Graphite carbon nitride-modified screen-printed electrode as a highly sensitive and selective sensor for detection of amaranth.

This work presented a particular electrochemical sensor for analysis of amaranth, an azo toxic dye. A graphite nitride carbon (g-C3N4) was used to modify an electro-treated screen-printed electrode (g-C3N4/SPE) for electroanalysis of amaranth. Physicochemical characteristics and analytical performance of g-C3N4/SPE were investigated by relevant equipment. The g-C3N4/SPE when comparing with bare SPE, possessed an impressive electrocatalytic performance towards the amaranth oxidation. As-developed sensor under the optimal circumstances exhibited an extended linear response range for different amaranth concentrations of 0.08 µM-340.0 µM, with a narrow practical limit of detection (LOD) of 0.02 µM, a limit of quantification (LOQ) of 0.08 µM, and an unparalleled sensitivity of 0.0702 µA/µM using differential pulse voltammetry (DPV). The applicability of as-fabricated sensor was verified by determining the amaranth in real samples, with acceptable recoveries.

Recent advances in carbon nanomaterials-based electrochemical sensors for food azo dyes detection.

Azo dyes as widely applied food colorants are popular for their stability and affordability. On the other hand, many of these dyes can have harmful impacts on living organs, which underscores the need to control the content of this group of dyes in food. Among the various analytical approaches for detecting the azo dyes, special attention has been paid to electro-analytical techniques for reasons such as admirable sensitivity, excellent selectivity, reproducibility, miniaturization, green nature, low cost, less time to prepare and detect of specimens and the ability to modify the electrode. Satisfactory results have been obtained so far for carbon-based nanomaterials in the fabrication of electrochemical sensing systems in detecting the levels of these materials in various specimens. The purpose of this review article is to investigate carbon nanomaterial-supported techniques for electrochemical sensing systems on the analysis of azo dyes in food samples in terms of carbon nanomaterials used, like carbon nanotubes (CNT) and graphene (Gr).

Green Synthesis of Zeolitic Imidazolate Frameworks: A Review of Their Characterization and Industrial and Medical Applications.

Metal organic frameworks (MOF) are a class of hybrid networks of supramolecular solid materials comprising a large number of inorganic and organic linkers, all bound to metal ions in a well-organized fashion. Zeolitic imidazolate frameworks (ZIFs) are a sub-group of MOFs with imidazole as an organic linker to metals; it is rich in carbon, nitrogen, and transition metals. ZIFs combine the classical zeolite characteristics of thermal and chemical stability with pore-size tunability and the rich topological diversity of MOFs. Due to the energy crisis and the existence of organic solvents that lead to environmental hazards, considerable research efforts have been devoted to devising clean and sustainable synthesis routes for ZIFs to reduce the environmental impact of their preparation. Green chemistry is the key to sustainable development, as it will lead to new solutions to existing problems. Moreover, it will present opportunities for new processes and products and, at its heart, is scientific and technological innovation. The green chemistry approach seeks to redesign the materials that make up the basis of our society and our economy, including the materials that generate, store, and transport our energy, in ways that are benign for humans and the environment and that possess intrinsic sustainability. This study covers the principles of green chemistry as used in designing strategies for synthesizing greener, less toxic ZIFs the consume less energy to produce. First, the necessity of green methods in today's society, their replacement of the usual non-green methods and their benefits are discussed; then, various methods for the green synthesis of ZIF compounds, such as hydrothermally, ionothermally, and by the electrospray technique, are considered. These methods use the least harmful and toxic substances, especially concerning organic solvents, and are also more economical. When a compound is synthesized by a green method, a question arises as to whether these compounds can replace the same compounds as synthesized by non-green methods. For example, is the thermal stability of these compounds (which is one of the most important features of ZIFs) preserved? Therefore, after studying the methods of identifying these compounds, in the last part, there is an in-depth discussion on the various applications of these green-synthesized compounds.

Investigating the role of T helper related cytokines in cerebrospinal fluid for the differential diagnosis of bacterial meningitis in pre-treated paediatric patients.

Purpose: Given the challenge in the diagnosis of bacterial meningitis (BM), we assessed different cytokines in the cerebrospinal fluid (CSF) of antibiotics pre-treated patients.Materials and methods: Laboratory tests and polymerase chain reaction (PCR) were performed for 480 CSF samples from children (2 m to 14 y), suspicious to meningitis and pre-treated with antibiotics, to detect bacterial and viral aetiologies. Sixty-one CSF were included and the levels of 13 cytokines such as IL-2, IL-4, IL-5, IL-6, IL-9, IL-10, IL-13, IL-17A, IL-17F, IL-21, IL-22, IFN-γ and TNF-α were measured using flow-cytometry.Results: All bacterial cultures were negative, but 29 and eight CSF were positive for bacterial and viral agents by PCR. IL-6, IL-10 and IFN-γ were significantly up-regulated in BM. T helper (Th) subset cytokines showed significant upregulation of Th1, Th2, Th17, Th22 and Tfh cytokines in BM. Common Th subsets cytokines (IL-6, IL-10 and TNF-α) were significantly different between the study groups. ROC curve analysis revealed good AUC for common Th related cytokines in discriminating BM.Conclusions: In pre-treated BM patients with negative bacterial cultures, cytokines IL-6, IL-10 and IFN-γ can predict BM which could be beneficial for rapid diagnosis and treatment to decrease the sequela of the disease.