Germanium determination by flame atomic absorption spectrometry: An increased vapor pressure-chloride generation system

A new chloride generation system was designed for the direct, sensitive, rapid and accurate determination of the total germanium in complex matrices. It was aimed to improve the detection limit of chloride generation technique by increasing the vapor pressure of germanium tetrachloride (GeCl4). In order to do so, a novel joint vapor production and gas-liquid separation unit equipped with a home-made oven was incorporated to an ordinary nitrous oxide-acetylene flame atomic absorption spectrometer. Several variables such as reaction time, temperature and acid concentration have been investigated. The linear range for germanium determination was 0.1-10 ng mL−1 for 1 mL sampling volume with a detection limit (3 s) of 0.01 ng mL−1. The relative standard deviation (RSD) was 2.4% for nine replicates of a 1 ng mL−1 germanium solution. The method was validated by the analysis of one non-certified and two certified geochemical reference materials, respectively, CRM GSJ-JR-2 (Rhyolite), and GSJ-JR-1 (Rhyolite), and GBW 07107 (Chinese Rock). Selectivity of the method was investigated for Cd2+, Co2+, Cu2+, Fe3+, Ga3+, Hg2+, Ni2+, Pb2+, Sn2+, and Zn2+ ions and ionic species of As(III), Sb(III), Te(IV), and Se(IV).