The detection of a copper ion by an optical fiber sensing system using a polyvinyl chloride (PVC) membrane containing
N,
N'-bissalicyliden-2, 3-diaminobenzofuran (SABF) as a detection port is discussed. A PVC membrane containing SABF and dioctylphthalate (DOP) was prepared and attached to the sensor port of an optical fiber sensor. A copper ion sample solution was added a 5 × 10
-2 mol dm
-3 counter ion solutions and a pH 6 buffer solution. Then, a sensor fixed in order PVC membrane was soaked in the sample solution. The absorbance of the colored membrane was measured by a spectrophotometer at 530 nm. The detectable concentration of the copper ion determined by the proposed method was over the range of 10
-610
-3mol dm
-3, and the reproducibility of the determined values of the copper ion was 2.0% as a relative standard deviation on repeatable experiments (six times) for 10
-4mol dm
-3 of the copper ion sample. A linear correlation between the determined values by the proposed method and those by AAS was obtained over a concentration range of 1 × 10
-5 1 × 10
-4 mol dm
-3. Coexisting metal ions had almost no effect on the determined values of copper ion. However, when zinc, nickel and magnesium ions coexisted with copper ions, it brought about negative interference to the determined values of copper ion.
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