Anionic forensic signatures for sample matching of potassium cyanide using high performance ion chromatography and chemometrics

Source Attribution of Cyanides Using Anionic Impurity Profiling, Stable Isotope Ratios, Trace Elemental Analysis and Chemometrics

“…Figure shows resolution of NaCN and KCN based on four anions (unk5, SO 4 , OX, and PO 4 ) into three main clusters (GE/BE, CZ, US/UK/ES), consistent with three factories (GE, CZ, and US) and inclusive of both KCN and NaCN samples. The four anions responsible for the observed clustering were previously selected using F-ratio analysis of the 11 original anions and resulted in tighter clusters based on country of origin as opposed to using 11 anions . Given that the combined HPIC data in this paper had potentially new and significant sources of data variance (e.g., from different operators, different HPIC systems, and new stocks), HCA and PCA was performed on the combined HPIC data starting with all 11 anions (unk1, unk2, Cl, unk3, NO 2 , unk4, CO 3 , unk5, SO 4 , OX, and PO 4 ) in order to detect any obvious outliers in regards to sample clustering according to source.…”

“…Variable selection was performed using the F-ratio method, iPLS, and GAPLS. The performance of four anion variables (unk5, SO 4 , OX, and PO 4 ) selected in reference was also evaluated for comparison. The number of latent variables (LVs) required for PLS calibrations used in the models (PLSDA, iPLS, and GAPLS) were computed by the software using cross-validation.…”

“…Thirteen anions were identified in the cyanide samples using the retention times of anion standards as references. The HPIC-1 data were originally collected and used in a previous study …”

“…While the general synthesis steps for cyanides are nearly uniform across different manufacturers, various factors including the reagents, manufacturing process, and local geology can each influence impurities and stable isotope signatures that remain in the final product and, in doing so, impart a chemical attribution signature (CAS). The potential forensic merit of organic and inorganic impurities as CAS for CTAs has been previously demonstrated. − Previous work using eight KCN stocks reportedly from four countries suggested that CAS might be used to determine country (or manufacturing facility) of origin . In this study, sample resolution was made possible by the analysis of anion impurities in KCN stocks by high performance ion chromatography (HPIC) with anion-exchange chromatography and conductivity detection and by applying chemometric analysis for pattern recognition and classification.…”

Profiling of volatile impurities in tetramethylenedisulfotetramine (TETS) for synthetic-route determination

“…The impurity profiling work described here has precedence in previous forensic research on other chemical-threat agents and precursors [16][17][18]. In those studies, the feasibility of obtaining forensic information from impurity profiling for sample matching and possible route and source determination were demonstrated.…”