Rapid determination of mercury in food colorants using electrothermal atomic absorption spectrometry with slurry sample introduction

The determination of mercury in different types of color food additives using electrothermal atomic absorption spectrometry is proposed. The procedure involves direct introduction of the additive samples as suspensions, and fast-program methodology is used to avoid mercury volatilization losses. Suspensions are prepared in a medium containing 0.1 % w/v Triton X-100, 1% v/v concentrated nitric acid, 2% w/v potassium permanganate, and 3% w/v silver nitrate before being directly introduced into the furnace. Calibration uses aqueous standards, and compensation of the background is carried out using the Zeeman device. The characteristic mass is 61 pg and the detection limit is 59 pg. The reliability of the procedure is checked by comparing the results obtained with other results based on microwave-oven sample digestion, and by analyzing a certified reference material.