Yankuang ceshi (Mar 2021)
Determination of Trace Elements in Attapulgite Clay by Inductively Coupled Plasma-Tandem Mass Spectrometry
Abstract
BACKGROUND Attapulgite clay is a water-rich magnesium aluminosilicate mineral with a layered chain structure. The different genesis of the deposit results in a different composition of trace elements in attapulgite clay. Elements Be, Cr, Ni, As, Cd, Sb, Hg, and Pb have adverse effects to health and environment, while V, Mn, Co, Cu, Zn, Mo, Sn and Ba can affect the performance and application of attapulgite clay. Therefore, accurate analysis of trace elements in attapulgite clay can provide a theoretical basis for the high-efficiency value-added deep processing of attapulgite clay. Determination of trace elements in rocks and minerals by inductively coupled plasma-mass spectrometry (ICP-MS) has the characteristics of low limit of detection (LOD) and high sensitivity. Complex spectral interference during the analysis is difficult to completely eliminate, even if collision reaction cell (CRC) technology is used. OBJECTIVES To establish an analytical method for the accurate determination of trace elements in attapulgite clay by ICP-MS/MS. METHODS In view of the spectral interference in the analysis process, in the MS/MS mode, O2 and NH3/He were added into CRC as reaction gases, and the corresponding oxide ions and cluster ions were generated by mass shift reaction to eliminate the interference. Internal standard elements with similar mass number and similar mass spectrometry behavior were selected to correct the matrix effect and stabilize the analysis signal. RESULTS The microwave digestion of attapulgite samples with mixed nitric acid, hydrochloric acid and hydrofluoric acid can not only accelerate the digestion speed of the sample, but also maintain the stability of the analytical elements in the digestion solution. The method was used to determine 16 trace elements in national standard reference material basalt (GBW07105). The relative errors of analytes were -9.60%-8.21%, and the relative standard deviation (RSD) was less than 6.0%. Under the selected analytical conditions, the LOD of analyte was 0.13-51.6ng/L. CONCLUSIONS ICP-MS/MS can effectively reduce the interference of mass spectrometry and improve the accuracy and sensitivity of some specific isotopes in complex media. The method is suitable for the rapid determination of trace elements in attapulgite clay.
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