Current Analytical Chemistry - Volume 21, Issue 8, 2025

Fossil fuels have been used extensively as primary energy sources, which has resulted in nearly depleted reserves, a contaminated environment, and a variety of negative health effects globally. Hydrogen has been proposed by researchers as an effective “carbon neutral” fuel. Large-scale hydrogen production through electrochemical water splitting necessitates the use of inexpensive, extremely effective, and earth-abundant electrocatalysts.

In this study, chitosan–sodium tripolyphosphate (TPP) nanoparticles are combined with CuO nanostructures to produce chitosan–TPP–CuO (CT/CuO) nanocomposite. Chitosan–TPP nanoparticles were first synthesized using the ionic gelation method. These nanoparticles were then extracted, and CuO was synthesized in situ in polymer nanoparticles using a simple chemical precipitation method. Chitosan and CuO are abundantly available and are environmentally beneficial materials. The porous structure and open channels within the chitosan polymer matrix host the CuO nanostructures, which promote electrolyte penetration, mass transport, and charge transfer, while the metal-oxide nanostructures act as catalytic centers. The structural and morphological properties of the CT/CuO nanocomposite were investigated using XRD, HRSEM, and HRTEM. The band gap and functional groups in the material were measured by UV–Vis DRS and FTIR methods, respectively. Elemental analysis was conducted utilizing EDS, HRSEM, and XPS. Thermal characteristics of the CT/CuO nanocomposite were investigated using TG-DTA and DSC methods. Electrochemical techniques were used to investigate the activities of HER and OER.

The XRD examination of the CT/CuO nanocomposite revealed semi-crystalline chitosan peaks and a monoclinic CuO structure. HRSEM and HRTEM pictures indicated that chitosan–TPP nanoparticles and CuO nanostructures were evenly spread and clustered to create a nanoparticulate matrix. UV–Vis DRS indicated that the CT/CuO nanocomposite had a direct band gap of 1.702 eV. The FTIR and XPS studies revealed the various bonds and oxidation states of the nanocomposite. Thermal analyses demonstrated that the inclusion of CuO increased the thermal stability of the CT/CuO nanocomposite. CT/CuO nanocomposite exhibited excellent OER and HER activity, requiring a low overpotential of 444 mV and 379 mV at 10 mA cm⁻² and -10 mA cm⁻², respectively.

Biopolymer metal-oxide nanocomposites could potentially be used as electrocatalysts in water splitting, energy conversion, storage devices, sensors, and several other fields.

The transmission of hantaviruses through rodents has been associated with the development of severe illnesses, including Cardiopulmonary Syndrome (CPS) and Hemorrhagic Fever with Renal Syndrome (HFRS). Environmental changes impacting rodent populations affect their global distribution. These are severe diseases, potentially lethal, and widespread, making them a public health issue.

Computational studies were conducted to better understand the envelope glycoproteins that are expressed by Hantavirus, which produce the cardiopulmonary syndrome and the hemorrhagic fever with renal syndrome.

The glycoprotein sequences were found through the utilization of specific computational tools, including the Intrinsic Disorder Predisposition (PIDP), Polarity Index Method Profile 3.0v (PIM 3.0v), and genomics software.

Examining the PIM 3.0v profile and the PIDP profile revealed distinct patterns in the envelope glycoproteins of different genotypes of Hantavirus. These patterns allowed for structural and morphological similarities to be identified. In particular, the PIM 3.0v profile shows that it is possible to discriminate between CPS and HFRS groups, and the PIDP profile shows the existence of an overlaid disorder profile of glycoproteins N and C from Hantavirus strains associated with CPS and HFRS.

Using the PIM 3.0v profile, our computer programs were able to identify isolates of Hantavirus envelope glycoproteins associated with cardiopulmonary syndrome and hemorrhagic fever with renal syndrome. We believe this research contributes to a deeper comprehension of these emerging viruses.

The present study aimed to investigate the prevalence of Salmonella sp. and Staphylococcus in seafood sample using multiplex polymerase chain reaction (mPCR). The thermostable nuclease (nuc) gene of Staphylococcus aureus and enterotoxin (stn) gene of Salmonella were used as target genes for mPCR detection.

In total, 10 seafood items, including fish, crabs, and prawns, which are generally available in Indian fish markets, were selected for the present study. Samples that carried both the strains Salmonella and Staphylococcus were selected for mPCR by targeting the stn and nuc genes.

Among 10 seafood samples collected, 7 of them carried Salmonella strain and 5 of them carried Staphylococcus strains. The results showed that 75% of the salmonella strains carried stn gene, and 75% of the Staphylococcus strains carried the nuc gene.

This study suggests that mPCR can be used for simultaneous detection by targeting the stn gene and nuc gene of salmonella and Staphylococcus food-borne pathogens in seafood.

Glycerol, sucrose, lactose, glucose, and fructose are important biomarkers in human sweat because their contents can reflect physiological status and health conditions. It is of high importance to determine them in sweat for health monitoring, disease diagnosis, physical training, etc.

The aim of this work is to develop a method based on capillary electrophoresis and amperometric detection for the simultaneous determination of glycerol and carbohydrates in sweat.

A capillary electrophoretic method based on pipette-tip-based detection electrodes and micro-injectors was developed for the simultaneous determination of glycerol, sucrose, lactose, glucose, and fructose in sweat samples.

Sweat samples diluted in the background electrolyte of 75 mM NaOH aqueous solution were electrokinetically introduced into a piece of separation capillary via pipette tip-based micro-injectors. Glycerol, sucrose, lactose, glucose, and fructose were determined by capillary electrophoresis in combination with a pipette-tip-based copper electrode.

At a DC voltage of 12 kV, the capillary electrophoretic separation of the five analytes could be achieved in less than 11 min in a piece of 40 cm long fused silica capillary containing 75 mM NaOH aqueous solution. Linearity was observed between the currents and concentrations, with the limits of detection ranging from 0.21 to 0.72 µM at a detection potential of 0.65 V. Glycerol, sucrose, lactose, glucose, and fructose in sweat samples were positively identified and accurately measured.

The method was successfully applied in the simultaneous determination of glycerol and carbohydrates in sweat samples with satisfactory assay results. It will find a wide range of applications in clinical diagnosis, health monitoring, and drug and food analysis.

Leishmaniasis is a disease caused by the Leishmania protozoa, with Cutaneous Leishmaniasis (CL) being the most common form of the illness. Paromomycin (PM) has recently garnered increased interest for its effectiveness against Leishmania, but it is hindered by limited efficacy, low oral bioavailability, and rapid clearance. As far as we know, there have been no studies examining the impact of nano lecithin-chitosan-containing paromomycin (Nano-PM) on CL. Therefore, the objective of the present study was to create Nano-PM and assess its effects on the promastigotes in vitro and on the lesions caused by Leishmania major in the BALB/c mice model in vivo.

The loading of PM into lecithin-chitosan nanoparticles was achieved using the ionic gelation method, and the resulting nanoparticles were characterized. The IC50 values for PM, Glucantim, and Nano-PM against promastigotes were determined after 24, 48, and 72 hours of treatment. The viability of promastigotes was assessed using the MTT assay. The Nano-PM formulation was administered local treatment to mice for a period of 28 days, during which lesion sizes were measured weekly. Furthermore, the parasite load in the infected mice was quantified using quantitative real-time polymerase chain reaction (qPCR).

IC50 of Nano-PM was significantly lower than Glucantim (p < 0.0001 after24 h incubation, p = 0.013 for 48h and p < 0.0001 for 72 h) and PM (p < 0.0001 after24 h, p = 0.003 for 48h and p < 0.0001 for 72h). All concentrations of Nano-PM had the highest toxicity on promastigotes in comparison with other groups after 24, 48, and 72 h treatment. Moreover, a significant reduction in the lesion size was found in the Nano-PM group in comparison with the control group after three (p = 0.0369) and four (p = 0.0009) weeks of treatment. More importantly, Nano-PM significantly reduced the parasite load compared to the control and the lecithin-chitosan groups (p = 0.001 for both).

Our findings showed that Nano-PM had lower toxicity (lower IC50) on promastigotes compared to Glucantim and PM. Moreover, Nano-PM treated mice showed reduced lesion size compared to the control group. Additionally, Nano-PM led to a significant decrease in parasite burden compared to the control group and the lecithin-chitosan group. Nevertheless, more complementary research is needed to approve our findings.

This study investigates the composition of tattoo pigments to ensure their safe application in tattoo art, evaluating the viability of UV-Vis and FT-IR spectroscopy, coupled with chemometrics, for predicting pigment contents in tattoo inks.

Analyzing pigments in tattoo inks poses challenges in maintaining quality. This study addresses the difficulties by proposing the use of UV-Vis and FT-IR spectroscopy, along with chemometrics, as potential solutions for effective monitoring.

The aim of this study was to determine the content of red (PR) 170/254 and pigment blue (PB) 15:3 in tattoo inks from diverse suppliers and examine the distinct chemical structures and existing impurities in the samples using UV-Vis and FT-IR spectroscopy, employing regression models for data analysis.

We collected UV-Vis and FT-IR spectra from the tattoo ink samples and utilized regression models for data analysis. We assessed correlations across spectrum areas, emphasizing coefficients of determination for cross-validation. Subsequently, we compare the results obtained from both spectroscopic methods in terms of pigment identity and evaluated the suitability of UV-Vis spectroscopy for analyzing changes in pigment concentration and structural evolution. Finally, we employed chemometric modeling to enhance predictions of FT-IR parameters, particularly in the functional group and fingerprint region of the spectra.

Significant correlations were observed across both UV-Vis and FT-IR spectrum areas, with coefficients of determination for cross-validation exceeding 0.7 for most parameters. Both spectroscopic methods yielded nearly identical results regarding pigment identity. UV-Vis spectroscopy proved to be a suitable method for analyzing changes in pigment concentration and structural evolution. Chemometric modeling enhanced predictions of FT-IR parameters, particularly in the functional group and fingerprint region of the spectra.

The study underscores the significance of utilizing UV-Vis and FT-IR wavelengths from various suppliers to determine pigment structures in tattoo inks. The consistent and comparable results from both spectroscopic methods highlight their efficacy in characterizing pigments. UV-Vis spectroscopy, in particular, emerged as a valuable tool for assessing changes in pigment concentration and structural evolution. The improved predictions through chemometric modeling further emphasize the utility of these analytical approaches in ensuring the safe use of tattoo inks in the art of tattooing.

The objective of this study is to develop a novel fluorometric aptasensor employing fluorescence resonance energy transfer (FRET) for the detection of Cadmium (II) (Cd²⁺) in water and food samples. The constructed aptasensor employed a fluorophore-quencher labeled aptamer combination not previously reported for Cd²⁺ detection. Additionally, its simple mix-and-detect pattern without immobilization or material-assisted steps represented an innovative design.

Utilizing 6-carboxyfluorescein (FAM)-modified aptamers and maleimide (BHQ-1)-modified aptamer complementary chain to construct a fluorescent detection probe, this aptasensor achieved a rapid, sensitive, and selective detection of Cd²⁺. Without Cd²⁺, the aptamer and its complementary strand undergo base pairing, bringing the FAM closer to the BHQ-1, and leading to FRET and a subsequent decrease in fluorescence intensity. The introduction of Cd²⁺ preferentially brought to the aptamer, changing its conformation and preventing the quenching of FAM by BHQ-1, thereby restoring the fluorescence intensity of the aptasensor.

Following optimization of experimental parameters, the aptasensor exhibited a linear response to Cd²⁺ concentrations ranging from 5 to 1200 nM, with a detection limit (LOD) of 0.43 nM. The aptasensor’s performance was unaffected by the presence of various ions, indicating its high specificity. Moreover, it could rapidly and accurately detect Cd²⁺ in water and food samples, including tap water, lake water, grapes, cabbage, and broccoli, demonstrating its substantial potential for practical application.

Therefore, the developed aptasensor represents an important tool for effective Cd²⁺ detection in water and food matrices, highlighting its potential as a critical tool for environmental monitoring and food safety.

Water quality assessment is a crucial task to manage water sources and control water pollution. The purpose of this study is to develop a Groundwater Quality Index (GWQI) to assess groundwater quality.

The GWQI was developed and functioned by weight (wi) and sub-index (qi) of ten selected water quality parameters. Principal Component Analysis (PCA) was applied to a water quality monitoring data set (year 2016 to 2019, 163 samples) at 27 locations in Quang Tri province, aiming to identify the weight of each parameter. Sub-index linear function was established based on the allowable limits for each parameter defined in the National Technical Regulation on drinking water quality. Multiplicate (GWQIM), additive (GWQIA), and reference (GWQIRef) formulas were used to compute the final GWQI indices. The sensitivity and suitability of the proposed GWQI in water quality evaluation were also tested.

Among the three GWQI calculation methods, GWQIM was found to be the most suitable in reflecting groundwater quality in the study area. From 2019 to 2022 (152 samples), in the province, 63.2% of GWQIM values were classified as EXCELLENT or GOOD, 17.1% as POOR, and 19.7% as VERY POOR, or UNFIT FOR DRINKING.

This improved GWQI can be applied to assess groundwater quality at local or regional scales.

Caffeine (CAF) is a widely used chemical in foods and pharmaceuticals that is consumed by a lot of people every day. Overconsumption of caffeine can lead to some undesirable symptoms. However, CAF is considered a crucial nervous system stimulant.

This study aimed to find an accurate and effective route for determining CAF using voltammetric techniques.

In this work, for the first time, a glycine (Gly) modified pencil graphite electrode (Gly/PGE) was used for the determination of CAF by square wave adsorptive stripping voltammetry (SWAdSV) technique.

The modification procedure of PGE by Gly in 100 mM sulfuric acid (H2SO4) was accomplished by performing the cyclic voltammetry (CV) technique for 10 cycles at a potential range of 0.8 to 1.8 V. Moreover, the characterization of Gly/PGE was done by applying the CV technique in aqueous and non-aqueous media and electrochemical impedance spectroscopy (EIS) in addition to scanning electron microscopy (SEM) technique. The movement type of CAF toward Gly/PGE was proven to be a diffusion-controlled process by conducting some measurements at different scan rates. The supporting electrolyte for the determination of CAF was studied, where 100 mM of H2SO4 provided the best result. Optimization of accumulation time, pulse size, and wave frequency were implemented and found to be 60 s accumulation time, 50 mV pulse size, and 25 Hz wave frequency. The stability of Gly/PGE was studied in different mediums, such as air, ultrapure water, and acetonitrile (CH3CN).

The determination of CAF under optimum conditions was within the linear concentration range of 0.1–75 µM, with a correlation coefficient of R² = 0.9990. The limit of detection (LOD) and limit of quantification (LOQ) were 0.070 and 0.231 µM, respectively.

An effective voltammetric methodology was suggested to determine CAF. This methodology has great promise to be applied in different matrices to determine CAF.

Milk, an essential part of diet is comprised of all indispensable nutrients. However, it proves to be beneficial only if it is available in its pure form.

The current study aimed to evaluate packaged milk samples collected from local markets of Karachi and to assess level of consumer awareness about health risks associated with substandard milk consumption.

Packaged milk samples were assessed collectively for physical parameters, and microbial load. Seventeen colour-based chemical tests were also conducted to detect different dyes, preservatives, and other added chemicals as adulterants in milk. A household-based community survey was conducted to evaluate consumer’s preferences regarding packaged milk consumption.

97% of tested milk samples were observed to have added solids and water in them. Chemical adulterants in tetra packaged milk were detected in order of Glucose > Cane sugar, Vegetable fat > Formalin, >Artificial colour > Neutralizer > Detergent >Urea, Annatto dye > Starch. For the household-based survey, a total of 266 respondents were interviewed. Although 61.7% of respondents preferred pasteurized milk, potential customer satisfaction with the quality of pasteurized milk was 74.4%. Multivariate analysis showed that customer satisfaction regarding pasteurized milk was significantly associated with the preference of customer [Odds Ratio (OR)=4.18, p=0.004], buying factors like price, offers, and discounts (OR=6.92, p=0.014), quality and availability (OR=4.81, p=0.003), and experienced negative health effects (OR=0.26, p=0.002).

The study concluded that more than 70% of the packaged milk samples were adulterated with detergents, artificial flavors and glucose which signify the compromised quality of the packaged milk and their products. Strict regular quality checks should be established and closely monitored by regulatory authorities and the government.

Nowadays, the challenge between clean water production and promoting an eco-friendly sorbent for the simultaneous fast and efficient removal of heavy metal ions is a hot topic and has attracted much attention.

The objective of this study was to fabricate a novel material (PATP@PET) by incorporating poly-(2-aminothiophenol; PATP) into the matrix of Saudi Arabian petroleum coke (PET) for simultaneous fast and efficient removal of heavy metal ions.

The FTIR, EDX, SEM, and XRD techniques assessed the chemical structure and surface morphology of the thio-functionalized petcoke. The effects of medium pH, mass dosage of sorbent, metal ion concentration, and coexisting ions were investigated and optimized using batch sorption.

The excellent sorption capacity of PATP@PET sorbent towards the divalent lead and cadmium ions (98.44% and 312.5 mg.g^-1 for Pb(II) and 90.15% and 217.4 mg.g^-1 for Cd(II)) was realized by strong complex formation with the sulfur atoms of green petcoke and the thiol groups of poly-2-aminothiophenol moieties. The adsorption equilibrium data was best fitted to the pseudo-second-order kinetic model and Langmuir adsorption isotherm. The reusability performance was tested for 10 cycles, and the simultaneous removal of Pb(II) and Cd(II) ions from industrial effluents was accomplished in 30 minutes with 100% removal efficiency at pH 6-7.

PATP@PET also demonstrated amazing performance for Cd(II) and Pb(II) removal in industrial wastewater samples. Subsequently, PATP@PET contributes to developing fast, efficient, low-cost water remediation solutions for heavy metal ions that can potentially be translated into industrial-scale applications.

Clematis tangutica, an indigenous medicinal herb native to the Qinghai-Tibet Plateau of China, has traditionally been associated with treating various inflammation-related diseases. While its therapeutic potential is recognized, a comprehensive characterization of its metabolite molecules and their anti-inflammatory properties has not been undertaken.

This study aimed to comprehensively profile the metabolite molecules of Clematis tangutica and identify potential anti-inflammatory active molecules using the Activity Labelled Molecular Networking (ALMN) approach.

The ALMN approach was employed to visually label activity to the feature-based molecular network, allowing for the profiling of potential anti-inflammatory active molecules in Clematis tangutica. Through correlating activity levels with the respective molecules, a detailed profiling was achieved.

Out of the 8,644 metabolite molecules in Clematis tangutica, ten were identified as the most potent anti-inflammatory molecules. Among these, Spiraeoside was notably annotated along with its structure.

This research successfully identified ten potent anti-inflammatory molecules from the vast metabolite profile of Clematis tangutica, including a detailed annotation of Spiraeoside. This marked a significant step in bridging traditional therapeutic knowledge with modern molecular profiling techniques.

Ganoderma lucidum, which is widely used as “Ganoderma” in China or other Asian countries (Japan, Korea, etc), exerts an important role in tonifying qi and calming the mind in clinical applications. Triterpenoids are the main active components in Ganoderma lucidum, with significant biological activities of hepatoprotective, anticancer, and anti-tumor, etc. However, the current analysis of triterpenoids in Ganoderma lucidum by mass spectrometry is limited, restricting its quality control and elucidation of its functional basis.

This work aimed to systematically characterize the triterpenoids in Ganoderma lucidum.

The Ganoderma lucidum powder was extracted by 50% ethanol/water and separated by Waters ACQUITY UPLC HSS T3 column (2.1 mm×100 mm, 1.8 μm). The data was obtained by Waters G2-Q-TOF mass spectrometry equipped with an electrospray ionization ion (ESI) source, and the MS data under positive and negative modes was acquired and analyzed.

A total of 43 triterpenoids were identified or tentatively characterized from the extracts of Ganoderma lucidum, including 32 known compounds and 11 potential new compounds. Among them, five triterpenoids were unambiguously identified by comparison with reference standards, including ganoderic acid A(28), ganoderic acid D(36), ganoderenic acid D(34), ganoderic acid F(43), and ganoderic acid G(16). The profiled triterpenoids could be divided into eight types according to the substituents at the C3, C7 and C15 positions of the parent structure. The mass fragmentation rules of Ganoderma lucidum triterpenoids were summarized. Under the positive ion mode, Ganoderma lucidum triterpenoids easily lost CH3 at the C10 position and H2O at C3, C7, and C15 positions, and the side chain bond at the C22(23) position was easily split. Under the negative ion mode, the split of the C and D rings was the characteristic feature.

The mass fragmentation behaviors of Ganoderma lucidum triterpenoids under positive ion mode were summarized and emphasized, and reliable scientific data and methods for systematic characterization of Ganoderma lucidum triterpenoids were also supplied.

Construction and Demolition Waste (CDW) constitutes a major portion of solid waste and presents a significant environmental challenge. This study aims to evaluate the transformation of CDW into a Recycled Aggregate (RA) as a sustainable strategy to mitigate environmental pollution.

The research assesses the mechanical properties and economic benefits of RA concrete, which is made by substituting natural aggregate with RA.

Results indicate that RA has lower density, higher water absorption, and reduced crushing strength compared to natural aggregates. However, RA concrete achieves optimal strength with a 40% replacement rate, marking a critical threshold for material efficiency. An economic analysis confirms the financial viability of using recycled concrete, indicating a favorable investment return. Advances in the research and application of RA suggest its expanding role in engineering applications.

A lifecycle assessment of carbon emissions from concrete production to site transportation was conducted. It revealed that the primary source of emissions in recycled concrete is the raw materials, accounting for about 85% of total emissions. This finding underscores the need to optimize raw material usage to enhance the sustainability of recycled concrete.

This research focuses on the valorization of lignocellulosic biomass in the form of activated carbon, which can be further utilized for adsorption studies. Presently, waste generated during cultivation, livestock production, and aquaculture is treated by conventional disposal methods like landfilling, open-field burning and composting, which leads to land contamination and air pollution. Moreover, a potential material like lignocellulosic biomass present in agricultural waste has not been utilized properly despite its many advantages.

Bio-based circular economy signifies the use of bio-based waste to produce value-added products, which will help in minimizing waste. In this research, activated carbon has been prepared from coconut shells by using two chemical agents such as H3PO4 and ZnCl2. The washed and dried coconut shells were activated in the temperature range of 600-900°C for 1 hr. The impregnation ratio of dried shells and activating agents taken was 1:1 to 1:3. The activated material was then washed and stored for further characterization and adsorption studies. All the obtained products were then compared to optimize the preparation conditions of temperature and ratio.

Experimental results revealed that, zinc chloride activation gives better results than phosphoric acid activation. Even though H3PO4 is also a good activator, it may cause corrosion of the equipment due to acid and alkali metal attacks. The optimized ratio of impregnation was found to be 1:1 with an activation temperature of 900°C.

These conditions of ratio discovered the mechanism of ZnCl2 activation. Zinc chloride activation allows the liquid activating agent to intercalate into the carbon matrix and also extends up to interlayers of carbon, which consequently produces pores at a temperature above its melting point. A high amount of activating agent increases the removal of light hydrocarbon and volatile matter due to collapsing of aliphatic and aromatic bonds, thereby causing weight loss.