Abstract:
Feldspar samples were digested with HCl-HNO
3-HClO
4-HF mixed acids and K, Na, Ca, Mg, Al, Ti and Fe in sample solutions were directly determined by Inductively Coupled Plasma-Atomic Emission Spectrometry (ICP-AES). The conditions for selection of analytical lines and the amount of dissolved acids were optimized. The best determination result was obtained when the sub-sensitive analytical lines were used for the high content elements. For low content elements, the sensitive analytical lines were used. The amount of HF had to be strictly controlled, which greatly impact on the determination of the results. The results were verified by the internal standard method and a non-internal standard method. The sub-sensitive analytical line of 396.152 nm was selected for high Au content samples. The best result was obtained by using an internal standard to calibrate the nonspectral interference, selecting the low content Au in feldspar as the internal standard and analytical line of 242.795 nm. The established method has been applied to the rapid determination of K, Na, Ca, Mg, Al, Ti and Fe in feldspar samples. The determination limits of the method were 3.5 6 μg/g for K
2O, 1.25 μg/g for Na
2O, 1.93 μg/g for CaO, 1.86 μg/g for MgO, 0.452 μg/g for Al
2O
3, 2.97 μg/g for TiO
2 and 1.57 μg/g for Fe
2O
3. The relative error (RE) ranged from -1.32% to 10.0% with a precision of 0.55%-7.2% (RSD,
n=10). The results were in agreement with the certified values and chemical method. This method provided the advantages of wide dynamic linear range, high efficiency and simple operation. The method has been applied to determine these components in various feldspar samples with accurate and reliable results.