Undergraduate Category: Physical & Life Sciences Degree Level: Chemistry Abstract ID #1240

Analysis of Spices and Burned Spice-Oxidizer Mixtures using Mass Spectrometry Emily E. Dunn1, Matthew J. Pavlovich1, Adam B. Hall1 1Barnett Institute of Chemical and Biological Analysis, Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA

ABSTRACT: In recent attempts to expand forensic abilities to analyze RESULTS: SPICE / OXIDIZER MIXTURES RESULTS: post-blast samples of homemade explosives, the Bureau of Alcohol, Tobacco, Quickstrip M and P Pepper in Methanol_20151029 #654-710 RT: 1.26-1.36 AV: 57 SB: 48 0.25-0.34 NL: 2.09E6 Quickstrip Tumeric in Methanol_20151002 #707-762 RT: 1.36-1.45 AV: 56 SB: 67 0.35-0.47 NL: 8.58E5 Quickstrip Cinnamaldehyde2 - Methanol Ethanol MethyleneChloride_20150917 #734-784 RT: 1.41-1.51 AV: 51 SB: 59 0.41-0.52 T: ITMSDART + c NSI Full ms [50.00-500.00]-MS Detection of SpicesT: ITMS + c NSI Full ms [50.00-500.00] T: ITMS + c NSI Full ms [50.00-500.00] Burning the Mixtures 286.06 368.99 147.04 Firearms and Explosives Forensic Laboratory has inspired our research in hydrogen 100 100 100 coumarin CHEMOMETRIC 90 90 90 (a) (b) peroxide/organic fuel mixtures. Using Direct Analysis in Real Time-Mass 80 80 80 147 m/z 183.14 70 70 70 291.07 345.12 ANALYSIS 286 m/z 273.09 Spectrometry (DART-MS), we optimized the analysis of several standalone spices and 60 60 369 m/z cinnamaldehyde60 307.09 50 50 177.03 133 m/z 50

then mixtures of the spices with , a strong oxidizer, in various 40 40 40 163.09

RelativeAbundance RelativeAbundance RelativeAbundance 127.07 Cinnamon Brand Models 105.05 339.04 30 30 30 397.25 369.08 309.05 255.14 330.12 217.10 401.08 ratios. Finally, after burning the oxidized mixtures, the residues created were 20 20 20 97.10 312.05 411.17 119.05 459.21 71.10 147.04 493.26 10 272.10 10 217.07 285.07 10 235.05 Stop & 340.06 384.97 86.12 112.07 168.13 201.06 227.12 360.13 398.16 426.14 485.04 83.08 203.12 421.14 451.09 483.09 analyzed to determine whether the spices could still be detected. The aim of this 0 0 0 Shop 50 100 150 200 250 300 350 400 450 500 50 100 150 200 250 300 350 400 450 500 50 100 150 200 250 300 350 400 450 500 m/z m/z m/z study is to investigate whether DART-MS could potentially be a viable method of Figure 2. DART-MS of Pepper Figure 3. DART-MS of Turmeric Figure 4. DART-MS of Cinnamon Figure 5. Cinnamon Mixture (a) before burning (b) after burning Spice detecting spices and giving insight to the origin of the materials in forensic post-blast Rack samples. Hydrogen Peroxide / Spice Mixtures McCormick H2O2 Mixes Ignited and Dissolved in Methanol_20151208 #1366-1425 RT: 2.60-2.71 AV: 60 SB: 65 0.25-0.37 NL: 8.68E5 T: ITMS + c NSI Full ms [50.00-500.00] Quickstrip Pepper and Tumeric H2O2 Mix_20151112 #1928-2039 RT: 3.73-3.92 AV: 112 NL: 8.55E6 H2O2 Mixtures - 4 Weeks Dissolved_20151211 #2118-2163 RT: 4.07-4.15 AV: 46 SB: 54 0.31-0.41 NL: 2.81E6 T: ITMS + c NSI Full ms [50.00-500.00] 286.08 T: ITMS + c NSI Full ms [50.00-500.00] 100 286.09 286.08 Pepper: 100 100 90 90 90 Spice 80 (a) (b) (c) (a)80 (b)80 (c) 70 Time 70 70 60 60 60 50 50 50 40 40

Recently, common household spices have surfaced RelativeAbundance 40 BACKGROUND: RelativeAbundance RelativeAbundance 30 30 Figure 12. Heat Map of DART-MS Spectra of Cinnamon 30 20 20 as a new source for fabricating improvised explosives. Like smokeless powder, these 20 312.02 Samples by Brand (lightest peaks are most abundant) 370.86 10 10 312.10 201.06 272.13 10 272.10 86.07 158.12 272.14 312.11 112.07 350.15 112.09 184.06 242.16 356.94 397.07 426.15 469.06 86.14 168.11 227.15 378.16 441.21 485.10 326.05 0 0 86.12 112.10 135.06 201.05 236.18 360.17 382.09 424.17 469.04 readily available spices are finely divided organic materials, whose high surface area 0 50 100 150 200 250 300 350 400 450 500 50 100 150 200 250 300 350 400 450 500 50 100 150 200 250 300 350 400 450 500 m/z m/z m/z to volume ratio allows them to be used as the fuel in a combustion reaction with an Figure 6. Pepper Mixture (a) Week 0 (b) Week 1 (c) Week 4 Figure 7. DART-MS Spectra of Pepper Mixture (a) Week 0 (b) Week 4 (c) After burning

Quickstrip Cinnamon, Cumin, Hot Pepper in H2O2 Mix_20151112 #408-536 RT: 0.79-1.03 AV: 129 NL: 5.75E5 H2O2 Mixtures - 4 Weeks Dissolved_20151211 #1397-1451 RT: 2.69-2.79 AV: 55 SB: 54 0.31-0.41 NL: 3.14E4 H2O2 Mixes Ignited and Dissolved in Methanol_20151208 #837-913 RT: 1.60-1.74 AV: 77 SB: 65 0.25-0.37 NL: 1.63E4 T: ITMS + c NSI Full ms [50.00-500.00] T: ITMS + c NSI Full ms [50.00-500.00] T: ITMS + c NSI Full ms [50.00-500.00] oxidizer. Investigators involved in the London bombing of 2005 determined that a 147.00 147.06 299.03 Cinnamon: 100 100 100 hydrogen peroxide and pepper mixture was used [1], and more recently in 2009 the 90 90 313.04 90 331.06 80 80 (a) (b) (c) (a) (b)80 341.08 (c) 70 70 70 U.S. Department of Homeland Security released a report citing hydrogen 147.05 348.03 60 60 60 360.02 50 peroxide/spice mixtures as a possible terrorist tactic [2]. 50 50 283.11 40 40 133.05 40

372.99 445.04RelativeAbundance 354.98 RelativeAbundance RelativeAbundance 253.08 30 219.13 30 235.10 237.14 30 189.08 383.11 127.12 175.12 418.03 273.08 387.06 441.20 219.10 461.98 20 105.06 331.10 20 20 175.09 467.12 203.11 139.10 413.16 125.12 10 96.16 444.88 10 199.05 286.87 10 99.06 103.09 237.07 413.18 97.10 85.10 488.21 177.11 343.99 81.12 368.98 445.02 463.03 69.06 0 0 0 50 100 150 200 250 300 350 400 450 500 50 100 150 200 250 300 350 400 450 500 50 100 150 200 250 300 350 400 450 500 m/z m/z m/z Figure 8. Cinnamon Mixture (a) Week 0 (b) Week 1 (c) Week 4 Figure 9. DART-MS Spectra of Cinnamon Mixture (a) Week 0 (b) Week 4 (c) After burning Quickstrip Pepper and Tumeric H2O2 Mix_20151112 #403-512 RT: 0.78-0.98 AV: 110 NL: 2.89E5 H2O2 Mixtures - 4 Weeks Dissolved_20151211 #683-733 RT: 1.32-1.41 AV: 51 SB: 54 0.31-0.41 NL: 1.11E5 H2O2 Mixes Ignited and Dissolved in Methanol_20151208 #658-714 RT: 1.25-1.36 AV: 57 SB: 65 0.25-0.37 NL: 1.62E5 T: ITMS + c NSI Full ms [50.00-500.00] T: ITMS + c NSI Full ms [50.00-500.00] T: ITMS + c NSI Full ms [50.00-500.00] Figure 13. PCA Scatter Plot of Cinnamon Brands 121.07 282.03 370.89 METHODS: 100 100 100 90 90 Turmeric: 90 (a) (b) (c) 80(a) (b)80 (c)80 70 70 DART-MS Detection of Spices 70 217.03 60 60 60 286.10 Pepper, Cinnamon, Turmeric, Cayenne Pepper, and Cumin detection were optimized. 50 50 50

40 40 248.06 40

RelativeAbundance

RelativeAbundance RelativeAbundance 320.04 30 235.02 30 30 Methanol at 1 mg/ml was determined as the best universal solvent, and helium gas 234.10 354.97 336.01 119.09 264.09 304.03 20 20 177.11 20 125.03 231.06 93.08 166.13 352.04 137.07 223.02 heated to 250C was used for ionization, detecting in positive ion mode. Standards for 10 10 10 241.05 203.11 388.67 83.08 151.09 251.96 303.93 369.07 392.03 445.01 463.03 111.13 167.05 199.12 296.95 368.99 437.09 109.14 71.11 253.15 444.86 480.17 79.10 339.08 388.76 467.87 83.11 327.14 413.19 0 0 0 the target compounds in each spice (piperine, coumarin and , 50 100 150 200 250 300 350 400 450 500 50 100 150 200 250 300 350 400 450 500 50 100 150 200 250 300 350 400 450 500 m/z m/z m/z curcumin, , and cuminaldehyde, respectively) were obtained and analyzed Figure 10. Turmeric Mixture (a) Week 0 (b) Week 1 (c) Week 4 Figure 11. DART-MS Spectra of Turmeric Mixture (a) Week 0 (b) Week 4 (c) After burning under the same conditions. Figure 14. HCA Dendrogram of Cinnamon Brands Chemometric Analysis of Cinnamon Brands

McCormick, Stop & Shop, and Spice Time brands, and a kitchen sample were

CONCLUSION: analyzed via DART-MS. MATLAB was used to create chemometric models to

differentiate among brands. • DART-MS was able to detect the target compounds from pepper, cinnamon, and turmeric, as well as those from cumin and

cayenne pepper at lower levels in most samples. Hydrogen Peroxide Mixtures • Chemometric analysis of cinnamon samples yielded three models that successfully categorized DART-MS spectra of

For each 0.1 g of spice, 272 μl of 50% concentrated H2O2 was added and mixed with a

Average Cross Average Error Validation Average Sensitivity Average Specificity

Technique

cinnamon samples by the four brands. The neural network model had zero cross validation error, while LDA had 100% wooden stirrer to avoid contact of the mixture with metal. Mixtures were analyzed LDA 1.53% 100% 100% via DART-MS immediately, and after 1 and 4 weeks of drying. About 0.01 g of the sensitivity and specificity. mixture was placed on a Quickstrip to analyze during Weeks 0 and 1, and for the • Piperine, coumarin, cinnamaldehyde, and curcumin were still detectable by DART-MS after mixing the spices with Week 4 analysis, 1 mL methanol was added to the remaining dried mixture and hydrogen peroxide; piperine and coumarin were detected in the mixture even after 4 weeks. kNN 9.28% 92% 97% spotted on the Quickstrip. After drying, small samples of the Pepper, Cinnamon, and Turmeric mixtures were burned on open aluminum trays and observed. Residues • When burning the spice/oxidizer mixtures, a small flame was sustained for a few seconds after the removal of the torch. Neural 0.00% 92% 97% were then dissolved in 1 mL methanol and analyzed via DART-MS. The samples containing the highest ratio of H2O2 to spice sustained the longest.

• DART-MS successfully detected piperine, coumarin, and cinnamaldehyde in the dissolved residues of the burned samples. Network Figure 1. Week 1 Quickstrip containing hydrogen peroxide / spice mixtures • With further research and analysis of real post-blast samples, DART-MS could likely be used as a method of identifying the constituents in homemade explosives from a forensic sample. Table 1. Supervised Learning Model Performances

[1] P. Chalk, Encyclopedia of Terrorism, Volume 1. ABC-CLIO, 2012. REFERENCES: [2] I. T. A. and C. Group, “Hydrogen Peroxide and Organic Fuel Mixtures as a Possible Homemade Explosive,” (2009).