Synthesis of the quinazolinone derivatives using an acid-functionalized magnetic silica heterogeneous catalyst in terms of green chemistry.

In this research, the synthesis of the quinazolinone derivatives by the reaction of diaminoglyoxime with anthranilic acid or methyl 2-amino benzoate over an acetic acid-functionalized magnetic silica-based catalyst in water was described. The acetic acid-functionalized catalyst was prepared using a three-step procedure from magnetite NPs that initially coated with a layer of silica through the sol-gel process, modified with an aminosilane layer and functionalized with bromoacetic acid. The catalyst was characterized by means of spectroscopic and microscopic techniques, and its activity was investigated for the synthesis of the quinazolinones, bisquinazolinone and oxadiazole quinazolinones obtained from diaminoglyoxime in water at room temperature.

Determination of Hg(II) ions in sea food samples after extraction and preconcentration by novel Fe3O 4@SiO 2@polythiophene magnetic nanocomposite.

This work describes a novel Fe3O4@SiO2@polythiophene magnetic nanocomposite and its application in the preconcentration of Hg(II) ions. The parameters affecting the preconcentration procedure were opted by a Box-Behnken design through response surface methodology. Three factors (uptake time, magnetic nanosorbent amount, and pH of sample) were selected as the main factors affecting the sorption step, while four variables (type, volume and concentration of the eluent as well as the elution time) were selected as main factors in the optimization study of the elution step. Following the sorption and elution of Hg(II), it was quantified by cold vapor atomic absorption spectrometry. Under the optimum condition, the limit of detection was 0.02 ng mL(-1) and all the relative standard deviations were less than 9.2 %. The obtained sorption capacity of this new sorbent was 59 mg g(-1). Finally, this nanocomposite was successfully applied to the rapid extraction of trace quantities of Hg(II) ions in sea food samples and satisfactory results were obtained.

Synthesis of 2-(1,2,4-oxadiazol-3-yl)quinazolin-4(3H)-ones from diaminoglyoxime-based nitrones.

Various 2-[5-(aryl)-1,2,4-oxadiazol-3-yl]quinazolin-4(3H)-ones have been synthesized from the reaction of diaminoglyoxime-based nitrones with methyl 2-aminobenzoate or 2-aminobenzamide in the presence of acetic acid at 100 °C. The reaction was extended as a one-pot three-component approach starting from diaminoglyoxime, aldehyde and methyl 2-aminobenzoate.

Determination of heavy metal ions in vegetable samples using a magnetic metal-organic framework nanocomposite sorbent.

This paper describes the synthesis and application of a novel magnetic metal-organic framework (MOF) [(Fe3O4-benzoyl isothiocyanate)/Cu3(benzene-1,3,5-tricarboxylate)2] to pre-concentrate trace amounts of Cd(II), Pb(II), Zn(II) and Cr(III) ions and their determination by flame atomic absorption spectrometry. A Box-Behnken design was used to find the parameters affecting the pre-concentration procedure through response surface methodology. Three factors including uptake time, amount of the magnetic sorbent and pH of the sample were selected as affecting factors in the sorption step, and four factors including type, volume and concentration of the eluent as well as the elution time were selected in the elution step for the optimisation study. The opted values were 30 mg, 10.1 min, 5.9, EDTA, 4.0 ml, 0.57 mol l(-1) EDTA solution and 13.0 min for the amount of the magnetic sorbent, uptake time, pH of the sample, type, volume, concentration of the eluent, and elution time, respectively. The limits of detection (LODs) were 0.12, 0.7, 0.16, and 0.4 ng ml(-1) for Cd(II), Pb(II), Zn(II) and Cr(III) ions, respectively. The relative standard deviations (RSDs) of the method were less than 7.2% for five separate batch experiments for the determination of 30 µg l(-1) of Cd(II), Pb(II), Zn(II) and Cr(III) ions. The sorption capacity of the [(Fe3O4-benzoyl isothiocyanate)/MOF] was 175 mg g(-1) for Cd(II), 168 mg g(-1) for Pb(II), 210 mg g(-1) for Zn(II) and 196 mg g(-1) for Cr(III). It was found that the magnetic MOF nanocomposite demonstrated a higher capacity compared with Fe3O4-benzoyl isothiocyanate. Finally, the magnetic MOF nanocomposite was successfully applied to the rapid extraction of trace amounts of the heavy metal ions from vegetable samples.

Determination of mercury(II) ions in seafood samples after extraction and preconcentration by a novel functionalized magnetic metal-organic framework nanocomposite.

This work describes a novel functionalized magnetic metal-organic framework nanocomposite [(Fe3O4-2,5-dimercapto-1,3,4-thiadiazole)/metal-organic framework] and its application in the preconcentration of Hg(II) ions. The parameters affecting the preconcentration procedure were optimized by a Box-Behnken design through response surface methodology. Three variables (uptake time, magnetic nanosorbent amount, and pH value) were selected as the main factors affecting the sorption step, while four variables (type, volume, and concentration of the eluent; and elution time) were selected as main factors in the optimization study of the elution step. Following the sorption and elution of analytes, the ions were quantified by cold vapor atomic absorption spectrometry. Under the optimum conditions, the limit of detection was 0.01 ng/mL and all the relative standard deviations were less than 10%. The obtained sorption capacity (in mg/g) of this new sorbent was 124. Ultimately, this nanocomposite was successfully applied to the rapid extraction of trace quantities of Hg(II) ions in seafood samples and satisfactory results were obtained.