Application of Ammonia Solution Coprecipitation Method in Strontium Isotope Analysis
10.19756/j.issn.0253-3820.241189
- VernacularTitle:氨水共沉淀法在锶同位素分析中的应用
- Author:
Wen-Gang LIU
1
;
Shuang WEI
;
Xiao-Wei ZHANG
;
Jian ZHANG
;
Hong-Ying ZHOU
Author Information
1. 中国地质调查局天津地质调查中心(华北地质科技创新中心),天津 300170
- Keywords:
Ammonia solution precipitator;
Cation-exchange resin;
Geological sample;
Strontium isotope analysis
- From:
Chinese Journal of Analytical Chemistry
2025;53(1):115-123
- CountryChina
- Language:Chinese
-
Abstract:
In the process of strontium(Sr)isotope analysis,the separation and purification of Sr are crucial for obtaining high-precision Sr isotope ratios.In this work,ammonia solution was used as a precipitating agent to initially separate and purify Sr from geological samples through coprecipitation,followed by the combination with cation-exchange resin to quickly and effectively obtain high-purity Sr components.The experimental conditions of ammonia coprecipitation reaction were optimized using typical high Rb/Sr ratio(mass ratio)standard sample JR-2.The results showed that using 3 mL of ammonia(1 mol/L)as the precipitating agent,at 120℃for 1 h,could effectively remove more than 90%of Rb,Na and K,with Sr recovery exceeding 95%.To verify the stability and applicability of this separation process,geological standard samples(JR-2,BCR-2,AGV-2,BHVO-2,GSP-2,W-2a)with different rock types and Rb/Sr ratios were practically validated.The results demonstrated that the coprecipitation process with ammonia solution removed more than 90%of Rb,Na and K,with Sr recovery greater than 95%.To further assess the applicability of this method for samples with high Rb/Sr ratios,Rb was added to the rhyolite standard material JR-2,adjusting its Rb/Sr ratio to 500.The results showed that this separation process could still effectively achieve the separation of Rb and Sr,and high-precision Sr isotope analysis results were successfully obtained by combining thermal ionization mass spectrometer(TIMS).Ammonia solution,as a precipitating agent,offered advantages such as low cost,low procedural blanks,simplicity,and a wide range of applicability.Therefore,the combination of ammonia solution coprecipitation and cation-exchange resin enabled rapid Sr purification from geological samples,providing a novel separation approach for high-precision Sr isotope analysis of samples with high Rb/Sr ratios,with broad application prospects.
