A sequential injection fluorometric procedure for rapid determination of total protein in human serum

A sensitive procedure for the quantification of total protein bovine serum albumen (BSA) in human serum was presented with sequential injection sampling and fluorometric detection. A few microliters of sample and fluorescamine solutions were aspirated into the holding coil to facilitate the reaction of protein with fluorescamine by giving rise to a blue-green–fluorescent derivative. The derivative was afterwards excited by a 400 nm radiation from a UV radiator, and the emitted fluorescence was monitored at the wavelength of 470 nm. By loading 5.0 μl of sample and 4.0 μl of fluorescamine solution 0.075% (m/v), a linear calibration graph was obtained within 0.3–12.5 μg ml−1, and a detection limit (3σ) of 0.1 μg ml−1 was achieved, along with a sampling frequency of 40 h−1 and a R.S.D. value of 2.1% at the 5.0 μg ml−1 levels. Protein contents in human serums were analyzed by using the present procedure, and reasonable agreements were obtained with those obtained by a documented spectrophotometric (Biuret) method.