Effect of transmembrane electrolyte diffusion on the detection limit of carrier-based potentiometric ion sensors

被引:194
作者
Mathison, S [1 ]
Bakker, E [1 ]
机构
[1] Auburn Univ, Dept Chem, Auburn, AL 36849 USA
关键词
D O I
10.1021/ac970690y
中图分类号
O65 [分析化学];
学科分类号
070302 ; 081704 ;
摘要
The detection limit of carrier-based ion-selective electrodes is explained by the presence of a locally elevated concentration of measuring ions at the sample-membrane phase boundary. Since ion-selective electrodes are responsive to phase boundary activities, such elevated concentrations render the potentiometric sensor insensitive to dilute bulk concentration changes. Different mechanisms for the continuous release of measuring ions from the membrane are conceivable. The extraction of inner electrolyte into the backside of the ion-selective membrane is predicted to lead to a concentration gradient of electrolyte across the membrane and therefore to a net nux of measuring ions from the inner filling solution to the sample. This effect is described by an extended model that respects the relevant extraction and diffusion processes. The extent of coextraction at the backside is predicted on the basis of potentiometric measurements on the range of anion interference. These predictions are found to relate well to experimental results with valino-mycin electrodes. The presence of lipophilic anions in the inner electrolyte is found to increase detection limits owing to the increased extraction into the membrane. An upper limit apparently exists beyond which the detection limit is no longer increased upon increasing the inner filling solution concentration. Stirring the sample decreases the detection limit owing to increased mass transport from the membrane surface to the bulk sample.
引用
收藏
页码:303 / 309
页数:7
相关论文
共 30 条
[1]   Determination of unbiased selectivity coefficients of neutral carrier-based cation-selective electrodes [J].
Bakker, E .
ANALYTICAL CHEMISTRY, 1997, 69 (06) :1061-1069
[2]   LIPOPHILICITY OF TETRAPHENYLBORATE DERIVATIVES AS ANIONIC SITES IN NEUTRAL CARRIER-BASED SOLVENT POLYMERIC MEMBRANES AND LIFETIME OF CORRESPONDING ION-SELECTIVE ELECTROCHEMICAL AND OPTICAL SENSORS [J].
BAKKER, E ;
PRETSCH, E .
ANALYTICA CHIMICA ACTA, 1995, 309 (1-3) :7-17
[3]   OPTIMUM COMPOSITION OF NEUTRAL CARRIER BASED PH ELECTRODES [J].
BAKKER, E ;
XU, AP ;
PRETSCH, E .
ANALYTICA CHIMICA ACTA, 1994, 295 (03) :253-262
[4]   DETECTION LIMIT OF ION-SELECTIVE BULK OPTODES AND CORRESPONDING ELECTRODES [J].
BAKKER, E ;
WILLER, M ;
PRETSCH, E .
ANALYTICA CHIMICA ACTA, 1993, 282 (02) :265-271
[5]   Origin of anion response of solvent polymeric membrane based silver ion-selective electrodes [J].
Bakker, E .
SENSORS AND ACTUATORS B-CHEMICAL, 1996, 35 (1-3) :20-25
[6]  
BAKKER E, 1996, J ELECTROCHEM SOC, V143, pL83
[7]   A POLYMER MEMBRANE POTENTIOMETRIC SENSOR FOR SILVER [J].
BATES, MRM ;
CARDWELL, TJ ;
CATTRALL, RW ;
DEADY, LW ;
GREGORIO, CG .
TALANTA, 1995, 42 (07) :999-1004
[8]   SELECTIVE ELECTRODES FOR SILVER AND ANIONS BASED ON POLYMERIC MEMBRANES CONTAINING COMPLEXES OF TRIISOBUTYLPHOSPHINE SULFIDE WITH SILVER [J].
BRICKER, J ;
DAUNERT, S ;
BACHAS, LG ;
VALIENTE, M .
ANALYTICAL CHEMISTRY, 1991, 63 (15) :1585-1589
[9]   RECOMMENDATIONS FOR NOMENCLATURE OF ION-SELECTIVE ELECTRODES - (IUPAC RECOMMENDATIONS 1994) [J].
BUCK, RP ;
LINDNER, E .
PURE AND APPLIED CHEMISTRY, 1994, 66 (12) :2527-2536
[10]   DONNAN EXCLUSION FAILURE IN LOW ANION SITE DENSITY MEMBRANES CONTAINING VALINOMYCIN [J].
BUCK, RP ;
TOTH, K ;
GRAF, E ;
HORVAI, G ;
PUNGOR, E .
JOURNAL OF ELECTROANALYTICAL CHEMISTRY, 1987, 223 (1-2) :51-66