Identification of inorganic pigments from paintings and polychromed sculptures immobilized into polymer film electrodes by stripping differential pulse voltammetry

Inorganic pigments in paintings and polychromed sculptures are studied by cyclic voltammetry and differential pulse stripping voltammetry using micro-sample coatings in Paraloid B72-film modified electrodes. Characteristic cathodic and anodic differential pulse profiles were obtained in the +0.4 to -1.0 V vs. SCE potential range for different cadmium, copper, lead, mercury and zinc pigments used in traditional colour palettes. Under optimized conditions, excellent reproducibility was obtained. Microsamples extracted from polychromed sculptures, wall paintings, canvas paintings, panel paintings and altarpieces from Spain, Ethiopia and Italy from the 12th to the 20th centuries have been analyzed and cadmium, copper, lead, mercury and zinc pigments such as cadmium red cadmium yellow, azurite, copper resinate, malachite, verdigris, lead-tin yellow, lead white, minium, Naples yellow, vermilion, chrome orange, chrome yellow and white zinc have been identified by this technique in agreement with PLM, SEM/EDX, XRD and FT-IR analysis. (C) 2000 Elsevier Science B.V. All rights reserved.