MERCURY IN PHARMACEUTICALS BY
GRAPHITE FURNACE ATOMIC ABSORPTION SPECTROMETRY WITH CHEMICAL MODIFIER
Viorica Alexiu,a Elena Chirtop,b Luminita Vladescu,c and Mihai Simiona
The mercury concentration in pharmaceuticals is usually very low. Therefore, to achieve a precise and accurate analysis it is necessary to have a proficient technique. The determination of mercury by graphite furnace atomic absorption spectrometry often requires the use of a chemical modifier. The chemical modifier is used to stabilize the analyte or volatilise the bulk of sample matrix. In this work, we have studied the effects of HCl+H2O2 and PdCl2 on the sensitivity of mercury determination in graphite furnace atomic absorption spectrometry. The best results were achieved using 10% PdCl2 and 4% HCl + 4% H2O2 concentration. The detection limits (3σ) of the method with 4% HCl + 4%H2O2 and PdCl2 10% as matrix modifiers, were 0.1 µg/mL and 0.02 µg/mL, respectively. After this work, a method with PdCl2 10% has been proposed for determination of mercury in pharmaceutical samples. The ashing and atomizing temperatures were 250 °C and 1800 °C, respectively. The method was successfully applied to the determination of mercury in pharmaceutical samples, with a recovery range of 96-102%.
Key words: GF-AAS, mercury, chemical modifier, thimerosal