GC-MS studies on acylated derivatives of 3-methoxy-4-methyl- and 4-methoxy-3-methyl-phenethylamines: regioisomers related to 3,4-MDMA

A series of side chain regioisomers of 3-methoxy-4-methyl- and 4-methoxy-4-methyl-phenethylamines have mass spectra essentially equivalent to the controlled drug substance 3,4-methylenedioxymethamphetamine (3,4-MDMA), all have molecular weight of 193 and major fragment ions in their electron ionization mass spectra at m/z 58 and 135/136. The acetyl, propionyl and trifluoroacetyl derivatives of the primary and secondary regioisomeric amines were prepared and evaluated in GC-MS studies. The mass spectra for these derivatives were significantly individualized and the resulting unique fragment ions allowed for specific side chain identification. The trifluoroacetyl derivatives provided more fragment ions for molecular individualization among these regioisomeric substances. These trifluoroacetyl derivatives showed excellent resolution on a non-polar stationary phase such as Rtx-1.     

GC-MS and GC-IRD analysis of 2-, 3- and 4-methylmethamphetamine and 2-, 3- and 4-methylamphetamine

4-Methylmethamphetamine has been detected in samples submitted for analysis in several states throughout Australia. Six ring substituted methyl isomers of methamphetamine and amphetamine were synthesised and analysed. As the regioisomeric 2-, 3- and 4-methylmethamphetamine and 2-, 3- and 4-methylamphetamine have virtually identical mass spectra, the use of MS is an ineffective technique to discriminate between these closely related compounds. We set out to determine whether the regioisomers could be differentiated by a combination of GC-MS, acetyl derivatisation and GC-IRD. We demonstrate that the three isomers of methylmethamphetamine and methylamphetamine can be separated by GC, and a combination of acetyl derivatisation and vapour phase IR can identify the specific ring substituted compound.     

Counterfeit Adderall Containing Aceclofenac from Internet Pharmacies

A nontargeted approach based on liquid chromatography equipped with a quadrupole time‐of‐flight mass detector (LC‐MS Q‐TOF) joined to nuclear magnetic resonance (NMR) analysis allowed rapid identification and quantification of the anti‐inflammatory drug aceclofenac in illegal Adderall tablets. The largest chromatographic peak had m/z = 354.030 and m/z = 376.012 matching, respectively, the ionic structures (M + H)⁺ and (M + Na)⁺ of a molecule M. The accurate mass data generated the molecular formula C₁₆H₁₃Cl₂NO₄. A screening of the pharmaceutical active substances having that molecular formula together with the MS/MS fragmentation pattern suggested aceclofenac. Aceclofenac structure was unambiguously confirmed by ¹H and ¹³C NMR experiments. The aceclofenac content was 90 mg/tablet (RSD 2%) as detected by quantitative NMR. Information on the identity and content of illegal drugs is required for legal purposes; it supports in evaluating the effective impact on users safety, and it is useful for control laboratories using a targeted approach in their analytical activities.     

GC–MS and GC–IRD studies on dimethoxyamphetamines (DMA): Regioisomers related to 2,5-DMA

The mass spectrum of the drug of abuse 2,5-dimethoxyamphetamine (2,5-DMA) is characterized by an imine fragment base peak at m/z 44 and additional fragments at m/z 151/152 for the dimethoxybenzyl cation and radical cation, respectively. Five positional ring isomers of dimethoxyamphetamines (DMA) have an isomeric relationship to 2,5-DMA. All six compounds have the same molecular weight and produce similar EI mass spectra. This lack of mass spectral specificity for the isomers in addition to the possibility of chromatographic coelution could result in misidentification. The lack of reference materials for the potential imposter molecules constitutes a significant analytical challenge. Perfluoroacylation of the amine group reduced the nitrogen basicity and provided individual fragmentation pathways for discrimination between these compounds based on some unique fragment ions and the relative abundance of common ions. GC–IRD studies provided additional structure–IR spectra relationships and yielded confirmation level identification for each of the six regioisomeric dimethoxyamphetamines. The amines and their perfluoroacylated derivatives were resolved by capillary gas chromatography and the amines showed excellent resolution on the more polar stationary phase, Rtx-200.     

GC–MS studies on acylated derivatives of 3-methoxy-4-methyl- and 4-methoxy-3-methyl-phenethylamines: Regioisomers related to 3,4-MDMA

A series of side chain regioisomers of 3-methoxy-4-methyl- and 4-methoxy-4-methyl-phenethylamines have mass spectra essentially equivalent to the controlled drug substance 3,4-methylenedioxymethamphetamine (3,4-MDMA), all have molecular weight of 193 and major fragment ions in their electron ionization mass spectra at m/z 58 and 135/136. The acetyl, propionyl and trifluoroacetyl derivatives of the primary and secondary regioisomeric amines were prepared and evaluated in GC–MS studies. The mass spectra for these derivatives were significantly individualized and the resulting unique fragment ions allowed for specific side chain identification. The trifluoroacetyl derivatives provided more fragment ions for molecular individualization among these regioisomeric substances. These trifluoroacetyl derivatives showed excellent resolution on a non-polar stationary phase such as Rtx-1.     

GC-IRD studies on regioisomeric ring substituted methoxy methyl phenylacetones related to 3,4-methylenedioxyphenylacetone

The methoxy methyl phenylacetones share an isobaric relationship (equivalent mass but different elemental composition) to the controlled precursor substance 3,4-methylenedioxyphenylacetone (3,4-methylenedioxyphenyl-2-propanone; 3,4-MDP-2-P). The ten ring substituted methoxy methyl phenylacetones are resolved by capillary gas chromatography on a modified cyclodextrin stationary phase. All ten regioisomeric ketones eluted before the controlled precursor substance 3,4-methylenedioxyphenylacetone. The vapor phase infrared spectra generated from the capillary column effluent clearly differentiated 3,4-MDP-2-P from the various methoxy methyl phenylacetones. Additionally the methoxy methyl phenylacetones provide unique individual infrared spectra. Infrared absorption frequencies and patterns confirmed the relative position of the methoxy-group and the acetone side-chain for the regioisomeric ketones.     

Identification of 1‐(2,3‐dihydro‐1H‐inden‐5‐yl)‐2‐(ethylamino)pentan‐1‐one (bk‐IVP) in a Seized Drug Exhibit

To circumvent the law by evading regulation and obscuring their identities in routine analyses, numerous substituted cathinones have entered the illicit drug market. These compounds have been coined “bath salts” by users. In the described case, the laboratory received an unknown white powder for controlled substances identification. The sample could not be immediately identified using standard methods and procedures. Ultimately, the structure was elucidated using GC‐MS, NMR, FTIR, GC‐SPIR, UV, and color tests to be 1‐(2,3‐dihydro‐1H‐inden‐5‐yl)‐2‐(ethylamino)pentan‐1‐one (bk‐IVP), a cathinone analog with a rarely observed nonoxygenated bicyclic ring system. Features of spectra and chemical tests are reported that distinguish this class of cathinones from heterocyclic analogs.     

Differentiation of regioisomeric ring-substituted fluorophenethylamines with product ion spectrometry

The electron ionization (EI) of aromatic ring-substituted isomers gives virtual identical mass spectra which seriously affects their analysis. Especially regioisomeric meta- and para-ring-substituted compounds cannot show any ortho-effect reactions making their differentiation by mass spectrometry impossible. Furthermore o-, m- and p-substituted compounds can only be separated insufficiently by chromatography due to their very similar retention that do not allow univocal identification. Product ion mass spectrometry has proved to be a useful tool to differentiate structurally closely related fluorophenethylamines even in the case of the meta- and para-isomers. A series of N-alkylated o-, m- and p-fluoroamphetamines and 1-(4-fluorophenyl)butan-2-amines have been synthesized in microscale and studied by product ion spectrometry. The combination of chemical ionization (CI) and product ion spectrometry of hydrogen fluoride loss ions [M+H?HF]⁺ allows a univocal differentiation of all studied fluoro-substituted phenethylamines without prior derivatization. This method with submicrogram detection limits provides great advantages for the differentiation between aromatic regioisomeric fluorophenethylamine designer drugs where other methods such as nuclear magnetic resonance (NMR) spectrometry lack sufficient sensitivity or might fail because complex mixtures have to be analyzed.     

Isomeric fluoro-methoxy-phenylalkylamines: a new series of controlled-substance analogues (designer drugs)

An impressively large number of clandestinely produced controlled-substance analogues (designer drugs) of amphetamine with high structural variety have been encountered in forensic samples in recent years. The continuous designer drug exploration and their widespread consumption results in an increasing number of reports regarding abuse and intoxication. This study presents the analytical properties of a series of new fluoro-methoxy-substituted controlled-substance analogues of amphetamine. Three ring positional isomeric fluoroamphetamines, two isomeric fluoromethoxyamphetamines, two N-alkyl 4-fluoroamphetamines, and one 4-fluorophenylbutan-2-amine were identified and differentiated by gas chromatography-mass spectrometry (GC-MS), 1H- and 13C-nuclear magnetic resonance (NMR), and gas chromatography-infrared spectroscopy (GC-IR). The regioisomeric 2-, 3-, and 4-fluoroamphetamines and the regioisomeric fluoro-methoxyamphetamines show virtually identical mass spectra so that this method is insufficient to discriminate between these closely related compounds. The mass spectra of the acetylated compounds allowed a differentiation of the 4-fluoroamphetamine from its regioisomeric 2- and 3-fluoroamphetamines. The gas chromatographic properties of the three regioisomeric fluoroamphetamines and their acetylated and trifluoroacetylated derivatives are also so similar that a complete separation of these compounds could not be achieved under GC-MS conditions. The two isomeric compounds 5-fluoro-2-methoxyamphetamine and 3-fluoro-4-methoxyamphetamine on the other hand showed significant different gas chromatographic retention times so that a separation was uncomplicated. The trifluoroacetylation of these compounds proved to be an effective method for their mass spectral differentiation. Gas chromatography-infrared spectroscopy and 1H- and 13C-nuclear magnetic resonance allowed an unequivocal differentiation of all studied regioisomeric fluoroamphetamines and fluoro-methoxyamphetamines.     

Characterization and Differentiation of Geometric Isomers of 3‐methylfentanyl Analogs by Gas Chromatography/Mass Spectrometry,Liquid Chromatography/Mass Spectrometry,and Nuclear Magnetic Resonance Spectroscopy

The cis and trans isomers of 3‐methylfentanyl and its three analogs were chemically synthesized, and these compounds were characterized and differentiated by gas chromatography/mass spectrometry (GC/MS), liquid chromatography/mass spectrometry (LC/MS), and nuclear magnetic resonance (NMR) spectroscopy. The cis and trans isomers of the 3‐methylfentanyl analogs were completely separated by GC/MS. Although the high temperature of the GC injection port caused thermal degradation of β‐hydroxy‐3‐methylfentanyl, the degradation was completely suppressed by trimethylsilyl derivatization. The isomers were also well separated by LC/MS on an octadecylsilyl column with 10 mM ammonium acetate and methanol as the mobile phase. The proton NMR signals were split when the hydrochloride salts of the 3‐methylfentanyl analogs were dissolved in deuterated chloroform because stereoisomers were formed by the coordination of the hydrochloride proton to the nitrogen of the piperidine ring of the 3‐methylfentanyl analogs.     

三种酸类易制毒化学品的衍生化气相色谱—质谱鉴定

基于五氟苄基溴（PFBBr）微波衍生化的气相色谱—质谱（GC-MS）鉴定N-乙酰邻氨基苯甲酸、邻氨基苯甲酸和苯乙酸三种酸类易制毒化学品,以苯甲酸为内标物。N-乙酰邻氨基苯甲酸衍生化产物特征碎片峰为119、181、317、359;邻氨基苯甲酸衍生化产物特征碎片峰为119、181、317;苯乙酸衍生化产物特征碎片峰为91、181、316。检测结果与直接测试比较,色谱峰型明显改善,检测灵敏度提高,检测限（S/N=3∶1）3~12ng。该方法可以用于N-乙酰邻氨基苯甲酸、邻氨基苯甲酸和苯乙酸的鉴定。     

Novel O‐propyl,S‐propyl,and N‐propyl substituted 1,4‐naphthoquinones and 1,4‐anthraquinones as potential fingermark development reagents for porous surfaces

Lawsone is a 2‐substituted‐1,4‐naphthoquinone derivative, which has been proposed as an alternative to the reagents currently used for fingermark detection on porous surfaces. 2‐substituted‐anthraquinones, which contain an additional conjugated benzene ring, have a similar chemical structure to that of lawsone. In this study, a new series of 2‐substituted‐1,4‐naphthoquinones and 2‐substituted‐1,4‐anthraquinones were synthesized and completely characterized by¹H NMR,¹³C NMR, IR, and HPLC‐TOF/MS analyses. All newly synthesized 2‐substituted‐1,4‐quinones were investigated for their ability to develop latent fingermarks on porous surfaces, and this ability was compared with that of lawsone. Each fingermark developed was graded using an established method; thus, quantitative data were attributed to each fingermark. It has been demonstrated that the 1,4 ‐ quinones react with amino acids present in latent fingermarks on selected paper surfaces to produce faint yellow‐orange impressions, which exhibit strong photoluminescence when illuminated with a forensic light source at 440 nm and observed through a red filter. None of the compounds caused background darkening. The results obtained were generally similar to those of lawsone, however, 8‐dibromo‐2‐(propylamino)naphthalene‐1,4‐dione and 5,8‐dibromo‐2‐(propylthio)naphthalene‐1,4‐dione yielded better results for copier paper and colored (blue) copier paper used in this analysis. To the best of our knowledge, this is the first study to examine the role of 1,4‐anthraquinone derivatives as potential fingermark development reagents. The results indicate that 1,4‐quinones have a potential to be used as reagents for enhancement of latent fingermarks.     

Positive and negative ion mass spectrometry of antiepileptic hydantoins and their analogs

Positive ion electron impact (PIEI), positive ion chemical ionization (PICI), and negative ion chemical ionization (NICI) mass spectra of seven compounds of hydantoins and their analogs are presented; their probable fragmentation modes are also presented. In the PIEI mode, intensities of molecular ions differed according to different compounds. Cleavage at outsides of both carbonyl groups was commonly observed for all compounds. In the PICI mode, all compounds showed [M + 1]+ quasi-molecular ions constituting the base peaks. In the NICI mode, [M - 1]- quasi-molecular anions were the base peaks except for trimethadione and paramethadione. All negative spectra showed anions at m/z 42 due to [NCO]-; these peaks seem useful for screening of antiepileptics. An extraction procedure for the anti-epileptics from human urine or plasma, and their separation by gas chromatography (GC), are also presented to serve for their actual identification by GC/mass spectrometry.     

The general toxicology unknown. II. A case report: doxylamine and pyrilamine intoxication

A general toxicology unknown case is presented to demonstrate our systematic approach. A 20-year-old male was found dead with multiple suicide notes. Overdose was suspected but substances were not known. Blood alcohol was negative. Urine was analyzed by enzyme-multiplied immunoassay technique and was negative for all drugs assayed. Urine was then extracted with ethyl acetate:hexane (1:1) at pH 10 and back-extracted into 1.0N sulfuric acid. The acidic layer was adjusted to pH 10, and re-extracted with ethyl acetate:hexane (1:1). The residue was analyzed by gas chromatography (GC) on a 3% OV-101 column. It was found to be negative for all commonly screened substances. However, several unknown peaks were observed. Electron impact mass spectra of these unknown peaks were obtained and searched for in our computer library of more than 25000 mass spectra. These unknown peaks were identified as doxylamine and pyrilamine by gas chromatography/mass spectrometry. The base peak and molecular ion for pyrilamine were at m/z 121 and 285, respectively. The base peak for doxylamine was at m/z 58. No molecular ion was observed for doxylamine. Both doxylamine and pyrilamine are antihistamines, but are promoted and used in the management of insomnia. Quantitation was performed on a GC using dexbrompheniramine as an internal standard. Blood concentrations for doxylamine and pyrilamine were 0.7 and 7.0 mg/L, respectively. Concentrations in other tissues were determined. Death was caused by combined doxylamine and pyrilamine intoxication; the manner of death was suicide.     

GC-MS检测新型策划毒品K3

目的基于气相色谱-质谱（GC-MS）检测结合特殊质谱库信息检索建立新型策划毒品的鉴定方法。方法未知样品用甲醇超声溶解,吸取上清液采用气相色谱-质谱（GC-MS）联用仪检测。结果测得A组分（t R=19.47min）的质谱特征碎片峰（m/z）信息为215.1（基峰）、144.9、294.1、337.1和365.1,B组分（tR=23.29min）的质谱特征碎片峰（m/z）信息为359.1（基峰）、127.1、144.0、155.0、232.1、284.1和342.0。经美国缉毒署毒品分析谱库检索获得的信息资料,鉴定为新型策划毒品＂K3＂,其主要组分为＂AKB48＂和＂AM2201＂,此类化合物具有大麻类似精神活性,归属合成大麻素。结论本方法可用于新型策划毒品组分的鉴定。     

Positive- and negative-ion mass spectrometry and rapid clean-up of some carbamate pesticides

Positive-ion electron impact (PIEI), positive-ion chemical ionization (PICI) and negative-ion chemical ionization (NICI) mass spectra of 9 carbamate pesticides are presented. In the PIEI mode, the spectra showed small molecular peaks, intense or base peaks due to M - CH3NHCO + H and peaks at m/z 58 due to CH3NHCO. In the PICI mode, peaks due to M + H, M + C2H5, M - CH3NHCO + 2H, CH3NHCO(m/z 58) and M-28 appeared. The cations at m/z 58 found in both PIEI and PICI modes seem very useful for screening of a carbamate. In the NICI mode, the spectra showed peaks due to M - CH3NHCO and characteristic anions appearing at mass numbers higher than molecular ones, which were probably due to dimerization of [M - CH3NHCO]-followed by hydrogen attachment. Carbamates, which had been added to urine, plasma, whole blood, the liver, kidney and brain, could be rapidly isolated by use of Sep-Pak C18 cartridges with chloroform as an elution solvent. They could be detected by wide-bore capillary gas chromatography with a SPB-5 column, with satisfactory separation from impurities in their underivatized forms.     

Positive and negative ion mass spectrometry and rapid isolation with Sep-Pak C18 cartridges of ten local anaesthetics.

The positive ion electron impact (PIEI), positive ion chemical ionization (PICI) and negative ion chemical ionization (NICI) mass spectra and a rapid isolation procedure using Sep-Pak C18 cartridges are presented for ten local anaesthetics. In the PIEI mode, molecular peaks were very small or missing for most compounds. Peaks at m/z 86 due to the diethylaminoethyl or propylaminoethyl group constituted base peaks in six compounds. In the PICI mode, peaks due to M + H and M + C2H5 appeared. The cation at m/z 86 was also observed for the six compounds. This ion seems useful for the screening of local anaesthetics. In the NICI mode, anions at m/z M - H constituted base peaks for all compounds, peaks at m/z M + 12 appeared in many compounds. The total ion current in the PIEI and PICI modes generally gave higher sensitivity than in the NICI mode. Local anaesthetics present in whole blood or cerebrospinal fluid (CSF) could be rapidly isolated by use of Sep-Pak C18 cartridges with chloroform/methanol as an elution solvent. Their detection was possible using wide-bore capillary gas chromatography with SPB-1 and HP-17 wide-bore capillary columns with satisfactory separation from impurities.     

Differentiation of methylenedioxybenzylpiperazines (MDBPs) and methoxymethylbenzylpiperazines (MMBPs) By GC-IRD and GC-MS

The substituted benzylpiperazines, 3,4-methylenedioxybenzylpiperazine (3,4-MDBP), its regioisomer 2,3-methylenedioxybenzylpiperazine (2,3-MDBP) and four isobaric ring substituted methoxymethylbenzylpiperazines (MMBP) have almost identical mass spectra. Perfluoroacylation of the secondary amine nitrogen of these isomeric piperazines gave mass spectra with differences in relative abundance of some fragment ions. However, the spectra did not yield any unique fragments for specific identification of one isomer to the exclusion of the other compounds. Gas chromatography coupled with infrared detection (GC-IRD) provides direct confirmatory data for the structural differentiation between the six isomers. The mass spectra in combination with the vapor phase infrared spectra provide for specific confirmation of each of the isomeric piperazines. The underivatized and perfluoroacyl derivative forms of the ring substituted benzylpiperazines were resolved on the polar stationary phase Rtx-200.     

A Fatal Case of CO2 Intoxication in a Fermentation Tank

Carbon dioxide (CO₂) is an odorless constituent of air. Higher concentrations can be detected in geothermal and automotive emissions, fermentation, and sublimation of dry ice. An unskilled worker entered a fermentation tank to clean it, which had not been done for about 5 months allowing for high concentrations of CO₂ to build up. A second worker entered the tank to rescue the first one. Shortly after both were found the first worker was rescued directly whereas the tank had to be rotated to pull the second worker out. Cardiopulmonary resuscitation was successful only for the first worker. Medico‐legal autopsy showed bruises, hematoma, myocardial hemorrhage, and edema of the lungs. The right lung was vacuum degassed in an argon atmosphere and quadrupole‐mass‐spectrometry showed an elevated CO₂ content in lung gases. Thus, CO₂ intoxication/asphyxia in a vitiated atmosphere due to fermentation of wine mash was established as the cause of death.     

Identifying reliable ions for the statistical differentiation of structurally similar fentanyl analogs

Definitive identification of fentanyl analogs based on mass spectral comparison is challenging given the high degree of structural and, hence, spectral similarity. To address this, a statistical method was previously developed in which two electron-ionization (EI) mass spectra are compared using the unequal variance t-test. Normalized intensities of corresponding ions are compared, testing the null hypothesis (H₀) that the difference in intensity is equal to zero. If H₀ is accepted at all m/z values, the two spectra are statistically equivalent at the specified confidence level. If H₀ is not accepted at any m/z value, then there is a significant difference in intensity at that m/z value between the two spectra. In this work, the statistical comparison method is applied to distinguish EI spectra of valeryl fentanyl, isovaleryl fentanyl, and pivaloyl fentanyl. Spectra of the three analogs were collected over a 9-month period and at different concentrations. At the 99.9% confidence level, the spectra of corresponding isomers were statistically associated. Spectra of different isomers were statistically distinct, and ions responsible for discrimination were identified in each comparison. To account for inherent instrument variations, discriminating ions for each pairwise comparison were ranked based on the magnitude of the calculated t-statistic (t_calc) value. For a given comparison, ions with higher t_calc values are those with the greatest difference in intensity between the two spectra and, therefore, are considered more reliable for discrimination. Using these methods, objective discrimination among the spectra was achieved and ions considered most reliable for discrimination of these isomers were identified.