Sensitive electrochemical determination of trace cadmium on a stannum film/poly(p-aminobenzene sulfonic acid)/electrochemically reduced graphene composite modified electrode

Effects of dust phenomenon on heavy metals in raw milk in western Iran

Introduction. After the Iraq war, the dust phenomenon has increased in western Iran. Our study aimed to evaluate the effect of the dust phenomenon on the content of heavy metals in raw milk in Ilam province. Study objects and methods. The dust samples were collected during one year. The concentrations of dust particles were determined with the Enviro Check Laser System, using the Dust Monitor Check. The concentration of heavy metals in dust was determined by using the high volume air samplers and glass fiber filters. Results and discussion. Heavy metals (lead, arsenic, zinc, copper, and iron) were measured at four sampling sites in raw milk by the atomic absorption method. The mean and standard deviations of dust particulate matter (PM10 and PM2.5) were 105.6 ± 90.5 and 25.9 ± 15.4 μg/m3, respectively. The amounts of arsenic, zinc, lead, and copper were higher in the spring and summer. Lead levels in western and southern regions were higher than those in the east, center, and north. Conclusion. We found similar trends for arsenic, zinc, copper, and iron in raw milk. Our results showed the potential effect of the dust phenomenon on the presence of heavy metals in raw milk.

Graphene-derived nanomaterials as recognition elements for electrochemical determination of heavy metal ions: a review

This review (with 155 refs.) summarizes the progress made in the past few years in the field of electrochemical sensors based on graphene-derived materials for the determination of heavy metal ions. Following an introduction of this field and a discussion of the various kinds of modified graphenes including graphene oxide and reduced graphene oxide, the review covers graphene based electrodes modified (or doped) with (a) heteroatoms, (b) metal nanoparticles, (c) metal oxides, (d) small organic molecules, (e) polymers, and (f) ternary nanocomposites. Tables are provided that afford an overview of representative methods and materials for fabricating electrochemical sensors. Furthermore, sensing mechanisms are discussed. A concluding section presents new perspectives, opportunities and current challenges. Graphical Abstract Schematic illustration of electrochemical sensor for heavy metal ion sensing based on heteroatom-doped graphene, metal-modified graphene, metal-oxide-modified graphene, organically modified graphene, polymer-modified graphene, and ternary graphene based nanocomposites.

Modification of gold surface by electrosynthesized mono aza crown ether substituted catechol-terminated alkane dithiol and its application as a new electrochemical sensor for trace detection of cadmium ions

Among the toxic metals, cadmium is a very dangerous pollutant because it can extremely damage organs in humans and animals. This toxic metal is introduced into water from different industries such as metal plating, batteries, and alloys. Cadmium bioaccumulates in vital organs and unlike organic pollutants does not show any biological degradation. In this study, an electroactive self-assembled monolayer (SAM) was developed by covalent attachment of a novel mono aza-crown ether substituted catechol-terminated hexane dithiol onto the gold surface. The electrochemical behavior of the fabricated SAM electrode was investigated using voltammetry techniques and electrochemical impedance spectroscopy (EIS). The obtained results from voltammetric experiments revealed that the crown ether moiety of SAM forms a selective complex with cadmium ion. Under optimal conditions, Cd²⁺ could be detected in the range of 15 μM to 65 μM with a detection limit of 4.5 μM. Selectivity measurements reveal that the sensor is specific for Cd²⁺ even in the presence of high concentrations of other metal ions. The proposed sensor was applied to the determination of cadmium ion in water samples with high sensitivity and good selectivity.

A phosphorylethanolamine-functionalized super-hydrophilic 3D graphene-based foam filter for water purification

A phosphorylethanolamine-functionalized graphene foam (PNGF) has been proposed as an active filtration material for the capture and removal of heavy metal ions in water. Benefiting from its abundant hydrophilic portion of oxygen, nitrogen and phosphorus groups, the PNGF is super-hydrophilic. The selected heavy metal ions, Pb(II) and Cd(II), could be rapidly and efficiently absorbed within 10min using the PNGF through a filtration model, which is obviously less time compared with the several hours or even longer time when employing the traditional shaking or stirring model. In addition, the used PNGF filters can be easily reused after a simple, low-cost detachment using HCl to remove the heavy metals, providing a new approach for water purification.

How cutting-edge technologies impact the design of electrochemical (bio)sensors for environmental analysis. A review

Through the years, scientists have developed cutting-edge technologies to make (bio)sensors more convenient for environmental analytical purposes. Technological advancements in the fields of material science, rational design, microfluidics, and sensor printing, have radically shaped biosensor technology, which is even more evident in the continuous development of sensing systems for the monitoring of hazardous chemicals. These efforts will be crucial in solving some of the problems constraining biosensors to reach real environmental applications, such as continuous analyses in field by means of multi-analyte portable devices. This review (with 203 refs.) covers the progress between 2010 and 2015 in the field of technologies enabling biosensor applications in environmental analysis, including i) printing technology, ii) nanomaterial technology, iii) nanomotors, iv) biomimetic design, and (v) microfluidics. Next section describes futuristic cutting-edge technologies that are gaining momentum in recent years, which furnish highly innovative aspects to biosensing devices.

Protic salt-based nitrogen-doped mesoporous carbon for simultaneous electrochemical detection of Cd(ii) and Pb(ii)

Nitrogen-doped mesoporous carbon (NMC) derived from a single small-molecule protic salt (p-phenylenediamine bisulfate) is used for sensing toxic heavy metal ions.

Nanomaterials-based electrochemical detection of chemical contaminants

Recent advances in the development of nanomaterials-based electrochemical sensors for environmental monitoring and food safety applications are assessed.