NIST候选标准物质RM2703中多元素取样行为的中子活化分析

Sampling Behavior of Multielements in Candidate NIST RM 2703 by Using Neutron Activation Analysis

本工作以0．8-1．4mg的取样量，用仪器中子活化分析（INAA）结合Ingamells模型，研究了用于微分析质控的NIST候选标准物质RM2703（海洋沉积物）和相同基体的常规有证标准物质NISTSRM2702的多元素取样行为。确认了2种物质中至少12种元素在1mg取样量水平具有满意的均匀度，相对标准取样不确定度小于1％。Dy，Hf，Lu，Sb的取样常数在具有较细粒径分布的RM2703中远比在SRM2702中小，显示了粒径分布对元素取样行为的影响。

Sampling behavior of multielements in candidate NIST RM 2703 and NIST SRM 2702 were characterized at sample sizes of 0.8 to 1.4 mg by instrumental neutron activation analysis （INAA） combining with Ingamells model. The two materials are the same in matrix but different in particle size distribution, the former is finer than the latter. At least 12 ele- ments are confirmed to be homogeneous enough with relative standard sampling uncertainties smaller than 1~ at 1 mg sample size level for both materials. The fact that the sampling constants of Dy, Hf, Lu and Sb in RM 2703 are much smaller than in SRM 2702 clearly indicates the influence of particle size distribution on sampling behavior.