Validation parameters were set to evaluate key performance metrics relevant for the intended application: reproducibility, repeatability, stability, and identification selectivity, emphasizing dataset intrinsic variance. Concordance of semi-quantitative results between methods was evaluated to identify potential bias. Spearman rank correlation coefficients (rs) were calculated from individual serum samples. Of the four methods tested, two were selected for validation. A total of 47 and 55 metabolites (RPLC-ESI+- and HILIC-ESI−-HRMS, respectively) met specified validation criteria. Quality assurance involved system suitability testing, sample release, run release, and batch release. The median repeatability and within-run reproducibility as coefficient of variation% for metabolites that passed validation on RPLC-ESI+- and HILIC-ESI−-HRMS were 4.5 and 4.6, and 1.5 and 3.8, respectively. Metabolites that passed validation on RPLC-ESI+-HRMS had a median D-ratio of 1.91, and 89 % showed good signal intensity after ten-fold dilution. The corresponding numbers for metabolites with the HILIC-ESI−-HRMS method was 1.45 and 45 %, respectively. The rs median ({range}) for metabolites that passed validation on RPLC-ESI+- was 0.93 (N = 9 {0.69–0.98}) and on HILIC-ESI−-HRMS was 0.93 (N = 22 {0.55–1.00}). The validated methods proved fit-for-purpose and the laboratory thus demonstrated its capability to produce reliable results for a large-scale, untargeted metabolomics study. This validation not only bolsters the reliability of the assays but also significantly enhances the impact and credibility of the hypotheses generated from the studies. Therefore, this validation study serves as a benchmark in the documentation of untargeted metabolomics, potentially guiding future endeavors in the field.

A new strategy for volatile organics detection – Molecularly imprinted polymers-enabled headspace extracting and electrochemical sensing

The widely accepted method for detecting trace odor compounds such as 2-methylisoborneol (2-MIB) requires high-cost solid-phase microextraction coupled with gas chromatography-tandem mass spectrometry (SPME-GC/MS). As for now, cases that directly used SPME-GC/MS in the field are unseen, and most detection activities are still carried out in rigorous laboratory conditions. However, lengthy logistics and storage issues can compromise sample conditions, underscoring the significance of on-site detection methods. Here, we reported molecularly imprinted polymers-enabled headspace extracting and electrochemical sensing (MHEES) with the core feature of using the same piece of MIP for both headspace extracting and electrochemical sensing, allowing rapid on-site detection of trace 2-MIB in natural water bodies with a total cost of less than $2.10 per test. MHEES demonstrated exceptional sensitivity during extensively repeated laboratory experiments, achieving a detection limit of 3.7 ng∙L−1 and a standard deviation of 4.58 %. The practicality of MHEES was confirmed by conducting two rounds of on-site analyses on different reservoirs with fluctuating seasonal concentrations of 2-MIB. The developing flow of MHEES, from molecules docking to on-site application, was rigorous and could be cross-referenced to related research. The proposed MHEES design can potentially revolutionize the field of analytical chemistry by providing a versatile and affordable platform for on-site volatile compounds detection. It can readily adapt to various organic compounds and effectively address real-world challenges such as monitoring emerging pollutants, tracing disease biomarkers in body fluids, inspecting food safety, identifying chemical reaction intermediates, and supporting healthcare applications.

Evaluation of analytical greenness metric for an eco-friendly method developed through the integration of green chemistry and quality-by-design for the simultaneous determination of Nebivolol hydrochloride, Telmisartan, Valsartan, and Amlodipine besylate

In recent years, the field of analytical chemistry has witnessed a notable shift towards the adoption of greener chromatographic methods, aiming to minimize the environmental impact. An effective strategy involves substituting conventional harmful organic solvents with environmentally friendly alternatives, reducing the use of hazardous chemicals that contribute to environmental concerns. However, separating drug substances without the use of buffers and organic solvents presence is a big challenge. To overcome this challenge, a combination of quality-by-design (QbD) and green analytical chemistry (GAC) was employed in this study for method development. A high-performance liquid chromatography (HPLC) method was successfully developed and validated for the simultaneous determination of Nebivolol hydrochloride, Telmisartan, Valsartan, and Amlodipine besylate. The method utilized a mobile phase composed of a mixture of 0.1 % formic acid in water (pH: 2.5) and ethanol. A regular octadecyl silica (ODS) column was employed, and UV detection at 220 nm was utilized. The method exhibited linearity within the concentration range of 25–75 μg/mL for Telmisartan and 150–450 μg/mL for Nebivolol Hydrochloride, Valsartan, and Amlodipine besylate and the correlation coefficient was greater than 0.999 for all the analytes. Limits of detection (LOD) and quantification (LOQ) were determined as 0.01 and 0.04 μg/mL for Telmisartan, 0.06 and 0.20 μg/mL for Nebivolol Hydrochloride, 0.08 and 0.25 μg/mL for Amlodipine besylate, and 0.14 and 0.46 μg/mL for Valsartan, respectively. The developed method underwent thorough validation, encompassing various parameters such as linearity, accuracy, precision, LOD, LOQ, robustness, and ruggedness. The mean recovery values were observed to range between 98.86 % and 99.89 %. The accuracy demonstrated was consistently above 98.98 % for both intra-day and inter-day precisions were with the relative standard deviations less than 2 %. To establish its robustness, a quality-by-design-based experimental design (DoE) approach was implemented. Additionally, the method's environmental friendliness was evaluated using the Analytical Greenness metric (AGREE) an analytical eco scale, both confirming its alignment with sustainable practices and reduced ecological impact. The sustainability of the solvent used in the current study was evaluated by Green Solvents Selecting Tool (GSST) Further, the developed method greenness was evaluated with the green analytical tools such as Analytical method greenness score (AMGS) and using the recently released White Analytical Chemistry (WAC) using RGB assessment tool. By employing this greener approach to chromatography method, this study contributes to the ongoing efforts in analytical chemistry to promote sustainable practices and minimize the environmental footprint of analytical methods.

A molecularly imprinting photoelectrochemical sensor based on Bi2O2S-sensitized perovskite Cs2AgBiBr6 for sarcosine determination.

An original molecular imprinting photoelectrochemical (PEC) sensor for sarcosine detection based on stable lead-free inorganic halide double perovskite Cs2AgBiBr6 is proposed. Cs2AgBiBr6 as a lead-free halide perovskite material possesses severalpositive optoelectronic properties for PEC analysis, such as long-lived component to the charge-carrier lifetime, and strong absorption of visible light. At the same time, two-dimensional materials also offer excellent electronic and mechanical properties; thus, Bi2O2S was used and combined with Cs2AgBiBr6 to provide a stable and large photocurrent, which also benefits from the stability of perovskite Cs2AgBiBr6. Based on this novel PEC assay, the detection range for sarcosine was between 0.005 and 5000ng/mL with a low detection limit of 0.002ng/mL. This work also improved the adhibition of metal halide perovskite in analytical chemistry field, providing a novel way for other small molecule detection.

A green method for the preparation of carbon quantum dots from yellow lupin peel waste for spectrofluorometric determination of nirmatrelvir

The COVID-19 pandemic has highlighted the urgent need for effective antiviral agents. One such promising drug is nirmatrelvir (NIRMA), which has demonstrated the ability to inhibit viral replication and reduce hospitalization and mortality rates. In the field of analytical chemistry, carbon quantum dots (CQDs) derived from fruit peel waste have gained attention for their eco-friendly and cost-effective properties. In this study, CQDs were synthesized from the peel biomass waste of yellow lupin and utilized for the spectrofluorometric determination of NIRMA in pharmaceutical tablets. The proposed method offers simplicity and speed compared to existing methods. The synthesis process involved washing and grinding the peel waste, followed by heating in propylene glycol and purification using a dialysis membrane. The resulting CQD solution showed fluorescence at an emission wavelength of 411 nm upon excitation at 325 nm. The validation of the method, including linearity, range, limit of detection and quantification, accuracy, precision, and robustness, was conducted following ICH guidelines. The fluorescence intensities exhibited a linear relationship with increasing NIRMA concentration in the range of 15–150 µg/mL. The limit of detection found to be 4.0 μg/mL, with %relative standard deviations ≤ 1.46. This spectrofluorometric method represents a novel approach for the determination of NIRMA using CQDs derived from yellow lupin peel waste.

Honeycomb-like triazine-based conjugated microporous polymers exhibiting simultaneous and ultrasensitive detection of fifteen polycyclic aromatic hydrocarbons using solid-phase microextraction technique

BackgroundSince the severe hazard to the ecosystem and widespread distribution through biological and man-made ways of polycyclic aromatic hydrocarbons (PAHs), it is very urgent to establish the ultrasensitive analytical method to quantitatively and directly monitor PAHs in real samples. However, because of the complicated environmental matrix and their trace concentration, the pre-concentration process is a necessary step to analyze of these compounds. In this study, solid phase microextraction (SPME) technique was proposed to separate and enrich fifteen trace PAHs from environmental samples. ResultsIn this work, a honeycomb-like triazine-based conjugated microporous polymers (T-CMPs) were prepared by Yamamoto reaction and firstly used as SPME coating material for the ultrasensitive direct-immersion-SPME of PAHs prior to high performance liquid chromatography-fluorescence detector (HPLC-FLD). The synthesized T-CMPs was characterized using various spectroscopy and electron microscopy techniques. The unique porous network of T-CMPs might deliver abundant adsorption sites for PAHs. Orthogonal experimental design (OED) was used to investigate the influence of four experimental parameters on the enrichment ability. Under optimal situation, a wide linear range (which lasted from 0.003 to 1000 μg L−1) with the coefficients of determination (R2) varying 0.9981 to 0.9993 was obtained. The limits of detection (LODs) for the analytes varied from 0.001 to 1.650 μg L−1, and the limits of quantification (LOQs) were between 0.003 and 4.960 μg L−1. The proposed method was effectively employed to the simultaneous and ultrasensitive detection of fifteen PAHs in industrial wastewaters. The relative recoveries for PAHs analysis varied from 74.6 % to 105 % with the relative standard deviations (RSD) of 0.1 %–7.5 % in real water samples. SignificanceThe prepared SPME coating material exhibited a simultaneous, high extraction and adsorption capacity for fifteen PAHs due to its honeycomb-like porous structure, ultra-large specific surface area, strong π-π stacking, and hydrophobic interactions. The present research developed a novel strategy for the construction of SPME fiber coating composites and demonstrated great application potential in the field of sample pretreatment and environmental analytical chemistry.

P-EcStat: A Versatile Design of Photoelectrochemical and Electrochemical Sensing System with Smartphone Interface via Bluetooth Low Energy

Electrochemical and photoelectrochemical sensors are a rapidly developing field in analytical chemistry. However, commercial systems often lack versatility and affordability, hindering wider adoption. Additionally, the absence of integrated excitation light sources limits their application in photoelectrochemical sensing. Here, we present a highly precise, versatile, affordable measurement system for both electrochemical and photoelectrochemical sensing applications. The system incorporates a three-electrode potentiostat with a synchronized excitation light source. This design enables the system to perform conventional electrochemical measurements like cyclic voltammetry, chronoamperometry, and photoelectrochemical amperometric measurements with controlled light excitation. The developed measurement system operates within a voltage range suitable for a measurable current range of 1 nA to 18 mA, with a high precision of 99%. The excitation source is a monochromatic LED system offering seven distinct wavelengths with digitally controlled intensity via a digital-to-analog converter. Furthermore, an Android-based user interface allows wireless system control via Bluetooth Low Energy. The report also details the construction of a photoelectrochemical experiment using copper (II) oxide nanorods synthesized by the hydrothermal process as the photoactive material employed to test the experiment on a potassium ferricyanide/potassium ferrocyanide solution. This user-friendly system allows broader exploration of electrochemical and photoelectrochemical sensing applications.

Enhancing sensitivity towards electrochemical miRNA detection using an affordable paper-based strategy

In the era of liquid biopsy, microRNAs emerge as promising candidates for the early diagnosis and prognosis of cancer, offering valuable insights into the disease’s development. Among all the existing analytical approaches, even if traditional approaches such as the nucleic acid amplification ones have the advantages to be highly sensitive, they cannot be used at the point-of-care, while sensors might be poorly sensitive despite their portability. In order to improve the analytical performance of existing electroanalytical systems, we demonstrate how a simple chromatographic paper-based disk might be useful to rationally improve the sensitivity, depending on the number of preconcentration cycles. A paper-based electrochemical platform for miRNA detection has been developed by modifying a paper-based electrode with a methylene blue (MB)-modified single-stranded sequence (ssDNA) complementary to the chosen miRNA, namely miR-224 that is associated with lung cancer. A detection limit of ca. 0.6 nM has been obtained in spiked human serum samples. To further enhance the sensitivity, an external chromatographic wax-patterned paper-based disk has been adopted to preconcentrate the sample, and this has been demonstrated both in standard and in serum solutions. For each solution, three miR-224 levels have been preconcentrated, obtaining a satisfactory lowering detection limit of ca. 50 pM using a simple and sustainable procedure. This approach opens wide possibilities in the field of analytical and bioanalytical chemistry, being useful not only for electrochemistry but also for other architectures of detection and transduction.

Ratiometric fluorescence detection of tetracycline in milk and tap water with smartphone assistance for visual pH sensing using innovative dual-emissive phosphorus-doped carbon dots

Tetracycline (TC) is a common antibiotic that poses risks to human and animal health when present in samples. pH is a crucial parameter for assessing water quality and food safety. The innovative ratiometric probe, designed based on dual-emissive phosphorus-doped carbon dots (DE-P-CDs), was synthesized through a green hydrothermal process. The sensor exhibited high analytical performance toward TC detection with a LOD of 5.78 μM and 6.18 μM, respectively, and visual pH detection. Furthermore, the DE-P-CDs were employed for visual pH sensing, with the solution color smoothly changing with variations in pH. The color transitioned from red to orange, green to dark green, and blue to dark blue, facilitating easy visual observation. This probe proves to be a versatile tool for detecting TC in milk and tap water samples, with visual capabilities for pH. Two metric tools which were AGREE and BAGI were also used to evaluate the method's greenness. The evaluation affirmed its outstanding environmental friendliness. It represents a valuable contribution to the fields of analytical chemistry, food, and environmental monitoring.

Analytical Insights: Ce-Ms Unveiled

Hyphenated techniques in the field of analytical chemistry involve combining different analytical methods to enhance the analysis of samples. One common approach is to combine chromatographic techniques with spectroscopic techniques. This makes it possible to comprehend the component included in a mixture on a more thorough level. It contains the various techniques such as GC-MS, LC-MS, LC-NMR, CE-MS, and LC-IR etc. Overall hyphenated technique offer improved analysis of samples in terms of specificity, accuracy, and precisions by combining multiple analytical methods, scientists can obtain more comprehensive information about the components. Capillary electrophoresis-mass spectrometry (CE-MS) has emerged as a powerful analytical tool for the comprehensive analysis of complex biological samples. This review provides a comprehensive overview of the latest advances in sophisticated hyphenated analytical techniques within the realm of CE-MS. It highlights the synergistic combination of capillary electrophoresis with mass spectrometry, showcasing its applications in proteomics, metabolomics, pharmaceutical analysis, and clinical diagnostics.