ABSTRACT
The use of quality control materials, performance evaluation materials (blind samples) and reference materials has been an accepted practice for determining the ability of testing laboratories to perform analyses correctly for as long as Quality assurance and Quality Control has been practiced. The results of analysis of the performance evaluation samples lends credibility and acceptance to laboratory accreditation programs and provides results that serve as an integral part of data review and certification. Since the best evaluation of performance occurs when the laboratories are challenged with blind samples that are as close to the samples that are submitted for analysis as possible, it is ideal if data purchasers submit well-characterized samples of their industrial or site-specific wastes to the laboratories as blind samples. The use of the materials provides tangible evidence of the performance or lack of performance of laboratories.
