A novel method for the determination of total protein in human serum by near infrared fluorescence recovery

A novel fluorometric method has been developed for the determination of tot al protein in human serum with a new near-IR reagent as a fluorescence prob e, based on the fluorescence recovery of the cyanine-CTAB system in the pre sence of protein. Maximum fluorescence is produced with maximum excitation and emission wavelengths at 765 and 812 nm, respectively. Under optimal con ditions, the calibration graphs are linear over the range 0.3-12.0 mug/mL f or protein. The detection limit is 70 ng/mL, and the relative standard devi ation of six replicate measurements is 1.14% for 6.0 mug/mL protein. The re sults are satisfactory.