INTRODUCTION

Direct (without any pre-treatment) atomic absorption or atomic fluorescence mercury determination in food and feed is difficult due to complex organic matrix. That is the reason why conventional AFS and AAS methods include sample digestion by acids and require compressed gases such as argon or oxygen. This makes analysis more complicated and costly and extends analysis time. Sample pre-treatment can also increase measurement errors. The use of a RA-915M/RA-915M+ mercury analyzer with a PYRO-915+ pyrolytic attachment or RA-915F mercury аnalyzer provides direct mercury determination in foodstuff, food/feed products and similar samples at a ppb level thereby saving time due to elimination of the sample preparation stage.

MEASURING METHOD

The principle of the method is based on the reduction of Hg(II) to the atomic state due to the thermal decomposition of the mercury compounds and the follow-up transporting of mercury atoms into the analytical cell of the analyzer by the air flow. The mercury concentration is then determined from the absorption of the 254-nm resonance radiation by mercury atoms measured using differential atomic absorption spectroscopy with Zeeman correction for background absorption.