Chromotropic acid as fluorogenic reagent. 1. Fluorimetric determination of beryllium

A highly sensitive and almost specific fluorimetric method has been developed for rapid determination of beryllium at ng/ml and sub-ng/ml levels with chromotropic acid as reagent at pH 4.8-6.0. The fluorescence intensity (λex=362 nm, λem=387 nm) is stable for 24 h. The calibration graph is linear over the range 0.1-60 ng/ml beryllium; a 1:1 complex is formed. Over sixty anions and cations, and some complexing agents such as EDTA, oxalate, tartrate, ascorbic acid, thiourea, phthalate, citrate, S2O2-3, SCN- and salicylate do not interfere even when present in large excess. The method has been applied successfully for the determination of beryllium in ores, alloys, steels, environmental waters and in biological samples. The method is virtually specific and requires no preconcentration or clean-up steps. (authors)