Committee endorses full validation of fentanyl GC‑FID method after methanol bias found in initial tests

A committee reviewing laboratory methods voted to relabel and proceed with a full validation of a quantitative fentanyl method after presenters identified a bias related to methanol in the extraction process.

Rachel (S3) said the lab evaluated a method provided by the DEA (method no. 127) that uses hydrogen as the carrier gas for GC‑FID quantitation of heroin and fentanyl. "During the initial evaluation of that method within our laboratory, we did see some differences in the analytical results," Rachel (S3) said, and investigators found that varying amounts of methanol in the 9:1 chloroform:methanol extraction affected the internal standard response. That change produced a bias greater than the lab's calibrator acceptance criterion (±5%). Rachel said removing methanol corrected the bias in subsequent tests and therefore the lab will perform a full validation rather than a verification.

Member (S4) asked about recovery criteria; Rachel (S3) said the validation sets recovery and accuracy requirements and that quantitative results must be within 5% to be considered fit for purpose. Member (S2) moved to change the agenda title from "qualitative" to "quantitative analysis of fentanyl using GCFIDMS," Member (S4) seconded, and the motion passed on a voice vote. The committee then voted to close the review of both methods and adjourned.

Why it matters: A full validation can affect how casework results are reported in criminal matters and may change laboratory procedures for extracting and calibrating fentanyl quantitation. The change in solvent composition and the choice of internal standard (tricosane, noted by the presenter) were central to the decision to validate fully rather than perform a limited verification.

Next steps: Staff will proceed with the full validation plan described in the materials submitted to the committee.