an ion chromatography (ic) method for simultaneous determination of benzoic, salicylic and sorbic acids was developed. in this method the samples were purified by solid-phase extraction. the analytes were then eluted with methanol from c18 cartridge. the separation was performed on ion-exclusion column by an isocratic elution with 0.25 mmol /l sulfuric acid solution containing 20% (v/v) acetone...

Polypeptides containing 2-aminoisobutyric acid (Aib) units as an unnatural amino acid residue were synthesized by papain-catalyzed chemoenzymatic polymerization of a tripeptide ethyl ester l-Ala-Aib-l-Ala-OEt in an aqueous medium. The Aib-containing polypeptide adopted an α-helix conformation in both the solid and solution phases, which was induced by the periodic Aib residue.

a solid state fermentation method was developed for the production of citric acid from date pulp (obtained of date syrup production from the process) by aspergillus niger ptcc 5010. poor yield was obtained when potassium ferrocyanide treated date pulp were used as substrate, but methanol at a 3-4% concentration markedly increased the forma-tion of citric acid from the waste. the optimum range o...

the silica boron sulfuric acid nanoparticles (sbsans) as an efficient heterogeneous solid acid catalyst with both brønsted and lewis acidic sites catalyzed the preparation of bis-4-hydroxycoumarin derivatives using reaction of aldehydes and 4-hydroxycoumarin under mild and solvent-free condition at room temperature. this new and efficient methodology has advantages in comparison with currently ...

Boc-protected l-fulleropyrrolidino-glutamic acid was readily prepared and employed for the synthesis of fullerene-containing peptides using the solid-phase Boc chemistry developed by Merrifield.

margarine contains a higher level of unsaturated and trans-fatty acids (tfa) than butter. the aim of this study was to investigate the physicochemical properties of these products in iranian market during storage. physicochemical analyses included fatty acid composition, peroxide and anisidine values, slip melting point (smp), color, chlorophyll content, solid fat content (sfc) and texture anal...

lilium ledebourii (baker) boiss. (liliaceae) is a critically endangered lily species native tonorthern iran, where it is protected by law. in order to develop a cost effective method for largescalepropagation, the effects of three culture systems (solid, liquid and temporary immersion)and two types of cytokinins [6-benzyladenine (ba) and thidiazuron (tdz)] were studied onthe in vitro plant rege...

In this study, we evaluated a two-step process for detoxification of waste roofing slate, involving cement hydrate removal and low temperature detoxification using oxalic acid. These treatments were conducted on raw material and intermediate product, respectively. Cement hydrate removal effectively eliminated most Ca-containing cement hydrate components from the raw material under the following...