Ultrasensitive fluorescence detection of bismuth ion (III) in plasma, urine and medicines by a terbium chelate probe

Abstract A novel, ultrasensitive probe of Bi3+ ion based on the fluorescence of a terbium chelate was presented and synthesized. This terbium chelate probe for Bi3+ is composed of a carbostyril-linked polyaminocarboxylate chelator and fluorescent terbium ion, and is highly fluorescent due to the sensitization of carbostyril to terbium ion. The extremely strong binding of polyaminocarboxylate chelator to Bi3+ replaced the binding of terbium ion, quenching the fluorescence of the probe. The probe based on this principle shows an ultra-high sensitivity for the detection of Bi3+ with a limit of detection as low as 0.1 pM in aqueous solution and 1 pM in urine and plasma solution respectively, at least 100-fold more sensitive than current various assays for Bi3+. The probe can be used to determine trace Bi3+ in medicines, urine and plasma. Due to a long fluorescence lifetime of the probe containing terbium ion, which allows the elimination of various short-lived nonspecific fluorescence via a time-delay measurement, this probe is particularly advantageous for the determination of biological samples like plasma and urine with autofluorescence.