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Combined Interpretations of the 2003, 2009, and 2016 Standards that apply to Volume 1 of the 2016 TNI Standard


Question:  Section begins with the statement “When an initial instrument calibration is not performed on the day of analysis, the validity of the initial calibration shall be verified prior to sample analyses by continuing instrument calibration verification with each analytical batch. The following items are essential elements of continuing instrument calibration verification:”. This is a forward looking statement meaning that the pass/fail status of the CCV standard being run is evaluated only in light of it’s impact on the samples which follow the CCV standard.  Section e) reads “If the continuing instrument calibration verification results obtained are outside established acceptance criteria, corrective actions must be performed. If routine corrective action procedures fail to produce a second consecutive (immediate) calibration verification within acceptance criteria, then either the laboratory has to demonstrate acceptable performance after corrective action with two consecutive calibration verifications, or a new initial instrument calibration must be performed.” The corrective action language in the standard only address what is necessary to proceed with analysis without recalibration. I referred to this evaluation as being “forward looking”. There is no interpretation given regarding any additional considerations, or limitation on corrective actions for nonconforming CCV events where they occur in the middle or the end of a sequence that requires acceptable bracketing CCVs such as in GC analysis without the use of internal standards.

TNI Response:  Running a second CCV in a sequence is not the intention of the standard. The practice of running two CCVs routinely would require that the laboratory evaluate each of them on every occasion. There must be a form of corrective action (i.e., instrument maintenance) prior to the second CCV being evaluated. Since no corrective action is being taken between the two CCVs, the laboratory is failing the requirement in e of performing routine corrective action (unless it can be documented that something occurred in the first CCV, such as poor sample introduction, that did not occur in the second CCV), and cannot use the second CCV to alleviate the failing of the first.


Question:  “Calibration shall be verified for each compound, element, or other discrete chemical species, except for multi-component analytes such as Aroclors...”  A laboratory is saying that they do not need to run a Chlordane standard to report non-detect chlordane results because of this NELAC Quality Systems Chapter 5 statement.  They are saying that the auditors allow it.  No continuing calibration is required for SW-846 Method 8082?

TNI Response:  It is important to read the entire Standard, not just a single phrase. The full language of the referenced section is as follows: "Calibration shall be verified for each compound, element, or other discrete chemical species, except for multi-component analytes such as Aroclors, Total Petroleum Hydrocarbons, or Toxaphene where a representative chemical related substance or mixture can be used." The requirement is that a representative chemical related substance or mixture is to be used to verify the calibration. If a representative substance were used, such as alpha or gamma Chlordane in lieu of Technical Chlordane, that would meet the requirements of this section.