Determination of Micro-amount of Lead and Chromium in Phosphate Ores by Graphite Furnace-Atomic Absorption Spectrometry

A method was established to determine the microamount of lead and chromium in phosphate ores by graphite furnace-atomic absorption spectrometry. The instrument operating parameters and the furnace program were optimized. Some factors which affect the determination results, such as acid digestion system, matrix modifier and interference from concomitant elements were discussed. The detection limits of the method were 0.25μg/g for lead and 0.29 μg/g for chromium. The recovery of the method was 93.2%～107.7% with precision of 2.2%～7.0%RSD(n=12). The method has been applied to the determination of micro-amount of lead and chromium in phosphate ores with satisfactory results.