Search

Polycyclic aromatic hydrocarbons are a class of chemicals that occur naturally. They generally demonstrate a high degree of critical toxicity towards humans. Acenaphthene and naphthalene contain compounds that are commonly found in the environment as compared to other PAHs. Consequently, a reliable method of detecting PAHs is crucial for the monitoring of water quality. A colorimetric method based on sodium nitrite-functionalized gold nanoparticles was developed in this study for acenaphthene and naphthalene detection. Different functionalized parameters are determined for the optimization of assay conditions. A linear relationship was found in the analyte concentration range of 0.1–10 ppm with the limit of detection for acenaphthene and naphthalene being 0.046 ppm and 0.0015 ppm, respectively, under the optimized assay conditions. The method's recovery rate for actual samples falls within the range of 98.4–103.0%. In selective and anti-interference tests, the presence of cations and anions has minimal impact on the detection of the analyte. The colorimetric detection method proposed in this study effectively determines the presence of the analyte in real water samples and has a high recovery rate. [ABSTRACT FROM AUTHOR]

Given the high toxicity and carcinogenic properties of pesticides, reducing pesticide residues is crucial for mitigating water pollution and promoting sustainable development. In the present study, a novel colorimetric method using gold nanoparticles (AuNPs) was designed for the detection of target analytes. The Turkevich-Frens method was used to synthesize AuNPs, which were then modified with sodium nitrite and L-cysteine for the detection of 1-naphthol and glyphosate, respectively. Different assay conditions strongly influenced the detection performance of the modified AuNPs, so the assay conditions were optimized for further investigation. In the presence of the target analytes (1-naphthol and glyphosate) under the optimum assay conditions, the absorption peak at 520 nm shifted and a corresponding color change was observed. The limits of detection of 1-naphthol and glyphosate were determined to be 0.15 and 0.27 ppm, respectively. In addition, the modified AuNPs had high selectivity for the target analytes and did not exhibit interference in the presence of other substances. This novel colorimetric method was then applied to detect the target analytes in mineral water and tap water with acceptable results. [ABSTRACT FROM AUTHOR]

• An effectiveness of TGA-modified gold nanoparticles in detecting azithromycin was demonstrated. • The detection limit of azithromycin was determined to be 0.035 ppm under optimal conditions. • The proposed colorimetric detection method is capable of detecting azithromycin in water samples. • A DFT investigation was conducted to understand the reaction mechanism in detecting azithromycin. The increasing use of synthetic pharmaceuticals contributes to environmental contamination and the accumulation of these drugs in the ecosystem. This buildup can have detrimental effects on human health and the natural environment. In this pioneering study, we successfully synthesized and modified gold nanoparticles (AuNPs) via thioglycolic acid (TGA) to detect the target analyte azithromycin (Azi) with precision. The detection mechanism involves the aggregation of TGA-modified AuNPs in the presence of azithromycin, leading to a color change from red to purple with increasing Azi concentration. Furthermore, the AuNPs demonstrated high selectivity for the target analyte and did not exhibit interference from other substances. The detection limit of Azi was determined to be 0.035 ppm under optimal conditions. The proposed colorimetric detection method is straightforward and capable of detecting Azi in water samples with a high recovery rate. A density functional theory (DFT)-based theoretical investigation was conducted to comprehensively understand the reaction mechanism involved in detecting Azi. The concordance between the theoretical and experimental FT-IR results supports the proposed binding interactions among AuNPs, TGA, and Azi, confirming the role of TGA as a stabilizer and functionalizer for AuNPs. The findings indicated that the modified AuNPs exhibited greater responsiveness to the target analyte (Azi) than to erythromycin (Ery) during the chemical reaction process. [ABSTRACT FROM AUTHOR]

[Display omitted] • The colorimetric method has good selectivity and anti-interference ability for the target analytes. • The limits of detection for phenanthrene and pyrene are 0.06 mg/L and 0.087 mg/L, respectively. • This colorimetric method was used to detect target analytes in real water with acceptable results. The existence and content of polycyclic aromatic hydrocarbons (PAHs) in the environment have gradually received attention because PAHs are widely detected in many sources. Therefore, an effective detection method for PAHs is necessary for further treatment. This study proposes a novel colorimetric detection method based on AuNPs to determine the contents of phenanthrene (Phe) and pyrene (Pyr). Trisodium citrate was used as a reducing agent to synthesize gold nanoparticles, and ammonium nitrate (NH 4 NO 3) was added as a reactant to detect the analyte content. Some assay parameters, such as the concentration of NH 4 NO 3 solution, the volume of NH 4 NO 3 solution, the concentration of MES buffer solution, the volume of MES buffer solution, and the reaction time influenced the analyte detection ability of AuNPs and were optimized. The limits of detection for Phe and Pyr are 0.06 mg/L and 0.087 mg/L, respectively. In addition, the detection method has good selectivity and anti-interference ability for the target analytes. This colorimetric method was used to detect target analytes in real water (tap water and mineral water) with acceptable results. [ABSTRACT FROM AUTHOR]

In the presence of PAEs, the DNA-modified AuNPs formed aggregations and resulted in the color change phenomenon. [Display omitted] • The DNA-modified AuNPs exhibited excellent sensitivity and selectivity for phthalate detection. • The limits of detection for DEP, DBP, and DEHP were 0.026 ppm, 0.077 ppm, and 0.144 ppm, respectively. • DNA-modified colorimetric probes can be used to detect phthalates. Phthalates, also called phthalic acid esters (PAEs), are well-known endocrine-disrupting chemicals (EDCs) that have been detected in residential and occupational environments. In the present study, a simple and rapid method is proposed for the detection of phthalates (diethyl phthalate (DEP), di-n-butyl phthalate (DBP) and di-(2-ethylhexyl) phthalate (DEHP)) based on DNA-modified gold nanoparticles (AuNPs). In the presence of phthalates, the DNA-modified AuNPs formed aggregates. Thus, a visible color change from red to blue and an increase in the absorption ratio with an increasing concentration of phthalates were observed. The limits of detection (LODs) for DEP, DBP, and DEHP were determined to be 0.026 ppm, 0.077 ppm, and 0.144 ppm, respectively. The sensitivity and selectivity test results showed that the DNA-modified AuNPs were able to detect phthalates. The proposed DNA-modified AuNPs (aptamer-E, aptamer-B and aptamer-H) are expected to have potential applications in environmental fields. [ABSTRACT FROM AUTHOR]