Detection Of Trace Amounts Research Articles

Factors that Affect Quantification in Surface-Enhanced Raman Scattering.

Surface-enhanced Raman scattering (SERS) is an analytical technique capable of detecting trace amounts of specific species. The uniqueness of vibrational signatures is a major advantage of SERS. This combination of sensitivity and specificity has motivated researchers to develop diverse analytical methodologies leveraging SERS. However, even 50 years after its first observation, SERS is still perceived as an unreliable technique for quantification. This perception has precluded the application of SERS in laboratories that rely on consistent quantification (for regulatory purposes, for instance). In this review, we describe some of the aspects that lead to SERS intensity variations and how those challenges were addressed in the 50 years of the technique. The goal is to identify the sources of variations in SERS intensities and then demonstrate that, even with these pitfalls, the technique can be used for quantification when factors such as nature of the substrate, experimental conditions, sample preparation, surface chemistry, and data analysis are carefully considered and tailored for a particular application.

Hydrogen-Bond-Regulated Tb3+-Centered Emission in a ZnII-TbIII Heterometallic Compound for Water Sensing in Ethanol and Gasoline.

Luminescent lanthanide compounds stand out for their distinctive characteristics including narrow emission bands, substantial Stokes shifts, high quantum yields, and unique luminescent colors. However, Ln3+ is highly susceptible to vibrational quenching from X-H (X = O/N) high-energy oscillators in the embedded organic antenna, resulting in significant nonradiative energy dissipation of the 5D excited states of Ln3+. Herein, we introduce a strategy based on supramolecular interactions to modulate the nonradiative transitions in a new ZnII-TbIII heterometallic compound, [ZnTb(HL)2(NO3)Cl2]·2CH3CN·H2O (ZnTb), based on a phenyl-substituted pyrazolinone-modified salicylamide-imide ligand (H2L). The regulation mechanisms are explored in detail both experimentally and theoretically. With the N,N'-dimethylformamide (DMF)-boosted Tb3+ luminescence, ZnTb⊃DMF (1 mg of ZnTb + 2 mL of DMF) realizes a rapid (3s) and sensitive detection of water in DMF with a detection limit of 0.021%. Further, ZnTb⊃DMF can detect trace amounts of water in ethanol and ethanol gasoline with a low detection limit of 0.023% and 0.048%. In addition, portable paper strips of ZnTb⊃DMF are prepared to improve its practicability, which can afford real-time and faster (1 s) in situ visual sensing of trace amounts of water in common organic solvents and ethanol gasoline with sensitivity comparable to the titration results. This study provides a new idea for the lanthanide luminescence modulation and application in the field of fluorescence sensing.

Selection of High-Affinity and Selectivity AFB1 Circular Aptamer for Biosensor Application.

Detecting trace amounts of aflatoxin B1 (AFB1), one of the most toxic food contaminants, is crucial for efficiently preventing potential health risks. Circular aptamers are promising candidates for bioanalytical applications due to their enhanced biological and structural stability as well as their compatibility with rolling circle amplification (RCA). Herein, we employed a high-efficiency magnetic chain graphene oxide-based SELEX to generate circular aptamers that bind AFB1 with high affinity and selectivity. Notably, the selected circular aptamer, CAFB1-A-2, exhibited a significant sequence similarity to the classical AFB1 linear aptamer but demonstrated a distinct thermodynamic mechanism for binding. The binding of CAFB1-A-2 was driven by both enthalpy and entropy, whereas the classical linear aptamer exhibited a notable entropy loss that required a greater enthalpy compensation. Utilizing this circular aptamer, we developed a sensitive AFB1 detection system featuring an RCA-assisted allosteric DNAzyme biosensor with a detection limit (LOD) of 265 pM. Furthermore, the constructed aptasensor successfully detected AFB1 in spiked rice and corn, achieving LODs of 11 and 9 μg/kg, respectively, within approximately 4 h. This study provides a sensitive and reliable alternative to the development of an aptasensor for AFB1, holding great potential in the field of food safety detection.

Visual detection of kanamycin with functionalized Au nanoparticles.

A simple and rapid colorimetric detection strategy, based on hydrogen bond identification of 6-thioguanine (6-TG) functionalized Au nanoparticles (AuNPs), is proposed for highly selective and sensitive determinationof kanamycin (KA). In this strategy, the hydrogen bond interaction between 6-TG and kanamycin induces AuNPs to agglomerate, with a consequent color change of AuNPs from wine red to purple or even blue. The kanamycin concentrations can be quantified by employing UV-vis spectrophotometer. The results display that kanamycin concentrations (0.005 to 18µM) are linearly related to A620/A520 (the absorbance ratio of 620nm and 520nm) with a LOD of 1.8nM and a LOQ of 5.9nM (S/N = 3). This strategy also reveals a high degree of selectivity among a series of common interfering species. Moreover, the strategy can be employed to detect trace amounts of kanamycin in real-life samples, and it shows satisfying resultscompared with high performance liquid chromatography. In general, this developed strategy is facile and inexpensive without the need for complex processing procedures and expensive instruments. In addition, this work may further exploit detection strategies for other organic contaminants, as well as make a strong contribution to the development of the colorimetric method.

Trace detection of antibiotics in wastewater using tunable core-shell nanoparticles SERS substrate combined with machine learning algorithms.

Surface-enhanced Raman scattering (SERS) show great potential for rapid and highly sensitive detection of trace amounts of contamination from the environment in the surface aquatic ecosystem. The widespread use of antibiotics has resulted in serious degradation of the water environment in the past few years, and their substantial residual contamination of wastewater has a harmful effect on ecosystems, which is associated with the development of antibiotic-resistant bacterial strains. However, in this study, a novel approach of core-shell nanoparticles GNRs@1,4-BDT@Ag was used for the quantitative measurement of the concentration of antibiotics in wastewater solutions using the SERS technique coupled with computational methods. In our experiments, we selected commonly used antibiotics such as ciprofloxacin and levofloxacin in wastewater solutions. We then obtained SERS spectra for each antibiotic and its various combinations at varying concentrations. We combined it with machine learning algorithms to accurately identify and quantify the SERS spectra of the residual antibiotics in the system. Principal Component Analysis (PCA) and Orthogonal Partial Least Squares Discriminant Analysis (OPLS-DA) were subsequently employed for clustering analysis of the SERS spectral datasets. To evaluate the performance of machine learning algorithms five metrics were applied. The classification results demonstrate that while most algorithms achieved over 95% accuracy in antibiotics status prediction, the Support Vector Machine (SVM) model had the best performance, attaining a remarkable prediction accuracy of up to 99%. This developed approach helps as a simple and expeditious tool for the analysis of antibiotics in wastewater and exhibits potential for broader applications in various domains.

Silica nanoparticles surface-decorated with Au-Ag alloy nanoparticles as highly sensitive, reproducible, and stable surface-enhanced Raman scattering (SERS) substrates

The optical properties of metal nanoparticles (NPs) are heavily influenced by their structure and composition, making them useful in surface-enhanced Raman scattering (SERS) applications. In addition, metal-embedded silica NPs have excellent plasmonic characteristics and high reproducibility that further enhance SERS measurements. Although silica NPs have been encapsulated in various metals and alloys, practical applications require strong, stable, and reproducible optical signals. Herein, we synthesized Silica nanoparticles surface-decorated with Au-Ag alloy nanoparticles (SiO2@AuAg NPs) to perform as excellent SERS substrates. SiO2@AuAg NPs were synthesized by introducing seed Au NPs onto a spherical SiO2 NP core, followed by the addition of Au and Ag ions. From the NP characterization results, we also elucidate the growth mechanism for AuAg alloy NPs depending on the ratio of added Au to Ag ions. SiO2@AuAg NPs synthesized under optimized conditions exhibited a strong SERS signal with high stability, sensitivity, and reproducibility. Finally, SiO2@AuAg NPs successfully detected crystal violet (CV), thiram, and carbaryl at levels of 6.95 ×10-7M, 5.56 ×10-7M, and 7.14 ×10-6M, respectively, which are lower than the pesticide residue limits set by the U.S. Environmental Protection Agency (EPA). The detection reproducibility was also high, with an approximate relative standard deviation (RSD) of only 8.4% even after 3 days. The SERS substrate not only has high SERS activity and stability but can also be used to detect trace amounts of chemicals, enabling accurate SERS-based applications.

A Supramolecular-Quantum Dot System for Broad-Spectrum Detection of Fentanyl Analogs.

Synthetic opioids, especially fentanyl and its analogs, have created an epidemic of abuse andsignificantly increased overdose deaths in the United States. Current detection methods have drawbacks in their sensitivity, scalability, and portability that limit field-based application to promote public health and safety. The need to detect trace amounts of fentanyl in complex mixtures with other drugs or interferents, and the continued emergence of new fentanyl analogs, further complicates detection. Accordingly, there is an urgent need to develop convenient, rapid, and reliable sensors for fentanyl detection. In this study, a sensor is prepared based on competitive displacement of a fluorescent dye from the cavity of a supramolecular macrocycle, with subsequent fluorescence quenching from graphene quantum dots. This approach can detect and quantify small quantities of fentanyl along with 58 fentanyl analogs, including highly potent variants like carfentanil that are of increasing concern. Detection of these agents is possible even at 0.01 mol% in the presence of common interferents. This simple, rapid, reliable, sensitive, and cost-effective approach couples supramolecular capture with graphene quantum dot nanomaterial quenchers to create a tool with the potential to advance public health and safety in the context of field-based detection of drugs in the fentanyl class.

DNA-Assisted CRISPR-Cas12a Enhanced Fluorescent Assay for Protein Detection in Complicated Matrices.

Proteins are important biological macromolecules that perform a wide variety of functions in the cell and human body, and can serve as important biomarkers for early diagnosis and prognosis of human diseases as well as monitoring the effectiveness of disease treatment. Hence, sensitive and accurate detection of proteins in human biospecimens is imperative. However, at present, there is no ideal method available for the detection of proteins in clinical samples, many of which are present at ultralow (less than 1 pM) concentrations and in complicated matrices. Herein, we report an ultrasensitive and selective DNA-assisted CRISPR-Cas12a enhanced fluorescent assay (DACEA) for protein detection with detection limits reaching as low as attomolar concentrations. The high assay sensitivity was accomplished through the combined DNA barcode amplification (by using dual-functionalized AuNPs) and CRISPR analysis, while the high selectivity and high resistance to the matrix effects of our method were accomplished via the formation of protein-antibody sandwich structure and the specific recognition of Cas12a (under the guidance of crRNA) toward the designed target ssDNA. Given its ability to accurately and sensitively detect trace amounts of proteins in complicated matrices, the DACEA protein assay platform pioneered in this work has a potential application in routine protein biomarker testing.

Chromogenic Photonic Crystal Detectors for Monitoring Small Molecule Diffusion at Solid-Solid Interfaces Using Stimuli-Responsive Shape Memory Polymers.

In situ monitoring of small molecule diffusion at solid-solid interfaces is challenging, even with sophisticated equipment. Here, novel chromogenic photonic crystal detectors enabled by integrating bioinspired structural color with stimuli-responsive shape memory polymer (SMP) for detecting trace amounts of small molecule interfacial diffusion are reported. Colorless macroporous SMP membranes with deformed macropores can recover back to the "memorized" photonic crystal microstructures and the corresponding iridescent structural colors when triggered by diffused small molecules. Systematic experimental and theoretical investigations using various microscopes, optical spectroscopy and modeling, spatio-resolved energy-dispersive X-ray spectroscopy, and theoretical diffusion calculations confirm the diffusion-induced shape memory and chromogenic mechanisms. Importantly, proof-of-concept sensing of temporospatial-resolved diffusion of bioactive ingredients used in drug delivery, including anti-inflammatory methyl salicylate in pain relieving patches and vitamin E barriers loaded in contact lens, and phthalates plasticizers in commercial PVC products has been demonstrated. These innovative detectors are inexpensive, reusable, and easy to operate and deploy for both qualitative and quantitative analyses, promising for opening new avenues in biomedical research, threat detection, and monitoring of plastics, food, and environmental safety. Moreover, reconfigurable photonic crystals with micrometer-scale resolution, which are of great importance in tunable and integrated nanooptics, can be fabricated by diffusion-enabled microcontact printing.

MnO2 nanoparticles enhance the activity of the Zr-MOF matrix electrochemical sensor for efficiently identifying ultra-trace tetracycline residues in food.

Anovel nanobiosensor was constructed by in situ locating nanometer MnO2 particles with controllable size and morphology in a Zr-MOF substrate to serve as an electrochemical probe. The synergistic effect of the two components, Zr-MOFs with high specific surface area and compatibility as a carrier for MnO2, resulted in improved electrochemical activity and excellent electrochemical identification performance for the MnO2@Zr-MOF/GCE biosensor. Under optimized experimental conditions and using CV and DPV technology, the biosensor showed a wide linear detection range (2-200μM), a low detection limit (2.577 × 10-8M), a recovery range (106.26-115.01%), and maximum relative standard deviation (5.155) for tetracycline(TC) identification. The recognition mechanism of the sensor was investigated adopting Laviron adsorption theory. The applicability of the sensor was verified through practical measurements. Overall, the MnO2 @Zr-MOF/GCE sensor possesses the advantages of fast analysis speed, high sensitivity, high selectivity, and simple operation, making it suitable for detecting trace amounts of TC in food.

Au Ordered Array Substrate for Rapid Detection and Precise Identification of Etomidate in E-Liquid Through Surface-Enhanced Raman Spectroscopy.

Etomidate (ET), a medical anesthetic, is increasingly being incorporated into e-liquids for consumption and abuse as a new psychoactive substance (NPS), leading to significant social issues. In this work, large-area Au micro- and nano-structured ordered arrays were engineered as surface-enhanced Raman spectroscopy (SERS) substrates for fast detection and precise identification of ET and its metabolites. This ordered array, characterized by abundant electromagnetic enhancement hotspots and structural uniformity, imparts unique properties to the SERS substrate, including ultra-sensitivity, spectral signal reproducibility, and precise quantitative capabilities. Furthermore, it effectively mitigates interference from the complex matrix of e-liquids, facilitating the rapid detection of trace amounts of ET molecules. This SERS rapid detection technology can act as a preliminary screening method for gold-standard spectroscopic analysis, facilitating the on-site rapid screening of suspicious samples and thereby enabling efficient detection and precise verification.

Facile and in situ production of reduced graphene oxide nanosheets paste electrode via electrochemical exfoliation of carbon paste electrode for fabricating a VEGF165 tumor marker aptasensor

The sensitive detection of trace amounts of vascular endothelial growth factor (VEGF165) in samples holds significant potential for clinical cancer diagnosis across various cancer types. This work introduces a simple, quick, and economical electrochemical method for exfoliating a graphite paste electrode (CPE) to directly synthesize a reduced graphene oxide nanosheet paste electrode (r-GONPE) for the determination of VEGF165. Thionine (Th) was used as a redox probe due to its strong interaction with the graphene surface. The functionalization of r-GONPE by thionine improves its stability while preserving the intrinsic properties of r-GONPE. Au nanoparticles were electrodeposited on the r-GONPE/Th electrode to stabilize the SH-aptamer by self-assembly for selective interaction and to enhance the speed of electron transfer. FESEM images confirmed the formation of a fixed, stable, very thin, and large few-layer reduced graphene oxide nanosheet on the outer surface of the CPE. The surface area of the bare CPE increased significantly after electrochemical exfoliation of the surface graphite layers (from 0.059 cm2 for CPE to 0.281 cm2 for r-GONPE). Electrical characterization showed that the conversion of graphite to graphene resulted in a five-fold increase in peak height and a decrease in peak separation by nearly 30 mV. The selective interaction of the VEGF165 with the r-GONPE/Th/nano-Au electrode modified with SH-aptamer reduced the oxidation peak current of thionine in the DPV signal. Thus, a wide linear calibration ranges from 5.0 pM to 320 pM and a low LOD of 1.03 pM (using the 3σ/S equation) were obtained. The aptasensor demonstrated consistent stability and strong selectivity against typical interferences when detecting picomolar concentrations of VEGF165. It also showed high accuracy and speed in detecting VEGF165 in human serum samples. Additionally, this aptasensor is advantageous due to its cost-effectiveness and simple fabrication process compared to traditional methods that use complex nanocomposites for signal enhancement.

A label-free colorimetric aptasensor for sensitive detection of aflatoxin B1 in peanuts based on dual catalytic hairpin assembly

Aflatoxin B1 (AFB1) is considered one of the most toxic and carcinogenic substances. Developing sensitive and accurate methods for detecting AFB1 in foodstuffs remains a major challenge. Herein, a label-free colorimetric aptasensor was constructed for the detection of AFB1 in peanuts, utilizing dual catalytic hairpin assembly (CHA) for signal amplification. Where, the recognition of AFB1 by its aptamer (Apta) induces the formation of an Apta-AFB1 complex, causing the trigger chain (T) to release from the Apta-T complex. The released T triggers the first CHA reaction in the presence of hairpins H1, H2, and H3, producing H1-H2-H3 complexes. Each sticky end of these complexes serves as the initiating strand for the second CHA cycle, exposing a G-rich sequence from H5 that induces the formation of a G-quadruplex/hemin DNAzyme. This DNAzyme catalyzes the H2O2-mediated oxidation of 3,3′,5,5′-tetramethylbenzidine (TMB), resulting in a color change. Under optimal conditions, the colorimetric signal is linearly related to the logarithm of AFB1 concentration in the range of 50 pM to 1.1 nM, with a detection limit of 13.49 pM. The spiked recoveries for AFB1 in peanuts range from 95.28 % to 104.50 %. This aptasensor provides a sensitive and accurate method for detecting trace amounts of AFB1, which is crucial for ensuring food safety.

Ultrafast ppb-Level Detection of Nitro-Furan Based Antibiotics in Aqueous Medium by an Oxadiazole-Grafted Luminescent Sensor.

This work is primarily focused on the utilization of an oxadiazole grafted 2D luminescent metal-organic framework, {[Zn2(4-tpom)2(oxdz)2]⋅4H2O}n (1), in the detection of trace amounts of nitrofuran-based antibiotics such as nitrofurantoin (NFT) and nitrofurazone (NFZ) in aqueous medium. The π-electron rich moieties and the H-bond accepting sites in the dual linkers (4-tpom and oxdz2-) enable the framework to interact efficiently with NFT and NFZ exhibiting a turn-off fluorescence response with the respective KSV (6.55×104 M-1 and 4×104 M-1) and LOD (89 ppb and 78 ppb) values. Furthermore, the efficiency of 1 in sensing commercially sold antibiotic tablet, Martifur-100 (contains nitrofurantoin as an active ingredient), is demonstrated as an example with an LOD value of 277 ppb. Its multicycle reusability and the ultrafast response toward these antibiotics are also reported. The nature of quenching of 1 by NFT and NFZ has been investigated with experimental and theoretical considerations.

SBA-Pr-IS-MN-DM: a new fluorescent chemosensor for trace detection of silver in aqueous solutions

Initially, SBA-Propyl-Isatin-Malononitrile (SBA-Pr-IS-MN) was prepared by the reaction of SBA-Pr-Cl with IS-MN, which was synthesized by the reaction of isatin and malononitrile. This organic and inorganic hybrid material can be functionalized by the sequential reaction with dimedone to obtain the target product SBA-Pr-Is-MN-DM, which was investigated as a chemosensor by fluorescence spectroscopy to detect trace amount of Ag+ among several other cations in aqueous media.

Detection of micro- and nanoplastic particles in leafy green vegetables by SERS coupled with gold-silver core-shell nanoparticles.

Asensitive and accurate method has been developedfor detecting and quantifying polystyrene (PS) and polyethylene (PE) in food samples using surface-enhanced Raman spectroscopy (SERS) with a simple preparation process. Themethod is designed to effectively detect and quantify mixtures of these polymers in varying ratios within the food matrix. By employing gold-silver core-shell nanoparticles (Au@Ag NPs) as the enhancing substrate, the SERS method demonstrated superior sensitivity in detecting trace amounts of micro- and nanoplastic particles (MNPs). For 1-µm PS microparticles, the limit of detection (LOD) values range from 12 to 50 mg/L or mg/kg in water, spinach, and kale, while for 100-nm PS nanoparticles, the LOD values range from 18 to 47 mg/L or mg/kg. For 1-µm PE microparticles, the LOD values range from 173 to 416 mg/L or mg/kg in the same matrices, whereas for 65-nm PE nanoparticles, the values range from 446 to 744 mg/L or mg/kg. The mixtures of PS and PE in varying ratios were also tested, with both plastics detectable even at trace levels, emphasizing the method's precision in detecting plastic contaminants. These findings highlight the potential of SERS as a powerful tool for monitoring MNP contamination in food products by detecting both individual plastics and their mixtures, enabling precise quantification of contamination and contributing to improved food safety.

Enzyme-Assisted Solid-Phase Microextraction Coupled with a DNA Nanowalker for Dual-Amplified Detection of Chloramphenicol in Animal-Derived Food Products.

Chloramphenicol (CAP), an aminoalcohol antibiotic, exerts its action on bacterial ribosomes, thereby obstructing protein synthesis. However, the use of CAP in husbandry may lead to its excessive accumulation in animal-derived food products. This presents potential risks to consumer health. This study developed a novel dual-amplification fluorescence detection method by integrating enzyme-assisted solid-phase microextraction (SPME) with a Fe3O4@Au NP-based DNA nanowalker for the detection of CAP in food. The combination of a quartz rod-based SPME biosensor and DNA nanowalker effectively eliminated matrix interference, enabling the conversion of CAP and enhancement of detection signals through two cyclic amplification processes. The strategy demonstrated high sensitivity with a limit of detection of 28.1 aM as well as a wide linear range from 0.1 fM to 1 nM (with R2 > 0.99). This method also demonstrates robust stability and accuracy in detecting trace amounts of CAP in both authentic and prepared positive samples.

A real-time PCR assay for detecting trace amounts of kiwi (Apteryx spp.) DNA

A real-time PCR assay for detecting trace amounts of kiwi (Apteryx spp.) DNA

Additively manufactured microwave sensor for glucose level detection in saliva

In this paper, a novel realization of an ink-on-glass microwave sensor for biomedical applications is proposed. The Aerosol Jet Printing (AJP) technology is leveraged to implement a compact single-layer coplanar waveguide sensor featuring arc-shaped interdigital fingers that can accommodate a droplet of the Material-Under-Test (MUT). Such geometry provides a high sensitivity to even a very small deviation of MUT`s electrical properties when placed as a superstrate. An application towards the detection of trace amounts of glucose in saliva, which is a biomarker for diabetes, is showcased. The design and fabrication process of an exemplary sensor is discussed in detail. A circular geometry feature is introduced that helps a droplet to lie over the sensitive region due to wettability difference of glass substrate and silver ink. Sensor operating in K-band is developed providing a tradeoff between circuit size and droplet volume. The study is conducted for an artificial saliva requiring roughly a 0.5 µL droplet where changes in mixture content are proportional to relative changes of sensor`s transmission coefficient in a broad frequency range for occupied vs. empty states. The obtained results show that 10 mg of glucose per 100 ml of saliva can be easily distinguished in a frequency range of 20–30 GHz, whereas a monotonical change is visible for frequencies 20–26 GHz, which indicates the applicability of this sensor towards the detection of saliva-glucose levels and potential application in the detection of small amounts of other substances in liquids.

Preferential Stripping Analysis of Post-Transition Metals (In and Ga) at Bi/Hg Films Electroplated on Graphene-Functionalized Graphite Rods

In this study, we introduce a novel electrochemical sensor combining reduced graphene oxide (rGO) sheets with a bismuth–mercury (Bi/Hg) film, electroplated onto pencil graphite electrodes (PGEs) for the high-sensitivity detection of trace amounts of gallium (Ga3+) and indium (In3+) in water samples using square wave anodic stripping voltammetry (SWASV). The electrochemical modification of PGEs with rGO and bimetallic Bi/Hg films (ERGO-Bi/HgF-PGE) exhibited synergistic effects, enhancing the oxidation signals of Ga and In. Graphene oxide (GO) was accumulated onto PGEs and reduced through cyclic reduction. Key parameters influencing the electroanalytical performance, such as deposition potential, deposition time, and pH, were systematically optimized. The improved adsorption of Ga3+ and In3+ ions at the Bi/Hg films on the graphene-functionalized electrodes during the preconcentration step significantly enhanced sensitivity, achieving detection limits of 2.53 nmol L−1 for Ga3+ and 7.27 nmol L−1 for In3+. The preferential accumulation of each post-transition metal, used in transparent displays, to form fused alloys at Bi and Hg films, respectively, is highlighted. The sensor demonstrated effective quantification of Ga3+ and In3+ in tap water, with detection capabilities well below the USEPA guidelines. This study pioneers the use of bimetallic films to selectively and simultaneously detect the post-transition metals In3+ and Ga3+, highlighting the role of graphene functionalization in augmenting metal film accumulation on cost-effective graphite rods. Additionally, the combined synergistic effects of Bi/Hg and graphene functionalization have been explored for the first time, offering promising implications for environmental analysis and water quality monitoring.