In this study, bio-synthesis of gold, silver and copper nanoparticles from aqueous solution of HAuCl4, silver nitrate and copper nitrate using water and ethanol extract of Malva parviflora L. at room conditions was successfully carried out. The leaf extract of Malva parviflora was obtained using ultrasound-assisted extraction method. The reaction process was monitored by UV–vis spectrophotometry. The synthesized gold, silver and copper nanoparticles were generally characterized by UV-vis spectroscopy, Transmission electron microscopy (TEM), Particle size analysis (PSA), Energy Dispersive X ray spectroscopy (EDX) and Zeta potential analysis. The effect of different variables on the biosynthesis such as, time and pH were studied.
Furthermore, cytotoxicity of extract and synthesized nanoparticles on cell culture were evaluated and non- cytotoxic concentration were evaluated by MTT- assay and 50% cytotoxicity concentration (CC50) was measured; then at the non- cytotoxic concentration of each of extracts and synthesized nanoparticles, their antiviral activity was examined by colorimetric MTT- assay. Results revealed that the ethanolic and water extract were non- cytotoxic in concentration of 0.0312 mg L-1. The synthesized gold and silver nano particle using water extract were not cytotoxic at concentrations of 0.0201 and 0.0018 nmol L-1, spectively. As well as the synthesized gold and silver nanoparticles using ethanolic (80%) extract at 0.0076 and 0.0025 nmol L-1, respectively and copper nanoparticles at concentration of 4.2 nmol L-1 were not cytotoxic. Furthermore the results .shoued that the water and ethanolic extract as well as synthesized silver nanoparticles have prominent antiviral activity

In another research, an optical sensing method based on plasmon absorbance of silver nanoparticles (AgNPs) was developed for the determination of 2- Mercaptobenzimidazol (MBI). AgNPs were synthesized by the leaf aqueous extract of Malva parviflora L. at room temperature. The addition of MBI to synthesized AgNPs in the presence of cethyl trimethyl ammonium bromide (CTAB) and acidic media resulted in the intensity decrease of plasmon absorbance peak. The effect of different variables such as pH, amount of CTAB and AgNPs and time was investigated and optimized. The obtained results indicated that the calibration graph was linear in the concentration range of 0.5–10 mg L-1 of MBI and the detection limit was 0.31 mg L-1. The relative standard deviation for eight replicate measurements of 2 and 8 mg L-1 of MBI was 4.2 and 2.3 %, respectively. The method was successfully applied to the determination of MBI in different water samples.

 

 

In this study, a simple and sensitive colorimetric method based on surface plasmon resonance of in-situ synthesized gold nanoparticles (AuNPs)was used for determination of ranitidine hydrochloride (Zantac) in biological samples and pharmaceutical formula. The stable and dispersed AuNPs were directly synthesized by reduction of HAuCl4 with ascorbic acid in micellar media according to a simple approach. The process of synthesis of gold nanoparticles dependent on the presence of the ranitidine which the intensity of surface plasmon resonance of gold nanoparticles was reduced. It was found that the amount of ranitidine could be detect based on the change ofthe plasmon resonance absorbance of AuNPs at 538 nm (∆A). The effect of pH, concentration of CTAB as stabilizer, ascorbic acid as reducing agent, HAuCl4concentration and time was studied and optimized. The proposed method is capable of determining ranitidine over a range of 0.285-5.700µmol L-1 (or 0.1-2.0μg mL-1) of ranitidine with a limit of detection 0.141µmol L-1 (0.05 μg mL-1). The relative standard deviation of the method was <3.5 %. Interference effects of various chemical species were studied.The method was successfully applied to the determination of ranitidine in human plasma and tablet samples.The accuracy of the proposed method was evaluated using a standard method and its authenticity was confirmed

In this research nano particles of carbon dots(CDs) was synthesized using glucose under ultrasonic conditions and then used as green reducing agent for preparation of gold nanoparticles (AuNPs). The synthesized AuNPs using CDs and in the presence of CTAB and Zineb (ethylene bis (dithiocarbamate) zinc) have a strong plasmon resonance absorption peak which its intensity increased upon addition of Zineb concentration
The variation of AuNPs absorbance peak was used for spectrophotomericaly detection of Zineb. The effect of different variables such as pH, amount of CDs and CTAB as stabilizer was investigated and optimized. The calibration curve was linear in the range of 2.5─100 ng mL ^-1 of Zineb and the limit of detection was 1.3 ng mL ^-1. Tha relative standard deviation for seven measurements of 20 and 80 ng mL ^-1 of Zineb was 2.7 and 3.8 % , respectively. The method was successfully applied to the determination of spiked Zineb in different water samples
 

In this research a dispersive liquid-liquid microextraction (DLLME) method for the determination of H2O2 is described. The reaction between hydrogen peroxide and iodide ions to produce I3- was used for this measurement and I3- extracted with DLLME procedure using carbon tetrachloride (extraction solvent) containing methyltrioctyl ammonium chloride which provides counter ion and also acts as the disperser. After extraction, the phase separation is performed by rapid centrifugation, and H2O2 in the enriched phase is determined by UV-Vis spectrophotometry. Several factors affecting the microextraction efficiency, such as type and volume of extraction solvents, extraction time and concentration of electrolyte were investigated. Under the optimum extraction condition, the method yields two linear calibration curves in the concentration rang of 1×10-8 - 2×10-7 mol L-1 and 2×10-7 - 18×10-7 mol L-1. The limit of detection based on three standard deviation of the blank was 6.3×10-9 mol L-1 and the relative standard deviation for seven replicate measurements of 1×10-7 and 5×10-7 mol L-1 was 2.67 and 1.05 %. The proposed method was successfully applied to determination of trace amount of H₂O₂ in lens solution, water and commercial oxidant samples.

In another research, a dispersive liquid-liquid microextraction (DLLME) method for the determination of gentamicin is described. The method is based on oxidation of the gentamicin by I3-.The reaction between hydrogen peroxide and iodide ions produces I3- which is extracted with DLLME procedure using carbon tetrachloride (extraction solvent) containing methyltrioctyl ammonium chloride which provides counter ion and also acts as the disperser. After extraction, the phase separation is performed by rapid centrifugation, and gentamicin is determined by UV-Vis spectrophotometry. Gentamicin reacts with I3- and reduces the absorbance of extracted I3- . Under the optimum extraction condition, the method yields a linear calibration curve for gentamicin in the concentration range of 0.4 - 80 μg mL-1. The limit of detection based on three standard deviation of the blank was 0.25 μg mL-1 and the relative standard deviation for seven replicate measurements of 1 and 40 μg mL-1 was 1.43 and 0.29 %. The proposed method was successfully applied to determination of trace amounts of gentamicin in milk, eye drops, urine and plasma.
 

 An optical chemical sensor based on immobilization of thorin using methyltrioctylammonium chlorid on triacethylcellulose polymer for determination lanthanum (ш) was developed. By immersion of the membrane of sensor into an acidic solution of lanthanum, the color is changed from orange to pink which lanthanum can be determined spectrophotometrically. The effect of various parameters on sensor response was studied and optimum conditions was established. This optode exhibits two linear range of 6×10-5-4× 10-4 mol L^(-1) and 8×10-6-1×10-4 mol L^(-1) of the lanthanum(ш) ion concentration at 540 and 370 nm, respectively with detection limit of 4.9×10-6 mol L^(-1). The regeneration of optod was accomplished completely at a short time with 0.1 mol L^(-1) ammonium oxalate ion solution. The relative standard deviation for eight replicate measurements of 2×10-5 , 8×10-5 and 2×10-4 mol L^(-1) La (ш) was 3.94 , 2.1 and 3.2 % , respectively. The proposed sensor was successfully applied to the determination of La3+ in aqueous solution.
In another research a highly selective optical chemical sensor was developed for mercury(п) ion based on immobilization gold nanoparticles (Au NPs ) using tetraethylthiuramdisulfide on triacethylcellulose polymer. Reduction of Au3+ to gold nanoparticles by ascorbic acid in the presence of Hg (п) results in the decrease of the intensity of plasmon resonance peak. The variation in the plasmon absorbance allow the colorimetric determination of mercury(п). The effect of various parameters on sensor response was studied and optimum condition was stablished. The calibration curve was linear in the range of 1-30 g L-1 of Hg (п) with detection limit 0.55 g L-1. The relative standard deviation for eight replicate measurments of 6 and 20 g L-1 was 4.9 and 2.7 % , respectively. The optode membrane exhibits good selectivity for Hg (п) over many cations and anions. A good agreement with the spiked method was achieved when the proposed optode was applied to the determination of mercury ion in water samples.

 : A new optical sensor has been established for the determination of Sb (III) by immobilizing methyltrioctylammonium chloride on triacetylcellulose membrane. The exchange of chloride as counter ion with iodide in the membrane changes the colorless film to yellow, when it is placed in acidic solution of Sb (III). The effect of different parameters such as amount of methyltrioctylammonium chloride, concentration of sulfuric acid and iodide was investigated and optimum conditions were established. The calibration curve was linear in the range of 0.66 - 230 µmol L-1 of Sb (III) ion with a limit of detection 0.60 µmol L-1. The sensor can readily be regenerated with 0.1 mol L-1 sodium citrate solution. This optode is stable and could be stored under water for more than a month without reagent leaching. The relative standard deviation for eight replicate measurements of 19.7 and 131.4 µmol L-1 Sb (III) was 4.03 and 1.68 %, respectively. The sensor was successfully applied to the determination of antimony in water samples and a pharmaceutical formulation (Glucantime).
In another research a novel optical sensor (optode) is developed for the determination of antimony(III) using methyltrioctylammonium chloride immobilized on glass membrane in sol-gel bed . The response of this sensor is also due to exchange of chloride with iodide in the membrane and formation a yellow complex between iodide and Sb (III) in sensor membrane. The effect of different parameters such as amount of tetraethoxy silan, ethanol and methyltrioctylammonium chloride in sol-gel preparation and concentration of sulfuric acid and iodide was studied. Under optimum conditions, the proposed membrane is capable of determining Sb (III) over a dynamic range between 2.63 – 131.41 µmol L-1 with a limit of detection 2.16 µmol L-1 The relative standard deviation for eight replicate measurements for 32.85 µmol L-1 of antimony was 4.15 %. The sensor can readily be regenerated by 0.1 mol L-1 sodium citrate solution in less than 10 S. The effect of interfering ions on sensor response was investigated. The sensor was applied to the determination of antimony in a pharmaceutical formulation (Glucantime) and different water samples with satisfactory results.