A Review on the Applications of Quantum Dots in Sample Preparation.

In recent years, despite significant advances in preconcentration and preparation techniques that have led to efficient recovery and accurate measurement of target compounds. There is still a need to develop adsorbents with unique and efficient features such as high pore volume and surface area, reactivity, easy synthesis, low toxicity, and compatibility with the environment, which increase the adsorption capacity and increase extraction efficiency. Semiconductor nanocrystals called quantum dots (QDs) with a size of less than 10 nm are three-dimensional nanoparticles with a spherical, rod, or disc structure that have significant potential in extraction as adsorbents due to their excellent properties such as low toxicity, reactivity, environmental friendliness, and hydrophilic and hydrophobic interactions.

Analysis of PAHs content, source identification and ecological risk assessment in surface sediments from the Caspian Sea.

The concentrations of Polycyclic Aromatic Hydrocarbons (PAHs) in surface sediments were investigated in the southern Caspian Sea. The results revealed that the total PAHs in sediments varied from 6.53 to 170.

Environmental impacts of fish cage cultures in the southern Caspian Sea.

In the last two decades, cage culture industries have developed in Iranian seas, supplying a portion of the needed protein and contributing to food security. In this paper, environmental impacts of cage culture are investigated, focusing on the physical, hydrodynamical, chemical, geological, and biological oceanographic aspects at the Abbas Abad fish farm in the southern Caspian Sea. Multidisciplinary field measurements were conducted from fall 2018 to late summer 2019 in different oceanographic aspects.

Polychlorinated biphenyls (PCBs) in the Persian Gulf and Gulf of Oman: baseline report on occurrence, distribution, and ecological risk assessment.

In the present study, 18 polychlorinated biphenyl (PCB) compounds were measured in marine sediments collected from 49 offshore stations in the Persian Gulf and the Gulf of Oman in 2019. After the last oceanographic cruise in 2006, no study has been performed on the offshore sediments of this region, and this is the first study on the PCBs in this area. The total amount of PCB compounds in the sediment samples ranged from 74.

Surface microplastics dynamics in the Persian Gulf and Arabian Sea using numerical modelling and CYGNSS satellite estimations.

Microplastics have long-term negative effects on marine environment. One of the most significant threats of microplastics is their ability to absorb chemicals which enhances the transfer of pollutants. These pollutants eventually enter the tissues of living organisms e.

Origin and comprehensive risk assessment of heavy metals in surface sediments along the Caspian Sea.

Metal concentrations (Cu, Zn, Cr, Fe, As, Pb, Ni, V, and Co) in surface sediments were determined in the southern Caspian Sea. Sediment pollution was investigated using geochemical index such as Enrichment Factor (EF) and ecological risk indices like modified Hazard Quotient (mHQ) and Toxic Risk Index (TRI). The highest calculated geochemical index was observed in sediments near the cities of Chalus and Ramsar, which are highly polluted due to human activities.

Distribution of hydrogen sulfide, nitrogen and phosphorous species in inshore and offshore sediments of the south Caspian Sea.

This study aimed to geochemically investigate the sediments of the south Caspian Sea at different depths in summer and winter 2020. Sampling was conducted in 5 transects along the south coastline of the Caspian Sea and sediment grain size, hydrogen sulfide, Oxidation-reduction potential (Eh), total nitrogen, nitrite, nitrate, ammonium, total phosphorus, organic and inorganic phosphorous were measured. Eh values showed significant differences between seasons and between different transects (p < 0.

Basin scale monitoring of microplastics and phthalates in sediments from the Persian Gulf and the Gulf of Makran using GIS-based algorithms: Insights towards spatial variation and potential risk assessment.

Information on sedimentary microplastics and phthalates has been restricted to the coastal regions of the Persian Gulf and the Gulf of Makran. Our basin-wide study monitored their levels, spatial behaviors, and potential risks using GIS-based techniques. Microplastics and phthalates ranged from 5 to 75 particles/kg d.

Distribution of microplastics in upstream and downstream surface waters of the Iranian rivers discharging to the southern Caspian Sea.

Microplastic pollution in the riverine ecosystems has caught many attentions in the scientific literatures. However, little information is available about the abundance and distribution of microplastics of the rivers discharging to the Caspian Sea. The aim of this study was to assess the spatial and seasonal distribution of microplastics in the surface waters of thirteen rivers discharging to the southern Caspian Sea.

Sources and hotspots of microplastics of the rivers ending to the southern Caspian Sea.

The occurrence of microplastics (MPs) in beach sediments of the southern Caspian Sea was well documented, however, there are still many unknowns about the abundances and distributions of MPs in the rivers ending to the Caspian Sea. Here, bank sediments of 26 sites in the thirteen rivers were surveyed in two seasons. However, there was not any significant difference (p > 0.

Effect of zinc nanoparticles on the growth and biofortification capability of mungbean () seedlings.

Unlabelled: Zinc insufficiency is a nutritional trouble worldwide, especially in developing countries. In the current study, an experiment was conducted to evaluate the effect of supplementation of MS media culture with different concentrations of ZnO nanoparticles (NPs) (0, 10, 20, 40, 80, and 160 ppm) on growth, nutrient uptake, and some physiological parameters of 7-days-old mung bean seedlings. ZnO NPs enhanced the Zn concentration of mung bean from 106.

Curcumin-Melamine For Solid-Phase Microextraction of Volatile Organic Compounds from Aqueous Samples.

The hybrid coating of curcumin and melamine was prepared by a simple electrochemical method. Some physical and chemical properties of the fiber were studied by several methods such as FT-IR, scanning electron microscopy and X-ray fluorescence spectroscopy. The fiber was stable at the inlet of a gas chromatograph at temperatures up to 280°C.

Catalytic nanozyme Zn/Cl-doped carbon quantum dots as ratiometric fluorescent probe for sequential on-off-on detection of riboflavin, Cu and thiamine.

A novel metal-doped Zn/Cl carbon quantum dots (Zn/Cl-CQDs) was developed successfully as ratiometric fluorescent probes for the sequential on-off-on detection of riboflavin, Cu ion and thiamine. The excellent catalytic performance of the Zn/Cl-CQDs nanozyme serves as an ideal platform for sensitive detection of thiamine. Due to the addition of riboflavin to the Zn/Cl-CQDs, the blue emission peak of Zn/Cl-CQDs at 440 nm remains unaffected and used as an internal reference approach, while the green emission peak of riboflavin at 520 nm appeared and increased remarkably.

Combining theoretical concepts and Geographic Information System (GIS) to highlight source, risk, and hotspots of sedimentary PAHs: A case study of Chabahar Bay.

Sedimentary PAHs are regionalized variables and their levels, source, and ecological hazards must be discussed in relation to their spatial locations. Our research targeted GIS and Chabahar Bay-Iran to trace spatial variability of PAHs, improve the diagnostic ratios and receptor models in source identification, and determine hotspot of PAH-originated hazards. The entropy Voronoi map distinguished an "entropy strip" in which ∑PAHs levels increased sharply.

Distribution, source and ecological risk assessment of polycyclic aromatic hydrocarbons in the sediments of northern part of the Persian Gulf.

Distribution, sources, and ecological risk of 43 compounds of polycyclic aromatic hydrocarbons (PAHs) in surficial sediments of the Persian Gulf were investigated. The sediments were sampled from 60 offshore stations during an oceanographic cruise in the winter of 2012. Gas chromatography high-resolution mass spectrometry was used for the PAHs determinations in sediment samples.

Nicotinamide-Functionalized Carbon Quantum Dot as New Sensing Platform for Portable Quantification of Vitamin B12 in Fluorescence, UV-Vis and Smartphone Triple Mode.

Development of an efficient, portable and simple nanosensor-based systems with reliable analytical performance for on-site monitoring of vitamin B12 (VB12) are still major problems and a challenging work for quality control of manufacturers. Herein, a new fluorescence, UV-Vis and smartphone triple mode nanosensors were designed for the simultaneous detection of VB12 with high sensitivity and accuracy. A novel nanosensor was synthesized through nicotinamide-functionalizing of carbon quantum dot (NA-CQDs) by an one-step microwave-assisted method with green approach.

Spatial distribution of microplastics in sandy beach and inshore-offshore sediments of the southern Caspian Sea.

The occurrence of microplastics (MPs) in nearshore zones of the southern Caspian coasts is well documented; however, no data are available on MP occurrence in offshore sediments. In this study, six sandy beach stations and 18 inshore-offshore stations (six transects) were surveyed. MPs were detected in all sediment samples.

Microplastic pollution in inshore and offshore surface waters of the southern Caspian Sea.

In this study, as the first comprehensive monitoring, the occurrence of microplastics (MPs) in inshore and offshore surface waters of the southern Caspian Sea was investigated. Our data indicated that MPs, which were detected in all the samples, were widely distributed in the thirteen studied stations. Non-normally distribution of the MPs was observed among the studied stations (p<0.

Occurrence of polychlorinated biphenyl congeners in marine sediment of Makran region, Chabahr bay, Iran.

In this study, selected PCB congeners (IUPAC numbers 28, 52, 101, 138, 153, and 180) were quantified in 34 stations of Chabahr bay and around it in the Makran region of Iran. The sum of total PCB concentrations varied from below the detection limit to 485 ng kg dry weight of sediment. Based on the Canadian Sediment Quality Guidelines, the effect of detected PCBs was negligible for aquatic organisms.

Intrinsic peroxidase-like activity of graphene nanoribbons for label-free colorimetric detection of dopamine.

Graphene nanoribbons (GNR) with intrinsic peroxidase mimic activity were introduced as a nanozyme with catalytic activity in oxidation of a typical chromogenic peroxidase substrate, 3,3',5,5'-tetramethylbenzidine (TMB), in the presence of HO. The proposed artificial enzyme was used as a label-free biosensor for rapid and sensitive colorimetric detection of dopamine (DA) according to a blue color fading which occurred due to the inhibition of TMB oxidation. Attractively, GNR exhibited an excellent catalytic activity over other carbon-based nanostructures due to its unique and extraordinary structural properties.

Rapid and sensitive fluorescence and smartphone dual-mode detection of dopamine based on nitrogen-boron co-doped carbon quantum dots.

A dual-mode fluorescence and colorimetric biosensor based on nitrogen-boron co-doped carbon quantum dot (N-B CQDs) for rapid and sensitive detection of dopamine (DA) was developed. The quantum dot luminescent materials, N-B CQDs, were prepared by a one-step microwave-assisted method. The N-B CQDs were characterized using SEM, HR-TEM, XRD, FT-IR, Raman, fluorescence, and UV-Vis techniques.

Enhanced LSPR performance of graphene nanoribbons-silver nanoparticles hybrid as a colorimetric sensor for sequential detection of dopamine and glutathione.

In the present study, a novel plasmonic sensing platform was proposed for sequential colorimetric detection of dopamine (DA) and glutathione (GSH) in human serum sample by taking advantage of plasmon hybridization in graphene nanoribbons/sliver nanoparticles (GNR/Ag NPs) hybrid. DA was detected based on etching strategy and morphology transition of label-free Ag NPs hybridized with GNR. As a result of the etching process, hexagonal Ag NPs were changed to smaller corner-truncated nanoparticles and a blue shift was observed in its plasmonic band, accompanied by the color change from green to red.

Preparation of a magnetic polystyrene nanocomposite for dispersive solid-phase extraction of copper ions in environmental samples.

The core shell nanostructure of magnetic polystyrene (PS@FeO) was prepared and its physic-chemical properties were studied FT-IR, SEM, TEM, VSM and BET + BJH. The new adsorbent was applied in the dispersive solid phase extraction technique for measuring copper ions in water, Soil and Oyster samples. Analysis is carried out using a flame atomic absorption spectrometry system.