What Does Your Proficiency Testing (PT) Prove? A Look at Inorganic Analyses, Proficiency Tests, and Contamination and Error, Part I

Abstract

Trace inorganic analysis is an essential part of analytical testing. In many cases, contamination can alter or skew elemental analysis, which leads to inaccurate results. Another way in which contaminants can alter results in a detrimental fashion is in regard to proficiency testing and laboratory audits. Proficiency testing (PT) is a series or schemes of samples that are intended to assess the performance of individuals or laboratories in specific areas or for specific analytical tests. PT is also designed to be used to improve processes and methods. If contamination and error enter into the analysis process, then the results can be altered, causing the analyst or laboratory to perform poorly in a PT scheme. In this two-part article, we examine the development, rationale, and best practices for PT, including how contamination can enter inorganic samples and how to eliminate or control those sources.