This review summarizes the evolution that has been made for organophosphates (OPs) detection technique using conventional technique (lab-based) and compact technique (colorimetric and electrochemical). Right after introduction section, a first section covers the types, chemical structure and risks of OPs. Methods for detection using conventional and compact technique were discussed next. An additional section covers the limitation of conventional detection technique and advantages of compact detection technique are addressed. Several Tables are presented that give an overview on the OPs detection using conventional and compact detection technique. A concluding section addresses a brief idea on the detection method available nowadays.
Epoxidized fatty hydrazides (EFHs) which have amine, amide and epoxide functional groups in their molecules are a versatile starting material for synthesizing of many industrially important compounds. In this report we describe the results of our preliminary study of synthesizing these compounds using a chemical reaction of epoxidized palm olein (EPO) and hydrazine monohydrate. The products were characterized by using Fourier transform infrared (FTIR) spectroscopy, nuclear magnetic resonance (NMR) technique and CHN elemental analyser. The optimum reaction conditions for the hydrazide preparation were investigated by studying effect of each important reaction parameters on the product yields. The study shows that the optimum conditions to produce EFHs were using EPO to hydrazine monohydrate (mol ratio of 1 to 12), n-hexane as the solvent and at the temperature of 69 ̊C.
Multidrug resistant Pseudomonas aeruginosa (P. aeruginosa) is known to be a problematic bacterium for being a major cause of opportunistic and nosocomial infections. In this study, reduced graphene oxide decorated with gold nanoparticles (AuNPs/rGO) was utilized as a new sensing material for a fast and direct electrochemical detection of pyocyanin as a biomarker of P. aeruginosa infections. Under optimal condition, the developed electrochemical pyocyanin sensor exhibited a good linear range for the determination of pyocyanin in phosphate-buffered saline (PBS), human saliva and urine at a clinically relevant concentration range of 1-100 μM, achieving a detection limit of 0.27 μM, 1.34 μM, and 2.3 μM, respectively. Our developed sensor demonstrated good selectivity towards pyocyanin in the presence of interfering molecule such as ascorbic acid, uric acid, NADH, glucose, and acetylsalicylic acid, which are commonly found in human fluids. Furthermore, the developed sensor was able to discriminate the signal with and without the presence of pyocyanin directly in P. aeruginosa culture. This proposed technique demonstrates its potential application in monitoring the presence of P. aeruginosa infection in patients.
Conducting polymers have been widely used in electrochemical sensors as receptors of the sensing signal's analytes and transducers. Polypyrrole (PPy) conducting polymers are highlighted due to their good electrical conductive properties, ease in preparation, and flexibility of surface characteristics. The objective of this review paper is to discuss the theoretical background of the two main types of electrochemical detection: impedimetric and voltammetric analysis. It also reviews the application and results obtained from these two electrochemical detections when utilizing PPy as a based sensing material in electrochemical sensor. Finally, related aspects in electrochemical sensor construction using PPy will also be discussed. It is anticipated that this review will provide researchers, especially those without an electrochemical analysis background, with an easy-to-understand summary of the concepts and technologies used in electrochemical sensor research, particularly those interested in utilizing PPy as a based sensing material.
Nitrocellulose (NC) has garnered significant interest among researchers due to its versatile applications, contingent upon the degree of nitration that modifies the cellulose structure. For instance, NC with a high nitrogen content, exceeding 12.5%, finds utility as a key ingredient in propellant formulations, while variants with lower nitrogen content prove suitable for a range of other applications, including the formulation of printing inks, varnishes, and coatings. This communication aims to present the outcomes of our efforts to optimize the nitration reaction of bacterial cellulose to produce high-nitrogen-content NC, employing the response surface methodology (RSM). Our investigation delves into the influence of the mole ratio of sulfuric and nitric acids, reaction temperature, and nitration duration on the nitrogen content of the resultant products. Utilizing a central composite design (CCD), we identified the optimal conditions for NC synthesis. Analysis of variance (ANOVA) underscored the substantial impact of these reaction conditions on the percentage of nitrogen content (%N) yield. By implementing the predicted optimal conditions-namely, a H2SO4:HNO3 mole ratio of 3:1, a reaction temperature of 35 °C, and a reaction period of 22 min-we successfully produced NC with a nitrogen content of 12.64%. Characterization of these products encompassed elemental analysis, Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), thermal gravimetric analysis (TGA), and field emission scanning electron microscopy (FESEM).
The wide availability and diversity of dangerous microbes poses a considerable problem for health professionals and in the development of new healthcare products. Numerous studies have been conducted to develop membrane filters that have antibacterial properties to solve this problem. Without proper protective filter equipment, healthcare providers, essential workers, and the general public are exposed to the risk of infection. A combination of nanotechnology and biosorption is expected to offer a new and greener approach to improve the usefulness of polysaccharides as an advanced membrane filtration material. Nanocellulose is among the emerging materials of this century and several studies have proven its use in filtering microbes. Its high specific surface area enables the adsorption of various microbial species, and its innate porosity can separate various molecules and retain microbial objects. Besides this, the presence of an abundant OH groups in nanocellulose grants its unique surface modification, which can increase its filtration efficiency through the formation of affinity interactions toward microbes. In this review, an update of the most relevant uses of nanocellulose as a new class of membrane filters against microbes is outlined. Key advancements in surface modifications of nanocellulose to enhance its rejection mechanism are also critically discussed. To the best of our knowledge, this is the first review focusing on the development of nanocellulose as a membrane filter against microbes.
Chemical contaminants such as heavy metals, dyes, and organic oils seriously affect the environment and threaten human health. About 2 million tons of waste is released every day into the water system. Heavy metals are the largest contributor which cover about 31% of the total composition of water contaminants. Every day, approximately 14 000 people die due to environmental exposure to selected chemicals. Removal of these contaminants down to safe levels is expensive, high energy and unsustainable by current approaches such as oxidation, biodegradation, photocatalysis, precipitation, reverse osmosis and adsorption. A combination of biosorption and nanotechnology offers a new way to remediate these chemical contaminants. Nanostructured materials are proven to have higher adsorption capacities than the same material in its larger-scale form. Nanocellulose is very promising as a high-performance bioadsorbent due to its interesting characteristics of high adsorption capacity, high mechanical strength, hydrophilic surface chemistry, renewability and biodegradability. It has been proven to have higher adsorption capacity and better binding affinity than other similar materials at the macroscale. The high specific surface area and abundance of hydroxyl groups within lead to the possible functionalization of this material for decontamination purposes. Several research papers have shown the effectiveness of nanocellulose in the remediation of chemical contaminants. This review aims to provide an overview of the most recent developments regarding nanocellulose as an adsorbent for chemical contamination remediation. Recent advancements regarding the modification of nanocellulose to enhance its adsorption efficiency towards heavy metals, dyes and organic oils were highlighted. Moreover, the desorption capability and environmental issue related to every developed nanocellulose-based adsorbent were also tackled.