Determination of copper in biological samples by flame atomic absorption spectrometry after precipitation with Me-BTAP

Blurry eyes and clouded minds: Metal and metalloid contamination of the visual-sensory system of elasmobranchs

Marine metal and metalloid pollution poses significant risks to elasmobranchs, especially in vital organs such as their sensory and visual systems. While contamination studies have traditionally focused on elasmobranch liver and muscle tissues, due to their significance in detoxification processes and human consumption, respectively, the eyes and brain of this group remain largely underexplored in ecotoxicology assessments. Metal and metalloid accumulation in these sensory organs may compromise key elasmobranch functions, impacting crucial survival behaviors, such as foraging and predator evasion. Detecting sublethal cellular effects caused by these contaminants in the eyes and brain employing biomarkers offers a pathway to assess pollutant sensory health effects before they extend to the organismal and population levels, although no studies have been carried out to date in this sense. This review compiles the current knowledge on metal and metalloid contamination in elasmobranch sensory systems, highlighting the need for further research to understand pollutant effects in these animals' ecological roles and inform conservation strategies.

Pore-Engineered Hydrogen-Bonded Supramolecular Fluorosensor for Ultrasensitive Determination of Copper Ions

The selective quantification of copper ions (Cu2+) in biosamples holds great importance for disease diagnosis, treatment, and prognosis since the Cu2+ level is closely associated with the physiological state of the human body. While it remains a long-term challenge due to the extremely low level of free Cu2+ and the potential interference by the complex matrices. Here, a pore-engineered hydrogen-bonded organic framework (HOF) fluorosensor is constructed enabling the ultrasensitive and highly selective detection of free Cu2+. Attributing to atomically precise functionalization of active amino "arm" within the HOF pores and the periodic π-conjugated skeleton, this porous HOF fluorosensor affords high affinity toward Cu2+ through double copper-nitrogen (Cu─N) coordination interactions, resulting in specific fluorescence quenching of the HOF as compared with a series of substances ranging from other metal ions, metabolites, amino acids to proteins. Such superior fluorescence quenching effect endows the Cu2+ quantification by this new HOF sensor with a wide linearity of 50-20 000 nm, a low detection limit of 10 nm, and good recoveries (89.5%-115%) in human serum matrices, outperforming most of the reported approaches. This work highlights the practicability of hydrogen-bonded supramolecular engineering for designing facile and ultrasensitive biosensors for clinical free Cu2+ determination.

Possible health risk assessment for heavy metal concentrations in water, sediment, and fish species and Turkmen pregnant women's biomonitoring in Miankaleh Peninsula, Iran

This study investigated the human biomonitoring of heavy metals in the water, sediments, and tissues of mostly consumed fish species using Turkmen pregnant women's biomarkers in winter 2019, at the Miankaleh Peninsula, north of Iran. Metal concentrations were measured in various fish organs as well as pregnant women's blood, hair, and nail as biological indicators. For this purpose, a total of 20 water and sediment, 14 fish, and 16 human samples were collected. Inductively coupled plasma mass spectrometry (ICP-MS) was used to evaluate the concentration of Cr, Co, Cu, As, Hg, and Pb. Results showed metals with the highest concentrations as Cu and Cr in water (93.35 and 80.91 µg/l, respectively), Hg and Pb in sediment (7.40 µg/g for both), Cu and Pb in the liver (27.00 and 18.9 µg/g for C. carpio; 1414 and 31.7 µg/g for L. auratus), muscle (10.00 and 18.80 for C. carpio; 37.20 and 8.27 µg/g for L. auratus), and skin (26.40 and 9.90 for C. carpio; 10.80 and 11.74 µg/g for L. auratus). In addition, Cu, in pregnant women samples, had the highest values at 2.53 mg/l, 8.87, 36.46, and 29.04 µg/g for blood, hair, fingernail, and toenail, respectively. However, Co showed the lowest concentration in all studied samples. Fish liver and fingernail of pregnant women did reveal the highest heavy metal accumulation, whereas fish muscle and blood of pregnant women had the lowest accumulated heavy metals. The concentration of Hg in water, sediment, fish muscle, and women's blood and hair exceeded the limits suggested by various organizations. Therefore, this study highlighted that heavy metal concentration, in particular Hg, in water, sediments, and fish is a serious risk to the health of local inhabitants who rely on fisheries products and recommended that necessary information should be provided to warn Turkmen pregnant women in consumption of Hg-contaminated fish in this area.

Mesoscopic engineering materials for visual detection and selective removal of copper ions from drinking and waste water sources

The monitoring and removal of abundant heavy metals such as Cu ions are considerable global concerns because of their severe impact on the health of humans and other living organisms. To meet this global challenge, we engineered a novel mesoscopic capture protocol for the highly selective removal and visual monitoring of copper (Cu²⁺) ions from wide-ranging water sources. The capture hierarchy carriers featured three-dimensional, microsized MgO mesoarchitecture rectangular sheet-like mosaics that were randomly built in horizontal and vertical directions, uniformly arranged sheet faces, corners, and edges, smoothly quadrilateral surface coverage for strong Cu²⁺-to-ligand binding exposure, and multidiffusible pathways. The Cu²⁺ ion-selectively active captor surface design was engineered through the simple incorporation/encapsulation of a synthetic molecular chelation agent into hierarchical mesoporous MgO rectangular sheet platforms to produce a selective, visual mesoscopic captor (VMC). The nanoscale VMC dressing of MgO rectangular mosaic hierarchy by molecularly electron-enriched chelates with actively double core bindings of azo- and sulfonamide- groups and hydrophobic dodecyl tail showed potential to selectively trap and efficiently remove ultratrace Cu²⁺-ions with an extreme removal capability of ~233 mg/g from watery solutions, such as drinking water, hospital effluent, and food-processing wastewater at specific pH values. In addition to the Cu²⁺ ion-selective removal, the VMC design enabled the continuous visual monitoring of ultratrace Cu²⁺ ions (~3.35 × 10^-8 M) as a consequence of strong chelate-to-Cu²⁺ binding events among all accumulated matrices in water sources. Our experimental recycle protocol provided evidence of reusability and recyclability of VMC (≥10 cycles). With our mesoscopic capture protocol, the VMC can be a promising candidate for the selective decontamination/removal and sensitive detection of hazardous inorganic pollutants from different water sources with indoor or outdoor applications.

Determination of copper ions in herbal medicine based on click chemistry using an electronic balance as a readout

The amount of copper affects the quality of herbal medicine greatly, it is necessary to develop some simple and sensitive methods to detect copper for the remote or resource-limited area. An electronic balance is one of the most familiar equipment that can be found nearly in all laboratories. The presence of Cu(i) can catalyze azide-alkyne cycloaddition reaction (called as click chemistry) with high efficiency. In this study, a simple method had been developed to detect copper ions in herbal medicine using an electronic balance as a readout device based on click chemistry. Cu(ii) is reduced to Cu(i) by sodium ascorbate in situ, which induces the "click" reaction between azido-DNA modified magnetic beads (MB-DNA) and alkynyl-DNA modified platinum nanoparticles (Pt NP-DNA) and results in the fixing of the platinum nanoparticles on the beads (called as MB-Pt NPs). MB-Pt NPs can be separated by a magnetic frame easily and transferred into a drainage reaction device containing hydrogen peroxide. Then, hydrogen peroxide can be decomposed by Pt NPs modified on MB to generate oxygen, which increases the pressure in the drainage reaction device and forces the water in the system to be discharged. The weight of the discharged water can be easily and accurately measured by an electronic balance. The weight of the water has a linear relationship with Cu(ii) in the range of 2.0-200 μM and a detection limit of 0.83 μM under 30 min of collected time. This method does not need complicated and expensive instruments, skilled technicians, and a complex data processing process. The proposed method had been applied to detect copper ions in herbal medicine with satisfactory results.

Flow injection online spectrophotometric determination of uranium after preconcentration on XAD-4 resin impregnated with nalidixic acid

In this work, spectrophotometer was used as a detector for the determination of uranium from water, biological, and ore samples with a flow injection system coupled with solid phase extraction. In order to promote the online preconcentration of uranium, a minicolumn packed with XAD-4 resin impregnated with nalidixic acid was utilized. The system operation was based on U(VI) ion retention at pH 6 in the minicolumn at flow rate of 15.2 mL min(-1). The uranium complex was removed from the resin by 0.1 mol dm(-3) HCl at flow rate of 3.2 mL min(-1) and was mixed with arsenazo III solution (0.05 % solution in 0.1 mol dm(-3) HCl, 3.2 mL min(-1)) and driven to flow through cell of spectrophotometer where its absorbance was measured at 651 nm. The influence of chemical (pH and HCl (as eluent and reagent medium) concentration) and flow (sample and eluent flow rate and preconcentration time) parameters that could affect the performance of the system as well as the possible interferents was investigated. At the optimum conditions for 60 s preconcentration time (15.2 mL of sample volume), the method presented a detection limit of 1.1 μg L(-1), a relative standard deviation (RSD) of 0.8 % at 100 μg L(-1), enrichment factor of 30, and a sample throughput of 42 h(-1), whereas for 300 s of the preconcentration time (76 mL of sample volume), a detection limit of 0.22 μg L(-1), a RSD of 1.32 % at 10 μg L(-1), enrichment factor of 150, and a sampling frequency of 11 h(-1) were reported.

Determination of cadmium and lead in human biological samples by spectrometric techniques: a review

The analysis of human biological samples, such as blood, urine, nails, and hair, is generally used for the verification of human exposure to toxic metals. In this review, various spectrometric methods for the determination of cadmium and lead in biological samples are discussed and compared. Several spectrometric techniques are presented and discussed with respect to various characteristics such as sensitivity, selectivity, and cost. Special attention is drawn to the procedures for digestion prior to the determination of cadmium and lead in hair, nails, blood, and urine.

An online preconcentration system for the determination of uranium in water and effluent samples

Amberlite XAD-4 resin functionalized with β-nitroso-α-naphthol was applied to an online system for the preconcentration and determination of uranium. U (VI) ions were retained on the minicolumn at an appropriate pH and then desorbed with acid solution. The amount of uranium in the eluate was measured spectrophotometrically at 650 nm using Arsenazo III as a colorimetric reagent. The limit of detection and the preconcentration factor were 1.8 μg L(-1) and 10, respectively. The chemical and flow variables affecting the preconcentration were studied. The influence of several ions on the system was also investigated. The method was successfully applied for the evaluation of uranium in water and in effluent samples.

Preconcentration and determination of iron and copper in spice samples by cloud point extraction and flow injection flame atomic absorption spectrometry

A flow injection (FI) cloud point extraction (CPE) method for the determination of iron and copper by flame atomic absorption spectrometer (FAAS) has been improved. The analytes were complexed with 3-amino-7-dimethylamino-2-methylphenazine (Neutral Red, NR) and octylphenoxypolyethoxyethanol (Triton X-114)wasadded as a surfactant. The micellar solutionwasheated above 50 degrees C and loaded through a column packed with cotton for phase separation. Then the surfactant-rich phase was eluted using 0.05 mol L(-1) H2SO4 and the analytes were determined by FAAS. Chemical and flow variables influencing the instrumental and extraction conditions were optimized. Under optimized conditions for 25 mL of preconcentrated solution, the enrichment factors were 98 and 69, the limits of detection (3s) were 0.7 and 0.3 ng mL(-1), the limits of quantification (10s) were 2.2 and 1.0 ng mL(-1) for iron and copper, respectively. The relative standard deviation (RSD) for ten replicate measurements of 10 ng mL(-1) iron and copper were 2.1% and 1.8%, respectively. The proposed method was successfully applied to determination of iron and copper in spice samples.

Nano-level determination of copper with atomic absorption spectrometry after pre-concentration on N,N-(4-methyl-1,2-phenylene)diquinoline-2-carboxamide-naphthalene

A novel, simple, sensitive and effective method has been developed for selective extraction and pre-concentration of copper on N,N-(4-methyl-1,2-phenylene)diquinoline-2-carboxamide-naphthalene. After pre-concentration, copper was eluted from sorbent with hydrochloric acid, and then flame atomic absorption spectrometry (FAAS) was used for its determination. The effect of pH, sample flow rate and the volume and concentration of eluent on the recovery of the analyte was investigated and the optimum conditions were established. A pre-concentration factor of 400, and an adsorption capacity of 6.9 mg g(-1) of the solid-phase sorbent or 82.8 mg g(-1) of ligand was achieved using the optimum conditions. The calibration graph was linear in the range of 1.0-4000 ng mL(-1) with the detection limit of 1.0 ng mL(-1). A R.S.D. value of 2.4% was obtained by this method for 400 ng mL(-1) of Cu(2+) solution. This procedure has been successfully applied to separate and determine the ultra trace levels of copper in the environmental samples, free from the interference of some diverse ions.