ISSN:
1040-0397
Keywords:
Casein
;
lead
;
milk
;
speciation
;
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
The complexation of lead with casein (CS) was studied by several voltammetric methods, as was the selective determination and speciation of lead in milk. First, cyclic voltammetry (CV) was used to examine the influence of adsorbed casein and complexation on the electrochemical response of lead at neutral and alkaline pHs. Second, by titrating solutions of CS with lead, two mathematical methods based on differential-pulse anodic stripping voltammetry (DPASV) for evaluating the binding properties of CS to lead were compared with a hanging mercury drop electrode (HMDE) and a Nafion-covered mercury film electrode (Nf-MFE). In all cases, the conditional stability constants for the Pb-CS complex agreed well and were close to log β′ = 5.5 at pH 7.0. Finally, lead was directly determined with the chemically modified electrode in acidified samples (≍pH 0.3) of whole and skim milk at the ng/ml level, with no need for preliminary acid digestion.
Additional Material:
9 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/elan.1140040609
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