La. Admin. Code tit. 55 § I-583

Current through Register Vol. 50, No. 9, September 20, 2024

Section I-583 - Analytical Procedures

A. Analytical procedures shall include the use of at least two tests (a screening test and a confirmation test, or two confirmation tests) performed for each analyte present. If a screening test is used, the confirmation tests shall be based on a different physical or chemical principle from that of the screening test and offer a higher degree of specificity. All confirmation tests shall be performed using gas chromatography/mass spectrometry or liquid chromatography/mass spectrometry. Screening tests may include, but not be limited to, colorimetric, enzymatic, or chromatographic analysis. Confirmation of the identity of an analyte in a different specimen from that used for the first test (e.g., blood and urine) is acceptable, as is reconfirmation in a second aliquot of the same specimen.

B. Positive identification of an analyte shall at a minimum be based on the possible presence of the analyte or the analyte class in the screening test and its presence in the confirmatory test. Confirmation shall be based on the identification of at least three major ions with that of a reference analyte, unless otherwise specified below. When confirmation is made by selective ion monitoring in either gas or liquid chromatography procedures, correlation between ion ratios of the base peak and another major peak shall be within 20 percent for gas chromatography/mass spectrometry procedures and within 30 percent for liquid chromatography/mass spectrometry procedures. When confirmation is made by multiple reaction monitoring using either gas or liquid chromatography procedures, the presence of a characteristic precursor ion and two product ions shall have an ion ratio within + or - 30 percent to that of a calibrator, or the average of all calibrators for the run. When the confirmation is made by gas or liquid chromatography coupled to a Time-of-Flight (ToF) or other high-resolution mass spectrometer (HRMS), the presence of a characteristic precursor ion with overall mass accuracy shall be less than 15 parts-per-million or + or - 5 millimass units. At least one additional product ion compared to that of a reference analyte shall also be present. Retention times between the analyte in question and the reference analyte shall be "within + or - 2 percent" for gas chromatography/mass spectrometry procedures and "within + or - 6 seconds or + or - 10 percent" for liquid chromatography/mass spectrometry procedures.

La. Admin. Code tit. 55, § I-583

Promulgated by the Department of Public Safety, Office of State Police, LR 26:2625 (November 2000), amended LR 37:1417 (May 2011), Promulgated by the Department of Public Safety, Office of State Police, LR 441272 (7/1/2018), Amended LR 451809 (12/1/2019), Amended LR 46775 (6/1/2020).

AUTHORITY NOTE: Promulgated in accordance with R.S. 32:663.