A PROCEDURE FOR THE ISOTOPIC ANALYSIS OF BORON BY NEGATIVE THERMAL IONIZATION MASS-SPECTROMETRY

Presented here is a simple and precise technique for the measurement of boron isotopes in carbonates and natural waters. Analytical uncertainty for this technique is +/- 0.7 parts-per-thousand analyzing as little as 1 ng B. A boron separation and concentration procedure using Amberlite(R) IRA-743 boron-specific anion-exchange resin is presented that results in 100 +/- 1% recovery of boron from sample solutions. A mass spectrometry technique to measure the BO2- ion has been improved, resulting in a five-fold increase in analytical precision, and an order of magnitude increase in ionization efficiency over previous negative ion techniques.