An ambient aerosol concentration enrichment system coupled with ICP-MS for real-time monitoring of airborne radioactive particles is now under development. ICP-MS is very sensitive to sample introduction conditions, so it is necessary to develop an easy-use calibration method for on-line quantitative analysis in field application. In this paper, a calibration method using standard solution instead of monodisperse particles was established and validated preliminarily. First of all, four parameters for the method were determined experimentally, including: uptake flow rate and nebulisation efficiency of the Microconcentric nebuliser, nebulisation/transport efficiency of Aridus Desolvating Sample Introduction System, and Relative Sensitivity Factor between 159 Tb and 174 Yb. Then, monodisperse terbium nitrate particles were generated by a commercial Vibrating Orifice Aerosol Generator. Continuous aerosols of ytterbium nitrate droplets were nebulised from standard solution. They were mixed together, desolvated through the membrane dryer and introduced into ICP-MS for on-line analysis of terbium nitrate particles. The air sampled from nuclear environment was also introduced into ICP-MS to investigate the effect of flow rate on instrument responses. Finally, atom numbers of 159 Tb in discrete terbium nitrate particles were determined using the calibration method and compared to the calculated value. Results show that when air flow rate increase from 10 mL min−1 to 100 mL min−1, the ratio of 159 Tb ion count to 174 Yb ion intensity keeps constant although instrument sensitivity decreases by a factor of 25. The relative standard deviation of 159 Tb atom number measured is better than 18%. The discrepancy with the calculated value could be attributed to the over-estimation of atom number in the particles generated by VOAG because there was some liquid leakage in the VOAG.

A technique for direction introduction and on-line quantitative analysis of aerosol particle by ICP-MS has been developed. Fast determination of Pu-239 concentration in aerosols based on Pu-242 aerosol particle addition calibration method and sampled by steel cylinders samplers from nuclear environment has been conducted. Results show that detection limit for Pu-239 concentration is 1.4 x 10(-3) Bq/m(3). The concentrations in these aerosol samples are between 3.1 x 10(-3) and 1.2 x 10(-2) Bq/m(3), all of which are at least one order of magnitude lower than the statutory tolerance.

An experimental sampler for rare gases (ESRG) which can collect radioxenon isotopes from atmosphere under normal temperature and low temperature is installed and studied. Its sampling efficiency is calibrated with ICP-MS (Inductively Coupled Plasma-Mass Spectrum) through analyzing the ~129Xe in the off-gas of ESRG. The main experimental results show that the sampling efficiency to xenon isotopes in ambient air is up to 40% when the adsorbent is effectually regenerated.

在有同质异位素干扰的情况下,通常从所测质谱峰中直接扣除叠加的同质异位素峰,获得同位素丰度比.这种方法适用于干扰元素存在两个以上的同位素,需丰度比已知.本工作拟已Yb存在的情况下测定176Lu/175Lu的同位素比值为例(存在176Yb对176Lu的干扰),探讨在有同质异位素干扰下用ICP-MS测定同位素比的方法.

电感耦合等离子体质谱法(ICP-MS)可用于分析周期表中的绝大多数元素,而氪和氙被认为属不能分析的元素,至今未见ICP-MS分析氪和氙的报道.在没有气体质谱计的情况下,为准确测量微量氪和氙,应用ICP-MS分析氪和氙同位素丰度比的技术及进行低浓度氪和氙半定量及定量的方法(另文发表),并拟在此基础上建立ICP-MS准确定量氪和氙气体同位素稀释法.

在环境分析及地球化学研究等工作中,有时需要对低浓度的稀有气体氪(Kr)和氙(Xe)进行定量分析.常用的分析仪器是气相色谱(GC)和专用气体质谱计.专用气体质谱计在对样品进行预处理后可达到很高的同位素比值分析精度,但是直接进样测定低浓度氪和氙样品浓度值的精度较低,价格昂贵、应用范围较窄.GC测量简单快速、仪器价格便宜,但是只能测定氪和氙的浓度,无法分析同位素丰度,而且检测限相对较高,难以胜任低于ppm浓度氪和氙样品定量分析的要求.电感耦合等离子体质谱计(ICP-MS)作为一种理想的多元素快速分析仪器,一般认为其不适合稀有气体分析.本文简要介绍本实验室发展的应用ICP-MS测定低浓度Kr和Xe的技术.

A double-focused ICP-MS coupled with a membrane desolvating sample introduction system is used for the determination of ultra-trace plutonium in atmospheric aerosols. 242Pu is used as spike for the isotope dilution analysis. The detection limit of 239Pu obtained is 0.4 fg/mL. The matrix effect was minimized by matrix separation using extraction chromatography. The limit of determination for plutonium in atmospheric aerosols obtained is 5.7×10 -8 Bq/m 3.