TY - JOUR

T1 - RESPONSE PATTERNS OF CHROMOIONOPHORE-BASED BULK OPTODES CONTAINING LIPOPHILIC ELECTROLYTES: TOWARD BACKGROUND-INDEPENDENT pH-SENSING

AU - Похвищева, Надежда Викторовна

AU - Прожерин, Илья Сергеевич

AU - Калиничев, Андрей Владимирович

AU - Пешкова, Мария Анатольевна

PY - 2023/7/31

Y1 - 2023/7/31

N2 - Despite a number of advantages of ion-selective optical sensors (optodes), their practical application is limited by their response mechanism, which leads to the dependence of the signal on the activity of two ions (analyte ion and the so-called reference ion) in the solution at the same time. Here, we show that the introduction of a lipophilic electrolyte into the polymeric optode membrane allows assessing the ionic activity of H+ cations regardless of the concentration of the background electrolyte containing a hydrophilic cation, with NaCl as an example of such an electrolyte. For the first time, the applicability of this approach is proven theoretically utilizing the numerical simulation of optode response. A correlation between the interfacial potential stability and the single-ion optical response is established. The predicted optical response is independent of background cation concentration to a significant extent. Theoretical conclusions are supported by experimental data obtained with chromoionophore-based optodes doped with various lipophilic electrolytes, including ionic liquids, by thin-film spectrophotometry and macrophotography coupled with digital color analysis. Most of the experimental sensor characteristics, such as the response range and its median, as well as its independence from the background electrolyte concentration are in quantitative agreement with the proposed theoretical description.

AB - Despite a number of advantages of ion-selective optical sensors (optodes), their practical application is limited by their response mechanism, which leads to the dependence of the signal on the activity of two ions (analyte ion and the so-called reference ion) in the solution at the same time. Here, we show that the introduction of a lipophilic electrolyte into the polymeric optode membrane allows assessing the ionic activity of H+ cations regardless of the concentration of the background electrolyte containing a hydrophilic cation, with NaCl as an example of such an electrolyte. For the first time, the applicability of this approach is proven theoretically utilizing the numerical simulation of optode response. A correlation between the interfacial potential stability and the single-ion optical response is established. The predicted optical response is independent of background cation concentration to a significant extent. Theoretical conclusions are supported by experimental data obtained with chromoionophore-based optodes doped with various lipophilic electrolytes, including ionic liquids, by thin-film spectrophotometry and macrophotography coupled with digital color analysis. Most of the experimental sensor characteristics, such as the response range and its median, as well as its independence from the background electrolyte concentration are in quantitative agreement with the proposed theoretical description.

KW - chromoionophore

KW - digital color analysis

KW - ion-selective optode

KW - ionic activity

KW - lipophilicity

KW - optical sensor

KW - organic electrolytes

KW - polymeric membranes

UR - https://www.mendeley.com/catalogue/a4a3dd7a-c49f-31a7-b4b3-a1edb4ba71f4/

U2 - 10.1021/acssensors.3c00742

DO - 10.1021/acssensors.3c00742

M3 - Article

VL - 8

SP - 3086

EP - 3094

JO - ACS Sensors

JF - ACS Sensors

SN - 2379-3694

IS - 8

ER -