Comparison of chemiluminescence from luminol solution and luminol–TiO₂ suspension after illumination of a 355 nm pulse laser

Abstract

Chemiluminescence (CL) from luminol solution and luminol-TiO₂ suspension after illumination of a 355 nm pulse laser is compared. Both the CL systems showed the CL spectra with maximum wavelength of 430 nm, suggesting that the emission was from the excite state of 3-aminophthalate ion. The TiO₂ photocatalytically induced luminol CL could be separately detected either when the pulse laser power was smaller than 0.15 mJ/pulse or a slit was placed beyond -2-2 mm in the vertical direction of the laser beam. The TiO₂ photocatalytically induced luminol CL intensity was linear to the laser power, while that of the 355 nm pulse laser-induced was nonlinear. A log-log plot between the 355 nm pulse laser-induced luminol CL intensity and laser power showed a near-linear regression fit with a slope of 2.11, suggesting that a two-photon absorption process of luminol was present in the 355 nm pulse laser-induced luminol CL. Adsorbed oxygen on the surface of TiO₂ seemed to greatly contribute to the photocatalytically induced CL.

Functionalized TiO2 Nanoparticles as Labels for Immunoassay

“…Some authors investigated the conversion of chemiluminescent substrates by TiO 2 for bio-sensing applications, though controversial results have been reported on the resulting catalytic efficiency. [9,10] Li and co-workers exploited carbon nanotubes decorated with TiO 2 NPs as probes for a two-site immunometric assay: [11] detection antibodies were covalently linked to the nanotubes, which simply joined them to TiO 2 NPs, and these last catalysed the oxidation of a chemiluminescent substrate. The authors attributed the generation of measurable signals to the amplification achieved by multiplying the number of TiO 2 NPs bound to the nanotubes.…”

“…There are few examples of application of TiO 2 NPs as enzyme mimics. Some authors investigated the conversion of chemiluminescent substrates by TiO 2 for bio‐sensing applications, though controversial results have been reported on the resulting catalytic efficiency . Li and co‐workers exploited carbon nanotubes decorated with TiO 2 NPs as probes for a two‐site immunometric assay: detection antibodies were covalently linked to the nanotubes, which simply joined them to TiO 2 NPs, and these last catalysed the oxidation of a chemiluminescent substrate.…”