Martin Söderström

Environmental Hazards of Sea-Dumped Chemical Weapons

Does the post-WWII burial at sea of chemical weapons still pose a human and environmental risk?

Identification of nerve agents and their homologues and dialkyl methylphosphonates by gas chromatography/fourier transform infrared spectrometry (GC-FTIR)

GC-Direct deposition-FTIR spectra of 55 nerve agent homologues and dialkyl methylphosphonates were analysed. Spectral features of these compounds are discussed. A method is proposed for identification of the alkyl and alkoxy groups of compounds belonging to sarin, tabun or dialkyl methylphosphonates families.

Identification of compounds relevant to the chemical weapons convention using selective gas chromatography detectors, gas chromatography-mass spectrometry and gas chromatography-Fourier transform infrared spectroscopy in an international trial proficiency test

Abstract The results of an international trial proficiency testr are described. Compounds relevant to the Chemical Weapons Convention were analyzed in rubber, paint and two soil samples by using GC with selective detectors, GC-MS and GC-FTIR. The analytical strategy is presented both for routine analyses and for spectral interpretation of a compound for which no reference spectra are available. Three examples are given of spectral interpretation of alkylphosphonates.

Determination of mustard gas hydrolysis products thiodiglycol and thiodiglycol sulfoxide by gas chromatography-tandem mass spectrometry after trifluoroacetylation.

A method for detecting mustard gas degradation products thiodiglycol (TDG) and thiodiglycol sulfoxide (TDGO) in water and sediment samples using gas chromatography-tandem mass spectrometry (GC-MS/MS) after derivatization with 1-(trifluoroacetyl)imidazole (TFAI) was described. Selected reaction monitoring mode (SRM) of tandem mass spectrometry was developed for analysis of TDG and TDGO derivatives while analysis by gas chromatography-atomic emission detector (GC-AED) was performed using the 181 nm sulfur canal. TFAI derivatization conditions were optimized and the method validated. Two derivatization agents were compared, TFAI and N,O-bis(trimethylsilyl) trifluoroacetamide (BSTFA), where derivatization using TFAI occurred quicker and under milder conditions than using BSTFA. Water samples containing TDG and TDGO were evaporated to dryness under nitrogen, dissolved in organic solvent followed by reaction with TFAI. The limit of detection (LOD) for TDG and TDGO were 0.01 and 5 ng/mL, respectively. The limit of detection for TDG was decreased by two orders of magnitude if TFAI is used for derivatization rather than silyl derivatizing agents (e.g., BSTFA). TFAI has three major advantages in comparison to BSTFA, the first is much higher sensitvity, the second is a very clean background of chromatograms, and the last one is very mild conditions of derivatization. Moreover, by-products are not formed during derivatization of TDGO by TFAI in comparison to derivatization by silylating agents.

Characterization of Ricin and R. communis Agglutinin Reference Materials

Ricinus communis intoxications have been known for centuries and were attributed to the toxic protein ricin. Due to its toxicity, availability, ease of preparation, and the lack of medical countermeasures, ricin attracted interest as a potential biological warfare agent. While different technologies for ricin analysis have been established, hardly any universally agreed-upon “gold standards” are available. Expert laboratories currently use differently purified in-house materials, making any comparison of accuracy and sensitivity of different methods nearly impossible. Technically challenging is the discrimination of ricin from R. communis agglutinin (RCA120), a less toxic but highly homologous protein also contained in R. communis. Here, we established both highly pure ricin and RCA120 reference materials which were extensively characterized by gel electrophoresis, liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI MS/MS), and matrix-assisted laser desorption ionization–time of flight approaches as well as immunological and functional techniques. Purity reached >97% for ricin and >99% for RCA120. Different isoforms of ricin and RCA120 were identified unambiguously and distinguished by LC-ESI MS/MS. In terms of function, a real-time cytotoxicity assay showed that ricin is approximately 300-fold more toxic than RCA120. The highly pure ricin and RCA120 reference materials were used to conduct an international proficiency test.

Identification of some nerve agent homologues and dialkyl methylphosphonates by gas chromatography/Fourier transform infrared spectrometry

GC-FTIR spectra of 55 nerve agent homologues and dialkyl methylphosphonates have been analyzed. Infrared spectral library searches together with retention index searches have been used for identification of nerve agent homologues and dialkyl methylphosphonates.

Comparison of in vitro metabolism and cytotoxicity of capsaicin and dihydrocapsaicin.

Capsaicin and dihydrocapsaicin are the major active components in pepper spray products, which are widely used for law enforcement and self-protection. The use of pepper sprays, due to their irreversible and other health effects has been under a strong debate. In this study, we compared metabolism and cytotoxicity of capsaicin and dihydrocapsaicin using human and pig liver cell fractions and human lung carcinoma cell line (A549) in vitro. Metabolites were screened and identified by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Using liver cell fractions, a novel aliphatic hydroxylated metabolite (m/z 322) was detected to dihydrocapsaicin but no structure was found corresponding to capsaicin. Instead, a novel phase I metabolite of capsaicin, corresponding to the structure of aliphatic demethylation and dehydrogenation (m/z 294) was identified. In addition, two novel conjugates, glycine conjugates (m/z 363 and m/z 365) and bi-glutathione (GSH) conjugates (m/z 902 and m/z 904), were identified for both capsaicin and dihydrocapsaicin. The medium of the exposed A549 cells contained ω-hydroxylated (m/z 322) and alkyl dehydrogenated (m/z 304) forms, as well as a glycine conjugate of capsaicin. As to dihydrocapsaicin, an alkyl dehydrogenated (m/z 306) form, a novel alkyl hydroxylated form, and a novel glycine conjugate were found. In A549 cells, dihydrocapsaicin evoked vacuolization and decreased cell viability more efficiently than capsaicin. Furthermore, both compounds induced p53 protein and G1 phase cell cycle arrest. Usefulness of the found metabolites as biomarkers for capsaicinoid exposures will need further investigations with additional toxicity endpoints.

Methodology for National Risk Analysis and Prioritization of Toxic Industrial Chemicals

The identification of chemicals that pose the greatest threat to human health from incidental releases is a cornerstone in public health preparedness for chemical threats. The present study developed and applied a methodology for the risk analysis and prioritization of industrial chemicals to identify the most significant chemicals that pose a threat to public health in Finland. The prioritization criteria included acute and chronic health hazards, physicochemical and environmental hazards, national production and use quantities, the physicochemical properties of the substances, and the history of substance-related incidents. The presented methodology enabled a systematic review and prioritization of industrial chemicals for the purpose of national public health preparedness for chemical incidents.

Results of a Saxitoxin Proficiency Test Including Characterization of Reference Material and Stability Studies

A saxitoxin (STX) proficiency test (PT) was organized as part of the Establishment of Quality Assurance for the Detection of Biological Toxins of Potential Bioterrorism Risk (EQuATox) project. The aim of this PT was to provide an evaluation of existing methods and the European laboratories’ capabilities for the analysis of STX and some of its analogues in real samples. Homogenized mussel material and algal cell materials containing paralytic shellfish poisoning (PSP) toxins were produced as reference sample matrices. The reference material was characterized using various analytical methods. Acidified algal extract samples at two concentration levels were prepared from a bulk culture of PSP toxins producing dinoflagellate Alexandrium ostenfeldii. The homogeneity and stability of the prepared PT samples were studied and found to be fit-for-purpose. Thereafter, eight STX PT samples were sent to ten participating laboratories from eight countries. The PT offered the participating laboratories the possibility to assess their performance regarding the qualitative and quantitative detection of PSP toxins. Various techniques such as official Association of Official Analytical Chemists (AOAC) methods, immunoassays, and liquid chromatography-mass spectrometry were used for sample analyses.

Chemical Analysis of Dumped Chemical Warfare Agents During the MODUM Project

MODUM project continued the work on monitoring of the chemical weapons (CW) dumped in the Baltic Sea started in previous projects. As a new aspect, on board analysis methods – headspace gas chromatography-mass spectrometry (GC–MS) and capillary electrophoresis (CE) – were developed and tested in laboratory conditions and during cruises. The GC–MS method could be successfully applied on board to verify that collected sediment samples contained degradation products for sulfur mustard, one of the major chemical warfare agents dumped in Baltic Sea. This method could in future project be used during cruises to redirect sample collection in order to make most of the available ship time. Other part of the analysis task during MODUM project was the work done at the reach back laboratories. These analyses were done to both verify the results obtain on board and to fully identify the chemicals related to the sea-dumped CW agents. Reach back analysis of CW-related chemicals were done on sediment samples collected around a wreck in Bornholm Deep (same samples as analyzed on board) and on monitoring samples collected in Bornholm, Gotland and Gdansk Deeps. The samples from Bornholm and Gotland Deeps are in line with previous findings. Samples from Gdansk Deep are in line with previous findings that this area has been used as a dump site. Additionally, α-chloroacetophenone (CN) was found in the area for the first time. In addition to the analysis of CW-related chemicals, a new method was developed for measurement for arsenic concentrations in sediment samples. A method was also developed for arsenic speciation, which could help in estimation of the source of arsenic in the sediments.