Rapid determination of boron in 61 soil, sediment, and rock reference materials by ICP-MS

Abstract

Boron (B) is an important geochemical tracer for environmental and geological studies. This study presents a rapid acid digestion method with ammonia dilution to detect boron in soil, sediment, and rock samples using inductively coupled plasma mass spectrometry (ICP-MS). It took only 30 minutes of digestion time to completely recover B in 50 mg of soil (GSS-7), sediment (GSD-18), and rock (GSR-2) reference materials at a high digestion temperature of 190 °C using 1 mL HNO3 and 1 mL HF in a PTFE-lined stainlesssteel bomb. No loss of B was found at a digestion temperature of 190 °C for 30 hours. The wellknown memory effect of B was eliminated by using an ammonia dilution method. Moreover, the alkaline sample solutions created by ammonia dilution also avoided the corrosiveness of HF in the ICP-MS sample introduction system. Rhodium is a more suitable internal standard element than In and Y in the alkaline medium. Compared to the standard sample cone + H skimmer cone (S + H cone), the standard sample cone + X skimmer cone (S + X cone) increases the sensitivity of B by a factor of 7.0–8.2 in ICP-MS. The proposed method was successfully applied for the rapid determination of B in soil, sediment, and rock reference materials.