WIHUIHHWIWIHIHHWNW“HWIWlllW THESIS Zoot This is to certify that the thesis entitled Interpreting Ion Mobility Spectrometry Plasmagrams of Heroin and Cocaine presented by Paul B. Galat Jr. has been accepted towards fulfillment of the requirements for Master of Science Criminal Justice degree in with Specialization in Forensic cience Jay A. Siegel, Ph. D. Major professor Date ”7/7/03 0-7 639 MS U is an Affirmative Action/Equal Opportunity Institution LHBRARY Michigan State PLACE IN RETURN BOX to remove this checkout from your record. To AVOID FINES return on or before date due. MAY BE RECALLED with earlier due date if requested. DATE DUE DATE DUE DATE DUE 11/00 C'JCIRClDatoDmpBS-p.“ INTERPRETING ION MOBILITY SPECTROMETRY PLASMAGRAMS OF HEROIN AND COCAINE BY Paul B. Galat Jr. A THESIS Submitted to Michigan State University In the partial fulfillment of the requirements for the degree of MASTER OF SCIENCE IN CRIMINAL JUSTICE WITH SPECIALIZATION IN FORENSIC SCIENCE Department of Forensic Science 2000 ABSTRACT INTERPRETING ION MOBILITY SPECTROMETRY PLASMAGRAMS OF HEROIN AND COCAINE BY Paul B. Galat Jr. Ion Mobility Spectrometry (IMS) is used to identify trace levels of illicit drugs such as cocaine, heroin, and methamphetamine. Occasionally when two or more types of drugs are present in the same sample the spectrometer will only indicate the presence of one drug or falsely indicate the presence of another. The IOSCAN Ion Mobility Spectrometer plasmagrams of cocaine, heroin, and a cocaine/heroin mixture were analyzed to determine the instrument saturation point and the maximum linear concentration for each drug. Characteristic plasmagram features of one and multiple component drug samples were additionally identified. This study demonstrated that cocaine has a much higher IMS response than heroin. Heroin impurities may trigger the spectrometer to falsely indicate the presence of cocaine. In drug mixtures of cocaine and heroin, the spectrometer will only indicate the presence of cocaine but the analyst may still identify the presence of heroin due to characteristic peak distortions. ACKNOWLEDGMENTS I would like to acknowledge Dr. Jay Siegel for his invaluable assistance in preparing me to become a forensic scientist and Forensic Scientist Christopher Bommarito for introducing me to the world of Forensic Chemistry. I would also like to thank Senior Forensic Chemist Angela DeTulleo and Forensic Chemist Mary Gay from the Drug Enforcement Administration. This project would not have been possible without their priceless combined efforts. iii TABLE OF CONTENTS List of Tables List of Figures Introduction IMS Benefits and Limitations IMS in the Field IMS Theory Physics Behind IMS History of IMS Previous IMS Drug Studies Project Details Cocaine IMS Response Heroin IMS Response Drug Mixture IMS Response Conclusion Areas for Further Research Bibliography page vi 10 12 14 15 20 26 29 31 33 LIST OF TABLES page TABLE 1 — Instrument Parameters 15 FIGURE (1) FIGURE (2) FIGURE (3) FIGURE (4) FIGURE (5) FIGURE (6) FIGURE (7) FIGURE (8) FIGURE (9) FIGURE (10) FIGURE (11) FIGURE (12) FIGURE (13) Plasmagram FIGURE (14) Plasmagram LIST OF FIGURES Barringer Ionscan.Model 400 Ion MObility Spectrometer Cocaine IMS Plasmagram Cocaine IMS 3D Plasmagram Cocaine IMS Response Cocaine IMS Linear Reponse Heroin IMS Plasmagram Acetylcodeine IMS Plasmagram (I MOnoacetylmorphine IMS Plasmagram Heroin HCL IMS Response Cocaine and Heroin IMS Response Heroin IMS Linear Response Heroin 25 ngs and Cocaine 8 ngs IMS Heroin 25 ngs and Cocaine 10 ngs IMS w page 16 17 19 20 21 22 23 25 25 26 27 29 INTRODUCTION In the world of forensic chemistry, Ion Mobility Spectrometry (IMS) is used to identify trace levels of drugs such as cocaine and heroin. Objects like automobiles, houses, and luggage can be scanned using IMS to determine if they have been in contact with drugs, even at extremely low concentrations. An ion mobility spectrometer can detect drugs in the nanogram (ng) range. One ng is one billionth of a gram. A common sugar packet found in a restaurant contains about a gram of sugar or one billion nanograms. Using this extremely sensitive technique in the field does pose some problems. Cocaine and heroin react differently in an Ion Mobility Spectrometer. When they are both present in the same drug sample, the spectrometer may only indicate the presence of cocaine. When only heroin is present, the plasmagram may indicate the presence of cocaine due to the decomposition of the heroin molecule. The goal of this project is to examine the manner in which the Barringer Ionscan Model 400 Spectrometer detects cocaine and heroin when they are present in drug exhibits alone and in combination. This project will enable the forensic chemist to better interpret IMS plasmagrams and eliminate instances of false positive results. IMS BENEFITS AND LIMITATIONS The two main benefits in using IMS for the detection of drugs, are its sensitivity and speed. As mentioned earlier, IMS is an extremely sensitive technique. The Locard Exchange Principle states that when two objects come in contact with each other, particles from each object will always be transferred between them. These particles may be so small that they may not be detected with conventional means. Particles in the nanogram range, which are too small to be seen with the naked eye, can effectively be detected with IMS. For instance, law enforcement officials may suspect that a perpetrator has used a car to transport drugs but they can not find the drug packages or visible residue of the fact. IMS technology can be used to scan the seats and trunk to determine if drugs were present in the automobile. Secondly, IMS is a fairly quick screening method for large areas. The portable vacuum unit can be used to search a whole automobile in under five minutes. The spectrometer can then analyze the sample in 8 seconds and presumptively indicate which drug particles are present. The only testing mechanism that is faster is a drug detection dog. A dog can scan a larger area faster but the dog can not indicate which drug is present. It is trained to give the same response to cocaine, heroin, methamphetamine, or marijuana. If used together, the drug dog and IMS make an excellent combination. For instance, in a drug raid at a residence, [0 the drug dog is brought in first to search the whole house to discover possible drug storage areas. If the dog indicates a specific area, IMS is then used to presumptively indicate that drugs may be present. IMS is limited by two factors. It is a presumptive test, which means it is unable to confirm that a specific drug is found. Different chemicals may give similar results on the instrument, thus IMS alone can not be used to positively identify drugs. For example, compounds commonly found on fabrics and plastics tend to generate responses in IMS. Techniques such as gas chromatography/mass spectrometry (GC/MS) must be used in conjunction with IMS to positively confirm the samples. GC/MS suffers from the fact that samples must be prepared before being analyzed. For trace analysis, the object in question must be wiped with an alcohol wipe, which is then extracted, and concentrated in order to be analyzed. A GC/MS instrument usually takes ten minutes to analyze the sample as compared to eight seconds for an IMS instrument. IMS can be combined with GC/MS to make an perfect union. A typical IONSCAN search is performed in this manner. An IMS filter disk is used to quickly scan a large area such as a car trunk. The disk is then analyzed and the drug particles are presumptively indicated through IMS. The trunk is then rescanned with the same filter disk, which is then extracted using solvents to positively identify the drugs through GC/MS. The second limitation to IMS is due to its incredible sensitivity. Great care must be taken to eliminate sources of contamination. Before an object is scanned, the filter disk must be shown to be drug free. A new disk is scanned once it is removed from the protective heat sealed container bag to insure that is clean. This is called a disk blank. The portable vacuum unit must be cleaned with alcohol wipes and the disk scanned after being placed in the vacuum. This is called a nozzle blank. Once the two blanks are shown to be drug free, the IMS instrument can be used. The manner in which an object is scanned is critical. In order to eliminate the possibility that your clothes are contaminated, you must scan from the front of the object to the back. For instance, if you were scanning an airplane’s cargo area you must start at the entrance and work to the back of the plane. This insures that the object is tested prior to the operators clothing coming in contact with it. IMS IN THE FIELD A typical IONSCAN house search in the field is described. An IONSCAN search team is requested by the field agents and briefed as to the history of the suspects and to possible locations of where drugs may be hidden. After the area is secured by the agents, a drug dog is allowed to search the house and suspect vehicles. The dog handler will alert the agents as to possible drug locations. The agents perform a quick search to locate obvious drug packages. If none are found, the IOSCAN team enters the home and begins the search. The filter disks are first examined to insure that they are drug free. The disks are placed in the vacuum nozzles with the vacuum turned on. The disks are then reexamined to insure that the vacuum and nozzles are not contaminated. The area in the home that the drug dog indicated is then lightly vacuumed and the disks removed. The disks are placed in the IONSCAN instrument and analyzed. If the instrument indicates that drugs are possibly present, the area is vacuumed more thoroughly to insure that the maximum amount of trace material is collected. The disks are then removed, sealed and submitted for extraction. The drugs are then analyzed in the laboratory using GC/MS to positively identify the sample. The current Ion Mobility Spectrometer used by the Drug Enforcement Administration and in this study is the Barringer IONSCAN Model 400. See Figure (l). FIGURE (1) Barringer Ionscan Mbdel 400 Ionscan Operators Manual, 1997, pg 1,2 IMS THEORY Ion Mobility Spectrometry (IMS) is a technique used to identify chemical substances through the measurement of their gas—phase ion mobilities (Eiceman and Karpas, 1994). These substances are rapidly heated to vaporization, the gases are ionized and allowed to migrate in a controlled electric field until reaching the detector. The drift time of the ions are characteristic of the chemical substance and may be used as a presumptive identification when compared to a known standard. A sample is collected on a Teflon filter disk, which is then inserted, into the ion mobility spectrometer. A heated stage called the desorber vaporizes the sample and the gases enter the ionization area. The 63Ni radioactive source ionizes the oxygen, nitrogen and water molecules in the air carrier gas. The major reactant ions formed are NHJ, N03 and Hg? These charged particles then ionize the instrument calibrant and the sample producing the product ions. The main method is proton transfer as per equation (1) UIO) ii + M (sample) -———> MH+ -+ (HZO)n (1) An electric field only allows ions of a chosen polarity to reside in the ionization area. Ions of the opposite charge are repelled and removed. In the case of drug analysis, positive ions are retained and in explosive analysis negative ions are utilized. Positive ions are used because most illicit drugs contain amino or amide functional groups that form stable positive ions. After the particles are ionized they are pulsed into the drift tube through the shutter. The shutter acts like a gate. The shutter opens and closes in twenty millisecond (ms) intervals. The ions are then allowed to migrate in the drift region under the influence of an applied electric field until they reach the detector. The detector consists of a collector plate, usually a Faraday cup that measures a change in electric potential as the positive ions strike the collector plate. The signals are then amplified and recorded. The drift times of the ions are measured and the sample's proportionality constant, K, can be calculated. The ions are pulsed into the drift tube twenty times for each sample. This whole process is completed in a total of eight seconds. ION MOBILITY SPECTROMETER Exhaust Flow Drift Flow 1) DEC REASING POYENHAL lMel Repelllng \ 82mg Efiugmg 3:3“! Collector We Grid NI 63 - 9 Siido _ Ionizing Source “WAKE? ii Sample Carrier Flow FIGURE (2) Ion Mobility Spectrometer Ionscan Operators Manual, 1997, p2,2 PHYS ICS BEHIND IMS The drift velocity of an ion (Vd) is equal to the proportionality constant (K) of the ion and the electric field strength (E) as per equation (2). Vd = KB or K=Vd/E (2) Usually K0 is used, which is the proportionality constant normalized to standard pressure (760 torr) and temperature (273 k) as per equation (3). KO = K (273/T)(P/760) (3) T is the temperature of the drift tube and P is the pressure in the spectrometer. The drift velocity (Vd) depends on the length of the drift tube (d) and the time traveled (t) as per equation (4). Vd = d/t (4) Finally by combining Eqs (2), (3), and (4), the proportionality constant can be expressed as per equation (5). K0 = [d/(E t)](273/T)(P/760) (5) Since drift tube distance (d), electric field strength (E), temperature (T) and pressure (p) are known, the K0 can be calculated from the drift time of the ions. The mobility of the ions depend on three factors: mass, shape, and electrostatic interactions. Heavier ions have a lower mobility than lighter ones, compact ions will drift through the buffer gas in the drift tube faster than non compact ions, and some neutral drift gas molecules may be attracted to the ions thus hindering their movement. These electrostatic interactions form when charged ions interact with the electron cloud surrounding the neutral gas molecules inducing a dipole moment (Eiceman and Karpas, 1994). The gas molecules are then attracted to the ions, thus slowing their drift times. When there are multiple reactant ions present, there is a competition among the ions. This competition prevents IMS from being a suitable analytical tool for some multiple compounds (Eiceman and Karpas, 1994). Also, drugs with different proton affinities may allow the charge to be unequally distributed between each constituent resulting in the compound with the highest proton affinities giving a larger response (Eiceman and Karpas, 1994). HI STORY OF IMS Modern analytical IMS was established in the 1970's where it was previously called Plasma Chromatography. Interest in the IMS field was limited to the original researcher, F.W. Karasek, because the technology was generally viewed as too complicated for practical use. Researchers were disillusioned with IMS as a chromatography technique (Eiceman and Karpas, 1994). In the early 1980's, the military realized that ion mobility spectrometry could be used in the battlefield as a chemical agent detector due 10 to its ability to be miniaturized, reasonable selectivity, and low detection limits. Plasma Chromatography has since been renamed Ion Mobility Spectrometry. With the advent of portable spectrometers, interest in IMS has grown tremendously. In keeping with tradition though, IMS spectra are presently called plasmagrams. Currently, IMS is used extensively in industrial and environmental monitoring programs. The hand held spectrometers can be used to detect leaks or locations where toxic chemicals are present. Such chemicals include phenols, furans, and acid vapors like hydrogen chloride and hydrogen cyanide. The minimum detection limit for these chemicals is 0.1 part per million (ppm) (Eiceman and Karpas, 1994). IMS is used by the military to detect organophosphorus compounds present in nerve agents and blister agents. In the forensic science world, IMS is used to detect drugs and explosives. Drugs such as heroin, cocaine, phencyclidine (PCP) and methamphetamine have been analyzed by IMS (Karasek et a1. 1976), (Brown and Skinner, 1994), (Brown and Comparin, 1994). A teflon filter disk is used to introduce the samples into the spectrometer. The filter disk is placed into a nozzle that is attached to a portable vacuum. The object to be searched is vacuumed and any trace drug evidence is trapped on the filter. The filter is then removed and placed into the spectrometer for analysis. In this manner, IMS can be used to search luggage at an airport, automobile trunks, safes, airplanes cargo holds, and anyplace or thing that might have stored drugs. IMS has even been used to scan individuals’ hands and clandestine drug records (Maloney, et al., 1994) and (Donnelly et al., 1994). Even though IMS is an extremely sensitive and fairly selective technique, it does posses a drawback. Different chemicals may give similar results, thus IMS is not a confirmatory test for narcotics and other materials. IMS is used only as a presumptive test and other techniques such as gas chromatography/mass spectrometry (GC/MS) must be used to confirm the presence of the narcotics. The Drug Enforcement Administration (DEA), has recognized the potential of this technology and has expanded it’s role in the fight against illegal drugs. PREVIOUS IMS DRUG STUDIES Previous work in the IMS field dealing with heroin and cocaine detection was done by Karesek, Hill, and Kim in 1976. By using a mass spectrometer connected to the plasma chromatograph, they were able to determine the identity of each peak of a total ion mass spectrum for both of the drugs. The concentration of heroin and cocaine used were 1000 nanograms (ng). In this study, concentrations were on the order of lng to 300 ngs. Additionally, they did not examine the plasmagrams of a mixture of the two drugs and determine what effect one type of drug has on the other. Fytch et al. in 1992, performed a study involving heroin and cocaine practical detection limits as a function of desorber temperature and possible signal changes due to interferences by such products such as herbs, vitamins, and household cleaning products. They determined that the practical detection limit of cocaine and the cocaine spectra did not vary with changing the desorber temperature or the concentration. Heroin spectra and its practical detection limit did vary slightly with changing the desorber temperature and concentration. Both drugs of interest still had detection limits that were in the low nanogram range. When cocaine was mixed with possible interferences, cocaine was able to be detected in ratios of 10,000 :1, interference products to cocaine. Heroin on the other hand, was detected in ratios of 100:1. Drug combination studies have been done. Detulleo—Smith (1996) found that false positives and false negatives of methamphetamine can be obtained when the samples also contain nicotine. Nicotine ions have migration times that are similar to methamphetamine. This problem can be minimized if the chemist pays close attention to the environment that is being scanned and at the peak shape of the methamphetamine/nicotine response. In response to the Detulleo-Smith study, Reese and Harrington (1999) expanded the identification of methamphetamine/nicotine mixtures with IMS and SIMPLISMA (SIMPLE-to-use-Interactive Self-Modeling Mixture Analysis). They used temperature programing in order to identify the two drugs. Brown and Skinner (1994) found that phencyclidine (PCP) and it’s intermediate, 1-piperidinocyclohexanecarbonitri1e (PCC), can easily be separated by IMS because PCP and FCC have significantly different migration times. Detulleo (1999) on behalf of the DEA has presented a summary of part this study at the 8th International Workshop on Ion Mobility Spectrometry in Buxton, England. The paper has not been published to date. PROJECT DETAILS Standard Teflon vacuum disks were utilized. Solutions of cocaine hydrochloride and heroin hydrochloride in methanol at concentrations of 0.001 mg/ml each were made. The cocaine, Merck lot number V4511, and the heroin, lot number 8283—886-98, were obtained from the Drug Enforcement Administration. A microliter syringe and a microliter Eppendorf pipette were used to transfer the solution to the filter disks. Each microliter (uL) of the methanol solution contained one nanogram of the target drug. The solutions were allowed to dry before the filters were inserted into the ion mobility spectrometer. The peak amplitude of the plasmagram was then recorded. Because the project involved working with samples at the trace level, certain precautions were applied. The project was performed in the dedicated trace evidence drug laboratory, which is physically l4 separated from the main forensic drug laboratory at the Drug Enforcement Administration. At the beginning of each day, the Barringer IONSCAN Model 400 was calibrated against a calibrant called a verific. The IONSCAN also has an internal calibrant, nicotinamide, which was utilized for each run. Before the drug was placed on the filter disk, the disk was scanned to ensure that it was free of contamination. The instrument parameters are listed in Table 1. TABLE 1 — Instrument Parameters Barringer IONSCAN Model 400 Tube Temperature 237° C Inlet Temperature 279° C Desorber Temperature 285° C Pressure 103.03 Kpa Drift Flow 300 cc/min Sample Flow 195 cc/min High Voltage 1746 V COCAINE IMS RESPONSE Cocaine had an average drift time of 14.9 milliseconds (ms) as per the cocaine plasmagram illustrated in Figure (3). The instrument calibrant that is introduced with every sample is nicotinamide. The Ko for cocaine is 1.1600. The plasmagram shows two readings for cocaine, cocaine and cochigh. The instrument is configured in such a manner that if there is a large amount of cocaine detected, the signal BARRINGER IONSCAN Narcotics Plasmagram 1200 _ I I l l I i I l i l T T fl T g I T I 1 Es ” 6% O O 1000 - QC; . 800v . ’5 3 600 - g 8 . i l 3‘ 4m- a . mo- 4 0 ~ .. ‘ ‘- L -1 1 k 1 l l 1 1 I l #1 l I l l l 1 A l I 0 1 2 3 4 5 6 7 6 9 10 11 12 13 14 15 16 17 16 u; m Drift Time (ms) (mama Dan Kc QE Mmumm Enan: mm; 1mg Cal 9.324 1.8576 1467 Cocaine 14.933 1.1600 0.99983 1066 11340 +11 14 CocHiah 14.933 1.1600 0.99963 1440 19431 +12 17 Comment: Cocaine HCL in MeOH pbg 60 ng1 run FIGURE (3) Cocaine IMS Plasmagram will be distributed in a second channel, called cochigh. which acts like an overflow system. Additional channels can be added if the K0 for the suspected compound is calculated. The delta indication is a measurement of how close a detected peak is to an expected position. The number of hits is a measurement of the number of segments in which the instrument detected the drug. There are twenty segments per scan. This reading was taken at the instrument’s saturation point for cocaine, 60 ng. WARRINGER iONSCAN Narcotics Plasmagram 2500’- -< 3 ‘U 2000- r: - .l: 9 :0 i 1500- a N1 - .1 1 \ 1. 1000- \ v _ '\\_ ‘\\.\ .‘1h——w—- \ \\.. 1 L—r—- 500' —- M :\ .|_ -1 0 .. " “AK-fin. “TIT- _ 012345 7691011121314151617161920 3 2% i. DriftTlmoimo) Emmi Dflml Kn 9E umumm QMUMm DID {Hm C61 9.324 1.8576 1467 Cocaine 14.933 1.1600 0.99963 1066 11340 +11 14 CocHiah 14.933 1.1600 0.99963 1440 19431 +12 17 ummmt Cocaine HCLinMeOHpbg Mngimn FIGURE (4) Cocaine IMS 3D Plasmagram The area under the response curve is measured in digital units (du). The twenty IMS segments per scan can be readily seen in the 3D plot as per Figure (4). One can notice that the cocaine concentration increases with each segment. There was also an indication of an additional product that had a drift time of around 11.5 and 12 ms. Since this technique is extremely sensitive, the identification of that product is difficult. It is suspected that it could be an impurity in the methanol or a breakdown product of the cocaine. In field applications there may be other peaks in the plasmagrams due to cocaine impurities or diluents. Diluents, such as lactose or caffeine, are commonly added to cocaine to increase its bulk size. Impurities or diluents will not affect the K0 value for cocaine. If a diluent has the same drift time, it may mask cocaine detection. The overall cocaine IMS response on the instrument is seen in Figure (5). The instrument became saturated and the signal was maximized at 60 ng. The average peak amplitude, as measured in digital units, quickly rose from 2 ng and became stable at 60 ngs. ‘15cxj.thn-----...- ---_- E----..-.-..-. ---- T- .......f..... --,,,-,._-... .i--.-.,,‘ .r..... . 1mm 4— 1 r( . -.... ._ ,, ~ 1 9 1200 _. .. -é -- --i...-. -4 _ .- .i~ ..,- 1...--.,. --H-- 1000 ”1.3-1-.-.1--. _- ...- l ! an f, i i - ' i i ! -.. 600 9..-.-. .‘ _- _. 1. -- -1 ._-- .- - _--. .1. -... .- i -.- -_. Mn ,9« —+ _ .1 1 2m3b‘f“ i 4‘ f “r— l.~« r - _-. ”F 1 (d0) ..--.1...‘ i l | l i Average Maximum Peak Amplitude in Digital Units 0 1 0 20 30 4O 50 6O 70 80 90 Cocaine mL Concentration in nanograms (ng) O 1:1 -- .. _ _ _._. FIGURE (5) Cocaine IMS Response The cocaine response is typical of other compound responses and can be used to describe the nature of IMS and why it is not generally used as a quantitation device. There exists a situation where the response of the instrument does not change with increasing concentration. This is due to the fact that the 63Ni radioactive source produces a fixed number of reactant ions. Once the reactant ions charges are consumed by the sample to make product ions, no increases in sample concentrations will produce more product ions. At relatively low concentrations, the reactant ions will be consumed to produce product ions proportional to the concentration of the sample. This results in a small range where the sample will produce a linear response. Because of the limited linear response, IMS is not used as a quantitation device. IMS is mainly used as a positive or negative indicator of drugs and other 19 substances. In the case of cocaine, the linear response was from 1 to 8 ngs as seen in Figure (6). Cocaine HCL IMS Linear Response ( ' =45. 550.991 Averae Max Peak Amplitude In Digital Units (du) Cocaine l-BL Concentration In nanograms (ng) FIGURE (6) Cocaine IMS Linear Response HERO IN IMS RESPONSE The heroin IMS response was quite different than the cocaine response. The main drift time for the drug was 17.0 ms as per the heroin plasmagram in Figure (7). The heroin response results in a typical three peak plasmagram. One of the three peaks had a significant area count and had a drift time of about 15.5 ms. At high concentrations of heroin, the peak from the additional product would cause the instrument to indicate the presence of cocaine. This may cause an inexperienced operator to conclude that the sample might be a mixture of heroin and cocaine. The maximum 20 digital units for the heroin response at this concentration, 40 ng, Like cocaine, was maximized at 60 ngs. EARRINGER was one half the area counts for that of cocaine. the instrument became saturated and the signal IONSCAN Narcotics Plasmagram T r l T T I l I T T i i T I I I I l 600 " E -1 \ “s 500 ~ £- 9 y 1 £ ) . 4m- i Kl ~ 2 .9 £ 300 ~ .1: .. 3 a 200 1- .1 1m- « 0 ~ ._ — - -- . l l l l l l J l I 1 J L l L I J J L o 1 2 3 4 5 6 7 9 10 11 12 13 14 15 16 17 18 19 20 Drift Time (ms) flmmfl lflhn 59 CE MuAmn QwflMm 0mm 1&5 Cal 9.555 1.6576 1592 Hofliigh 17.024 1.0423 LOWS 624 4629 4-28 8 Heroin 17.024 1.0423 1.00099 519 6490 +26 17 FIGURE (7) Heroin IMS Plasmagram The source of the extra peaks at 15.5 ms and at 12.5ms can be contributed to the breakdown products of heroin. Heroin is made from the acetylation of morphine. Some of 21 the common side products are acetylcodeine and O6 monoacetylmorphine. Ionscan plasmagrams of these products reveal a standard three peak spectra as per Figures (8) and (9). wARRINGER IONSCAN Narcotics Plasmagram 800 b . 700 a \ -l 600 - i 9 1 3 ii ‘0 500 - 2 / . O 400- I . i 300 1- . 2m _ d 100 - i ‘ O 1- “ — — ‘ ‘ ‘ ‘ l l 01234567891011121314151617181920 Drift 1111100116) imam! Qnm! Kn 9E Imumm immfimn Edi 1mm Cal 9.485 1.8676 1610 LSD 16.182 1.0090 0.90981 506 8110 -25 17 Comment: 40096061yICOdeinestd amdpbgalia/QQ run2 FIGURE (8) Acetylcodeine IMS Plasmagram mARRINGER IONSCAN Narcotics Plasmagram I I I fi I I I I I I I I I I I I I I I 800” 4 8 700” \ -1 600- ) . 3 3 5m» 2 . 2 O z 400- 8 - 8 a 300-- .. 6 200- Q J 100' -4 Di- L l L l l l l J l l l l l l I l l l l 012 3 4 5 6 7 8 9 10111213141516 171819 21 DrittTinio(m9) Shflmfl Dflmn Kn 9E MQMMm EmmAmn mm: run Cal 9.490 1.8576 1506 PCP 13.888 1.2694 0.99990 119 990 +17 10 Comment: 40 ng 6-monoacetyimorphine amd pbg 3/18/99 FIGURE (9) C%.M0noacetylmorphine IMS Plasmagram The instrument can indicate these by-products by adding additional channels through the software. Some drugs such as marijuana have multiple channels of indication. Once the drift time of the ions are known, the K0 can be calculated. The Ko must be known in order to introduce new channels. By having new channels placed in the software, the analyst will receive aid in characterizing the substance. There are problems with manually adding additional channels, though. Some channels may already be in use by other drugs and many other compounds found in the field may have the same drift time, thus giving false indications of possible drugs found. One can also notice that the IM Spectrometer gave false indications of lysergic acid diethylamide (LSD) and phencyclidine (PCP) in the plasmagrams of acetylcodeine and Ch monoacetylmorphine. This further enforces the concept that IMS alone can only be used as a nonconfirmatory test. Other methods such as gas chromatography/mass spectrometry (GC/MS) must be used in conjunction with IMS to confirm the presence of illicit drugs. The operator must also realize that some compounds analyzed by IMS may produce mulitple peaks in their plasmagrams. The total heroin IMS response also differs from that of cocaine. The response curve, as illustrated in Figure (10), rises quickly and becomes relatively stable at 60 ng. The maximum digital units, 700 du, is half of that of the cocaine response at the same concentration. This can readily be seen in Figure (11). Heroin HCL IMS Response g 900 . 1., 1 my ’ .. n, . soo— eeeeee 11 -~ D. i a_._l k _ i __ if, .i__.ii m-_ ' E ,3 700 i ‘ 3 :24 am * —-=- 7 t * s: __ 1*“ 3 E 500 lib ,, 4., b, 1 iii 1 “- :1 1 1 : 53 40° “" ‘ 1 ‘l 35" 300 1 W , a 7 j i {civil = s 200,. i 1, - z 3 8» | ' 1 1 i g 100 1. — ~ , r. ‘7 , 7:7 ,7, av— 5 0 ’1: i ‘ i 1 i 1 ' o 25 50 75 100 125 150 175 200 225 250 275 300 325 Heroin HCL Concentration In nanograms (ng) FIGURE (10) Heroin HCL IMS Response Cocaine and Heroin IMS Response 1650 g 1500 i; 1350 _ 1200 g g 1050 g 5 g 900 g 5 3 750 E 600 8:3 450 E a. 300 < 5 15g 0 1O 20 30 40 50 60 70 80 90 Concentration in nanograms(ng) 5'3? Cocaine A Heroin FIGURE (11) Cocaine and Heroin IMS Response 25 Another reason that IMS is not used for quantitation purposes is the fact that IMS lacks the precision needed for quantitations. Relative standard deviations were seen from 1 to 26%. The lack of precision can be seen in the response curve of Figure (10) and by the linear response as per Figure (12). Heroin HCL IMS Linearity Response Average Max Peak Amplitude in Digital Units (du) 0 5 10 15 20 25 30 ' Heroin HCL Concentration in nanograms (ng) FIGURE (12) Heroin IMS Linear Response The heroin response was somewhat linear from 1 to 25 ngs. This is in contrast to the cocaine linear range of 2 to 8 ngs. DRUG MIXTURE IMS RESONSE The last segment of the study involved the examination of plasmagrams of mixtures of heroin and cocaine. An IMS 26 scan was performed at the maximum concentration, cocaine 8 ngs and heroin at 25 ngs where each of the drugs had a linear response. With this mixture, the plasmagram indicated the presence of both drugs as per Figure (13). BARRINGER IONSCAN Narcotics Plasmagram d .1 .1 «.1 q .1 .4 d .4 —4 .1 d - d d Q) 700- .s . 8 O U 600- . 500 - ~ . 3 8 4m- 5 \ q ‘ i I 3 t 300- 8 9 . °‘ 3 s i 1 200 - I I . mo- . o ,. -* v 1 1 l l i L L 1 J l l l l L l L l L l 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 19 19 20 Driit Time (ms) immmd Qnmc K9 CE MnUMm immAmn mm: Lmn Cal 9.497 1.8576 1510 Cocaine 15206 1.1600 0.99997 649 6314 +0 15 00:111in 15206 1.1600 0.99997 1107 0161 -1 9 mm 12.955 1.3618 0.99996 225 2572 +24 19 Heroin 16.926 1.0423 0.99997 166 1350 +45 11 ammmm cmcmm HER25 FIGURE (13) Heroin 25 ngs and Cocaine 8 ngs IMS Plasmagram 27 The most interesting fact is that the area count for cocaine in the mixture is approximately doubled as compared to the cocaine plasmagram. This is due to the fact that the three peak plasmagram of O6 monoacetylmorphine and acetylcodiene in heroin have a similar drift times of that of cocaine. Since they have similar drift times, the peaks from these products coelute with the cocaine. The instrument also gave an indication of hashish due to these compounds. Additionally, one can observe that the heroin area count in the mixture is reduced by half. Further analysis involved varying the concentration of cocaine and keeping the heroin concentration constant at 25ngs. The same basic results occurred when the cocaine concentration was reduced. When the cocaine concentration was increased to just lOngs, the instrument only indicated the presence of cocaine but the three peaks of heroin were still visible as per Figure (14) The fact that the instrument only indicates cocaine in the mixture is due to two factors. The instrument has a much higher response for cocaine than heroin and the three peaks of a heroin have similar drift times of that of cocaine. 28 BARRINGER iONSCAN Narcotics Plasmagram T I I I l I I I I I I I I I ‘I Q 7 T I I 700- .s . 3 o o 600 r I a 500 " s .., 9 6 P 400 - :5 X ‘ '5 = i "‘ 2 mm- 3 I . o. 3 .5 am- I I . 100 ~ . 0 +- _ I 1 g 1 2L 1 l l l l l l L J l l L l 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Drift Time (1119) 150mm Qflmc a: GE MmQMm SNmAmn Dfln LEM Cal 9.497 1.6576 1510 Cocaine 15.206 1.1600 0.99997 649 6314 +0 15 606111911 15.206 1.1600 0.99997 1107 9161 -1 9 Nahum 12.955 1.3616 0.99996 225 2572 +24 16 Heroin 16.926 1.0423 0.99997 166 1350 +45 1 1 ammmm COO 8196 HER 25 FIGURE (14) Heroin 25 ngs and Cocaine 10 ngs IMS Plasmagram CONCLUSION In summary, the data from this study indicates that cocaine has a linear IMS response from 1 to 8 ngs while heroin has a linear response from O to 25 ngs. The instrument becomes saturated and the signal maximized for 29 cocaine and heroin each at 60 ngs, but the cocaine area count will be double that of the heroin. The heroin plasmagram has three peaks which is due to the presence of heroin impurities,<% monoacetylmorphine and acetylcodeine. When heroin is mixed with cocaine in an exhibit, the cocaine will more readily be seen because the instrument response for cocaine is higher and the heroin impurities have similar drift time elution as that of cocaine. Even though cocaine may mask the instrument detection of heroin, the plasmagram will reveal the three peaks indicative of heroin. How does this information help the forensic chemist in the field? When a chemist reviews a plasmagram and sees that cocaine has been indicated, there are several considerations he/she must make. Knowing that the instrument is more sensitive to cocaine, a small cocaine response means that there may not be enough cocaine on the disk for extraction to confirm the sample by GC/MS. Since the instrument favors cocaine, other drugs may be hidden from detection. If the law enforcement agent suspects the object in question (i.e. a suitcase) has been used to transport heroin and the IMS plasmagram reveals cocaine, it does not necessarily mean that the suitcase did not have heroin in it. It could be that the cocaine in the suitcase masked the detection of the heroin. In this case, the chemist could search the plasmagram for the three characteristic peaks of heroin to determine if the suitcase contained a drug mixture. 30 This study also reaffirms several key concepts of IMS technology. It is a fast, easy, and extremely sensitive technique for detecting trace levels of drugs. The technology also has drawbacks. Since it is so sensitive, one must use caution to insure that the sample disks are not contaminated prior or during searches. The instrument becomes saturated fairly quickly and can not used as a quantitation device in the field. Drug impurities and other products can be detected and have similar drift times like those of the target drugs. These products can mask the detection of drugs or cause the instrument to indicate that drugs may be present when they are not. Because of these problems IMS is only a presumptive test and requires additional testing to confirm the presence of the controlled substances in the sample. With this study, the forensic chemist in examining the IMS plasmagrams will be better able to interpret the plasmagrams to determine if the sample contains a single component or a mixture. At low sample levels, the concentration may be estimated. The chemist will also be able to distinguish between instrumental false positive readings. AREAS FOR FURTHER RESEARCH This study examined the plasmagrams produced by the spectrometer at the optimal instrument parameters. Preliminary research at the Drug Enforcement Administration 31 has shown that changing the instrument parameters will gain slight improvement in detecting one type of drug while hindering the detection of another. Research into modifying the IMS software by adding additional channels for drug impurities would be helpful. Studies that examine the relationship between cocaine and other illicit drugs such as marijuana and methamphetamine can be helpful in interpreting plasmagrams. This study used pharmaceutical grade cocaine. Examining the effects of illicit cocaine and cocaine that has been mixed with diluents would be helpful in determining whether the common diluents could mask cocaine detection. BIBLIOGRAPHY Brown, P. A., Comparin, J. H. 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