Spectrophotometric determination of lead with 1-(2-pyridylazo)-2-naphthol and non-ionic surfactants Application to acetic acid extracts of ceramic enamels.
The Pb-PAN system in the presence of non-ionic surfactants (polyoxyethylene nonylphenols) has been studied spectrophotometrically. The optimum conditions for Pb determination are pH 9 (Na(2)B(4)O(7)-HClO(4)), 5% surfactant and measurement at 555 nm. The system obeys the Lambert Beer law over the Pb concentration range 1.3-4.5 ppm; the molar absorptivity is 2.02 x 10(4) l.mole(-1).cm(-1) at 555 nm. The relative standard deviation is 0.9% and the limit of detection 0.12 ppm. Lead can be determined in acetic acid extracts of ceramic enamels by extraction with sodium diethyldithiocarbamate into carbon tetrachloride and stripping with 4M hydrochloric acid to remove interferent species. The results obtained are in agreement with those obtained by a standard AAS method.
Escriche
J M
JM
Department of Analytical Chemistry, Faculty of Chemical Sciences, Valencia University, Burjasot, Valencia, Spain.
Estelles
M L
ML
Cabeza
A S
AS