The purpose of this paper was to use adsorptive stripping chronopotentiometry for the determinationof Ni (II) in worldwide consumed beverages without any sample pretreatment, using
dimethilglyoxime(DMG) as complexing agent and a glassy carbon mercury film electrode as the working electrode. Ni(DMG)
2 complex is adsorbed onto the mercury film at an electrolysis potential of -500 mV for 60 sand then reduced by a -5
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A constant catho
dic current. The sensitivity of the method was stu
diedfor certified reference water and black tea in the pH range 6.5-11. At pH 9.5 in ammonia buffer, adetection limit of 0.2
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g L
-1 was achieved; the instrumental precision (expressed as rsd %) was1.5%, and the accuracy, expressed as obtained recoveries both from certified and not certifiedmatrixes, ranged from 93.0 to 95.5 %. The chronopotentiometric analysis executed on commercialbeverages provided evidence that black tea samples were the richest source of Ni (II) (1500-3700
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g L
-1), followed by coffee (100.0-300.5
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g L
-1); bottled mineral water showed a Ni (II) concentrationlower than 4.6
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g L
-1. Among alcoholic beverages, red wines presented the highest content of Ni (II)(55.5-105.0
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g L
-1). Significant
differences were noticed between Ni (II) levels of fermented and
distillated alcoholic beverages; moreover, canned cola and beer
did not show higher Ni (II) levelswith respect to the glass-bottled products.Keywords:
Adsorptive stripping chronopotentiometry; beverages; nickel