Direct determination of gold in whole blood and plasma by electrothermal atomisation atomic absorption spectrometry using Zeeman-effect background correction and matrix modifications

Abstract

Addition of 1000 µg ml^–1 of Ni or 200 µg ml^–1 of Pd-1000 µg ml^–1 of Mo matrix modifiers to 80-fold diluted whole blood and 200-fold dilute plasma has allowed the direct determination of Au using aqueous standards. With Pd-Mo, peak-height and peak-area measurements were satisfactory for both tube-wall and platform atomisation (91–108% recovery). With Ni however, peak-area measurements and platform atomisation were required to achieve quantitative recovery of added Au. For the dilution factors applied in this study, the lower limit of measurement was 0.16 µg ml^–1 of Au for plasma and 0.064 µg ml^–1 of Au for whole blood, based on 95% confidence limits. Solution detection limits in the presence of the Pd-Mo modifier were 0.4 µg l^–1 of Au for aqueous or dilute HNO₃ solutions and 0.8 µg l^–1 of Au for diluted samples of whole blood or plasma. Storage experiments indicated that glass containers were better than plastic to avoid deposition and loss of Au over periods of up to 80 min.