Application of Nafion/ Cobalt Hexacyanoferrate Chemically Modified Electrodes for the Determination of Electroinactive Cations by Ion Chromatography

Abstract

An amperometric detector based on the chemical moditlcation ofNafjon and cobalt(H) hexacyaooferrate(II,~) thin tIlm (Nation/&CN-Fe) onto a glassy carbaa (CC) electrode was t i d y developed for the determination of electrohdve d o n s (Li+, Na', K', Rb+, Cs+andN€&+) insingIecohnrmio0 chromatography. A set of well-debxl peaks of deetroinactive cation was obtained. Tbe dative s&adard deviations (RSDs) ofchromatographicpeakheight (L4) fortheseCaliomwereall below 3.8%. The catiorrp were detected ccmveniently in the bcoocentrabioo range d 6 . 0~ i 0 -6 3 . 0~ 10-3 m o v~ and tbeii correlatjoo coefEcients were all above 0.99. The detection limits of the catioap were 9.2 x 10-6 mol/L for Li' , 3.4 x d L for Na+ , 6.3 x lo-' d L for K+ , 7.8 x lo-' md/L for Rb' , 6.2 x lo-' d L for Cs' and 6.2 x * Project supported by the h a b o d Natural Science Foundation of Ch~na (No. 29975009).&. l3 'Ihe detection potential was + 0.30 V ( vs. SCE), the injection volumes of the standard and sample solutions were all 25 pL and the chromatopun3 were evaluated by measuring peak heights.Sample preparation: rainwater samples were collected in Putuo district, which was located in the west of S h a n h . After collection, the samples were stored immediately in a refrigerator ( 4 "c) , and analyzed within