DETERMINATION OF MERCURY IN PHARMACEUTICALS BY
GRAPHITE FURNACE ATOMIC ABSORPTION SPECTROMETRY WITH CHEMICAL MODIFIER

Viorica Alexiu,^a Elena Chirtop,^b Luminita Vladescu,^c and Mihai Simion^a

^a Magistra C&C, 9^th Aviator Belghiru Street, Constanta, Romania, Tel/Fax: 0040241634742,
E-mail: baumtech@rdslink.ro, baumtech@yahoo.com.

^b Pharmaplant-Biogalenica, 313^th, Splaiul Unirii Street, Bucharest, Romania

^c University of Bucharest, 13^th B, Regina Elisabeta Street, Bucharest, Romania

Abstract

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