develop consensus standards for use by TNI's programs. This group has a support role in assisting other programs with activities such as guidance and standards interpretation.
fosters the generation of data of known and documented quality is through the National Environmental Laboratory Accreditation Program, or NELAP. The purpose of this program is to establish and implement a program for the accreditation of environmental laboratories.
is to establish and maintain a national PT program to support TNI’s National Environmental Laboratory Accreditation Program, and other activities.
Field Activities Program (NEFAP) Executive Committee is to establish and implement an accreditation program for field sampling and measurement organizations (FSMOs).
Audit Sample Program is to develop consensus standards for the manufacture and analysis of audit samples for source emission testing.
on a variety of topics of interest to the environmental measurement community. TNI also hosts two regularly scheduled meetings per year, typically in January and August. Both are a week long and involve open meetings of TNI committees as well as training courses and other special sessions.Standard Interpretation
Standard: 2009 TNI
Section: V1M4, Section 1.7.4.3
REQUEST:
Under Matrix Duplicates it states that the precision may be expressed as RPD or another statistical treatment. We do not do matrix duplicates, we perform sample duplicates only and use percent recovery. Are we required to run matrix duplicates, or are we okay running sample duplicates only? If we are allowed to run sample duplicates only, do we have to express precision as RPD, or can we stick to percent recovery? If we need to switch to matrix duplicates do we need to use RPD or can we use percent recovery?
TNI FINAL RESPONSE:
(Quality Systems Expert Committee and NELAP AC, 1-20-14)
Any laboratory-duplicated sample (however named, such as matrix duplicates, sample duplicates, or matrix spike duplicates) must be evaluated for precision. A percent recovery evaluates accuracy, but not precision. Precision must be evaluated by a statistical technique such as RPD, absolute difference or Percent relative standard deviation (% RSD).