ION SENSING FILM OPTODES - DISPOSABLE ION SENSING PROBES FOR THE DETERMINATION OF NA- CONCENTRATIONS IN SERUM(, K+, CA2+ AND CL)

Highly selective ion sensing film optodes for the determination of fou r kinds of ions (Na+, K+, Ca2+, Cl-) were prepared with plasticized PV C membranes containing the respective ionophores and a newly prepared lipophilic anionic dye. The principle of the optical response of these sensing films is based on ion-pair extraction of the ion-ionophore co mplex and a deprotonated or protonated lipophilic anionic dye. These f ilm optodes are for disposable use and can detect ions by simply immer sing them into a glass vessel which is filled with the sample solution and determining the ion by measuring the absorbance change at the res pective maximum absorption wavelength of the lipophilic anionic dyes i n the visible region. The theoretical response of these films was also discussed based on the ion-extraction model. The ion selectivity of t hese films was sufficient for the determination of Na+, K+, Ca2+ and C l- in diluted serum samples, and satisfactory results were obtained in serum analysis