Boron isotope ratios in plants enriched in 10B as determined by direct injection nebulization inductively coupled plasma mass spectrometry

Abstract

The determination of boron (B) isotope ratios (11B/10B) in small amounts of 10B enriched cotton plants was performed by inductively coupled plasma mass spectrometry (ICP-MS) with direct injection nebulization (DIN). Boron isotope ratios were determined in 1.0 M hydrochloric acid (HCl) extracts and in total digests produced by high pressurized microwave oven. Both procedures resulted in contaminants free solutions, without losses of B and with low carbon (C) residues. Small sample volumes (50 μL) were introduced by DIN into the plasma, reducing memory effects and allowing 45 determinations hr−1. Instrumental mass biases from −1.00–4.66% were found for solutions with 10B isotopic compositions ranging from 20–70 atom %. Isotopic ratios from 1.091–1.834 were determined with precision characterized by RSD<1.4% for samples with B concentration ranging from 15–50 μg g−1. The detection limit was 0.4 ng B mL−1. Boron isotope ratios determined by both procedures were in agreement at the 95% confidence level.