Silica-based room temperature phosphorescence substrates: wide dynamic ranges, low background, and programmable figures of merit.
The use of silica-based substrates for room temperature phosphorescence (RTP) was investigated. Contrary to reports in the literature, bare silica was shown to provide higher sensitivity (S/B) for RTP than filter paper when the specific surface areas of the two substrates were similar. The surface heterogeneity of bare silica resulted in nonlinear, discontinuous response curves for a model analyte, phenanthrene. However, analytically useful calibration curves were obtained on silica thin-layer phases in the presence of coadsorbed surfactant. The dynamic range on the silica substrate was 4 times greater and the background phosphorescence was 2 orders of magnitude lower than filter paper. The programming of figures of merit for silica-based substrates via the silica specific surface area is demonstrated.
Department of Chemistry, University of Cincinnati, Ohio 45221.
L A
LA
Ciolino
J G
JG
Dorsey
D005470:Fluorometry / Q000379:methods*; D008163:Luminescent Measurements; D010209:Paper; D010616:Phenanthrenes / Q000737:chemistry; D012822:Silicon Dioxide / Q000737:chemistry*; D013501:Surface-Active Agents; D013696:Temperature
D010616:Phenanthrenes; D013501:Surface-Active Agents; C031181:phenanthrene; D012822:Silicon Dioxide