Tris(2-methyl-8-quinolinolato)iron(III) as a novel spectrophotometric probe for silanol detection.

Tris(2-methyl-8-quinolinolato)iron(III) was proposed as a sensitive spectrophotometric silanol-detecting probe based on the coordination ability of silanol groups on the surface of octadecylsylanized silica gel (ODS silica gel) for reversed-phase high-performance liquid chromatography. A peak of the iron(III) complex on a chromatogram abruptly collapsed as the silanol content in an ODS column increased, indicating that the iron(III) complex could sense trace amounts of silanol groups. The change of the peak parameters, such as the peak height and the peak area was highly related to the output of some nitrogen-containing compounds used as silanol-detecting probes as a function of the silanol content in an ODS column. The response of the peak height of the iron(III) complex to the silanol content was much more sensitive than the response of the nitrogen-containing probes, and was comparable to that of tris(2-methyl-8-quinolinolato)gallium(III), which had been proposed as a fluorometric silanol-detecting probe based on the coordination ability of the silanol groups.