M. Khodari et al., DETERMINATION OF AG(I) WITH CHEMICALLY-MODIFIED CARBON-PASTE ELECTRODE BASED ON 2,3-DICYANO 1,4-NAPHTHOQUINONE, Talanta, 41(12), 1994, pp. 2179-2182
The utility of carbon paste modified with 2,3-dicyano 1,4-naphthoquino
ne (CYNQ) for the voltammetric determination of Ag(I) is demonstrated.
The method is based on the formation of Ag(I) complex with CYNQ by ac
cumulation from the aqueous solution to the electrode surface without
an applied potential. Using the medium exchange technique, the electro
de was transferred to another media followed by linear-scan voltammetr
ic measurements. The reduction peak of the Ag(I)-CYNQ complex was obse
rved at +0.22 V (vs. SCE). The silver response is studied with respect
to paste composition, pH of the measurement solution, reproducibility
, interference and other variables. A detection limit of 5 x 10(-8)M w
as obtained and the calibration curve was linear over the range 1 x 10
(-6)-8 x 10(-5)M.