Interlaboratory development and proposition for a new quality control sample for chemical forensics analysis of chemical warfare agents
Solja Säde,
Grégoire Delaporte,
Carlos G. Fraga,
Hanna Hakulinen,
Karin Höjer Holmgren,
Marie Spiandore,
Crister Åstot,
Anuradha Akmeemana,
Mirjam de Bruin-Hoegée,
Justin Doward,
Karen Jacques,
Saiful Anuar Kesah,
Samantha See,
Stuart Thomson,
Jens Flinck,
Leena Kalliovirta,
Paula Vanninen
Affiliations
Solja Säde
Finnish Institute for Verification of the Chemical Weapons Convention (VERIFIN), Department of Chemistry, University of Helsinki, P.O. Box 55, FI-00014, Helsinki, Finland; Corresponding author at: VERIFIN, University of Helsinki, A.I.Virtasen aukio 1, 00560, Helsinki, Finland.
Grégoire Delaporte
Analytical Chemistry Department, DGA CBRN Defence, 91710, Vert-Le-Petit, France
Carlos G. Fraga
Air Force Research Laboratory, 10 E. Saturn Blvd., Edwards Air Force Base, CA, 93524, USA
Hanna Hakulinen
Finnish Institute for Verification of the Chemical Weapons Convention (VERIFIN), Department of Chemistry, University of Helsinki, P.O. Box 55, FI-00014, Helsinki, Finland
Karin Höjer Holmgren
Swedish Defence Research Agency (FOI), CBRN Defence and Security, Cementvägen 20, 90182, Umeå, Sweden
Marie Spiandore
Analytical Chemistry Department, DGA CBRN Defence, 91710, Vert-Le-Petit, France
Crister Åstot
Swedish Defence Research Agency (FOI), CBRN Defence and Security, Cementvägen 20, 90182, Umeå, Sweden
Anuradha Akmeemana
National Center for Forensic Science, University of Central Florida, Orlando, FL, 32826, USA
Mirjam de Bruin-Hoegée
Van ’t Hoff Institute for Molecular Sciences, Faculty of Science, University of Amsterdam, P.O. Box 94157, 1090GD, Amsterdam, the Netherlands; TNO Defence, Safety and Security, Department of CBRN Protection, Lange Kleiweg 137, 2288GJ, Rijswijk, the Netherlands
Justin Doward
Defence Science and Technology Group, 506 Lorimer Street, Fishermans Bend, 3207, Victoria, Australia
Karen Jacques
Dstl Porton Down, Salisbury, Wiltshire, SP4 0JQ, UK
Saiful Anuar Kesah
Department of Chemistry Malaysia, Jalan Sultan, 46661, Petaling Jaya, Selangor, Malaysia
Samantha See
DSO National Laboratories, 12 Science Park Drive, Singapore, 118225
Stuart Thomson
Organisation for the Prohibition of Chemical Weapons (OPCW), The Hague, the Netherlands
Jens Flinck
Department of Mathematics and Statistics, University of Helsinki, Pietari Kalmin katu 5, FI-00014, Helsinki, Finland
Leena Kalliovirta
Department of Mathematics and Statistics, University of Helsinki, Pietari Kalmin katu 5, FI-00014, Helsinki, Finland
Paula Vanninen
Finnish Institute for Verification of the Chemical Weapons Convention (VERIFIN), Department of Chemistry, University of Helsinki, P.O. Box 55, FI-00014, Helsinki, Finland
A new quality control (QC) test sample for gas chromatography–mass spectrometry (GC–MS) was created and analysed to test the comparability and repeatability of chemical forensics results within the Organisation for the Prohibition of Chemical Weapons (OPCW)–designated laboratories. The QC test sample was designed in collaboration between four laboratories and consists of 27 compounds which evaluate the performance of GC–MS instruments. This solution was analysed with GC–MS(EI) in 11 laboratories, seven of which were OPCW designated. The participating laboratories analysed the sample multiple times on consecutive days, as well as after the analysis of a set of complex matrix samples. Retention times, retention indices, peak areas, peak tailing values, signal-to-noise ratios, and isotope ratios were extracted from the GC–MS data, and statistical multivariate analyses with principal component analysis and Hotelling's T2-tests were conducted. The results from these analyses indicate that differences between GC–MS analyses by multiple laboratories were not statistically significant at the 5% level, as the approximate p-value for the null hypothesis of “no differences between the runs” was 0.69. However, similar data processing methods and data normalisation are essential for enabling the reliable comparison of chemical fingerprints between laboratories. A composition for the QC sample and criteria for acceptable GC–MS performance for chemical forensics are proposed. The composition and criteria differ from the currently used chemical weapons verification analysis QC sample by e.g. broadening the range for retention index calculations by addition of new alkane compounds, including new chemicals with concentrations close to the limit of detection (10–100 ng/ml), and including compounds with higher polarity to emulate real-life forensic samples. The proposed criteria include monitoring of retention indices, isotope ratios, peak tailing, signal-to-noise ratios, peak height, mass spectra, and sensitivity of the instrument. The new compounds and criteria will be the subject of future confidence building exercises to validate their relevancy on a large scale.
