Single UV-absorbing background electrolyte (BGE) has been designed for simultaneous detection of alkali metals and anions. The BGE is composed of a cationic buffer component and an anionic chromophore. Tris, sulfosalicylic acid, trimellitic acid, 1,5-naphthalenedisulfonic acid were tested as the cationic and anionic components in the BGE, respectively. 1,5-naphthalenedisulfonic acid was selected as the anionic chromophore of the BGE for the separation of cations and anions. In Tris/1,5-naphthalenedisulfonic acid BGE, K+, NH4+, Na+, Li+, ascorbate, sorbate, benzoate, lactate, acetate, HCO3−, phosphate, formate and fluoride could be detected within 9 minutes with detection limits ranging from 0.1 to 1 ppm under the optimized conditions. This newly developed method allows a larger choice of components to define BGE in simultaneous detection of cations and anions in indirect photometric detection. The applicability of this type of BGE has been demonstrated in the analysis of a real sample. The results obtained were comparable to those obtained by inductively-coupled plasma spectroscopy (ICP) and ion chromatography (IC).