SENSITIVE, FLUORESCENT DETECTION OF HYDRAZINE VIA DERIVATIZATION WITH 2,3-NAPHTHALENE DICARBOXALDEHYDE

The derivatization of hydrazine with 2,3-naphthalene dicarboxaldehyde (NDA) followed by fluorescence detection is shown to be an effective method for the selective determination of extremely low concentrations of hydrazine in solution. Kinetic studies of the reaction between hydrazine and NDA indicate that the reaction is first order in both hydrazine and NDA, and is dependent upon an acidic pH (optimum pH = 2.5) for the formation of the fluorescent derivative. The NDA-hydrazine derivative is readily formed (time response < 5 min) and is strongly fluorescent in the green (A(ex) = 403 nm and lambda(em) = 500 nm). A linear concentration dependence is observed over a dynamic range from 50 ng/l to 500 mu g/l of hydrazine (correlation coefficient, r > 0.999), with a signal-to-noise ratio of 3:1 for 50 ng/l of hydrazine. The selectivity of the NDA reagent is examined with respect to several possible interferents, including ammonia, and is shown to be a highly specific reagent for hydrazine.