Abstract:
BACKGROUNDBoron is an important trace element in high calcium biological samples, such as teeth and bones. Boron content and isotopic composition are important environmental tracers. However, the calcium content in biological samples is relatively high (>90%), and it is impossible to separate and enrich boron isotopes by using the conventional boron-special resin separation process.
OBJECTIVESTo establish an efficient method for treatment of boron isotopes in high calcium samples.
METHODSAn acetic acid-ammonium acetate buffer (pH=6.0) was used as a resin regeneration solution to replace ammonia. The adsorption pH of boron resin, boron-special resin (Amberlite IRA 743) was dropped from 8-9 to 6.0, thus the precipitation was avoided during digestion of the high calcium biological samples under alkaline conditions. Only one step of ion exchange is necessary to enrich boron in biological samples. The boron isotope of samples after separation was determined by multi-collector inductively coupled plasma-mass spectrometry (MC-ICP-MS) using a standard-sample-standard bracketing method.
RESULTSA one-step ion exchange method was used for separation and enrichment. The analytical accuracy of MC-ICP-MS for the determination of boron isotopes in teeth was less than 0.42‰, reaching the same level as other separation and determination methods.
CONCLUSIONSThis method is not only suitable for boron isotope tracing of high calcium biological samples such as teeth and bones, but also provides a reference for the analysis of high calcium soil and marine sediment.
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