TRAINING AID FOR TRAINING IN THE DETECTION OF TRIACETONE TRIPEROXIDE (TATP), PRODUCTION METHODS AND USE FOR DOG TRAINING

Abstract

Baits for training in the detection of explosives including triacetone triperoxide (TATP) adsorbed in the form of a solid or gas on a solid support include a cellulosic material, in particular cellulose acetate. Production processes for producing the baits for training in the detection of explosives are also related from acetone, hydrogen peroxide and an acid in a molar ratio, as well as the use of these baits in training dogs for the detection of TATP explosives, are also described.

Claims

1. A bait for training in the detection of explosives, the bait comprising: a maximum of 0.05 g of triacetone triperoxide (TATP) adsorbed on a solid support comprising a cellulosic material, wherein the bait comprises a maximum of 10% by weight of water, said percentage being expressed by weight with respect to the total weight of the bait, wherein the cellulosic material is acetylated cellulose.

2. The bait according to claim 1, wherein the solid support is a single piece.

3. The bait according to claim 2, wherein the solid support is a single piece having a volume between 100 mm.sup.3 and 2300 mm.sup.3.

4. The bait according to claim 1, wherein the TATP content is 50 mg to 0.5 mg of TATP.

5. The bait according to claim 1, wherein TATP is in the form of a TATP vapour adsorbed on the support.

6. A process for obtaining a bait for training in the detection of explosives as described in claim 1, the process including the following steps: a) obtaining an aqueous suspension of TATP, and b) adsorbing the TATP from the aqueous suspension of step a) on a solid support comprising a cellulosic material, wherein the cellulosic material is acetylated cellulose.

7. The process according to claim 6, wherein the aqueous suspension of TATP is obtained by a process including the following steps: a-i) mixing acetone and hydrogen peroxide at a temperature of 3 to 16° C.; a-ii) adding acid to the mixture obtained in a-i) for a time of 10 to 30 minutes; a-iii) stirring the mixture of a-ii) for at least 5 hours, obtaining triacetone triperoxide (TATP); and a-iv) suspending the triacetone triperoxide (TATP) of step a-iii) in water, obtaining the aqueous suspension of TATP; wherein the stoichiometric ratio of acetone:hydrogen peroxide:acid is 3:3:1, and the amount of acetone is less than 10 mmol.

8. A process for obtaining the bait for training in the detection of explosives as described in claim 1, comprising keeping solid TATP and a solid support comprising a cellulosic material in the same closed container for a minimum period of 7 days, without contact between the two solids, wherein the cellulosic material is acetylated cellulose.

9. The process according to claim 8, wherein the solid TATP is obtained by a process including the following steps of: i) mixing acetone and hydrogen peroxide at a temperature of 3 to 16° C.; ii) adding acid to the mixture obtained in a) for a time of 10 to 30 minutes; and iii) stirring the mixture of b) for at least 5 hours, obtaining solid triacetone triperoxide (TATP); wherein the stoichiometric ratio of acetone:hydrogen peroxide:acid is 3:3:1, and the amount of acetone is less than 10 mmol.

10. The obtaining process according to claim 9, wherein said process comprises the following additional steps: iv) suspending the triacetone triperoxide (TATP) of step iii) in water, obtaining the aqueous suspension of TATP; and v) filtering the suspension of step iv).

11. The process according to claim 7, wherein the amount of acetone is equal to or less than 2.7 mmol.

12. The process according to claim 7, wherein the acid of step a-ii) or ii) is selected from the group consisting of sulfuric acid, hydrochloric acid, and nitric acid.

13. Use of the TATP bait described in claim 1 for training dogs, in the detection of TATP explosives.

14. The use of the bait according to claim 13, wherein the desorption of TATP from the cellulosic material takes place at atmospheric pressure and a temperature between 10° C. and 35° C., and wherein the cellulosic material is acetylated cellulose.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0088] FIG. 1. Thermogram for a bait loaded with TATP (replicate 2). It is possible to see the drop in weight of the bait as temperature increases: For this replicate (T=105° C., W.sub.H2O/W.sub.BAIT: 5.9%).

[0089] This analysis was repeated three times under the same conditions, resulting in a water content (W.sub.H2O/W.sub.BAIT) of 5% by weight with respect to the initial weight of the TATP bait.

[0090] FIG. 2: Raman spectrum of cellulosic materials that can be used as a solid support in some embodiments of the TATP baits of the present disclosure. This figure shows the RAMAN spectrum of the support made of cellulose acetate without the adsorbed TATP explosive. The dashed line shows the characteristic signals of cellulose acetate, while a continuous line shows those of titanium oxide, based on the information provided by the databases: “Renishaw minerals and inorganic materials database” and “Renishaw polymeric materials database”.

[0091] FIG. 3: Raman spectrum of polymeric material coating the perimeter of cellulosic materials of cellulose acetate that can be used as a solid support in some embodiments of the TATP baits of the present disclosure. This figure shows the RAMAN spectrum of the perimeter of a support without the adsorbed TATP explosive. The dashed line shows the characteristic signals of calcium oxide and the continuous line shows those of zinc oxide. A line with the ends ending in an arrow shows the characteristic band of the polymeric material coating the perimeter. Identification made based on the information provided by the databases: “Renishaw minerals and inorganic materials database” and “Renishaw polymeric materials database”.

[0092] FIGS. 4a-4d: Scanning electron microscope (SEM) photographs of different parts of the solid support (without TATP). The measurements taken of the diameter of the cellulose acetate fibres are shown in yellow.

[0093] FIG. 5: Representative chromatograms in SCAN mode of the Hauts-TATP baits (FIG. 5a) and the Hodei-TATP baits (FIG. 5b).

[0094] FIGS. 6a-6d: Scanning electron microscope (SEM) photographs of different parts of the Hauts-TATP support according to particular embodiments of the present disclosure.

[0095] FIG. 7: Raman spectrum of the base of the cylinder-shaped support included in the Hauts-TATP baits according to particular embodiments of the present disclosure. The characteristic signals of TATP are shown in a dashed line, the form of an arrow shows those of the DADP and a continuous line shows those of acetone. The characteristic signals of each compound (TATP, DADP and acetone) have been obtained by comparison with a previous publication (L. Jensen, P. M. Mortensen, R. Trane, P. Harris, R. W. Berg. Appl. Spectrosc. 63(1), 92-97, 2009).

[0096] FIGS. 8a-8d: Scanning electron microscope (SEM) photographs of different parts of the Hodei-TATP support according to particular embodiments of the present disclosure.

[0097] FIG. 9: Raman spectrum of the base of the Hodei-TATP baits. The characteristic signals of TATP are shown in a continuous line, the form of an arrow shows those of DADP [L. Jensen, P. M. Mortensen, R. Trane, P. Harris, R. W. Berg. Appl. Spectrosc. 63(1), 92-97, 2009] and dashed lines shows those corresponding to the components of the support (cellulose acetate, TiO.sub.2, ZnO and CaO). Identification made based on the information provided by the databases “Renishaw minerals and inorganic materials database” and “Renishaw polymeric materials database”.

[0098] FIGS. 10a-10c: SCAN mode chromatograms performed by means of HS-SPME-GC/MS of the sample of the TATP 1 2 bait used in Example 5 (FIG. 10a), sample of the TATP 1 3 bait used in Example 5 (FIG. 10b) and sample of the TATP 1 3 bait at the time of its manufacture (July 2019).

EXAMPLES

1. Synthesis of a Bait Comprising Solid TATP Adsorbed on a Support Made of Cellulosic Material (Baits Referred to as Hauts-TATP)

[0099] To carry out the synthesis of Hauts-TATP baits, 199 μl (2.7 mmol) of 98% v/v acetone (Panreac, Barcelona, Spain) and 278 μl (2.7 mmol) of 30% v/v hydrogen peroxide (Sigma-Aldrich, Saint Louis, United States) were mixed in a round-bottomed flask and in a 9° C. ice/water bath while the solution was stirred. 37.8 μl (0.675 mmol) of 98% w/w sulfuric acid (Scharlau, Barcelona, Spain) were added for 15 minutes. The reaction was left to stir in the bath for a minimum of 5 hours. After this time, 14 ml of ultrapure water were added to the precipitated TATP obtained after the reaction to be able to filter the TATP through a vacuum system. A glass wool filter (Scharlab, Barcelona, Spain) with a thickness of 47 mm was placed on the Buchner funnel. Supports made of acetylated cellulose forming the baits of the disclosure were placed on top, and then the suspension of TATP was added onto these supports. Subsequently, cleaning was done with 10 ml of water to remove any trace of acid, and it was left to filter for half an hour to dry the Hauts-TATP baits. The baits obtained were stored in a screw-top glass vial in the freezer until use at −18° C. The amount of water was determined by thermogravimetry, not being more than 10% by weight with respect to the total weight of the bait (W.sub.H2O/W.sub.BAIT).

[0100] Following the procedure described above, a sufficient amount of TATP was achieved for a maximum of 6 Hauts-TATP baits, these baits containing an amount of 21 mg to 0.7 mg of solid TATP.

[0101] The supports made of cellulosic material used for the synthesis described in this section were 6 mm Krypton Slim® and 6 mm Extra+ Slim® brand tobacco filters (cellulose acetate).

[0102] In the following SEM photographs (FIG. 6), it can be observed how the solid explosive is adsorbed between the cellulose acetate fibres throughout the entire internal volume of the solid support used.

[0103] Furthermore, the presence of the explosive in the bait was verified by measuring the base of the bait in which the greatest amount of TATP was deposited in the filtering process. FIG. 7 shows the characteristic bands of TATP (Table 2) in the Raman spectrum. As mentioned above, DADP and acetone appear naturally in baits because they are TATP degradation products. The presence of the three mentioned molecules can be observed in the Raman spectrum. The presence of these degradation compounds was also observed in the analysis by means of HS-SPME-GC/MS (FIG. 5).

TABLE-US-00002 TABLE 2 Characteristic bands of the TATP obtained by comparison with a previous publication (L. Jensen, P. M. Mortensen, R. Trane, P. Harris, R. W. Berg. Appl. Spectrosc. 63(1), 92-97, 2009) Wave length /cm-1 3014 3000 2945 2720 2329 1452 1276 1201 951 895 868 823 623 563 403 314 244

2. Synthesis of a Bait Comprising TATP Vapour Adsorbed on a Support (Baits Referred to as Hodei-TATP)

[0104] To carry out the synthesis of Hodei-TATP baits, 199 μl (2.7 mmol) of 98% v/v acetone (Panreac, Barcelona, Spain) and 278 μl (2.7 mmol) of 30% v/v hydrogen peroxide (Sigma-Aldrich, Saint Louis, United States) were mixed in a round-bottomed flask and in a 9° C. ice/water bath while the solution was stirred. 37.8 μl (0.675 mmol) of 98% w/w sulfuric acid (Scharlau, Barcelona, Spain) were added for 15 minutes. The reaction was left to stir in the bath for a minimum of 5 hours. After this time, 14 ml of ultrapure water were added to the precipitated TATP obtained after the reaction to be able to filter the TATP through a vacuum system. A glass wool filter (Scharlab, Barcelona, Spain) with a thickness of 47 mm was placed on the Buchner funnel and the aqueous suspension of TATP was filtered. Subsequently, cleaning was done with 10 ml of water to remove any trace of acid, and it was left to filter for half an hour to dry the solid TATP.

[0105] Once the necessary quantity of solid TATP has been obtained by reproducing the procedure described above one or more times, the following was performed to obtain the Hodei-TATP bait: The solid was carefully collected with a spatula without rubbing or hitting. It was gradually transferred to the bottom of a glass tube 120 mm long and 1.2 cm wide. Once the amount of between 6 mg and 200 mg of TATP is placed in a horizontal position in the container, a support made of cellulosic material, in particular 6 mm Krypton Slim® and 6 mm Extra+ Slim® brand tobacco filters (cellulose acetate), was arranged in the test tube, without touching the solid TATP. In particular, the distance between the solid TATP and the support made of cellulose acetate was kept between 1.5 cm and 3 cm. Subsequently, the test tube was covered with a plastic stopper and left to rest for a period between 7 days and 30 days, at a temperature between 10° C. and 35° C. After this time, the support made of cellulosic material with TATP vapour was removed from the test tube and kept in a sealed vial until use.

[0106] As can be seen in the SEM image (FIGS. 8a-8d), unlike the Hauts-TATP baits where solid particles were visible in the cellulose acetate fibres (see FIGS. 6a-6d), in the case of Hodei-TATP baits, no solid particles of the explosive are observed in the fibres. This proves, as explained above, that in the process of making the Hodei-TATP baits there is no redeposition process for the explosive, but rather it is the aroma/vapour of the TATP explosive that remains adsorbed on the cellulosic material itself.

[0107] The presence of this TATP aroma in the fibres of the bait could be verified by means of HS-SPME-GC/MS analysis (FIG. 5b) and in a less evident way by means of Raman spectroscopy analysis. The presence of TATP in these baits is lower than in the Hauts-TATP baits and this is noted in the Raman spectrum (FIG. 9). In this case, the bands corresponding to the components of the solid support are very present, while the signals corresponding to the explosive are more tenuous. Signals corresponding to the degradation products of TATP are also present.

3. Use of Hauts-TATP Baits for Training Dogs in the Detection of Explosives

[0108] To demonstrate the efficacy of baits where solid TATP is adsorbed on a cellulosic support, canine training was carried out for two days with the training baits according to the present disclosure.

[0109] Before canine training, several syntheses of the baits of the present disclosure were carried out as described in section 1 of the examples, and each bait was given a number. The baits were weighed to determine the amount of TATP contained in them. The baits used and the amounts of TATP contained in them are found in the following Table 3.

TABLE-US-00003 TABLE 3 Weights (in mg) of each of the amounts of TATP explosive in the baits used Baits used in the tests TATP mg TATP1 1 14.4 TATP1 2 2.6 TATP1 3 15 TATP1 5 2.4 TATP2 1 0.7 TATP2 2 9.8 TATP2 3 4.9 TATP2 6 20.7 TATP3 2 HCl 6.62 TATP3 3 HCl 4.3 TATP4 1 15.3 TATP4 3 0.9 TATP4 6 7 TATP5 2 12.3 TATP5 4 3.2 TATP5 5 5.1

[0110] Baits TATP3 2 HCl and TATP3 3 HCl were obtained following the procedure previously indicated in section 1 of the examples, with the exception that 27% hydrochloric acid (Tracepure®, Merck, Darmstadt, Germany) was used, maintaining a 3:3:1 molar ratio of acetone:hydrogen peroxide:acid.

[0111] Then the baits that would be used for each training test were randomly chosen.

[0112] The temperature ranged from 10° C. to 23° C. and the humidity from 83% to 93%. Seven sniffing dogs of different breeds, ages and sex, that had been previously trained in the detection of the explosive in question, were used.

[0113] To perform 8 types of easy and short exercises (not more than 5 minutes), 5 different scenarios, both open and closed, were used since outdoor locations better simulate operational conditions, due to the variability of external stimuli, unlike closed scenarios, where conditions are more stable. The locations were: open field, wooden shed with gardening instruments, living room, garage, and the entrance of an office building with a strong ventilation duct.

[0114] The training was divided into two blocks: detection and discrimination. The detection block was made to ensure that the dog detects the explosive; in contrast, the discrimination block was made to ensure that the dog can differentiate it from other scents. In this case, as one of the reagents, and also degradation products of TATP, is acetone; it was one of the distractors used. In this same way, the same supports made of acetylated cellulose were used to create the Hauts-TATP baits and the vials where they were stored to ensure that the dogs were looking for the scent of the explosive and not the supports. The training was carried out using positive reinforcement techniques (if the dogs were able to detect the bait, they were given a toy). The exercises performed are listed in the following Table 4.

TABLE-US-00004 TABLE 4 Exercises carried out in training with police dogs with Hauts-TATP baits Positive Block Location Type of exercise baits Negative baits Identification Open field with Detection of the bait 1 — concrete blocks hidden in the concrete blocks Wooden shed with Detection of the bait 1 — gardening synthesised with instruments hydrochloric acid. Entrance of an Detection of the bait 1 — office building with hidden in the ventilation a strong duct ventilation duct. Entrance of an Detection of the bait 1 — office building with hidden in the holster of a strong a “downed” person ventilation duct. Discrimination Open field with Detection and 1 Two vials concrete blocks discrimination of the bait hidden in the concrete blocks that are arranged in zigzag Open field with Detection and 1 Two vials concrete blocks discrimination of the bait hidden under a stone. Living room Detection and 1 Two tobacco discrimination of the filters bait hidden between Two different magazines locations with 2 μl of acetone each Garage Detection and 2 Two tobacco discrimination of two filters bait hidden in different Three different vehicles. locations with 10 μl of acetone each

[0115] Of the 58 positive baits, 55 were detected correctly, given that there were three false positives (the presence of TATP was wrongly flagged on three occasions), therefore, the sensitivity of dogs to correctly detect TATP was 94.8%.

[0116] 85 of the 86 distractors were detected correctly, since a negative bait, specifically a vial, was detected as a false negative, thus giving a specificity, or ability to determine correctly when a compound is not 98.8% TATP.

[0117] All baits tested worked equally well and the few errors detected (false positives, negatives or non-detections) cannot be attributed to an insufficient amount of TATP in the training baits. In fact, the bait containing the least amount was used in an outdoor open field, being located under a stone, one of the most difficult exercises to perform in training, giving positive results.

4. Use of Hodei-TATP Baits for Training Dogs in the Detection of Explosives

[0118] To demonstrate the efficacy of baits (Hodei-TATP) in which solid TATP is adsorbed in vapour form on a support made of cellulosic material, dog training was carried out for two days with the training baits obtained according to the procedure described in section 2 of the examples. In particular, the conditions in which the adsorption of TATP vapour on the cellulosic support made of cellulose acetate took place to obtain the Hodei-TATP baits used in the training sessions are included in Table 5.

TABLE-US-00005 TABLE 5 Synthesis conditions of Hodei-TATP baits used in canine training Baits of the same .sup.1Exposure Amount of Exposure Synthesis Baits synthesis distance/cm TATP/mg time/days period Hodei 1 1 2 2 10.9 27 June Hodei 1 2 Hodei 2 1 3 2.5 16.7 27 June Hodei 2 3 Hodei 3 3 3 3 30 26 July .sup.1The syntheses of the Hodei-TATP baits have been carried out in a tube 12 cm long and 1.2 cm wide.

[0119] These tests with Hodei baits were carried out by 4 dogs, as shown in Table 6. Training was performed at 18° C. and 93% humidity, using positive reinforcement techniques (if the dogs were able to detect the bait, they were given a toy). There were two false positives, giving a selectivity of 90.0%. Only one discriminant was wrongly flagged as a false negative, giving a specificity of 97.7%.

TABLE-US-00006 TABLE 6 Exercises carried out in training with police dogs with Hodei-TATP baits. positive Location Type of exercise baits negative baits Identification Open field Detection of the bait 1 — with concrete hidden in the concrete canisters canisters Wooden shed Detection of the bait 1 — among gardening instruments Discrimination Open field Detection and 1 Two vials with concrete discrimination of the canisters baits hidden under a rock Living room Detection and 1 Two tobacco filters discrimination of the and two different baits hidden between locations with 5 μl magazines of acetone each Garage Detection and 1 Two tobacco filters discrimination of the and three different baits hidden in different locations with 10 μl vehicles of acetone each
5. Demonstration of the Durability of TATP in the Bait with a Support Made of Acetylated Cellulose

Study 5.1

[0120] This first study consisted of training designed for dogs trained in the detection of TATP from the canine unit of the Navarre Provincial Police carried out on 15 Jul. 2021. To carry out this training, 2 baits were used for which both the TATP synthesis and the production of the bait had taken place 24 months previously (TATP 1 2 and TATP 1 3 baits). In both cases, both the synthesis of the TATP and the manufacture of the bait took place according to the procedure described herein.

[0121] During these 15 months these TATP 1 2 and TATP 1 3 baits have been used by the canine unit of the ERTZAINTZA with a frequency of 1 time every 2 months (about 12 times), for at least 1 hour of exposure and training. This means that each of the reused baits that have been used in this experiment have been used for at least 12 hours in multiple training spaces: open spaces, rooms, cars, people, etc.

[0122] To demonstrate the efficacy of reused baits, dog training was performed for one day with the training baits described above. The baits used in this test and the amounts of TATP contained in them are found in the following Table 7.

TABLE-US-00007 TABLE 7 Weights (in mg) of each of the amounts of TATP explosive in the baits used in this test when they were carried out in July 2019 Baits used in the 2021 tests TATP weight in mg TATP 1 2 2.6 TATP 1 3 15.0

[0123] All tests were carried out on the same day. The temperature ranged from 18 to 20° C. and the humidity from 83% to 93%. Five sniffing dogs of different breeds, ages and sex, that had been previously trained in the detection of the explosive in question, were used.

[0124] To perform 3 types of easy and short exercises (not more than 5 minutes), 3 different scenarios, both open and closed, were used since outdoor locations better simulate operational conditions, due to the variability of external stimuli, unlike closed scenarios, where conditions are more stable. The 3 locations were: open field, living room and garage.

[0125] The training was divided into two blocks: detection and discrimination. The detection block was made to ensure that the dog detects the explosive; in contrast, the discrimination block was made to ensure that the dog can differentiate it from other scents. In this case, the same supports made of acetylated cellulose used to produce the baits of the present disclosure and the vials where they were stored were used to ensure that the dogs were looking for the scent of the explosive and not the supports. The training was carried out using positive reinforcement techniques (if the dogs were able to detect the bait, they were given a toy). The exercises performed are listed in the following Table 8.

TABLE-US-00008 TABLE 8 Exercises carried out in training with police dogs with Hauts-TATP baits. Positive Negative Block Location Type of exercise baits baits Identification Open field Point-to-point bait 1 — detection Living room Detection of a bait 2 — hidden in the ground and/or pots Discrimination Open field Point-to-point bait 1 2 (empty detection vial and white filter) Garage Detection and 2 2 (blank discrimination of 2 filters) baits hidden in two vehicles Living room Detection of a bait 1 1 (blank hidden in the filter) ground and/or pots

[0126] Of the 35 positive baits, 31 were detected correctly, given that there were three false positives (the presence of TATP was wrongly flagged on three occasions), therefore, the sensitivity of dogs to correctly detect TATP was 88.6%. 24 of the 25 distractors were detected correctly, since a negative bait, specifically a support filter, was detected as a false negative, thus giving a specificity, or ability to determine correctly when a compound is not 96% TATP. As can be seen, there is a decrease in the sensitivity and specificity values of the reused priming charge, but they are still suitable for reinforcing and training dogs.

Study 5.2

[0127] The second study consisted of HS-SPME-GC/MS analysis of the two baits used for study 5.1. FIGS. 10a-10b show the chromatograms of the two baits that were synthesised two years ago and that have been used over this time by the canine unit of the ERTZAINTZA for training their dogs. In particular, as can be seen (FIG. 10b), an intense signal of the explosive can be seen in the support of the TATP 1 3 bait (t.sub.R: 10.3 min) characterised and identified as TATP when compared with the mass spectral library. In the same way, it is possible to find the same signal (t.sub.R: 10.3 min) on the support of the other sample used, TATP 1 2 (FIG. 10a). In addition to the signal corresponding to the TATP, it is possible to observe signals identified as acetone, dichloromethane, hexane or DADP (see FIGS. 10a and 10b) upon comparing their mass spectra against the spectral library. These compounds may be related to the degradation of TATP itself (in the case of acetone or DADP) or to the contamination of the supports during use over these two years.

[0128] The degradation of TATP and its loss can be clearly seen if the signal intensity of the baits at this present moment (July 2021) is compared with the signal intensity at the time these baits were created (July 2019). FIG. 10c shows the chromatogram of the TATP 1 3 bait at the time of its manufacture in July 2019. As can be seen, the TATP signal intensity is almost twice that obtained by the two baits two years later (see the dashed line that corresponds to the maximum of the signals in 2021). It is also observed that the bait does not have as many interference signals because it had just been manufactured.

[0129] For all these reasons, in this double study it has been empirically verified that: [0130] An analytical signal has been found in the analyses of the volatile components of the reused bait by means of HS-SPME-GC/MS that has been unequivocally identified as TATP. [0131] After 12 hours of use and exposure of these baits and after two years of storage at 4° C., the presence of TATP is observed although the signal intensity of this compound has decreased by almost half when compared with the results obtained at the time of manufacture. [0132] Baits continue to offer levels of specificity and selectivity that allow dog training.