Ion chromatography (IC), developed by Small et al. [1], is widely recognized as a simple and powerful analytical technique for the determination of various inorganic and organic anions and cations [2]. Sulfonated and carboxylated polymer resins and silicas are commonly employed as cation−exchange stationary phases in IC for cationic species. The application of unmodified silica gels as cation−e...

The need of an inorganic gel for the preparation of microbiological media arises frequently in nutritional studies. The isolation of fastidious microorganisms, such as the nitrifying bacteria, may be facilitated by the use of solid media prepared with silica gel rather than with agar. Until recently, the procedures available for the preparation of silica gel were time-consuming and inconsistent...

In this work, we report synthesis of surface modified superparamagnetic iron oxide nanoparticles (SPION) by co-precipitation method using FeSO4.7H2O and Fe2(SO4)3.5H2O as precursors and trisodium citrate dihydrate as surfactant. Surface modification of the as prepared samples was performed in pot by sol-gel precipitation method u...

A rapid, sensitive and specific high-performance thin-layer chromatographic (HPTLC) method was developed and validated for determination of minocycline in human plasma, saliva, and gingival fluid samples. Densitometric analysis of minocycline was carried out at 345 nm after single step extraction with methanol. The method uses TLC aluminium plates pre-coated with silica gel 60F-254 as a station...

pH-sensitive field effect transistors (FET) were modified with organophosphate hydrolase (OPH) and used for direct detection of organophosphate compounds. OPH is the organophosphate degrading gene product isolated from Pseudomonas diminuta. OPH was selected as an alternative to acetylcholinesterase, which requires inhibition mode sensor operation, enzyme regeneration before reuse, long sample i...

The 2-hydroxy fatty acids tend to yield streaks in thin-layer chromatography on silica gel plates. If potassium oxalate is included with binder-free silica gel, good spots are obtained. Similar difficulties are found in paper chromatography of the fatty acid derivatives of coenzyme A, especially with long-chain acids. The same thin-layer system gives good spots with these compounds.

As part of a general study of the interaction between gases and solids in the laboratory of Alfred Magnus (Fig. 1) at the University of Frankfurt, Magnus and Grähling (2) reported the adsorption of ozone on silica gel in 1929. These measurements were complicated by the thermal instability of ozone, which, as shown by Magnus and Grähling, was further catalyzed by silica gel. A second problem was...

The optical properties of multi-functionalized cobalt ferrite (CoFe2O4), cobalt zinc ferrite (Co0.5Zn0.5Fe2O4), and zinc ferrite (ZnFe2O4) nanoparticles have been enhanced by coating them with silica shell using a modified Stöber method. The ferrites nanoparticles were prepared by a modified citrate gel technique. These core/shell ferrites nanoparticles have been fired at temperatures: 400°C, 6...

sulphuric acid adsorbed on silica gel is a practical and useful catalyst for acetylation of varius alcohols, phenols and amines.

silica gel has been used for synthesis of biscoumarin derivatives starting from 4-hydroxycoumarin and aryl aldehydes. the reaction conditions are completely in agreement with green chemistry principles including sing water as media and a recyclable and safe catalyst. this method is also simple and inexpensive and leads to high yield of products in short reaction times.