Gold-plating of Mylar lift films to capitalize on surface enhanced Raman spectroscopy for chemical extraction of drug residues

The method of residue extraction through electrostatic lifting provides a distinctive mode of performing ultra-trace analysis. These lifts provide a medium for analyte extraction via nanomanipulation-coupled to nanospray ionization-mass spectrometry (NSI-MS). This method of extraction can be coupled to Raman spectroscopy for supplemental verification of analytes using surface enhanced Raman scattering (SERS). The gold surface used for SERS provides an enhanced effect on peak signal intensity allowing ultra-trace amounts to be detected more effectively. The aim of this research is to utilize gold-coated films with electrostatic lifting in order to collect latent materials and analyze chemicals of interest contained in them via SERS.     

Nanomanipulation‐Coupled Nanospray Mass Spectrometry Applied to the Extraction and Analysis of Trace Analytes Found on Fibers*

Abstract: This article presents the novel instrumentation of nanomanipulation coupled to nanospray ionization‐mass spectrometry, which is used to directly probe trace analytes found on individual fibers. The low detection limits and sample volumes associated with nanospray ionization‐mass spectrometry make it the ideal instrument to implement for trace analysis. Nanospray ionization‐mass spectrometry, coupled with the nanomanipulator, allows for the direct probing of trace particulates on fibers. The technique is demonstrated by dissolving an electrostatic particle of cocaine from a fiber, collecting the analyte solution in a nanospray tip, and transferring the tip directly to the mass spectrometer to complete analysis. The utility of this technique is evident through the minimal sample preparation and short analysis time. The use of nanomanipulation coupled to nanospray ionization‐mass spectrometry could improve on current trace particulate analysis by reducing both detection limits and sample size required to complete analysis.     

Direct Analyte‐Probed Nanoextraction Coupled to Nanospray Ionization–Mass Spectrometry of Drug Residues from Latent Fingerprints

Here, we present a method of extracting drug residues from fingerprints via Direct Analyte‐Probed Nanoextraction coupled to nanospray ionization–mass spectrometry (DAPNe‐NSI‐MS). This instrumental technique provides higher selectivity and lower detection limits over current methods, greatly reducing sample preparation, and does not compromise the integrity of latent fingerprints. This coupled to Raman microscopy is an advantageous supplement for location and identification of trace particles. DAPNe uses a nanomanipulator for extraction and differing microscopies for localization of chemicals of interest. A capillary tip with solvent of choice is placed in a nanopositioner. The surface to be analyzed is placed under a microscope, and a particle of interest is located. Using a pressure injector, the solvent is injected onto the surface where it dissolves the analyte, and then extracted back into the capillary tip. The solution is then directly analyzed via NSI‐MS. Analyses of caffeine, cocaine, crystal methamphetamine, and ecstasy have been performed successfully.     

Development of a quantitative LC-MS/MS method for the analysis of common propellant powder stabilizers in gunshot residue

In traditional scanning electron microscopy/energy dispersive X-ray analysis of gunshot residue (GSR), one has to cope more and more frequently with limitations of this technique due to the use of lead-free ammunition or ammunition lacking heavy metals. New methods for the analysis of the organic components of common propellant powder stabilizers were developed based on liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). A multiple reactions monitoring scanning method was created for the screening of akardite II, ethylcentralite, diphenylamine, methylcentralite, N-nitrosodiphenylamine, 2-nitrodiphenylamine, and 4-nitrodiphenylamine, present in standards mixtures. Five out of seven of these target compounds can be selectively identified and distinguished from the two others with a high accuracy. Samples from the hands of a shooter were collected by swabbing and underwent solid phase extraction prior to analysis. Detection limits ranging from 5 to 115 mug injected were achieved. Results from several firing trials show that the LC-MS/MS method is suitable for the detection of stabilizers in samples collected following the firing of 9 mm Para ammunitions.     

Vacuum collection of gunpowder residues from clothing worn by shooting suspects, and their analysis by GC/TEA, IMS, and GC/MS

Experiments were conducted to collect gunpowder (propellant) residues from shooters' clothing by vacuum and to analyze them by gas chromatography/thermal energy analyzer (GC/TEA), ion mobility spectrometry (IMS), and gas chromatography/mass spectrometry (GC/MS). The residues were collected on fiberglass and Teflon filters using the portable vacuum sampler, all supplied with the IMS instrument. Several solvents were examined for the extraction of the propellant components from the filters. The extracts were centrifuged and/or filtered, concentrated by evaporation, and analyzed without any additional clean-up procedure. Based on the results of the study, an operational method for analysis of gunpowder residues was introduced into casework without changing the present operational technique for gunshot (primer) residue (GSR) analysis on clothing implemented by the Israel Police. In the modified method, the clothing is first sampled by double-side adhesive-coated aluminum stubs (the tape-lift method) for GSR analysis (the existing method), followed by vacuum collection for propellant residue examination. The issue of interpretation of the analytical results is discussed.     

The Optimal Distance of the Electrode to the Lifting Film Surface when Lifting Dust Footwear Impressions Using an Electrostatic Dust Print Lifter

Footwear impressions are one of the valuable physical evidence encountered at crime scenes and its identification can facilitate narrowing down the suspects and establishing the identity of the criminals. The technique of electrostatic lifting (ESL) dust shoeprints at crime scenes is well established with scenes of crime examiners. And in the procedure, the recovery of the original item containing the impression should be made as good as it can and not damage the marks. In this study, the different particle sizes of SiO₂ were used to simulate dust and light soil residues, comparing different particle sizes and electrode positions were used to compare the adsorption ability on the surface of electrostatic lifting film in high‐voltage electrostatic field for the collection of shoeprints. The results indicated that lifting film in electrostatic field will be pressed down to the dust surface, the compaction and electrostatic adsorption force will vary with the distance between the high‐voltage electrode and film surface. Reducing the distance can increase the electric field strength near the lifting film, and the adsorption capacity of Mylar aluminum‐plating film to dusts can be improved significantly. Adsorption capacity of the lifting film was related to the size of dust particles and significantly improved with the increase of the particle charge. The optimum distance which can get the best adsorption capacity between the electrode and film surface is from 10 to 15 mm.     

血液中64种常见有机氯菊酯类农药的快速筛查

目的建立人体血浆中64种有机氯菊酯类农药多残留的气相色谱（GC）快速筛查分析方法。方法空白人体静脉抗凝血用乙腈沉淀蛋白,乙酸乙酯∶环己烷（v/v,3∶1）进行液液萃取净化,使用HP-5色谱柱,采用气相色谱进行定性、定量分析。对方法进行优化并进行方法学评价。结果 64种农药在0.001~0.1μg/mL范围内线性关系均良好,相关系数在0.990 1~0.999 9之间。检出限在0.001~0.15μg/mL范围内,方法定量限在0.001~0.5μg/mL之间,回收率总体于80%~110%之间,相对标准偏差小于15%,方法检出限总体于0.01μg/mL以下,日内精密度在1.5%~11.5%之间,日间精密度在2.9%~13.9%之间。结论本文建立的人体血浆的农药多残留快速筛查测定法,符合农药残留分析方法的要求,可在相关研究和实践中选用。     

Analysis of drugs of abuse in hair by automated solid-phase extraction, GC/EI/MS and GC ion trap/CI/MS

In our laboratory, analysis of human hair for the detection of drugs of abuse was first performed in 1995. Initially, requests for hair analysis were few, and it is only since 1997 that these analyses have become routine. As demand grew, we developed an automatic solid-phase extraction method; the use of a robot ASPEC allowed us to drop certain fastidious manipulations, and to treat a large number of samples at a time. This method is described, along with analysis by gas-chromatography-mass spectrometry (GC/MS) in selected ion monitoring mode (SIM), for the following drugs: codeine, 6-monoacetylmorphine (6-MAM), morphine, cocaine, methadone, ecstasy (MDMA) and Eve (MDE). This requires prior derivatization with propionic anhydride. The different validation parameters, linearity, repeatability, recovery and detection limits are described, as well as the application of this method to some real cases. Analysis of these cases is also performed by an ion trap GC/MS in chemical ionization mode (GC/IT/CI/MS) in order to demonstrate the usefulness of this technique as a complement to routine analysis. Analysis by GC/IT/CI/MS indeed avoids the risk of false-positive results by the identification of metabolites.     

UPLC-MS/MS法检测血痕中常见烟草、毒品和药物成分

目的建立UPLC-MS/MS测定血痕中尼古丁、可替宁、甲基苯丙胺、氯胺酮、吗啡、O6-单乙酰吗啡、地西泮、三唑仑、艾司唑仑、佐匹克隆和利血平的方法。方法以甲醇为提取液,采用基质提取溶液配制标准溶液制作定量曲线。采用超高效液相色谱柱对待测样品进行分离;以电喷雾离子源正离子（ESI＋）模式和多反应监测（MRM）模式进行质谱分析。优化实验条件,并进行方法学评价。结果选择UPLC HSS T3色谱柱,乙腈-5mmol/L甲酸铵＋0.1%（v/v）甲酸作为流动相,甲醇作为提取溶剂。11种检测物检出限（S/N=3）和定量限（S/N=10）分别为0.04~2.82ng和0.13~7.64ng,1~500ng/mL范围内的线性关系良好。除利血平、吗啡外的检测物回收率为（53.8±5.3）%~（107.2±12.6）%。结论采用本文UPLC-MS/MS方法对血痕中11种常见烟草、毒品和药物成分进行检测,能够满足实际检案的要求,可在相关检验中选用。     

Organic explosives analysis using on column-ion trap EI/NICI GC-MS with an external source

In this study, a standard method by gas chromatography coupled with mass spectrometry (GC/MS) for the analysis of classical organic explosives was developed. This method was validated in the EI mode, based on the XPT 90-210 standard method. Detection limits (LOD) and quantitation limits (LOQ) were both determined using electronic impact (EI) and negative ion chemical ionization (NICI) modes. These were compared and results showed that in the NICI mode, detection limits were lower than in the EI mode, thus NICI mode appeared to be the best way to analyze nitrate esters. Results of ion trap MS detection were then compared with those obtained in a previous study with single quadrupolar technology. Major ions that were obtained using ion trap MS detection in these two modes were reported.     

General unknown screening in hair by liquid chromatography-hybrid quadrupole time-of-flight mass spectrometry (LC-QTOF-MS)

The retrospective investigation of the exposure to toxic substances by general unknown screening of hair is still a difficult task because of the large number of possible poisons, the low sample amount and the difficult sample matrix. In this study the use of liquid chromatography-hybrid quadrupole time-of-flight mass spectrometry (LC-QTOF-MS) was tested as a promising technique for this purpose. In the optimized procedure, 20mg hair were decontaminated with water and acetone and two times extracted by 18h incubation with 0.5ml of a mixture of methanol/acetonitrile/H(2)O/ammonium formate at 37°C. A mixture of deuterated standards from different drug groups was added for quantification and method control. The united extracts were evaporated to a residue of 0.5ml and 5μl were injected without clean-up for LC-QTOF-MS measurement (instrument Agilent 6530) with positive electrospray ionization and in data dependent acquisition mode. For peak identification the accurate mass data base and spectral library of the authors was used which contains accurate mass CID spectra of more than 2500 and theoretically calculated accurate mass data of more than 7500 toxicologically relevant substances. Validation at the example of 24 illegal drugs, their metabolites and benzodiazepines resulted in limits of detection of 0.003-0.015ng/mg, and limits of quantification of 0.006-0.021ng/mg with good accuracy and intra- and interday reproducibility. The matrix effect by ion suppression/enhancement was 72-107% for basic drugs and 42-75% for benzodiazepines. Yields of the hair extraction above 90% were determined for 59 drugs or metabolites. The method was applied to hair samples from 30 drug fatalities and from 60 death cases with known therapeutic drug intake at life time. Altogether 212 substances were identified with a frequency per drug of 1-40 (mean 4.2) and per case of 2-33 (mean 10.2), between them 35 illegal drug related substances and 154 therapeutic drugs. Comparison with the data known from case histories and from the analysis of blood, urine and gastric content showed only a low agreement, with many unexpected drugs detected and many reported drugs not detected in hair. Basic drugs and metabolites such as opioides, cocaine, amphetamines, several groups of antidepressants, neuroleptics, beta-blockers or the metamizole metabolite noramidopyrine were found with high frequency whereas acidic and several neutral drugs such as cannabinoids, salicylic acid, furosemide, barbiturates, phenprocoumone or cardiac glycosides could not be detected with sufficient sensitivity, mainly because of the low ion yield of positive ESI for these compounds. The advantage of a comprehensive acquisition of all substances is paid by a lower sensitivity in comparison to targeted screening LC-MS/MS procedures. In conclusion, the procedure of sample preparation and LC-QTOF-MS analysis proved to be a robust and sensitive routine method in which the qualitative screening for a wide variety of toxic substances in hair is combined with the quantitative determination of selected illegal drugs.     

LC-MS/MS-MRM筛选血液中22种有毒生物碱成分

目的建立液相色谱-串联质谱法对血液中的22种常见有毒生物碱成分进行筛选分析。方法血液以丁丙诺菲为内标经液液提取后,用液相色谱-串联质谱仪以电喷雾电离(ESI )、多反应监测(MRM)方式进行分析。结果以化合物的保留时间、两对母离子/子离子对定性,最低检出限为0.1～20ng/mL。结论该方法选择性佳、灵敏度高,适用于法医毒物分析和临床毒物分析中有毒生物碱的分析。     

Desorption electrospray tandem MS (DESI-MSMS) analysis of methyl centralite and ethyl centralite as gunshot residues on skin and other surfaces

Abstract:  A direct and sensitive method for the detection of methyl centralite (MC) and ethyl centralite (EC) as gunshot residues (GSRs) has been developed. This method uses desorption electrospray ionization (DESI)-tandem mass spectrometry and directly desorbs and detects analytes from surfaces without any sampling process. Typical transitions for MC and EC, m/z 241 to m/z 134 and m/z 269 to m/z 148, respectively, were used to improve the assay sensitivity. It has been shown that MC and EC can be detected on various surfaces, with detection limits of 5–70 pg/cm². Interferences, detection time after shooting and the number of times hands were washed after shooting were also evaluated. None of the materials interfered with the results and the detection window for organic GSRs was up to 12 h and hands could be washed at least six times. Further samples were analyzed to confirm the reliability of this method, and showed that it could discriminate shooters from nonshooters. This method should be of significance in forensic science, especially in analyzing GSRs, because of its simplicity, high throughput, and the direct detection of MC and EC on suspects' hands, clothes, and hair.     

Rapid determination of flunitrazepam in alcoholic beverages by desorption electrospray ionization-mass spectrometry

Desorption electrospray ionization-mass spectrometry (DESI-MS), a novel ambient ionization technique, was used in this study for determining flunitrazepam in various alcoholic beverages. Using this technique, no pretreatment of the samples was necessary and identification of the drug was accomplished in individual samples in minutes. In addition, the acquired mass spectra provide the information of the identity of the drink based on the detected characteristic ions from the matrices. This study also demonstrates the capability of DESI-MS to perform quantitative analysis of simulated evidence samples with a limit of quantification of 3μg/mL. Furthermore it has been shown that this method can be used for high-throughput analysis whereby six samples were analyzed in a row within 6 minutes and no observable sample carry-over was noted. DESI-MS shows potential as a rapid, sensitive, and selective technique for forensic analysis of spiked beverages which are typical evidence of drug facilitated sexual assault and robbery cases.     

液相色谱-串联质谱法分析生物检材中的河豚毒素

目的建立血液、尿液以及肝中河豚毒素(tetrodotoxin,TTX)的液相色谱-串联质谱分析方法,并进行方法学验证。方法血液、尿液和肝用1%乙酸甲醇溶液去蛋白后,上清液用固相萃取法净化,LC-MS/MS检测。结果血液、尿液和肝中TTX检出限分别为2ng/mL、2ng/mL和4ng/g。血液和尿液在4～100ng/mL、肝在5～100ng/g的范围内线性关系良好,相关系数r≥0.9973;日内精密度和日间精密度均在12.80%以内;回收率大于47.2%。结论所建方法高效、灵敏、准确,可以为河豚毒素中毒的法医学鉴定、临床诊治以及食品安全的监控提供技术保障。     

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.     

Screening of benzo- and thienodiazepines in urine with Emit ST and thin-layer chromatography within the scope of substance abuse

All 24 Benzo- and Thienodiazepines which are used in drugs in the FRG were added to drug free urine in different concentrations and examined by Emit ST as well as by TLC. In addition the acid hydrolysis products of diazepines were analysed by TLC. A modification of the extraction procedure is described, which shortens analysis time considerably. The detection limits were determined and it will be discussed how both methods, Emit and TLC, are suited for a wide-ranging drug screening program.     

GC-MC法测定血液中丙泊酚

目的 建立血液中丙泊酚的气相色谱-质谱联用(GC-MS)分析方法.方法 血液以2,4-二甲基-6-叔丁基苯酚为内标,用乙醚进行液液萃取,离心后取有机层,水浴下挥干,GC-MS检测.结果 血液中丙泊酚与内标分离良好,在0.02～10 μg/mL范围内线性良好,线性方程为y=0.3136 x-0.0068,相关系数为0.9...     

液相色谱/质谱法检测血液中的艾司佐匹克隆

目的建立手性分离-液相色谱/质谱法,用于分离检测血液中艾司佐匹克隆。方法血液经HLB小柱固相萃取后,采用手性分离柱,用电喷雾正离子模式离子化、多反应监测模式检测艾司佐匹克隆,外标法定量。结果采用本文方法可有效分离佐匹克隆的左旋、右旋异构体,血中艾司佐匹克隆在1～100ng/mL范围内线性关系良好,相关系数为0.996 4,最低检出限为0.8ng/mL,回收率为76%～88%,日内与日间精密度均小于8%。结论本文所建方法简便、快速、分离度好,适用于血液中艾司佐匹克隆的检测。     

The identification of the emulsifier component of emulsion explosives by liquid chromatography-mass spectrometry

ABSTRACT: The widespread availability of emulsion explosives for commercial blasting has inevitably lead to their diversion for criminal misuse. Present techniques for the characterization of emulsion explosives and their residues is generally based on the detection and identification of the oxidizer and the hydrocarbon components. Use of these components is problematic for residue identification because ammonium nitrate, waxes, and oils are relatively common in the urban environment and even their co-detection does not exclude them being sourced from materials other than explosives. The detection of the emulsifier component offers increased evidential value as certain emulsifiers used in explosive formulations are manufactured for that specific use, or have limited environmental distribution. In the current study liquid chromatography-mass spectrometry (LC-MS) was utilized for the characterization of two emulsifiers in common use; ethanolamine adducts of polyisobutylene succinic anhydride and sorbitol mono-oleate (SMO). The LC-MS technique enabled the detection of both emulsifiers in preblast samples; however, only SMO was detected in postblast residues. The analysis of the hydrocarbon component by gas chromatography-mass spectrometry was achieved in the same procedure.