Development Of Fully Automated Ion Exchange Devices For Isotope Separations

After the isotope mass spectrometers came out,the isotope tracer technology has been applicated to quantative study in many fields including ecology,marine science,and environmental science because of high sensitivity,low detection limit and high effiency.However,the existing fully automated solid phase extraction systems are mainly applied to separate organic analysis.It can not be used to separate isotope with HCl,HNO₃ and HF because of the metal material.The traditional methods of ion exchange column pretreatment have some disadvantages,such as time consuming,inefficiency,easy pollution.Therefore,we report our development of a fully automatically ion exchange device with perfluor materials and sealing flow path.This device consists of auto-sampler,elution system,column system,collection system and control system.The auto-sampler which consists of a 20-mL pump and12-mL cavity with liquid level sense and valves can finish automatic and accurate sampling.A multiposition valve and a magnetic valve were designed to realize the automatic processes of selective solution,sample loading,column eluting,isolates collecting,cleaning and column pretreatment.The liquid level sense can prevent bubbles into column and eliminate the interference from pressure of column and block.Meanwhile,the accuracy and precision are greatly improved compared with STM32microprocessor.In this paper,we take Rb and Sr as an example and HCl as eluting solutions.The experiment results have shown that the accuracy of pump was RSD lower than 1%when the volumes were between 2.50 mL and 10.00 mL.When the concentrations of HCl were 2.5 moL/L and 4 moL/L,the ideal elution curve was achieved and the recovery of column more than 95%.The blank of this process was 0.01 ng/mL and meet MC-ICP-MS determination request.The device can separate about 240 samples for 24 hour because of high efficiency with injection ways.We focused on the application of automated ion exchange device on line to separate Rb and Sr from standard sample GBW 04411 and geological samples,then we determinated ⁸⁷ Sr/⁸⁶ Sr by MC-ICP-MS.In this paper,the results shown that the recovery of Sr was better than 95%and the determinated value of GBW 04411 was7.60000±0.000008?2?,n=50?which the recommended value was 7.59999±0.00020.The results agreed well with the value got from the recommended value.The RSD of the determinated value of ⁸77 Sr/⁸66 Sr was lower than 0.05%.It stated that the stability and reliability of this device was well.The fully automated ion exchange device can be used to Sr?Nd?Pb isotope on line separation.Meanwhile,it also can be used to stable isotope metal too,such as Cu?Fe?Zn?Ca?Mg et al.In addition,the fully automated ion exchange device can provides a new solution for high throughout isotope on line separation because there are many advantages including high efficiency?low contamination?fully automatic et al.