Automatic Separation And Enrichment Of Molybdenum Isotopes In Geological Samples

With the development of isotope mass spectrometer technology,especially the rapid development of Multi-Collector Inductively Coupled Plasma Mass Spectrometry,non-traditional isotopes have become one of the hotspots in geology.Molybdenum isotopes are a kind of non-traditional isotopes,which have a good tracer of the evolution of ancient ocean,the source of ore-forming materials,modern hydrosphere and the exploration of element circulation.However,the content of molybdenum in most geological samples is very low,which is difficult to the accurate determination of molybdenum isotopes in geological samples.Ion exchange method is the most commonly used method for the separation and enrichment of isotopic samples,which has the advantages of high separation efficiency and recovery rate,low process blank,simple operation and good reproducibility.But the main disadvantage of this method is that the operation steps are tedious and time-consuming.This thesis aims at the two main shortcomings of the existing separation process of molybdenum isotope separation and enrichment,such as time-consuming and large reagent consumption.A novel separation enrichment method of molybdenum isotope was established.Firstly,Co-precipitation method was used to rapidly separate molybdenum from most interfering elements.Secondly,Bio-Rad AG?1-X8 anion exchange resin was used to completely separate molybdenum from the pre-separation solution by exchange column.An automatic device of ion exchange was established in order to overcome the shortcomings of time-consuming of ion exchange.The sample recovery rate was 98%?n=10?,and the blank mass of molybdenum was less than 0.05ng.The ion-exchange device can automatically complete the pre-balance,clean,elution,regeneration and component collection of molybdenum isotope ion-exchange column.The automatic device can process 64 samples in a batch.Molybdenum isotopes in NIST SRM 3134,a diabase sample W-2a and a manganese nodule sample NOD-P-1 were separated with the proposed separation enrichment method,and then determined by Neptune Plus Multi-Collector Inductively Coupled Plasma Mass Spectrometer.The analysis results were:?⁹⁸Mo_{SRM 3134}=0.00600.094‰?2SD?,?⁹⁸Mo_{SRM 3134}=-0.0500.08‰?2SD?,?⁹⁸Mo_{SRM 3134}=-0.9000.07‰?2SD?.The results are consistent with the published value of literature within the allowable error range.This nevol method of co-precipitation and automatic ion exchange column separation and enrichment of molybdenum isotopes simplifies the process of molybdenum isotopes separation in geological samples and provides a new technical means for the study of molybdenum isotopes.