Application of Site Specific Samples as On-Site Reference Material

Oral Presentation

Prepared by J. Richardson1, M. Wilken2
1 - The Dow Chemical Company, 1897 Building H-21, Midland, MI, 48667, United States
2 - The Dow Chemical Company, 1790 Building office 225, Midland, MI, 48674, United States


Contact Information: jjrichardson@dow.com; 989-636-1420


ABSTRACT

The Dow Chemical Company has implemented a qualification system for environmental contract laboratories which is complementary to the standard laboratory qualification and certification process of using commercial PT samples as part of their accreditation. This system uses blended, diluted, and intensively homogenized real internal water samples which are submitted annually to the laboratories in replicates and dilutions for analysis of the most common environmental parameters such as metals, anions, TOC, and volatile and semi-volatile organic components. This qualification process has been applied for several years now and addresses potential matrix inherent effects which commercial PT samples (spiked water) or reference material might not, necessarily, adequately cover.

The program is accompanied by an evaluation of the overall laboratory services from sample pick-up to data package delivery. It is supported by regular on-site audits by Dow’s quality managers. The entire process allows us to identify those laboratories with the highest quality and performance to achieve the status of a Dow preferred laboratory.

As an on-going quality control in site investigations, we are using the same principle by blending samples from that specific site and sending them camouflaged and embedded in the sample pool to the analyzing laboratory, as well as to “reference” laboratories. These “site-specific” samples serve as “reference material” for components which are not stable over a long period of time. Furthermore, these samples, while submitted as replicates and dilutions, can serve as true laboratory duplicates, can be used for the determination of the precision (RPD), the quality of the analytical process over a range of concentrations and will be evaluated against established performance criteria.