Lead is determined in environmental samples and in rocks using the206,207,208Pb(p,xn)206Bi reaction. Bismuth is separated by anion exchange or by extraction with antimony diethyldithiocarbamate. Sources of errors such as volatilization of the matrix due to heating during the irradiation, variations of the abundance of the lead isotopes and the standardization were studied in detail. For concentrations between 11 mg/g and 3.7 g/g the relative standard deviation ranges from 2.6 to 5.4%. The detection limit is 10 ng/g.
Authors:G. Wauters, C. Vandecasteele and K. Strijckmans
This paper considers the variable isotopic composition of lead as a possible source of systematic errors in proton activation analysis. The importance of this source of error was evaluated for environmental and geological samples. As proton activation analysis is frequently used for the certification of lead, the error was determined for three sediment reference materials. Inductively coupled plasma-mass spectrometry was used for the determination of the isotopic composition of lead. The systematic error amounted for the sediments to approximately 1%.
The temperature in powdered rock and environmental samples irradiated with 23 MeV protons was measured. Under helium (3–9·105 Pa) the obtained temperature is considerably lower than under vacuum. Irradiation under helium at a sufficiently low beam intensity allows to avoid systematic errors that may occur in charged particle activation analysis due to volatilization of matrix components.
Authors:G. Wauters, C. Vandecasteele, K. Strijckmans and J. Hoste
Cadmium, thallium and lead are determined in environmental samples using the111,112,113Cd(p,xn)111In,203Tl(p,3n)201Pb and206,207,208Pb(p,xn)206Bi reactions.111In.201Pb and206Bi are chemically separated by anion exchange and anodic deposition of lead(IV). oxide. Detection limits are 6, 44 and 25 ng/g for cadmium, thallium and lead, respectively. The results obtained for certified reference materials are in good agreement with the certified values.
Authors:K. Strijckmans, G. Wauters, S. Van Winckel, J. Dewaele and R. Dams
A novel method for the determination of lead in copper by proton, activation analysis has been developed. The bismuth activity formed was, separated from the matrix activity by anion exchange chromatography. Special attention was paid to possible systematic errors. The method was applied to BCR reference materials and yields a precision, of 2–3% at the g/g concentration level.