The paper presents accuracy analysis of CHEMFET-based characterization of ion activities in aqueous solutions. Two measurement methods are analyzed and compared: independent sensor-based and sensor array-based. Electrolyte characterization errors due to non-ideal voltage measurements, existence of interferent ions, and inaccurate sensor parameters are considered.
W artykule przedstawiono relacje pomiedzy potencjałem elektrody jonoselektywnej a stężeniem jonów w roztworze. Przedstawiono przykład wykonania wzorca aktywności. Przeanalizowano niepewność stężenia jonów we wzorcach przygotowywanych poprzez rozpuszczanie soli, we wzorcach powstałych poprzez rozcieńczenia oraz we wzorcach otrzymanych automatycznie metodą wielokrotnego rozcieńczania wzorca.
EN
The relationship between the potential E of the ion-selective electrode and ion concentration c are presented in the paper - eqs. (1)-5). The operations needed to prepare an activity standard, basing on eqs. (7) - (10), are listed and an example is given, haw to make it. Basing on eq. (11), linking concentration c, mass of salt m* and volume of solution V, the relative concentration uncertainty ur(c) is derived - eq. (12), and using a scale and non-ideal salt not having 100% content (cont) of substance of interest, the eq. (14) is obtained. After dilutions - eq. (15), concentration uncertainty changes - eq. (17). The next example is placed illustrating the change. The concentration uncertainties of standards obtained using multiple dilution method implemented on the automatic system SAWCEJS [5] are calculated in sec. 4.