This study developed an electrocolorimetric extraction technique as a simple, rapid, and green method for the simultaneous preconcentration and determination of Ni(II) in chocolate samples. The system was designed using… Click to show full abstract
This study developed an electrocolorimetric extraction technique as a simple, rapid, and green method for the simultaneous preconcentration and determination of Ni(II) in chocolate samples. The system was designed using an agarose gel (3% w/v) solution containing 10% v/v 80 mM dimethylglyoxime (DMG) and 10% v/v 0.03 M ammonia as colorimetric reagents to determine Ni(II) ions. When voltage was applied to the system, Ni(II) ions were extracted from the donor solution into the gel and formed Ni-DMG complexes with a pink color. Under the optimal conditions, a good linear range was obtained from 30 to 750 µg L-1 (R2 > 0.998) with a detection limit of 1 µg L-1. Inter- and intra-assay results showing relative standard deviations were less than 2.6% and 1.9%, respectively. Our developed method was applied to determine Ni(II) in chocolate samples. The results were in agreement with those obtained using ICP-OES.
               
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