We are pleased to announce that Nelson Labs will be at the Smithers Extractables & Leachables (E&L) USA 2025 in Alexandria, Virginia this May 20-21, 2025.
Be sure to to connect with our consultants in the exhibition area who are available to answer any testing and/or compliance questions you may have.
Join our presentation:
Session III: Executing E&L Studies
Topic: Considerations on how to use Retention Index Information (NIST) to Support Mass Spectral Based Identifications in GC/MS
Speaker: Piet Christiaens, PhD, Scientific Director, Nelson Labs
Tuesday, May 20, 2025
1:30 – 2:00pm EDT
Abstact: The identity of an extractable or leachable is a critical foundation of toxicological risk assessment, as it is through the identity that the risk assessor obtains information about the compound’s toxicological profile and ultimately establishes a tolerable intake (TI). It is therefore of utmost importance to have identifications of compounds with the highest level of confidence achievable. The typical “generic” approach labs are taking to identify GC/MS-compounds is to perform library searches with commercial databases and suggest the identity of a compound, based upon the quality of the mass spectral match, based on different criteria (eg Match Factor, Reverse Match Factor, Probability, InLib Score). However, the identification of a compound only based on its mass spectrum may not offer a sufficient confidence that the mass spectral interpretation is correct. To increase the confidence, a second piece of independent information – which supports the compounds identity – is necessary. In addition to the mass spectral information, the NIST library also contains chromatographic information of most of the compounds. As chromatographic information (i.e. Retention Index) is completely independent from the compound’s mass spectral fingerprint, Retention Index information could be used in support of identification if the information is sufficiently accurate. In a first step, the presentation will evaluate how well the Retention Index information from NIST correlates with the retention time (converted to RI) over 3100 compounds – confirmed with analytical standards – that are in the Nelson Database. Based upon the statistics, we will evaluate if and how acceptance criteria can be derived for the RI-reconciliation (ΔRI). Once acceptance criteria for the ΔRI have been derived, the presentation will explain and evaluate how this criterion can be of value to augment mass spectral identifications, to reject false MS-identifications or how it could assist in structure elucidation performed by HRAMS GCMS.
More information about the conference can be found here.
