Isotopic Determination of Silicon by Mass Spectrometry in Plants and Soils Labeled with ³⁰Si

Abstract

A method for isotopic determination of silicon by mass spectrometry in plants and soils labeled with ³⁰Si is reported. The development of this method is for use with studies involving the physiological process of absorption, transport, and redistribution of Si in the soil-plant system by use of the stable isotope ³⁰Si as a tracer. The procedure leads to SiF₄ formation, and the isotopic determination of Si was based on the measurements of the ²⁸SiF₃ ⁺, ²⁹SiF₃ ⁺, and ³⁰SiF₃ ⁺ signals. Relative standard deviation of ³⁰Si abundance measurements (n = 6) were lower than 0.1%, and the detection limit was 0.5 mg Si (dry mass).

Keywords:

• Isotopic determination
• labeled compounds
• mass spectrometry
• plants and soils
• silicon
• stable isotopes

Partial financial support and fellowships from Brazilian agencies (FAPESP, CNPq) are greatly appreciated.

Notes

∗Results expressed in % (w/w).

∗∗Results expressed in mg Kg⁻¹.

Relative standard deviations (n = 6, expressed in %) are specified in brackets.