Single UV-absorbing background electrolyte for simultaneous detection of cations and anions in capillary electrophoresis

Single UV-absorbing background electrolyte (BGE) has been designed for simu ltaneous detection of alkali metals and anions. The BGE is composed of a ca tionic buffer component and an anionic chromophore. Tris, sulfosalicylic ac id, trimellitic acid, 1,5-naphthalenedisulfonic acid were tested as the cat ionic and anionic components in the BGE, respectively. 1,5-naphthalenedisul fonic acid was selected as the anionic chromophore of the BGE for the separ ation of:cations and anions. In Tris/1,5-naphthalenedisulfonic acid BGE, K, NH4+, Na+, Li+, ascorbate, sorbate, benzoate, lactate, acetate, HCO3- pho sphate, formate and fluoride could be detected within 9 minutes with detect ion limits ranging from 0.1 to 1 ppm under the optimized conditions. This n ewly developed method allows a larger choice of components to define BGE in simultaneous detection of cations and anions in indirect photometric detec tion. The applicability of this type of BGE has been demonstrated in the an alysis of a real sample. The results obtained were comparable to those obta ined by inductively-coupled plasma spectroscopy (ICP) and ion chromatograph y (IC).