An improved procedure for separation/purification of boron from complex matrices and high-precision measurement of boron isotopes by positive thermal ionization and multicollector inductively coupled plasma mass spectrometry.In order to eliminate boron loss and potential isotopic fractionation during chemical pretreatment of natural samples with complex matrices, a three-column ion-exchange separation/purification procedure has been modified, which ensures more than 98% recovery of boron from each step for a wide range of sample matrices, and is applicable for boron isotope analysis by both TIMS and MC-ICP-MS. 
THERM