Naphthoresorcinol (1,3-Dihydroxynaphthalene) is a fluorescent dye (Λex=330 nm, Λem=380 nm) that can react with the NPPD (a tracer) and concentrated HCl and develop a red color. Naphthoresorcinol could be used as a background electrolyte (BGE) to determine the carbohydrates[1][2][3].
[1]. Vyas S, et, al. Fluorescence and light scattering studies on the interaction of 1,3-dihydroxynaphthalene with ionic and non-ionic surfactants. Polymer Photochemistry. 1984; 4(4):245-253. [2]. Suzuki S, et, al. Development of a field kit for use by non-scientists for chemical tracking using 5-(4-nitrophenyl)-2,4-pentadien-1-al. Forensic Sci Int. 2013 May 10;228(1-3):e25-7. [3]. Lee YH, et, al. Determination of carbohydrates by high-performance capillary electrophoresis with indirect absorbance detection. J Chromatogr B Biomed Appl. 1996 May 31;681(1):87-97.