Search Results (107)

A simple and efficient dispersive micro solid-phase extraction (DMSPE) method using nano-TiO₂ as a sorbent was developed for the separation and preconcentration of (ultra) trace levels of lead in water samples prior to quantification by electrothermal atomic absorption spectrometry (ETAAS). Key experimental parameters affecting the DMSPE process, including pH, ionic strength, sorbent dosage, and preconcentration factor, were optimized. The optimized method demonstrated a preconcentration factor of 20, a relative standard deviation below 4.5%, and a detection limit of 0.11 µg/L. The procedure was validated using certified reference material (CRM TM-25.5) and applied to real water samples from a lake, a residential well, and industrial wastewater. Satisfactory recoveries (89–103%) confirmed the reliability of the method for the determination of low lead concentrations in complex matrices. Full article

The analysis of wastewater is essential in environmental chemistry, particularly for monitoring emerging contaminants and assessing ecological impacts. In this context, hyphenated chromatographic techniques are widely used, with liquid chromatography being one of the most common. However, gas chromatography coupled with mass spectrometry (GC-MS) remains a valuable tool in this field due to its sensitivity, selectivity, and widespread availability in most laboratories. This review examines the application of validated methods for wastewater analysis using GC-MS (MS), highlighting its relevance in identifying micropollutants such as pharmaceuticals, drugs of abuse, pesticides, hormones, and industrial by-products. The validation of analytical methods is crucial to ensuring the reliability and reproducibility of data and the accurate monitoring of contaminants. Key parameters, including sample volume, recovery efficiency, and detection and quantification limits, are discussed, evaluating different approaches to optimising the identification of different classes of contaminants. Additionally, this study explores advances in sample preparation techniques, such as solid-phase microextraction (SPME), dispersive liquid–liquid microextraction (DLLME), and solid-phase extraction (SPE), which enhance efficiency and minimise interferences in the analysis. Finally, future perspectives are discussed, including the integration of emerging technologies such as high-resolution mass spectrometry, the miniaturisation of GC systems, and the development of faster and more sustainable analytical methods. Full article

A 3D-printed device was designed and printed by a stereolithographic technique (SLA) and coated with a highly selective solid phase extraction resin for on-site diclofenac extraction from wastewater, avoiding the transport and treatment of large volumes of samples in the laboratory. The best results in terms of chemical and mechanical resistance were obtained with Rigid 10K resin. The “stick-and-cure” impregnation technique was used to coat the 3D-printed device with Oasis^® HLB resin. The coated 3D-printed device can be reused up to eight times without losing extraction efficiency. The eluent and derivatization reagent volumes were optimized by a multivariate design. The proposed method allowed for the extraction and determination of diclofenac by PTV-GC-MS, achieving methodological detection and quantification limits of 0.019 and 0.055 μg L⁻¹, respectively, with a preconcentration factor of 46. The analysis time was 23 min per sample. To validate the proposed methodology, addition/recovery tests were carried out in different wastewater samples, obtaining recoveries above 90%. The methodology was applied at the wastewater treatment plant (WWTP) of Calvià (Mallorca, Spain), finding diclofenac in concentrations of 15.39 ± 0.07 μg L⁻¹ at the input of the primary decantation process, 4.48 ± 0.03 μg L⁻¹ at the output of the secondary decantation, and 0.099 ± 0.001 μg L⁻¹ at the output of the tertiary treatment, demonstrating the feasibility of the on-site extraction method in monitoring diclofenac over a wide concentration range. Finally, a greenness index of 0.58 for the proposed on-site sample preparation was achieved according to the AGREEprep metrics, making it an eco-friendly alternative for diclofenac monitoring. Full article

Sample pretreatment is one of the most important steps in guaranteeing the success of a chromatographic analysis. The selected methodology must ensure simultaneously that a sample is “clean” enough for analysis and that the target analytes are not removed in the process. This can be especially difficult when working with complex matrices such as natural waters and wastewater. For pharmaceutical active compounds (PhACs) analysis by solid-phase extraction (SPE) followed by ultra-high performance liquid chromatography coupled to tandem mass spectrometry (UPLC-MS/MS), and due to the high level of organic matter in wastewater, the water samples are filtered consecutively through three filters, a paper filter, a glass microfiber filter of 1 µm, and a Nylon filter of 0.45 µm. This filtration allows the sample’s passage through the SPE cartridge to be faster, and there is no cartridge clogging, allowing for greater efficiency in the adsorption process. The big question is whether the PhACs are eliminated during filtration, since they may be adsorbed to organic matter. This work aimed to determine if the best approach for quantifying PhACs in wastewater and surface waters would be to filter them prior or to perform SPE directly. Both approaches analyzed a total of 26 PhACs. Turbidity (TUR) and permanganate index (PI) were determined, and their values were high for samples with a high organic matter content. A statistical analysis was performed to determine the best approach to treat these water samples and whether any correlation existed between PhAC concentrations, PI, and TUR. The PhAC quantification shows a positive correlation with TUR and a negative correlation with PI for most of the target PhACs. However, there are not significantly different results for filtered and not-filtered wastewater samples. Full article

Landfill leachate, a complex wastewater generated from municipal solid waste (MSW) landfills, presents significant environmental challenges due to its high organic content and toxic pollutants. This study proposes a sustainable solution by employing the green synthesis of copper oxide nanoparticles (CuO NPs) using durian (Durio zibethinus) husk extract, which serves as a natural reducing and stabilizing agent. This approach transforms agricultural waste into a valuable resource for environmental remediation. The synthesis was carried out under mild conditions, avoiding harmful chemicals and reducing energy consumption. The CuO NPs were characterized by scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HR-TEM), X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDX), Fourier-transform infrared spectroscopy (FTIR), and UV-Vis spectroscopy to examine their morphology, crystallinity, purity, and optical properties. SEM and HR-TEM analyses revealed mainly spherical nanoparticles with an average size of 35–50 nm and minimal aggregation. XRD analysis confirmed the presence of a highly crystalline monoclinic phase of CuO, while the EDX spectrum showed distinct peaks corresponding to copper (72%) and oxygen (28%) by weight, confirming the high purity of the material. Preliminary tests demonstrated the photocatalytic efficiency of the CuO NPs, achieving up to a 79% reduction in chemical oxygen demand (COD) in landfill leachate. These findings underscore the potential of green-synthesized CuO NPs for environmental applications, offering an innovative, sustainable method for wastewater treatment and supporting the advancement of solid waste management practices. Full article

A sol-gel approach was used to prepare a thin hydrogel membrane based on an organic-inorganic polymer matrix embedded with pre-synthesized gold nanoparticles (AuNPs). The organic polymers utilized were poly(vinyl alcohol) (PVA) and poly(ethylene oxide) 400 (PEO) while tetraethoxysilane (TEOS) served as a precursor for the inorganic silica polymer. AuNPs were synthesized using D-glucose as a reducing agent and starch as a capping agent. A mixture of PVA, PEO, pre-hydrolyzed TEOS, and AuNP dispersions was cast and dried at 50 °C to obtain the hybrid hydrogel membrane. The structure, morphology, and optical properties of the nanocomposite membrane were analyzed using TEM, SEM, XRD, and UV-Vis spectroscopy. The newly designed hybrid hydrogel membrane was utilized as an efficient sorbent for the simultaneous speciation analysis of valence species of chromium and manganese in water samples via solid-phase extraction. This study revealed that Cr(III) and Mn(II) could be simultaneously adsorbed onto the PVA/PEO/SiO₂/AuNP membrane at pH 9 while Cr(VI) and Mn(VII) remained in solution due to their inability to bind under these conditions. Under optimized parameters, detection limits and relative standard deviations were determined for chromium and manganese species. The developed analytical method was successfully applied for the simultaneous speciation analysis of chromium and manganese in drinking water and wastewater samples. Full article

A fast and green approach for the non-chromatographic assaying of volatile metalorganic compounds (VMOCs) is presented, involving the use of thermal desorption microwave-induced plasma optical emission spectrometry for the multi-species simultaneous determination of VMOCs in wastewater plant samples after headspace solid-phase microextraction (HSSPME-TD-MIP-OES), and optimized as a tool for the assessment of ambient exposure to hazardous VMOC pollutants. With the aim of VMOC monitoring, all species are separated and quantified within 10 s in comparison with about 10–20 min required by conventional GC-based procedures. Calibration against aqueous standards was carried out for several metalorganic species. The method was successfully applied for the quantitative extraction of As, Bi, Hg, Sb, Si and Sn compounds. Limits of detection ranging from 5 to 30 ng L⁻¹ and relative standard deviations lower than 4% were obtained. The method is appropriate for high-sample-throughput measurements, and it proved to be suitable for the analysis of wastewater and sewage sludge samples. Full article

In this study, the novel composite materials of activated carbon (AC) and persulfate (PS) doped by nitrogen (N) and sulfur (S) were successfully synthesized through one-step mechanical ball milling. Different from the previous liquid-phase activation process of PS, the direct in situ solid-phase activation of PS was achieved through the newly generated chemical bonds between AC and PS. The increased crystal surface exposure and highly electronegative atoms provided more reactive sites for the modified composites, enabling them to extract electrons from the pollutant. Compared to S doping, the N-doped composite exhibited a higher oxidative degradation ability, with a removal rate of 93.6% for tetracycline (TC, 40 mg/L) within 40 min. The interactions between AC and PS that occur in the interior of the composite avoid the limitations of mass transfer between the solid–liquid interface, thus expanding the pH application range of the catalytic reaction and minimizing the interference of other components in the solution. The synergistic effect between active oxygen species and electron transfer is the main mechanism for promoting pollutant degradation. This research puts forward a new insight into the activation approach of PS and proposes a feasible method for the advanced treatment of TC wastewater. Full article

The improper disposal of hospital wastewater (HWW) is a primary source of pharmaceutical pollution in aquatic systems. The complexity of the HWW matrix presents significant challenges for analytical chemists, necessitating meticulous sample preparation as the initial step for the analysis, followed by instrumental analysis. In the present study, a combination of dispersive solid phase extraction and solid phase extraction was evaluated for the preparation of HWW samples from two hospitals in Porto Alegre, Brazil, both for screening and quantitative analysis. The experiments performed by UHPLC-QTOF MS allowed the identification of 27 compounds and 23 suspected compounds. Furthermore, the UHPLC-QqQ-MS analysis enabled the quantification of 21 compounds, with concentrations ranging from 1.17 µg L⁻¹ to 213.33 µg L⁻¹. Notably, the pharmaceutical ciprofloxacin was detected at a concentration that exceeded the reported risk level for Microcystis aeruginosa. The environmental risk assessment revealed that the risk quotient (RQ) for several of the compounds quantified in the two HWW matrices exceeded 1, with the risk quotient of the mixture of compounds (RQ_mix) being approximately 30 × 10⁶ for Hospital A and 20 × 10⁶ for Hospital B. According to these findings, the two HWW systems exhibited risk levels for aquatic species and small rodents, thereby contributing to the persistence of pharmaceuticals in the environment. Full article

Background: The use of illicit drugs and stimulants is a burgeoning socioeconomic problem, ultimately leading to an increase in street crimes and deteriorating human health. The persistent presence of CNS drugs in wastewater can also lead to downstream adverse effects on aquatic wildlife and humans. Objectives: In the present study, a method was developed for the solid-phase extraction and quantitative liquid chromatography coupled with tandem quadrupole/time-of-flight mass spectrometry (LC-QToF-MS) analysis of CNS stimulant drugs and their metabolites in municipal wastewater. The targeted species included amphetamine, methamphetamine, methylenedioxy-methamphetamine (MDMA), methylenedioxyethylamphetamine (MDEA), cocaine, and benzoylecgonine (BE). Methods: The method was validated and applied to analyzing wastewater samples collected at the University of Mississippi and the City of Oxford wastewater treatment plants (WWTPs) during weekends when the university hosted home college football games. Results: Our results indicate that while amphetamine, methamphetamine, MDMA, cocaine, and BE were all detected at quantifiable levels, amphetamine and BE were present in significantly higher concentrations in wastewater during football games. Conclusion: The insights from this study can be utilized to monitor long-term drug use trends, providing local law enforcement agencies with relevant data on consumption patterns over time. Full article

Due to their antibacterial and antifungal properties, parabens are commonly used as biocides and preservatives in food, cosmetics, and pharmaceuticals. Parabens have been reported to exist in various water matrices at low concentrations, which renders the need for sample preparation before their quantification using analytical techniques. Thus, sample preparation methods such as solid-phase extraction (SPE), rotating-disk sorptive extraction (RDSE), and vortex-assisted dispersive liquid–liquid extraction (VA-DLLE) that are commonly used for parabens extraction and preconcentration have been discussed. As a result of sample preparation methods, analytical techniques now detect parabens at trace levels ranging from µg/L to ng/L. These compounds have been detected in water, air, soil, and human tissues. While the full impact of parabens on human health and ecosystems is still being debated in the scientific community, it is widely recognized that parabens can act as endocrine disruptors. Furthermore, some studies have suggested that parabens may have carcinogenic effects. The presence of parabens in the environment is primarily due to wastewater discharges, which result in widespread contamination and their concentrations increased during the COVID-19 pandemic waves. Neglecting the presence of parabens in water exposes humans to these compounds through contaminated food and drinking water. Although there are reviews that focus on the occurrence, fate, and behavior of parabens in the environment, they frequently overlook critical aspects such as removal methods, policy development, and regulatory frameworks. Addressing this gap, the effective treatment of parabens in water relies on combined approaches that address both cost and operational challenges. Membrane filtration methods, such as nanofiltration (NF) and reverse osmosis (RO), demonstrate high efficacy but are hindered by maintenance and energy costs due to extensive fouling. Innovations in anti-fouling and energy efficiency, coupled with pre-treatment methods like adsorption, help mitigate these costs and enhance scalability. Furthermore, combining adsorption with advanced oxidation processes (AOPs) or biological treatments significantly improves economic and energy efficiency. Integrating systems like O₃/UV with activated carbon, along with byproduct recovery strategies, further advances circular economy goals by minimizing waste and resource use. This review provides a thorough overview of paraben monitoring in wastewater, current treatment techniques, and the regulatory policies that govern their presence. Furthermore, it provides perspectives that are critical for future scientific investigations and shaping policies aimed at mitigating the risks of parabens in drinking water. Full article

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. Full article

Trace concentrations of dyes are often present in textile wastewater streams and present a serious environmental problem. Thus, these dyes must be removed from wastewater either by degradation or sequestration prior to discharge of the wastewater into the environment. Existing processes to remove these wastewater contaminants include the use of solid sorbents to sequester dyes or the use of biochemical or chemical methods of dye degradation. However, these processes typically generate their own waste products, are not necessarily rapid because of the low dye concentration, and often use expensive or non-recyclable sequestrants or reagents. This paper describes a simple, recyclable, liquid–liquid extraction scheme where ionic dyes can be sequestered into poly(α-olefin) (PAO) solvent systems. The partitioning of anionic and cationic dyes from water into PAOs is facilitated by ionic PAO-phase anchored sequestering agents that are readily prepared from commercially available vinyl-terminated polyisobutylene (PIB). This is accomplished by a sequence of reactions involving hydroboration/oxidation, conversion of an alcohol into an iodide, and conversion of the resulting primary alkyl iodide into a cationic nitrogen derivative. The products of this synthetic sequence are cationic nitrogen iodide salts which serve as anionic sequestrants that are soluble in PAO. These studies showed that the resulting series of cationic PIB-bound cationic sequestering agents facilitated efficient extraction of anionic, azo, phthalein, and sulfonephthalein dyes from water into a hydrocarbon PAO phase. Since the hydrocarbon PAO phase is completely immiscible with water and the PIB derivatives are also insoluble in water, neither the sequestration solvent nor the sequestrants contaminate wastewater. The effectiveness and efficiency of these sequestrations were assayed by UV–visible spectroscopy. These spectroscopic studies showed that extraction efficiencies were in most cases >99%. These studies also involved procedures that allowed for the regeneration and recycling of these PAO sequestration systems. This allowed us to recycle the PAO solvent system for at least 10 sequential batch extractions where we sequestered sodium salts of methyl red and 4′,5′-dichlorofluorescein dyes from water with extraction efficiencies of >99%. These studies also showed that a PIB-bound derivative of the sodium salt of 1,1,1-trifluoromethylpentane-2,4-dione could be prepared from a PIB-bound carboxylic acid ester by a Claisen-like reaction and that the sodium salt of this β-diketone could be used to sequester cationic dyes from water. This PIB-bound anion rapidly and efficiently extracted >99% of methylene blue, malachite green, and safranine O from water based on UV–visible and ¹H NMR spectroscopic assays. Full article

This study evaluates antibiotic residues and bacterial loads in influent and effluent samples from three wastewater treatment plants (WWTPs) in Romania, across four seasons from 2021 to 2022. Analytical methods included solid-phase extraction and high-performance liquid chromatography (HPLC) to quantify antibiotic concentrations, while microbiological assays estimated bacterial loads and assessed antibiotic resistance patterns. Statistical analyses explored the impact of environmental factors such as temperature and rainfall on antibiotic levels. The results showed significant seasonal variations, with higher antibiotic concentrations in warmer seasons. Antibiotic removal efficiency varied among WWTPs, with some antibiotics being effectively removed and others persisting in the effluent, posing high environmental risks and potential for antibiotic resistance development. Bacterial loads were higher in spring and summer, correlating with increased temperatures. Eight bacterial strains were isolated, with higher resistance during warmer seasons, particularly to amoxicillin and clarithromycin. Full article

Wastewater (WW)-based epidemiology is an approach for the objective surveillance of the consumption of (illicit) drugs in populations. The aims of this study were to monitor drugs of abuse, cognitive enhancers, and their metabolites as biomarkers in influent WW. Data obtained from different sampling points and mean daily loads were compared with previously published data. The prevalence of analytes was monitored in WW grab samples collected monthly over 22 months at two sampling points and 24 h composite WW samples collected over 2 weeks at a WW treatment plant in the same city. Quantification was performed using a previously validated and published method based on solid-phase extraction followed by liquid chromatography coupled with high-resolution tandem mass spectrometry. Grab samples allowed for frequent detection of ritalinic acid and sporadic detection of drugs of abuse. The daily mean loads calculated for 24 h WW composite samples were in accordance with data published in an international study. Furthermore, loads of amphetamine and methamphetamine increased compared with those observed in a previously published study from 2014. This study showed frequent quantification of ritalinic acid in the grab samples, while drugs of abuse were commonly quantified in the composite WW samples. Daily mean loads were in accordance with trends reported for Germany. Full article