TY - JOUR
T1 - Exploiting the pH-Cross Sensitivity of Ion-Selective Optodes to Broaden Their Response Range
AU - Steininger, Fabian
AU - Palmfeldt, Johan
AU - Koren, Klaus
AU - Kalinichev, Andrey V.
N1 - Publisher Copyright:
© 2024 American Chemical Society.
PY - 2024/9/27
Y1 - 2024/9/27
N2 - While the pH cross-sensitivity of chromoionophore-based ion-selective optodes (ISOs) has often been regarded as a significant limitation, this paper demonstrates how this apparent drawback can be transformed into a beneficial feature. The response range of chromoionophore-based ISOs shifts proportionally with changes in the sample pH. Thus, integrating them with a stable pH gradient across the optode surface, such as those provided by immobilized pH gradient (IPG) gels, allows for significant enhancement of the effective measuring range of chromoionophore-based ISOs while preserving their maximum sensitivity. We show that the measuring range of sodium-selective chromoionophore-based optodes can be increased up to 2.5 log units when used with commercially available IPG gels. This improvement in measuring range is directly correlated with the pH difference in the pH gradient across the optode, suggesting that even greater enhancements are possible with more substantial pH gradients. Furthermore, this approach is not confined to sodium-selective optodes but can be readily adapted to other ion-selective chromoionophore-based optodes, broadening their potential applications and impact in the field of chemical sensing. This work paves the way for the development of more versatile and highly sensitive optodes across a broad range of analytes, leveraging the pH cross-sensitivity as a tool for enhanced performance.
AB - While the pH cross-sensitivity of chromoionophore-based ion-selective optodes (ISOs) has often been regarded as a significant limitation, this paper demonstrates how this apparent drawback can be transformed into a beneficial feature. The response range of chromoionophore-based ISOs shifts proportionally with changes in the sample pH. Thus, integrating them with a stable pH gradient across the optode surface, such as those provided by immobilized pH gradient (IPG) gels, allows for significant enhancement of the effective measuring range of chromoionophore-based ISOs while preserving their maximum sensitivity. We show that the measuring range of sodium-selective chromoionophore-based optodes can be increased up to 2.5 log units when used with commercially available IPG gels. This improvement in measuring range is directly correlated with the pH difference in the pH gradient across the optode, suggesting that even greater enhancements are possible with more substantial pH gradients. Furthermore, this approach is not confined to sodium-selective optodes but can be readily adapted to other ion-selective chromoionophore-based optodes, broadening their potential applications and impact in the field of chemical sensing. This work paves the way for the development of more versatile and highly sensitive optodes across a broad range of analytes, leveraging the pH cross-sensitivity as a tool for enhanced performance.
KW - chromoionophores
KW - immobilized pH gradients
KW - Ion-selective optodes
KW - optical sensors
KW - sensor characteristics
UR - http://www.scopus.com/inward/record.url?scp=85201764542&partnerID=8YFLogxK
U2 - 10.1021/acssensors.4c01481
DO - 10.1021/acssensors.4c01481
M3 - Letter
C2 - 39172736
AN - SCOPUS:85201764542
SN - 2379-3694
VL - 9
SP - 4555
EP - 4559
JO - ACS Sensors
JF - ACS Sensors
IS - 9
ER -