An optimized procedure for boron separation and mass spectrometry analysis for river samples

摘要: An optimized procedure for the separation of boron from natural river samples and an improved mass spectrometry determination isotopic ratio are presented. The chemical procedure, based on use boron-specific resin Amberlite IRA 743, is especially efficient in separating organic matter-rich like waters. The properties 743 have been investigated. two factors important determining affinity are: pH value ionic strength solution which B to be extracted. A logarithmic relationship between partition coefficients values found. High significantly lowers fixation onto resin. The knowledge controlling enables us design a simple miniaturized characterized by (i) three chromatographic steps using, respectively, 50, 10 3 μl resin, (ii) no evaporation step each column, (iii) final residual matter sublimation boric acid at 75 °C. Boron ratios measured using cesium metaborate technique, with graphite mannitol. Adequate loading conditions enable obtain typical signal intensities 5×10−12 250 ng boron. No in-run fractionation observed, external reproducibility standards processed through entire as well samples, corresponds 0.35‰ (±2σ). According this precision, slight, but reproducible 0.4‰ observed whose origin discussed, still unclear.