A portable luminescence spectrofluorometer weighing only 1.5 kg that uses multiple light emitting diodes (LEDs) as excitation sources was developed and evaluated. Excitation using a sequence of seven individual broad-band LED emission sources enabled the generation of excitation-emission spectra using a light weight (<1.5 kg) spectrometer. Limits of detection for rhodamine 6G, rhodamine B, and fluorescein were 2.9, 3.2, and 11.0 nM, respectively. Generation of excitation-emission matrices (EEMs) enabled the analysis of samples containing mixtures of rhodamine B and fluorescein. Buffered saline plant and animal feed extracts were also analyzed using this instrument. These samples included the woody plants <i>Pistacia lentiscus</i> (Evergreen pistache or Mastic) and <i>Philyria latifolia</i>, and the herbaceous species <i>Medicago sativa</i> (alfalfa), <i>Trifolium spp</i>. (clover), and a feed concentrate. Application of multi-way principal component analysis (MPCA) to the resulting three-dimensional data sets enabled discernment among these various diet constituents.
Vol. 3, Iss. 4 Virtual Journal for Biomedical Optics
Safwan Obeidat, Baolong Bai, Gary D. Rayson, Dean M. Anderson, Adam D. Puscheck, Serge Y. Landau, and Tzach Glasser, "A Multi-Source Portable Light Emitting Diode Spectrofluorometer," Appl. Spectrosc. 62, 327-332 (2008)