Determination of Sliver, Tin and Boron in Soil or Sediment Samples with Microwave Digestion by Mixed Mode Inductively Coupled Plasma-Mass Spectrometry

The analytical method of sliver, tin and boron in soil or sediment samples was developed by mixed mode inductively coupled plasma-mass spectrometry. A mixture of nitric acid, hydrochloric acid and hydrofluoric acid was utilized to digest the sample in a high-throughput closed microwave, and then the mass spectrometry sampling system was optimized and the mass spectrometry analysis mode for determination was adjusted. The mixed acid digestion solution could facilitate thorough digestion of refractory borosilicates and silicon-tin compounds in samples. Microwave sealed digestion method could improve the sample digestion efficiency and effectively avoid the loss of volatile element boron. Polytetrafluoroethylene (PTFE) atomizer, atomizer chamber and sapphire central tube could effectively reduce the background value of the instrument introduced by hydrofluoric acid solution medium corrosion quartz injection system. Using helium (He) as collision gas and the kinetic energy discrimination (KED) analysis of silver and tin could effectively reduce the interference of polyatomic ions, especially the interference of polyatomic ions formed by zirconium, niobium, zinc and oxygen, nitrogen and argon with higher geochemical abundance on 107Ag. The boron is basically free of polyatomic ion interference, so it could effectively improve the sensitivity of the method for boron by standard mode (STD). Subsequently, the detection limits of silver, tin and boron were 0.007, 0.12, 0.43 mg/kg, and the precision (RSD, n=12) and error (RE, n=12) of the method were 2.29%-9.53% and -9.95%-6.10%, respectively. Compared with the traditional atomic emission spectrometry method, this method has the advantages of simple process, high efficiency and low detection limit, which is suitable for the simultaneous analysis of multiple elements in large quantities of sample.