Chapter 10 Interlaboratory and intralaboratory surveys Reference methods and reference materials

Abstract

This chapter focuses on the interlaboratory and intralaboratory surveys in context to reference methods and reference materials. Developments in instrumentation and chemical matrix modification techniques have brought dramatic improvements in analytical performance. Other analytical techniques, such as inductively-coupled plasma emission spectrometry (ICP) and ICP-mass spectrometry also have wide application in the clinical analysis of trace elements. Some of the most important potential sources of error in trace metal determination are discussed in the chapter. One of the most important sources of random error is in the volumetric handling of liquid samples or standards. Differences in the surface tension and viscosity of specimens, calibration solutions or controls may cause major problems in analytical performance. The collection and sampling of tissues or solids is a difficult and complex source of error. There are several sources of random and systematic error that can be attributed to instrument characteristics and variation during an analytical run. The method of calibration is a major potential source of systematic error. Contamination is one of the most important and persistent sources of both random and systematic error in trace metal analysis, and it pervades all aspects of sample collection, storage, and manipulation.