A new luminol derivative as a fluorescent probe for trace analysis of copper(II)

A new luminol derivative has been synthesized and its fluorescence has been studied. The luminol derivative emits at 460 nm in pH 10.0 phosphate buffer which is different from the original luminol that emits at 425 nm under the same conditions. Cu²⁺ exhibits strong fluorescence quenching effect on the luminol derivative and the quenching mechanism is discussed in detail. This luminol derivative can be applied as a fluorescent probe for ultra-trace analysis of Cu²⁺. The effects of pH, interferents and the stability have also been investigated. The fluorescent probe shows good reproducibility, and the relative standard deviation of response to Cu²⁺ is 0.7% (n=6). The lower linear range and the limit of detection are 0-500 and 0.27 nmol L^-1, respectively.