Simplified apparatus for determination of mercury by atomic absorption and inductively coupled plasma emission spectroscopy

A simplified apparatus has been applied to the determination of mercury by cold vapor generation. The equipment consists of a reaction flask incorporating a side arm in which a rubber septum is mounted. A sample solution is injected from a syringe through the rubber septum into the reaction flask, where it is mixed with a stannous chloride reducing solution. The elemental mercury generated is then swept with a carrier gas to the inductively coupled plasma (ICP), an absorption cell of an atomic absorption spectrometer, or a nondispersive UV monitor for determination. Detection limits were 0.009 and 0.005 micrograms with atomic absorption and the UV monitor, respectively, and 0.09 micrograms with the ICP. Repeatability of the procedure was 1.4% at 0.66 micrograms injected mercury with the ICP and 5.2% at 0.45 micrograms injected with atomic absorption. Tuna and halibut samples fortified with from 0.09 to 1.31 micrograms mercury/g were analyzed by the AOAC official method and the procedure described here. The average mercury recovery was 103% with the ICP, and 99% with the UV monitor and with atomic absorption. The procedure is free from interference by elements commonly present in biological material.