Chemical Review and Letters
Volume:3 Issue: 4, Autumn 2020

In this project, ultra-trace amounts of Fenvalerate residue in raisin, were determined via vortex-assisted surfactant-enhanced emulsification liquid–liquid micro extraction (VSLLME) method and by using HPLC-PDA detector at 225nm. In the VSLLME method, the extraction solvent is dispersed into the aqueous samples by assistance of vortex agitator. Meanwhile, the addition of a surfactant, which was used as an emulsifier, could enhance the rate of the mass-transfer from aqueous samples to the extraction solvent. The main parameters relevant to this method were investigated and the optimum conditions were established: 20 µL chlorobenzene was used as extraction solvent, 0.9 mmol.L-1CTAB was selected as the surfactant, the extraction time was fixed at 60s, 2% sodium chloride was added and the extraction process was performed under the room temperature. Under the optimum conditions, limit of detection (LOD) was 0.3 ng mL-1. The relative standard deviation (RSD, n=6) was 2.87%. The linearity was obtained by five points in the concentration range of 0.3 to 100.0 ng mL-1. Correlation coefficients (R2) was 0.9997, and the enrichment factor (EF) was 114. Finally, the proposed method has been successfully applied for determination of Fenvalerate in real samples. The recoveries of the target analyte in raisins samples were between 84.13% and 92.12%.

Iranian white Cheese is a traditional type of cheese in Iran which is popular and widely consumed because of its pleasant organoleptic properties. To manufacture this cheese, raw milk is heated below pasteurization temperature, therefore, pathogenic and spoilage bacteria remain and cause several diseases in public health. In this research three kinds of nanocomposite films based on LDPE incorporated 1) Ag, CuO, ZnO, 2) Cloisite 15A, Cloisite 20A, Cloisite 30B that produced by extrusion method were used for packaging of the cheese and kept in 4°C during 28 days. Data analysis carried out using SPSS statistical software based on a completely randomized design. The results showed the nanocomposite films incorporated with metal nanoparticles had a significant decrease in the growth of Staphylococcus aureus, coliform, mold and yeast after 28 days, while, the growth of lactic acid bacteria decreased but less than control film. Sensory properties of cheese samples packed in active films were not significantly changed. However, physicochemical characteristics such as pH and moisture content were affected significantly by active films. Overall migration of packaging active films in food simulants were within amounts allowed by national and international legislations.

In this research, the performance of single-walled carbon nanotube (SWCN) as a sensor and nanocarrier for procarbazine (PC) was investigated by infra-red (IR), natural bond orbital (NBO), frontier molecular orbital (FMO) computations. All of the computations were done using the density functional theory method in the B3LYP/6-31G (d) level of theory The calculated negative values of adsorption energy, enthalpy changes, Gibbs free energy changes showed the PC interaction with SWCN is exothermic, spontaneous and experimentally possible. The increasing of specific heat capacity (CV) of SWCN after adsorption of PC showed the thermal conductivity improved during the interaction process and this nanostructure is an excellent sensing material for the detection of PC. The NBO results demonstrate in all of the evaluated conformers a chemical bond with SP3 hybridization is formed between the medicine and SWCN. The great values of thermodynamic constants showed the adsorption process is irreversible and SWCN is not a suitable nanocarrier for delivery of PC. The density of states (DOS) spectrums showed the bandgap of SWCN decreased sharply after the adsorption of PC and this nanomaterial can be used as a sensor for electrochemical detection of PC.

Waste produced from car breaker companies severely affects the environment. So far, the only way to manage this complex waste is to bury it. In this research, the waste converted to hydrocarbons and carbon black by co-pyrolysis process in the designed high performance co-pyrolysis system. The results showed that the as-obtained maximum yield of heavy oil and light hydrocarbon wax, carbon black and non-condensable gas can be listed as mass basis of 8, 34, 3, 40 and 15%, respectively. The ratio of 5 W/W% treated expanded perlite as catalyst to waste increased the amount of light hydrocarbons to 34 W/W%.

Since their discovery by Burg and Schlesinger in 1937, amine-boranes have enjoyed a rich preparative history and have experienced reinvigorated interest as valuable compounds. These borane complexes have been implemented in a variety of applications, spanning from reagents in organic syntheses to hydrogen storage materials. The importance of amine-boranes derives especially from their reductive abilities. Given the utility of amine-boranes and their current resurgence, a mini review on their general properties and notable preparations is both timely and potentially of interest to organic and materials chemists alike.

Today, the use of new technologies in the food industry has become very important and widely used. Identifying these technologies and expanding them is very important for industrial societies. One of the new methods for analyzing and measuring materials in trace levels is electrochemical sensors. In the electrochemical sensors the reaction between food analytes and sensors are happen. These sensors have the ability to generate electrical signals appropriate to the concentration of the analytes. These sensors have been very effective in measuring and determining compounds and are being developed using new techniques. These sensors have many advantages over older and more expensive methods, while also being highly accurate. These sensors have a lot of potential and benefits, so in this study, it has been tried to define these new methods by using practical examples and described the use of these new methods in various industries, especially in the food industry.

Unlike other related compounds, vitamin D has multi-function operations against 2019-nCoV virus via intervention in several parts of its lifecycle. In one hand, this compound induces antimicrobial peptides like cathelicidins and proteins like defensins that lead to lower viral replication rates and also reduces the concentrations of pro-inflammatory cytokines (it causes inflammation that results in multi-organ failure). In the other hand, a vitamin D agonist, calcitriol, modulates the expression of members of the renin‑angiotensin system, including angiotensin converting enzymes like ACE2 (the cell receptor for 2019-nCoV viral spike protein). Thus, vitamin D may reduce the spike rate of the virus to the lung cells, resulting in inhibition of the virus in entry stage. About vitamin B series, there is a report that claims vitamin B12 may inhibit RNA-dependent-RNA polymerase activity of nsp12 from the 2019-nCoV virus.‏Also, vitamins C, and E (anti-oxidants with anti-inflammatory effects) could be effective in inhibiting the damages of the organs caused by the acute immune response (inhibiting the release of high concentrations of free radicals) during COVID-19 as well as boosting the human immune system. It must be mentioned that, in spite of the presented supporting references, this paper is prepared for researcher, not for all people.

Electrides are interesting and promising materials with cavity-trapped electrons which can be used as source of electron donor in different systems. Hereby, we have explored the possible formation of electride materials based on tetracyanoethylene (TCNE) backbone at MP2 computational level. This is achieved by systematic addition of up to four Na atoms to TCNE backbone. Our results predict high thermodynamic stability in the Nan@TCNE (n=1-4) systems. Moreover, based on the evaluation of four criteria, non-nuclear attractor (NNA), electron localization function (ELF), electron density laplacian (∇^2 ρ(r)), and non-linear optical (NLO), TCNE-Na1 and TCNE-Na2 and TCNE-Na4 species are conventional donor-acceptor systems (lithium salt). In contrast, the TCNE-Na3 species can be introduced as sodium electride with cavity-trapped electrons. Therefore, Na:TCNE ratio is very significant factor to provide species with electride feature through the addition of Na atoms to TCNE backbone.