USGS42 and USGS43: human-hair stable hydrogen and oxygen isotopic reference materials and analytical methods for forensic science and implications for published measurement results

Because there are no internationally distributed stable hydrogen and oxygen isotopic reference materials of human hair, the U.S. Geological Survey (USGS) has prepared two such materials, USGS42 and USGS43. These reference materials span values commonly encountered in human hair stable isotope analysis and are isotopically homogeneous at sample sizes larger than 0.2 mg. USGS42 and USGS43 human-hair isotopic reference materials are intended for calibration of δ(2)H and δ(18)O measurements of unknown human hair by quantifying (1) drift with time, (2) mass-dependent isotopic fractionation, and (3) isotope-ratio-scale contraction. While they are intended for measurements of the stable isotopes of hydrogen and oxygen, they also are suitable for measurements of the stable isotopes of carbon, nitrogen, and sulfur in human and mammalian hair. Preliminary isotopic compositions of the non-exchangeable fractions of these materials are USGS42(Tibetan hair)δ(2)H(VSMOW-SLAP) = -78.5 ± 2.3‰ (n = 62) and δ(18)O(VSMOW-SLAP) = +8.56 ± 0.10‰ (n = 18) USGS42(Indian hair)δ(2)H(VSMOW-SLAP) = -50.3 ± 2.8‰ (n = 64) and δ(18)O(VSMOW-SLAP) = +14.11 ± 0.10‰ (n = 18). Using recommended analytical protocols presented herein for δ(2)H(VSMOW-SLAP) and δ(18)O(VSMOW-SLAP) measurements, the least squares fit regression of 11 human hair reference materials is δ(2)H(VSMOW-SLAP) = 6.085δ(2)O(VSMOW-SLAP) - 136.0‰ with an R-square value of 0.95. The δ(2)H difference between the calibrated results of human hair in this investigation and a commonly accepted human-hair relationship is a remarkable 34‰. It is critical that readers pay attention to the δ(2)H(VSMOW-SLAP) and δ(18)O(VSMOW-SLAP) of isotopic reference materials in publications, and they need to adjust the δ(2)H(VSMOW-SLAP) and δ(18)O(VSMOW-SLAP) measurement results of human hair in previous publications, as needed, to ensure all results on are on the same scales.     

Synthesis of 2,3- and 3,4-methylenedioxyphenylalkylamines and their regioisomeric differentiation by mass spectral analysis using GC-MS-MS

3,4-methylenedioxyamphetamine (MDA) derivatives are increasingly abused central nervous system stimulants with neurotoxic properties. In recent years a number of controlled substance analogs (designer drugs) with high structural variety reached the illegal market making their identification an arduous task. The underivatized compounds give very similar or even virtually identical electron impact mass spectra containing mainly intense C(n)H(2n+2)N(+) immonium ions. Using tandem mass spectrometry (MS-MS) the additional structural information contained in the collision induced dissoziation (CID) mass spectra of molecular ions using electron impact (EI) and especially chemical ionization (CI) allowed an unequivocal differentiation of 18 studied regioisomeric 1-(methylenedioxyphenyl)-2-propanamines and 1-(methylenedioxyphenyl)-2-butanamines.Further synthetic methods are presented for 1-(3,4-methylenedioxyphenyl)-N-propyl-2-butanamine, N-isopropyl-1-(3,4-methylenedioxyphenyl)-2-butanamine and four 1-(2, 3-methylenedioxyphenyl)-2-butanamines. N-alkylated 1-(3, 4-methylenedioxyphenyl)-2-butanamine compounds (e.g. MBDB) are also known to be abused psychoactive agents (entactogenes) without the sympatomimetic effects of the 3,4-methylenedioxyamphetamines.     

中国控辩协商制度研究--刑事诉讼特别程序之探讨

逐步扩大简易程序和其他速决程序的适用范围,是近年来世界各国刑事诉讼法的发展趋势之一.随着我国当事人主义诉讼模式的初步确立,对抗性审判的程度得到了进一步增强,但刑事案件数量持续上升与司法资源有限之间的矛盾却日益突出,在此情形下,借鉴美国辩诉交易制度及西方其他国家的刑事诉讼特别程序,创设具有中国特色的控辩协商制度这种非审判式案件处理方式,就成为我们可供考虑的选择.     

Shotgun shooting in northern India--a review (1980-1999)

Central Forensic Science Laboratory (CFSL), Chandigarh undertakes the examination of the crime cases of some northern states of India. The shooting cases of last two decades (1980-1999) involving shotguns were analysed in this laboratory. This paper consists of the study of 360 actual cases of shotguns for evaluation of various parameters, such as type of firearm, number of firearm and firing, location of wound, age, occupation, sex and caste of accused and victim, etc. Out of 360 cases, 253 (70%) were classified as homicidal, 68 (19%) accidental, 11 (3%) suicidal, 9 (2.5%) hunting and 19 (5.5%) cases of insufficient information including the cases of illegal possession of firearm. Single Barrel Breech Loading (SBBL) gun 144 (40%) was preferred over Single Barrel Muzzle Loading (SBML) 109 (30.3%), Double Barrel Breech Loading (DBBL) 72 (20%) and Double Barrel Muzzle Loading (DBML) gun 35 (9.7%). All the breechloader guns were of 12 bore. Muzzleloader gun were recovered only from the remote rural areas. Three hundred and thirty-one (92%) cases involved single, 22 (6%) double and 7 (2%) more than two shotgun. Majority of cases were found of single firing 288 (80%), followed by double 29 (8%) and multi-firing 18 (5%). Eleven (3%) cases were of misfiring and in 14 (4%) cases information was not available. Accidental and suicidal cases had only one firing. The mean age for male and female victim was 31 and 24 years, respectively. Occupationally, agriculture is predominating over business, service and security guards for accused and for victim agriculture followed by service, business, student and security guards are in the descending order. Caste wise the most aggressive community of Kshatriyas is predominating as accused and victim over lower cast people. Head (64%) being a vital part was chosen most frequently for committing suicide followed by body (36%). Service personnel committed maximum number of suicide.     

Synthesis of standards of the most important markers of Leuckart p-methoxymethamphetamine (PMMA). Examination of the influence of experimental conditions and a drug diluent on SPE/TLC profiling

The synthesis of characteristic markers of PMMA obtained by Leuckart method was described. The effectiveness of a procedure of SPE/TLC screening profiling of impurities was studied on the basis of selected impurities. The influence of glucose (a drug diluent) on the profile quality was investigated. The intermediate product (characteristic for the Leuckart synthesis) N-formyl-p-methoxymethamphetamine (1) and by-products: N-formyl-p-methoxyamphetamine (2), p-methoxyamphetamine (3), N,N-dimethyl-p-methoxyamphetamine (4), (RS) and (RR/SS) diastereoisomers of bis(1-methyl-2-(4-methoxyphenyl)ethyl)amine (meso-5 and rac-5), (RS) and (RR/SS) diastereoisomers of N-methyl-bis(1-methyl-2-(4-methoxyphenyl)ethyl)amine (meso-6 and rac-6), N-methyl-1,3-bis(4-methoxyphenyl)propane-2-amine (7) were synthesized. The substrate p-methoxyphenylacetone and the impurities 1 and 4 were used in the study of influence of experimental conditions and glucose on the profiling process and results. The experiments were carried out according to a 2(4) factorial design. The proposed criterions of the profile quality are based on matrix presentation of TLC patterns. They take into account the number of spots revealed, differences between R(f) values and intensity of fluorescence, simultaneously.     

The association between body mass index and pulmonary thromboembolism in an autopsy population

Abstract: To evaluate the association between obesity and pulmonary thromboembolism (PTE) in a forensic context, 160 autopsy cases of fatal PTE were compared with age‐ and gender‐matched controls. The mean age of cases was 66 years (range 26–98 years; M/F 74:86). The mean body mass index (BMI) of cases with PTE was 30.88 (range 14.95–79.51), which was significantly higher than in the controls (mean BMI = 25.33; range 12.49–61.84) (p < 0.0001). Comparing the group with PTE with controls showed that five (3.1%) compared to 20 (12.5%) were underweight, 39 (24.4%) compared to 67 (41.88%) were of normal weight, 49 (30.63%) compared to 43 (26.88%) were overweight, 43 (26.88%) compared to 24 (15%) were obese, and 24 (15.0%) compared to six (3.75%) were morbidly obese. In each category of above‐normal BMIs, there were significantly greater numbers in the groups with PTE: overweight (p < 0.01), obese (p < 0.001), and morbidly obese (p < 0.0001).     

(1S,2S)-1-Methylamino-1-phenyl-2-chloropropane: Route specific marker impurity of methamphetamine synthesized from ephedrine via chloroephedrine

Identification of route specific marker impurities of (S)-(+)-methamphetamine can provide us with very useful information for (S)-(+)-methamphetamine abuse criminal investigation. (1S,2S)-(+)-Chloropseudoephedrine and (1R,2S)-(-)-chloroephedrine are well known impurities of (S)-(+)-methamphetamine synthesized by metal catalyzed hydrogenation of (1R,2S)-(-)-ephedrine or (1S,2S)-(+)-pseudoephedrine. In this report (1S,2S)-1-methylamino-1-phenyl-2-chloropropane is identified as a route specific marker impurity from metal catalyzed hydrogenation method for the synthesis of (1R,2S)-(-)-ephedrine or (1S,2S)-(+)-pseudoephedrine via its chloro-derivative. (1S,2S)-1-Methylamino-1-phenyl-2-chloropropane is a ring-opening compound of cis-1,2-dimethyl-3-phenylaziridine by reacting with HCl in high temperature condition of GC inlet.     

Identification and synthesis of some contaminants present in 4-methoxyamphetamine (PMA) prepared by the Leuckart method

The clandestine synthesis of ring and side chain modified phenylisopropylamines continues to be a major source of these drugs of abuse. One method used for the synthesis of the amphetamine and related compounds involves the treatment of the appropriate ketone with formamide or ammonium formate followed by acid hydrolysis of intermediate N-formyl derivative. In this paper the synthesis of 4-methoxyamphetamine (PMA, 1) by the Leuckart method is investigated. The identification by means of gas chromatography-mass spectrometry (GC-MS) of methoxy derivative of N-(beta-phenylisopropyl)benzaldimine 9, methoxy derivative of N-(beta-phenylisopropyl)benzyl methyl ketimine 5, 1-(4-methoxyphenyl)-N-(4-methoxybenzyl)-2-propanamine 10, (RR/SS) and (RS) 1-(4-methoxyphenyl)-N-[2-(4-methoxyphenyl)-1-methylethyl]-2-propanamine 6a-6c, (RR/SS) and (RS)-1-(4-methoxyphenyl)-N-methyl-N-[2-(4-methoxyphenyl)-1-methylethyl]-2-propanamine 7a-7c, (RR/SS) and (RS)-1-(4-methoxyphenyl)-N-formyl-N-[2-(4-methoxyphenyl)-1-methylethyl]-2-propanamine 8a-8c in crude PMA, are reported. The identity of these compounds was confirmed by independent synthesis of reference compounds. The NMR, MS, IR data, stereochemistry and some chromatographic properties of synthesized compounds are discussed. Finally, the results of the GC-MS analysis of illicitly prepared tablets, containing PMA 1 and 4-methoxymethamphetamine (PMMA, 2), are outlined. The presence of 4-methoxydimethylamphetamine 11, 4-methoxyethylamphetamine 12, and 4-hydroxymethamphetamine 13 are reported in these tablets. The identity of 2, 11, and 12 was confirmed by their independent synthesis.     

中日法律的近代转型的比较分析

19世纪中叶 ,中日两国均在西方殖民主义的武力威胁之下 ,开始了法律的近代化转型 ,但又有所差别 ,表现在 :一、社会背景不同。二、变革过程不同。三、主体不同。四、立法目的不同。五、具体内容与实施程度不同。六、历史作用不同。     

Disentangling the Disability Quagmire in Psychological Injury and Law

This paper aims to critically analyze the evolution of six models of conceptualization, determination, and prediction of occupational disability relevant in the medico-legal context of psychological injury. The six models are the (a) biomedical, (b) forensic, (c) psychosocial, (d) ecological, (e) economic, and (f) biopsychosocial. We will discuss the key commonalities and differences among the models, including disciplinary tradition, research paradigm, recognition of person–environment interaction, key tenets, and implications for practice and research in psychological injury. The paper will highlight and discuss psychosocial issues, often underemphasized in forensic psychological practice, including: (a) balanced assessment of primary, secondary, and tertiary gains and losses, (b) self-perception, (c) disability identity, (d) beliefs and expectations, (e) coping, (f) adaptation and positive growth, (g) social stigma and social reactions to disability, including disability harassment, and (h) recognition of system-based environmental influences and demands. We will provide a special focus on the current state of the science and practice of prediction of disability, of particular interest to researchers and clinicians involved in clinical and occupational prognostication in psychological injuries. Finally, we will draw conclusions and recommendations for future research and best practices in the psychological injury area using a cross-diagnostic, dynamic, functionally based, and integrated biopsychosocial and forensic model of disability.     

Identification and synthesis of by-products found in 4-methylthioamphetamine (4-MTA) produced by the Leuckart method

The synthesis of the designer drug 4-methylthioamphetamine (4-MTA) has been carried out using the well-known Leuckart reaction in four versions. The treatment of 4-methylthiophenylacetone with formamide, mixture of formamide/formic acid, ammonium formate, and mixture of ammonium formate and formic acid followed by acid hydrolysis brought about the formation of 4-MTA contaminated with a number of impurities. The gas chromatography mass-spectrometry (GC-MS) analysis of the reaction mixtures allowed identification of the most prominent impurities, such as diasteromers of N,N-di-[β-(4-methylthiophenyl)isopropyl]amine, N,N-di-[β-(4-methylthiophenyl)isopropyl]methylamine, N,N-di-[β-(4-methylthiophenyl)isopropyl]formamide, the Schiff bases derived from 4-MTA and 4-methylbenzaldehyde (benzaldimine) and 4-methylthiophenylacetone (ketimine) as well as some heterocycles: 4-methyl-5-(4'-methylthiophenyl)pyrimidine, 4-(4'-methylthiobenzyl)pyrimidine, 2,6-dimethyl-3,5-di-(4'-methylthiophenyl)pyridine, 2,4-dimethyl-3,5-di-(4'-methylthiophenyl)pyridine. The correctness of identification was confirmed by independent synthesis of these compounds. Each synthesized reference compound was characterized by means of MS, (1)H and (13)C NMR, and IR methods. The stereochemistry of (RR/SS) diasteromer of N,N-di-[β-(4-methylthiophenyl)isopropyl]amine was confirmed by a crystallographic method.     

Ten methods for calculating the uncertainty of measurement

While forensic laboratories are coming under increasing pressure to provide meaningful estimates of measurement uncertainty, there has been little discussion of this topic in the literature. This article summarizes ten bases for estimating this parameter: (1) proficiency tests; (2) readability limits; (3) independent reference materials; (4) operational limits applied during calibration; (5) expert judgment; (6) precision control samples without (6) and with (7) contributions from extramural sources of error; (8) error budgets; (9) historical performance; and (10) ruggedness tests. Based on the assumptions underlying each approach, the forensic community will need to apply a variety of discipline-specific approaches to arrive at satisfactory estimates of measurement uncertainty.     

“法”义新论

"法"在字源和词源上有三个系统,即灋、佱、。许慎在《说文》中仅以战国篆文为据,未能考察商至战国前期文字发展的理路,对"灋"的词源解释有误。廌与作为神兽的獬豸有差异,并无掌法神兽之义。灋字在西周时代作为"废"的本字使用,与后世的"法"义并无关联。宗周文化系统中有一个表规范、法则意义的"佱"字;南方文化中有一个表达规范、法则、效法甚至法律的"",因此在先秦时代有宗周的"佱"和南方的""两个与后世"法"有渊源关系的概念系统。这两个系统在春秋中叶至战国时代发生碰撞、融合,最终以""吸纳并取代"佱",并写作"灋"为终结。具有"刑罚"、"审判"之义的"法",通过"灋"的字源和词源无法解释,而当与宗周文化系统之外的南方文化中的系统有关。     

Gm(11) grouping of dried bloodstains

An absorption inhibition method for the detection of gamma marker Gm(11) in dried bloodstains is described. Particular reference is made to the association of Gm(11) with Gm(-1, -2). When a dried bloodstain fails to inhibit anti-Gm(1) and anti-Gm(2), this may represent a true Gm(-1, -2) result or there may be insufficient material to inhibit either antibody. The detection of Gm(11) in a bloodstain extract provides an objective means of confirming the apparent absence of Gm(1) and Gm(2) as representing a true Gm(-1, -2) result. This antigen compares very well with other blood group systems with regard to the amount of bloodstain required for analysis and its stability. No evidence is available for preferential loss of Gm(1) and Gm(2) relative to Gm(11) in dried bloodstains.     

Hair analysis for delta(9)-THC,delta(9)-THC-COOH,CBN and CBD,by GC/MS-EI. Comparison with GC/MS-NCI for delta(9)-THC-COOH

A sensitive analytical method was developed for quantitative analysis of delta(9)-tetrahydrocannabinol (delta(9)-THC), 11-nor-delta(9)-tetrahydrocannabinol-carboxylic acid (delta(9)-THC-COOH), cannabinol (CBN) and cannabidiol (CBD) in human hair. The identification of delta(9)-THC-COOH in hair would document Cannabis use more effectively than the detection of parent drug (delta(9)-THC) which might have come from environmental exposure. Ketamine was added to hair samples as internal standard for CBN and CBD. Ketoprofen was added to hair samples as internal standard for the other compounds. Samples were hydrolyzed with beta-glucuronidase/arylsulfatase for 2h at 40 degrees C. After cooling, samples were extracted with a liquid-liquid extraction procedure (with chloroform/isopropyl alcohol, after alkalinization, and n-hexane/ethyl acetate, after acidification), which was developed in our laboratory. The extracts were analysed before and after derivatization with pentafluoropropionic anhydride (PFPA) and pentafluoropropanol (PFPOH) using a Hewlett Packard gas chromatographer/mass spectrometer detector, in electron impact mode (GC/MS-EI). Derivatized delta(9)-THC-COOH was also analysed using a Hewlett Packard gas chromatographer/mass spectrometer detector, in negative ion chemical ionization mode (GC/MS-NCI) using methane as the reagent gas. Responses were linear ranging from 0.10 to 5.00 ng/mg hair for delta(9)-THC and CBN, 0.10-10.00 ng/mg hair for CBD, 0.01-5.00 ng/mg for delta(9)-THC-COOH (r(2)>0.99). The intra-assay precisions ranged from <0.01 to 12.40%. Extraction recoveries ranged from 80.9 to 104.0% for delta(9)-THC, 85.9-100.0% for delta(9)-THC-COOH, 76.7-95.8% for CBN and 71.0-94.0% for CBD. The analytical method was applied to 87 human hair samples, obtained from individuals who testified in court of having committed drug related crimes. Quantification of delta(9)-THC-COOH using GC/MS-NCI was found to be more convenient than GC/MS-EI. The latter may give rise to false negatives due to the detection limit.     

Formation of Trifluoroacetylated Ephedrine During the Analysis of a Pseudoephedrine-Formaldehyde Adduct by TFAA Derivatization Followed by GC-MS

Abstract:  (+)-Pseudoephedrine reacts with formaldehyde to form (4 S ,5 S )-3,4-dimethyl-5-phenyloxazolidine. Gas chromatography–mass spectrometry (GC-MS) analysis after the reaction of this oxazolidine with excess trifluoroacetic acid anhydride (TFAA) shows predominantly N , O- bis(trifluoroacetyl)pseudoephedrine with some of the monotrifluoroacetylated derivative. In addition, variable amounts of N , O- bis(trifluoroacetyl)ephedrine were detected by GC-MS. N , O- bis(trifluoroacetyl)ephedrine was not detected upon trifluoroacetylation of the source (+)-pseudoephedrine, and nuclear magnetic resonance analysis of the (4 S ,5 S )-3,4-dimethyl-5-phenyloxazolidine showed no evidence of the (4 R ,5 S ) isomer. This suggests that the N ,O-bis(trifluoroacetyl)ephedrine is formed by epimerization during the TFAA derivatization and GC-MS analysis of the pseudoephedrine-formaldehyde adduct.     

The relationship between bedding and face-down death in infancy: mathematical analysis of a respiratory simulation system using an infant mannequin to assess gas diffusibility in bedding

Rebreathing is a model for the relationship between a prone sleeping position and sudden infant death syndrome. This study used a mechanical simulation model to establish the relationship between types of bedding and rebreathing potential for an infant placed prone (face down) at different postnatal ages. The infant mannequin was connected to a respirator set to deliver physiologically appropriate combinations of tidal volume (V(T)) and respiratory rates (RR) across a range of postnatal ages (0-18 months). Before measurements were made, CO(2) flow was regulated to 5+/-0.1% of end-tidal PCO(2) (EtCO(2)). After the model was placed in a prone position, any increase in the fractional concentration of inspired CO(2) (FiCO(2)) was measured. FiCO(2) increased immediately and rapidly, and reached a maximum value within a few minutes. The maximum FiCO(2) ranged from under 2% to over 10%, depending on the bedding. FiCO(2) was also affected by V(T) and RR. This model is not applicable to actual infants because of the large tissue stores of CO(2) in infants; however, it is useful for evaluation of gas diffusibility of bedding and will simplify the investigation of sleeping environments when a baby is found dead with its face covered by soft bedding. In general, the higher the FiCO(2), the greater the rebreathing potential. Theoretically, considering the paucity of body stores of O(2), changes in FiO(2) would be affected not by changes in FiCO(2), but by CO(2) production and gas movement around the infant's face. The rapid decrease of FiO(2) is approximated at the inverse of the FiCO(2) timecourse, suggesting the significance of not only CO(2) accumulation but also O(2) deprivation in the potential space around the baby's face.     

Exemption of certain systems of records under the Privacy Act. Final rule

This final rule exempts four systems of records (SORs) from subsections (c)(3), (d)(1) through (d)(4), (e)(4)(G) and (H), and (f) of the Privacy Act pursuant to 5 U.S.C. 552a(k)(2): The Automated Survey Processing Environment (ASPEN) Complaint/ Incidents Tracking System (ACTS), HHS/CMS, System No. 09-70-0565; the Health Insurance Portability and Accountability Act (HIPAA) Information Tracking System (HITS), HHS/CMS, System No. 09-70-0544; the Organ Procurement Organizations System (OPOS), HHS/CMS, System No. 09-70- 0575; and the Fraud Investigation Database (FID), HHS/CMS, System No. 09-70-0527.     

A fatality caused by accidental production of hydrogen sulfide.

A 55-year-old male Caucasian truck driver was dead at the scene after breathing hydrogen sulfide (H(2)S) produced by an accidental transfer of sodium hydrogen sulfide (NaHS) from a tanker truck to a tank containing 4% sulfuric acid (H(2)SO(4)) and iron(II) sulfate (FeSO(4)). Autopsy of the decedent's body revealed pulmonary edema and passive congestion in lungs, spleen, kidneys, and adrenal glands. Postmortem biological samples were analyzed for carbon monoxide, cyanide, ethanol, and drugs. Since a potential exposure to H(2)S was involved, blood was also analyzed for sulfide (S(2-)). The analysis entailed isolating S(2-) from blood as H(2)S using 0.5M H(3)PO(4), trapping the gas in 0.1M NaOH, and determining the electromotive force using a sulfide ion specific electrode. Acetaminophen at a concentration of 14.3 microg/ml was found in blood, and metoprolol was detected in the blood, liver, and kidney samples. The blood S(2-) level was determined to be 1.68 microg/ml. It is concluded that the cause of death was H(2)S poisoning associated with a hazardous material accident in an industrial situation.     

Identification of common impurities present in the synthetic routes leading to 4-methylthioamphetamine (4-MTA). Part II: Reductive amination and nitropropene route

In this paper the by-products arising during the synthesis of 4-methylthioamphetamine (4-MTA) by LiAlH(4) reduction of 1-(4-methylthiophenyl)-2-nitropropene (nitropropene route) and reductive amination of 4-methylthiophenyl-2-propanone in the presence of NaCNBH(4) are investigated. The identification of 4-methylthio derivatives of N-(β-phenylisopropyl)benzaldimine, 4-methylthio derivative of N-(β-phenylisopropyl)benzyl methyl ketimine, 1-(4-methylthiophenyl)-N-(4-methylthiobenzyl)-2-propanamine, (RS) and (SS/RR)-N,N-di-[β-(4-methylthiophenyl)isopropyl]amine, 4-methylthiobenzyl ether and methylthiobenzoic acid methyl ester as most prominent impurities in crude 4-MTA synthesised by reductive amination of 4-methylthiophenyl-2-propanone, is reported. Methylthio derivatives of 2-methyl-3-phenylaziridine, 2-benzylaziridine, and 4-methylthio derivative of BMK oxime as route-specific markers of nitropropene route leading to 4-MTA, were also characterized. The identity of these compounds was confirmed by their independent synthesis.