Polymeric membrane sensors with boronic acid functionalized boron dipyrromethene for selective measurement of dopamine

Boronic acid functionalized boron dipyrromethene (BABDP) was studied as a new fluorescent probe for the detection of catechols and catecholamines. Dopamine (DA) and catechol induced a strong fluorescence quenching effect due to the photoinduced electron transfer (PET) process. In homogeneous assay, the fluorescence changes were observed in the solutions with dopamine concentration from 10−8 M to 10−2 M at pH 7.4, and the catechol induced less but still significant response. The selectivity toward dopamine was greatly improved by using hydrophobic polymer films containing BABDP and cation exchanger. Positively charged dopamine was exchanged into the membrane and interacted with BABDP to produce the signal change, while the interference from neutral catechol was eliminated. The results measured from both optical and electrochemical sensors confirmed the selective measurement of dopamine in the range of 10−4 M to 10−2 M at physiological pH.