TY - JOUR

T1 - Effect of buffers and pH in antenna sensitized Eu(III) luminescence

AU - Nielsen, Lea Gundorff

AU - Sørensen, Thomas Just

N1 - Funding Information: We thank the Carlsbergfoundation, Villum Fonden, Novo Nordisk Fonden, Eliteforsk, and the University of Copenhagen for generous support. We thank Ruifang Su for assistance in the preparation of the manuscript. Publisher Copyright: © 2023 IOP Publishing Ltd.

PY - 2023

Y1 - 2023

N2 - The photophysics of a europium(III) complex of 1,4,7,10-tetraazacycododecane-1,4,7-triacetic acid-10-(2-methylene)-1-azathioxanthone was investigated in three buffer systems and at three pH values. The buffers—phosphate buffered saline (PBS), 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid (HEPES), and universal buffer (UB)—had no effect on the europium luminescence, but a lower overall emission intensity was determined in HEPES. It was found that this was due to quenching of the 1-azathioxanthone first excited singlet state by HEPES. The effect of pH on the photophysics of the complex was found to be minimal, and protonation of the pyridine nitrogen was found to be irrelevant. Even so, pH was shown to change the intensity ratio between 1-azathioxanthone fluorescence and europium luminescence. It was concluded that the full photophysics of a potential molecular probe should be investigated to achieve the best possible results in any application.

AB - The photophysics of a europium(III) complex of 1,4,7,10-tetraazacycododecane-1,4,7-triacetic acid-10-(2-methylene)-1-azathioxanthone was investigated in three buffer systems and at three pH values. The buffers—phosphate buffered saline (PBS), 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid (HEPES), and universal buffer (UB)—had no effect on the europium luminescence, but a lower overall emission intensity was determined in HEPES. It was found that this was due to quenching of the 1-azathioxanthone first excited singlet state by HEPES. The effect of pH on the photophysics of the complex was found to be minimal, and protonation of the pyridine nitrogen was found to be irrelevant. Even so, pH was shown to change the intensity ratio between 1-azathioxanthone fluorescence and europium luminescence. It was concluded that the full photophysics of a potential molecular probe should be investigated to achieve the best possible results in any application.

KW - buffer effects

KW - lanthanide luminescence

KW - pH effects

KW - photophysics

U2 - 10.1088/2050-6120/acb63a

DO - 10.1088/2050-6120/acb63a

M3 - Journal article

C2 - 36696692

AN - SCOPUS:85147720737

VL - 11

JO - Methods and Applications in Fluorescence

JF - Methods and Applications in Fluorescence

SN - 2050-6120

IS - 1

M1 - 015005

ER -