Section 774. Chemical testing: selectivity

A. The laboratory shall evaluate selectivity by following the checks established within the method, which may include mass spectral tuning, second column confirmation, ICP inter-element interference checks, chromatography retention time windows, sample blanks, spectrochemical absorption or fluorescence profiles, co-precipitation evaluations, and electrode response factors.

B. A confirmation shall be performed to verify the compound identification when positive results are detected on a sample from a location that has not been previously tested by the laboratory. Such confirmations shall be performed on organic tests such as pesticides, herbicides, or acid extractable or when recommended by the analytical test method except when the analysis involves the use of a mass spectrometer. Confirmation is required unless stipulated in writing by the client. All confirmation shall be documented.

C. The laboratory shall document acceptance criteria for mass spectral tuning.

Historical Notes

Derived from Volume 25, Issue 07, eff. January 1, 2009.

Statutory Authority

§ 2.2-1105 of the Code of Virginia.