Ashley Kevin, Shulman Stanley A, Brisson Michael J, Howe Alan M
US Department of Health and Human Services, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, 4676 Columbia Parkway, MS R-7, Cincinnati, OH 45226-1998, USA.
J Environ Monit. 2012 Feb;14(2):360-7. doi: 10.1039/c1em10695c. Epub 2011 Oct 28.
Inductively coupled plasma mass spectrometry (ICP-MS) is becoming more widely used for trace elemental analysis in the occupational hygiene field, and consequently new ICP-MS international standard procedures have been promulgated by ASTM International and ISO. However, there is a dearth of interlaboratory performance data for this analytical methodology. In an effort to fill this data void, an interlaboratory evaluation of ICP-MS for determining trace elements in workplace air samples was conducted, towards fulfillment of method validation requirements for international voluntary consensus standard test methods. The study was performed in accordance with applicable statistical procedures for investigating interlaboratory precision. The evaluation was carried out using certified 37-mm diameter mixed-cellulose ester (MCE) filters that were fortified with 21 elements of concern in occupational hygiene. Elements were spiked at levels ranging from 0.025 to 10 μg filter(-1), with three different filter loadings denoted "Low", "Medium" and "High". Participating laboratories were recruited from a pool of over fifty invitees; ultimately twenty laboratories from Europe, North America and Asia submitted results. Triplicates of each certified filter with elemental contents at three different levels, plus media blanks spiked with reagent, were conveyed to each volunteer laboratory. Each participant was also provided a copy of the test method which each participant was asked to follow; spiking levels were unknown to the participants. The laboratories were requested to prepare the filters by one of three sample preparation procedures, i.e., hotplate digestion, microwave digestion or hot block extraction, which were described in the test method. Participants were then asked to analyze aliquots of the prepared samples by ICP-MS, and to report their data in units of μg filter(-1). Most interlaboratory precision estimates were acceptable for medium- and high-level spikes (RSD <25%), but generally yielded greater uncertainties than were anticipated at the outset of the study.
电感耦合等离子体质谱法（ICP-MS）在职业卫生领域的痕量元素分析中应用越来越广泛，因此美国材料与试验协会国际组织（ASTM International）和国际标准化组织（ISO）已颁布了新的ICP-MS国际标准程序。然而，这种分析方法缺乏实验室间性能数据。为了填补这一数据空白，开展了一项关于ICP-MS测定工作场所空气样品中痕量元素的实验室间评估，以满足国际自愿协商一致标准测试方法的方法验证要求。该研究按照调查实验室间精密度的适用统计程序进行。评估使用经认证的直径37毫米的混合纤维素酯（MCE）滤膜，这些滤膜添加了职业卫生领域关注的21种元素。元素添加水平为0.025至10μg/滤膜（-1），有三种不同的滤膜负载量，分别表示为“低”、“中”和“高”。参与实验室是从五十多名受邀者中招募的；最终，来自欧洲、北美和亚洲的20个实验室提交了结果。将每种含有三种不同水平元素含量的经认证滤膜的一式三份样品，以及添加了试剂的介质空白样品，分发给每个参与实验室。还向每个参与者提供了测试方法的副本，并要求他们遵循该方法；参与者不知道添加水平。要求实验室通过测试方法中描述的三种样品制备程序之一来制备滤膜，即热板消解、微波消解或热块萃取。然后要求参与者用ICP-MS分析制备好的样品的等分试样，并以μg/滤膜（-1）为单位报告数据。对于中高水平的加标（相对标准偏差<25%），大多数实验室间精密度估计值是可以接受的，但总体上产生的不确定度比研究开始时预期的要大。
