Alkali metal ion sensing using absorbance changes based on aggregation of silica nanoparticles modified chemically with crown ethers was written by Nakahara, Yoshio;Hayashi, Takafumi;Kawa, Haruna;Kimura, Keiichi. And the article was included in Chemistry Letters in 2011.HPLC of Formula: 66943-05-3 This article mentions the following:
Crown-ether-modified SiO2 nanoparticles (Crown-SNPs) were prepared by simple chem. modifications of SiO2 nanoparticles. The organic moiety introduced into SiO2 nanoparticles was characterized by solid-state 13C NMR and elemental anal. No morphol. damage of SiO2 nanoparticles was recognized according to SEM observation. When an alkali metal salt was added to a solution containing crown-SNPs, the absorbance changes, whose extent was dependent on the kind and the concentration of a metal ion, were observed In the experiment, the researchers used many compounds, for example, 1,4,7,10-Tetraoxa-13-azacyclopentadecane (cas: 66943-05-3HPLC of Formula: 66943-05-3).
1,4,7,10-Tetraoxa-13-azacyclopentadecane (cas: 66943-05-3) belongs to ethers. The oxygen atom in ethers are more electronegative than carbon, thus the hydrogens which are alpha to the ethers are more acidic than the simple hydrocarbons. Ethers can form hydrogen bonds with other molecules (alcohols, amines, etc.) that have O―H or N―H bonds. The ability to form hydrogen bonds with other compounds makes ethers particularly good solvents for a wide variety of organic compounds and a surprisingly large number of inorganic compounds.HPLC of Formula: 66943-05-3
Referemce:
Ether – Wikipedia,
Ether | (C2H5)2O – PubChem