Tap Water Samples Research Articles

Monitoring of tritium concentrations in tap water and rainwater collected in Thailand.

This study aimed to measure tritium (3H) concentrations in Thailand. Nationwide tap water samples were collected in July 2021. Rainwater samples were collected monthly during May-October 2020, April-October 2021, and February-March 2022 in Chonburi province and in Chiang Mai province during July-November 2021, January 2022, and March-June 2022. The measurements of 3H activity concentrations were conducted by Osaka Sangyo University (OSU) and were compared with measurements by the Thailand Institute of Nuclear Technology (TINT). The results from OSU and TINT showed that 3H concentrations in tap water were matched in the ranged from 0.08±0.03 to 0.28±0.04BqL-1, while those in rainwater samples collected from Chonburi province and Chiang Mai province are also matched in the ranged from 0.11±0.02 to 0.21±0.03BqL-1 and 0.19±0.02 to 0.57±0.04BqL-1, respectively. Our measured result suggests that 3H concentration in tap water and rainwater shows a similar relation depending on latitude.

Transforming Food Biowaste into Selective and Reusable Adsorbents for Pesticide Removal from Water

With growing concerns regarding environmental pollution and the need for sustainable waste management practices, this study investigates the potential of utilizing spent coffee grounds (SCG) as a precursor for producing functional carbon materials aimed at organophosphorus pesticide remediation under environmentally relevant conditions. Carbonization of SCG is followed by various activation methods, including treatment with potassium hydroxide, phosphoric acid, and carbon dioxide, individually or in combination. The resulting biochars are systematically analyzed for their adsorption performance towards malathion and chlorpyrifos. Screening tests revealed a selective adsorption preference towards aromatic chlorpyrifos over aliphatic malathion. Activation processes significantly influence adsorption kinetics and efficiency, with physical activation showing notable adsorption rates and capacity enhancements. Moreover, the SCG-derived biochars exhibit a pronounced dependency on adsorption temperature. Adsorption, regeneration, and reuse of the most promising material are tested in a real, spiked tap water sample, proving that the presence of ions in tap water did not affect the adsorption and that the material has the potential to be reused more than ten times. This work proposes a straightforward approach for recycling SCG by converting it into functional carbon materials, underscoring the importance of selecting the appropriate activation processes and conditions for practical applications in pesticide remediation.

The effect of water filter pitchers on the mineral concentration of tap water.

To investigate the effect of water filter pitchers on the concentration of different minerals in tap water. Nine water filter pitchers (A-I) were chosen based on consumer preferences and Amazon reviews. Each filter was tested for its ability to modify the concentrations of fluoride, calcium, magnesium, potassium, and sodium in tap water. Tap water samples were collected before and after filtration, at various intervals (1, 5, 10, 30, 50, 75, and 100 L) during filtration, and analyzed using an ion-specific electrode (fluoride) and atomic absorption spectrometry (other minerals). Statistical analyses were conducted to compare filtered and unfiltered water mineral concentrations. Water filter pitcher effect: Filters F (p < 0.001) and G (p = 0.030) decreased fluoride concentrations. All filters except I (p = 0.235) and H (p = 0.717) decreased calcium concentrations (p < 0.01). Filters E (p = 0.018), D (p = 0.014), and G (p = 0.010) decreased magnesium concentrations. Filters I (p = 0.028) and D (p = 0.009) increased potassium concentrations. Filter A (p = 0.002) increased sodium concentrations, while C (p = 0.034) decreased sodium concentrations. Effect of filter aging: All filters affected mineral concentrations over time but to varying extents. Filter G had the most pronounced effect on reducing mineral concentrations compared to all others. No filter was able to completely remove fluoride from tap water, contrary to the claims made by three manufacturers. The present study highlighted that water filter pitchers vary greatly in their ability to affect mineral concentrations in tap water during their use. Further research is needed to develop more effective water treatment solutions.

Silver Nanoparticles Formed Directly on a Screen-Printed Electrode/Graphene Oxide: A One-Step Electrochemical Synthesis and an Effective 2,4,6-Trichlorophenol Electrochemical Sensor

Abstract A graphene oxide/silver nanoparticles (GO/AgNPs) nanocomposite was synthesized directly onto a screen-printed electrode (SPE) using a one-step electrochemical synthesis process. The obtained result is that the SPE electrode was modified by AgNPs with an average diameter of 11.5 nm which distributed evenly on GO sheets. A 0.01 M AgNO3 solution dropped onto the SPE/GO electrode and a chronoamperometry (CA) method with a potential of −1.2 V and a time period of 10 seconds were the optimal synthesis conditions. Then, the SPE/GO/AgNPs electrode was applied in developing an electrochemical sensor to detect 2,4,6-trichlorophenol (2,4,6-TCP) using a square wave voltammetry method. A reasonable cost, a wide linear range (0.05–1.0 mM), a low detection limit (0.85 μM), a high repeatability, a good selectivity, a high durability, and especially, a rapid detection time (&lt; 1 minute) thanks to the ability to directly detect 2,4,6-TCP were the outstanding advantages of the fabricated electrochemical sensor. Moreover, the electrochemical sensor based on the SPE/GO/AgNPs electrode was also applied to detect 2,4,6-TCP in a tap water sample using a standard addition method.

Ni/N/MPC Nanocomposites Synthesized via Microwave-Assisted Biomass Conversion for Efficient H2O2 Detection

In order to improve the sensitivity and stability of the material for the detection of hydrogen peroxide, Ni/N/MPC nanocomposites were synthesized by Ni-based biomass doped with nitrogen. Nickel atoms offer such advantages as good catalytic activity and low cost, while nitrogen doping facilitates the formation of stable hybrid structures and the formation of abundant functional groups on the surface of nanocomposites. The linear equation characterizing the electrode response from the Ni/N/MPC nanocomposites was derived from the relationship between the current signal I and H2O2 concentration, demonstrating a linear range of 0.05–240.15 mmol l−1, along with a detection limit of 0.84 μmol l−1 (S/N = 3). In contrast, the electrochemical signals from Ni/NGCE and Ni/N/GCE sensors were significantly lower than those obtained from the composite materials during cyclic voltammetry testing. In practical sample analysis, the recovery rate and RSD of H2O2 in tap water samples were 97.2%–98.6% and 5.5%–6.4%, respectively. The Ni/N/MPC/GCE sensing platform presents excellent stability and enhanced sensitivity.

Novel quinoline-based chemosensor as specific fluorescence sensing of copper ions in cancer cells and for organelle-specific imaging application

This work reports a simple synthesis of a quinoline-based organic molecule, (E)-N′-((6-methoxy-2-oxo-1,2-dihydroquinolin-3-yl)methylene) picolinohydrazide (PHMQ), and its ability to distinguish Cu2+ ion. Through the use of spectroscopic and photometric titration techniques, PHMQ’s selectivity toward various cations and anions was examined. In just two minutes, PHMQ showed fast detection of Cu2+ ions, and clear spectral fluctuations proposed persistent PHMQ-Cu2+ complex formation. The calculated emission quenching constant (1.46 × 105 L/mol) and binding constant (1.25 × 104 L/mol) values suggested that strong emission quenching occurs between the PHMQ and Cu2+ ions. A linear reduction in fluorescence response was noted for Cu2+ ions concentrations between 2–26 μM, with a detection limit of 43.4 nM. Job’s plot, ESI-mass, NMR titration experiments, and density functional theory (DFT) simulations established a 1:1 stoichiometry for the PHMQ-Cu2+ complex. Additionally, PHMQ was efficaciously utilized to quantify Cu2+ ions in drinking and tap water samples and HeLa cells, illustrating durable cellular penetrability and a fluorescence ’Turn-Off’ response to Cu2+ ions. This sensor also established usefulness in mitochondrial-targeted imaging. For the detection of Cu2+ ions in biological and environmental environments, PHMQ is a promising detector due to its high sensitivity, selectivity, and quick response.

Novel amino-functionalized MOF-based sensor for zinc ion detection in water and blood serum samples

Aquatic systems with low zinc levels can experience a significant decrease in carbon dioxide uptake and limited growth of phytoplankton species. In this study, we describe the use of a new fluorescent sensor based on NH2-MIL-53(Al), and modified with glutaraldehyde and sulfadoxine, for selectively detecting zinc ions in water and blood serum samples. Characterization of the synthesized material was performed using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), Brunauer–Emmett–Teller (BET) surface area analysis, X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM), confirming successful functionalization and preservation of the MOF structure. The sensor’s performance for Zn2+ detection was evaluated by spectrofluorometry, demonstrating a significant fluorescence enhancement upon Zn2+ binding due to the interaction between Zn2+ ions and the sulfonamide groups. With a detection limit as low as 3.14 × 10–2 ppm, the sensor demonstrates high selectivity for Zn2+ over other common metal ions. The sensor’s response is rapid, stable, and reproducible, making it suitable for practical applications. Real sample analysis was conducted in tap water and blood serum samples, with the results compared to those obtained using ICP-OES and a colorimetric test with 5-bromo-PAPS. The comparison confirmed the high accuracy and reliability of the fluorescent sensor in detecting Zn2+ ions in complex matrices. NH2-MIL-53(Al) modified with glutaraldehyde and sulfadoxine shows potential as a selective fluorescent sensor for Zn2+ detection, making it a valuable tool for monitoring the environment and biology.

Novel 3D plate-like g-C3N4/BiOCl heterojunction as a highly efficient photocatalyst for the degradation of carbofuran in wastewater under visible light irradiation

The g-C3N4/BiOCl (gCN-BCl) heterojunction photocatalyst was synthesized using a low-temperature precipitation method for effective photocatalytic degradation of carbofuran (CBF). All gCN-BCl composites demonstrate greater efficacy in removing CBF compared to its individual constituents. The synergistic effect of incorporating the 0D structured BiOCl onto the 2D structured g-C3N4 was comprehensively examined using various microscopic, X-ray, and spectroscopic analytical techniques. Additionally, optical and photoelectrochemical analyses were conducted. The findings validated that the interaction between the two semiconductors at the heterointerfaces enhanced remarkable physical and structural stability, promoted high charge separation and transfer properties, and improved photocatalytic degradation. Under optimal conditions, 5-gCN-BCl (0.25 g/L) achieved a CBF (5 mg/L) removal efficiency of 95.7 % under visible light irradiation of 120 min, achieving 3.1- and 5.9-times higher degradation rate than the pure BiOCl and g-C3N4, respectively. The radical trapping experiments indicated that the h+ and •O2− were the primary reactive species involved in the CBF degradation. Furthermore, the potential toxicity of CBF and its intermediates was assessed, revealing that the photocatalytic degradation process significantly lowered the ecotoxicity of pesticide wastewater. The potency of 5-gCN-BCl was also evaluated in tap water and real wastewater samples, with CBF degradation efficiencies of 85.8 %, 47.6 %, and 38.7 % in tap water, municipal, and pesticide industry wastewater, respectively. Additionally, artificial neural network (ANN) modeling was employed to predict and optimize the photocatalytic degradation process, providing further insights into the system’s performance. The outcomes of this work offer valuable insights into the development of heterojunction photocatalysts with superior stability and efficacy for eliminating pesticides from water bodies.

Highly efficient Z-scheme CeO2/Bi2MoO6 heterojunction strengthened by redox mediator for photoelectrochemical detection of tetracycline with enhanced sensitivity

Accurate monitoring of antibiotics that pose risks to the environment and human health is essential. The photoelectrochemical system has emerged as a rapid and precise method for detecting environmental pollutants. However, current photoelectrochemical materials made of semiconductors face challenges due to poor photoelectric conversion efficiency. In this study, a Z-scheme CeO2/Bi2MoO6 heterojunction structure was successfully prepared by a cost-effective hydrothermal method. By leveraging built-in electric field and the Ce3+/Ce4+ redox mediator, this heterojunction achieved high photoelectrochemical conversion efficiency and functioned effectively as a sensor for tetracycline (TCH). The designed sensor demonstrated two linear ranges of 0.05–100 nM and 100–300 nM with an ultra-low detection limit of 15.4 pM for TCH. Additionally, the sensor exhibited excellent selectivity and high stability, demonstrating its potential for TCH detection in tap-water and milk samples. This study presents a simple and reliable method for the practical detection of antibiotic residues in environmental and food samples.

Green and Mild Fabrication of Magnetic Poly(trithiocyanuric acid) Polymers for Rapid and Selective Separation of Mercury(II) Ions in Aqueous Samples.

The removal and detection of highly toxic mercury(II) ions (Hg2+) in water used daily is essential for human health and monitoring environmental pollution. Efficient porous organic polymers (POPs) can provide a strong adsorption capacity toward heavy metal ions, although the complex synthetic process and inconvenient phase separation steps limit their application. Hence, a combination of POPs and magnetic nanomaterials was proposed and a new magnetic porous organic polymer adsorbent was fabricated by a green and mild redox reaction in the aqueous phase with trithiocyanuric acid (TA) and its sodium salts acting as reductive monomers and iodine acting as an oxidant. In the preparation steps, no additional harmful organic solvent is required and the byproducts of sodium iodine are generally considered to be non-toxic. The resulting magnetic poly(trithiocyanuric acid) polymers (MPTAPs) are highly porous, have large surface areas, are rich in sulfhydryl groups and show easy magnetic separation ability. The experimental results show that MPTAPs exhibit good adsorption affinity toward Hg2+ with high selectivity, rapid adsorption kinetics (10 min), a large adsorption capacity (211 mg g-1) and wide adsorption applicability under various pH environments (pH 2~8). Additionally, MPTAPs can be reused for up to 10 cycles, and the magnetic separation step of MPTAPs is fast and convenient, reducing energy consumption compared to centrifugation and filtration steps required for non-magnetic adsorbents. These results demonstrate the promising capability of MPTAPs as superior adsorbents for effective adsorption and separation of Hg2+. Based on this, the prepared MPTAPs were adopted as magnetic solid-phase extraction (MSPE) materials for isolation of trace Hg2+ from aqueous samples. Under optimized conditions, the extraction and quantification of trace Hg2+ in water samples were accomplished using inductively coupled plasma mass spectrometry (ICP-MS) detection after MSPE procedures. The proposed MPTAPs-based MSPE-ICP-MS method is efficient, rapid, sensitive and selective for the determination of trace Hg2+, and was successfully employed for the accurate analysis of trace Hg2+ in tap water, wastewater, lake water and river water samples.

Portable Detection of Copper Ion Using Personal Glucose Meter.

A simple and sensitive method for Cu2+ detection was developed using the Cu+-catalyzed alkyne-azide cycloaddition reaction, Fe3O4 magnetic nanoparticles (MNPs) as the reaction platform, and a portable blood glucose meter (PGM) as the detection method. Gold nanoparticles (AuNPs) were labeled with glucose oxidase (GOx) and alkyne-functionalized, terminally thiolated ssDNA (C2). In the presence of Cu2+ and ascorbate, the functionalized AuNPs were captured onto MNPs modified with azide-functionalized ssDNA (C1) via the Cu+-catalyzed alkyne-azide cycloaddition reaction. The GOx on the AuNPs' surface oxidized glucose (Glu) into gluconic acid and H2O2, reducing the Glu content in the reaction solution, which was quantitatively detected by the PGM. Under optimal conditions, the PGM response of the system showed a good linear relationship with the logarithm of Cu2+ concentration in the range of 0.05 to 10.00 μmol/L, with a detection limit of 0.03 μmol/L (3σ). In actual tap water samples, the spiked recovery rate of Cu2+ was between 92.30% and 113.33%, and the relative standard deviation was between 0.14% and 0.34%, meeting the detection requirements for Cu2+ in real water samples.

A Novel Methylene Blue Indicator-Based Aptasensor for Rapid Detection of Pseudomonas aeruginosa.

Pseudomonas aeruginosa is a significant opportunistic pathogen highly prevalent in the environment, requiring early detection methods to prevent infections in vulnerable individuals. The most specific aptamer for P. aeruginosa, F23, has been used for the development of various assays and sensors for early diagnosis and monitoring. In this study, a novel F23-based electrochemical aptasensor was designed using disposal gold screen-printed electrodes (Au-SPEs) with high reproducibility. Methylene blue (MB) was used as an exogenous indicator, which significantly amplified the electrochemical signal and improved the sensitivity of detection. The aptasensor explored a limit of detection (LOD) of 8 CFU·mL-1 and high selectivity for P. aeruginosa over other interfering bacteria. Furthermore, it showed potential to detect P. aeruginosa in tap water samples, offering a point-of-care tool for rapidly controlling the growth of this bacterium in various applications.

Low-cost portable sensor for rapid and sensitive detection of Pb2+ ions using capacitance sensing integrated with microfluidic enrichment.

Lead ion (Pb2+) pollution is a critical global issue due to its ability to accumulate in the human body, resulting in severe health problems. Despite extensive research efforts devoted to the detection of Pb2+ contamination, practical, rapid, and field-deployable sensors for Pb2+ is yet to be developed to effectively safeguard the environment and public health. Herein, a label-free affinity-based sensing device is developed based on printed circuit board (PCB) for low-cost, easy-to-use, and real-time on-site detection of Pb2+ ions. The sensors are prepared by forming a self-assembled monolayer of glutathione (GSH) on the surface of gold-plated PCB electrodes, which serves as a molecular probe to recognize Pb2+. Rapid and sensitive detection is achieved by using capacitance sensing integrated with microfluidic enrichment. The sensor's interfacial capacitance is used to indicate specific binding, while the capacitance reading process simultaneously induces alternating current electrothermal (ACET) acceleration of analyte's travel towards the probes. Thus, the enrichment and detection are integrated into a single step, making pre-concentration unnecessary and shortening the assay time to 30s. This Pb2+ sensor has demonstrated one of the lowest limits of detection reported so far (1.85 fM) with a linear range of 0.01-10pM. To evaluate the sensor's specificity, non-target metal ions are tested, all showing negligible responses. Testing of tap water sample also yields reasonable results, validating the sensor's robustness. The above-mentioned features, together with a commercial portable readout, make this sensor well-suited for point-of-use Pb2+ detection at low cost.

Ion-chromatographic determination of common anions in drinking water in some regions of the Republic of Armenia

The present study investigated the anion composition of drinking water from various cities and villages in Armenia, including spring water and tap water samples. The simultaneous separation was achieved for fluoride, chloride, bromide, nitrite, nitrate, sulfate, and phosphate anions with the correlation coefficients &amp;gt;0.998. Validation of the method was carried out in accordance with the requirements of guidelines in terms of selectivity, specificity, system suitability, linearity, accuracy, precision, lower limits of detection and quantitation, robustness, and stability. The method was suitable for routine drinking water quality assessment in line with the national or World Health Organization (WHO) regulations. The validated method was further used to analyze drinking water samples from different regions of Armenia. The observed concentrations for the anions in drinking water complied with the WHO limits for drinking water with some exceptions. The test method can be submitted to quality control laboratories as a convenient and practical tool for routine analysis and monitoring studies.

A three-components-based disposable electrochemical sensor for the detection of heavy metal ions in water

The development of an efficient sensor based on a novel three-components nanocomposite is presented for the detection of heavy metal ions (Cd2+ and Pb2+) in water. For the preparation of three-components nanocomposite surface, the polydopamine reduced graphene oxide (PyDA/RGO) composite was initially prepared by a one-step polymerization of dopamine (DA) on RGO followed by surface modification of the prepared composite with cysteine (Cys). The formation of three-components nanocomposite surface (i.e., Cys/PyDA/RGO) was initially confirmed through physical characterization techniques, including X-ray diffraction and infrared spectroscopy, whereas scanning electron microscopy revealed the surface morphology after each step of sensor fabrication. The electrochemical properties of the sensing platform were evaluated through electrochemical techniques, including cyclic voltammetry and electrochemical impedance spectroscopy with an external ferri‐−/ferrocyanide redox probe. The prepared three-components nanocomposite on disposable pencil graphite electrode (Cys/PyDA/RGO/PGE) showed an improved charge transfer rate as compared to PyDA/RGO/PGE and bare PGE electrode. Targeted heavy metal ions were detected on the sensor surface using differential pulse voltammetry with greater sensitivity, showing detection limits of 0.77 and 1.13 ppb for Cd+2 and Pb+2 ions in citrate buffer solution, respectively. The sensor demonstrated comparable performance in the tap water samples.

Novel polycyclic "turn-on" and "turn-off" pyrazoline and pyrazole fluorescent sensors for selective real-world monitoring of Fe3+/Fe2+ in aqueous environments.

Seven novel polycyclic pyrazoline and pyrazole sensors were synthesised and screened for useful photophysical properties with pyrazoline 2 and pyrazole 7, displaying an Fe3+ "turn-off" response in aqueous environments with Fe3+ limits of detection (LoD) of 2.12 μM and 3.41 μM, respectively. Both 2 and 7 sensors functioned in aqueous environments with real-world examples of Fe3+ detection in tap water and mineral water samples. 2 and 7 are suitable for the detection of Fe3+ at concentrations below the maximum iron limits for drinking water set by the Environmental Protection Agency (EPA) and European Union (EU).

Persistence of Helicobacter Pylori Coccoid Forms in Different Environments

Objective: The present study aims to determine the possibility of H. pylori coccoid forms to survive in our surrounding environments, thus exhibiting public health hazard. Method: Helicobacter pylori strain Makkah 7 accession number HQ622108, was inoculated in samples of soil, well, tap, swimming pool, and sewage water; in which, an average initial inoculum of 107 CFU/ml was inoculated. The experiment was conducted, outdoor where ambient temperature varied between 39-55°C in Jeddah city, Saudi Arabia. The survival rate of H. pylori strain was quantitatively and qualitatively studied for five months. Results: Viable counts were undetectable after 24 hours, while total count varied between 107 to 106, and declined to 103 bacterial cell/ml five months later. Interestingly, microscopic examination revealed few non-motile rods and motile coccoid forms. All samples were removed and placed at 4°C for one month. Following, total count, morphology, and motility were examined, showing motile coccoid forms. Electron microscopic and, molecular studies were carried out, confirming that the species is H. pylori, which was detected by using 16S rRNA primer for H. pylori with a product size of 163 bp. The ability of H. pylori strain to persist and survive, by being motile in the coccoid form, for five months under such hostile environment, strongly indicates that the coccoid form plays a vital role in the transmission, recrudescence, and therapeutic failure. It is indeed a hazardous and a crucial infectious phase of this bacterium. Conclusion: Detecting coccoid forms in water and soil, accompanied by their eradication, must be seriously considered and applied. Consequently, hindering and preventing different diseases caused by H. pylori.

Multivariate statistical analysis as a tool for monitoring drinking water sources in an Atlantic Rainforest Conservation Unit.

Water quality monitoring is paramount in identifying and mitigating pollution sources, protecting aquatic ecosystems, and ensuring safe water for human and wildlife consumption. This study is aimed at evaluating the quality of drinking water sources in three communities located in a Sustainable Use Conservation Unit in the municipality of Mangaratiba, Rio de Janeiro, Brazil, employing a multivariate statistical analysis. A total of 161 water samples were collected from January to December 2022, encompassing 32 surface water and 129 tap water samples. Physicochemical parameters were determined in situ employing a Horiba U50 multiparameter probe. The samples were stored and transported at 4°C to the laboratory for microbiological analyses concerning total coliforms and Escherichia coli using a commercial enzymatic test. All samples contained coliforms, while E. coli were detected in 87% of the samples. The multivariate analysis indicated that the microbiological water quality in sampling region R2 was influenced by rainy periods and that, in general, the water quality within R3 was the most affected by the transport of solids to the water sources. The statistical methods applied herein aided in characterizing the study areas and detecting points of attention regarding physicochemical and microbiological parameters that significantly influence the water quality of each sampling point. Representative points for each study region were identified and may be employed for future monitoring and prevention actions.

One-step detection of nanoplastics in aquatic environments using a portable SERS chessboard substrate

Nanoplastics present a significant hazard to both the environment and human health. However, the development of rapid and sensitive analysis techniques for nanoplastics is limited by their small size, lack of specificity, and low concentrations. In this study, a surface-enhanced Raman scattering (SERS) chessboard substrate was introduced as a multi-channel platform for the pre-concentration and detection of nanoplastics, achieved by polydomain aggregating silver nanoparticles (PASN) on a hydrophilic and a punched hydrophobic PVDF combined filter membrane. Through a straightforward suction filtration process, nanoplastics were captured by the PASN gap in a single step for subsequent SERS detection, while excess moisture was promptly eliminated from the filter membrane. The PASN-based SERS chessboard substrate, benefiting from the enhanced electromagnetic (EM) field, effectively discriminated polystyrene (PS) nanoplastics ranging in size from 30 nm to 1000 nm. Furthermore, this substrate demonstrated favorable repeatability (RSD of 8.6 %), high sensitivity with a detection limit of 0.001 mg/mL for 100 nm of PS nanoplastics, and broad linear detection ranges spanning from 0.001 to 0.5 mg/mL (R2 = 0.9916). Additionally, the SERS chessboard substrate enabled quantitative analysis of nanoplastics spiked in tap and lake water samples. Notably, the entire pre-concentration and detection procedure required only 3 μL of sample and could be completed within 1 min. With the accessibility of portable detection instruments and the ability to prepare substrates on demand, the PASN-based SERS chessboard substrate is anticipated to facilitate the establishment of a comprehensive global nanoplastics map.

Biomass Carbon Dots as Fluorescent Probes for Fast and Highly Selective Detection of Fe3 + in Water Media.

In this study, a novel fluorescent probe for the rapid and highly selective detection of Fe3 + based on biomass carbon dots (b-CDs) was developed. The b-CDs were obtained via one-step hydrothermal synthesis by utilizing laurel fallen leaves. And the as-synthesized b-CDs were applied for sensing Fe3+ based on fluorescence (FL) quenching effect both in water and phosphate buffer solution (PBS) with a wide linear range from 1 µM to 300 µM, the detection limits (LODs) respectively to be 0.34 µM in water and 0.48 µM in PBS solution. The FL intensity of b-CDs was quenched fleetly within 1min after adding Fe3+. The sensing mechanism of the b-CDs + Fe3+ system can be attributed to the internal filtration effect (IFE) mechanism and the electron transfer (ET) between b-CDs and Fe3+ in water, and only the IFE mechanism in PBS solution based on multiple experimental evidences. Moreover, the as-proposed probe was successfully adopted for monitoring Fe3+ in lake water and tap water samples. This research shows some merits of economic, simplicity, green, high selectivity, and quick response for Fe3+ determination, and provides an approach for the water quality monitoring of Fe3+ and the effective utilization of waste biological materials.