Comparison of motor oils using high-temperature gas chromatography-mass spectrometry

The analysis of motor oils has wide applications in the forensic science field from comparing lubricants transferred between an automobile and a victim or crime scene to differentiating the compositions of plastic explosives. In this study, 40 unused motor oils were analyzed and compared by high-temperature gas chromatography-mass spectrometry to determine the potential for oil individualization. Oil samples were also collected from the crankcase dipsticks of 30 cars. Twenty-six of these oils could be differentiated from each other based on visual comparisons of the unresolved envelope (baseline rise due to incomplete separation) and the resolved hydrocarbons in the raw total ion chromatograms (TICs) and smoothed TIC data. Four of these oils were analyzed as unknowns and were correctly related to the corresponding vehicle. The use of extracted ion profiles (EIPs) was explored as a means to further discriminate between the indistinct samples based on the polycyclic aromatic hydrocarbon (PAH) content. The research discussed in this paper demonstrated that differentiation of motor oils was possible by examining the TIC, smoothed TIC, and EIP data.     

Comparison of gasolines using gas chromatography-mass spectrometry and target ion response

Gas chromatography-mass spectrometry was used to compare gasoline samples obtained from different sources based on the difference in amounts of certain components found in the headspace of gasoline using target response data. Many suspected arson cases involve comparing an ignitable liquid extracted from fire debris to a liquid found in a suspect's possession to determine if they could have had a common source. Various component ratios are proposed for determining if an unevaporated gasoline sample could have originated from the same source as an evaporated gasoline extracted from fire debris. Fifty and 75% evaporated gasoline samples were both found to contain similar ratios of certain components when compared with its unevaporated source gasoline. The results of the comparisons in this study demonstrate that for cases involving gasoline that has been evaporated up to 50% and extracted from pine, it is possible to eliminate comparison samples as originating from the same source. The results of the 75% comparisons suggest it may be possible to apply the same type of comparison to cases involving 75% evaporated gasoline.     

Determination of clofelin in blood by gas chromatography-mass spectrometry

Gas chromatography--mass spectrometry is proposed for measuring clofelin (clonidine) in cadaveric blood. The method includes liquid-liquid extraction of clonidine from the blood, derivatization with pentafluorobenzyl bromide, and subsequent purification of derivatization products before chromatographic analysis. The range of 0.5-50.0 ng/ml covers therapeutic and lethal concentrations of clonidine in the blood. The method was tried on expert material in Chelyabinsk Regional Bureau of Forensic Medical Expert Evaluations and can be used in forensic chemical and toxicological analysis.     

血液中丙泊酚的GC-MS分析

目的应用气质联用仪(GC-MS),建立快速、灵敏地分析血液中丙泊酚的定性定量方法。方法血液1mL,加入内标,采用液液提取方法处理,GC-MS选择离子(SIM)模式测定。结果在0.1～10μg/mL范围呈良好的线性关系,相关系数R2为0.9931,最低检测限(LOD)为0.05μg/mL。结论所建立的方法简便、快速、特异性强、灵敏度高,可满足法庭毒物分析和临床毒物分析的需要。     

Identification of impurities and the statistical classification of methamphetamine using headspace solid phase microextraction and gas chromatography-mass spectrometry

The profiling of impurities in methamphetamine (MA) using headspace solid phase microextraction (HS-SPME) and gas chromatography-mass spectrometry (GC-MS) is described. The extraction of the impurities with an SPME fiber was examined under varying conditions. Optimal chromatograms were obtained when a 50 mg MA sample at 85 degrees C for 30 min was extracted using a fiber coated with divinylbenzene/carboxen/polydimethylsiloxane. MA samples from nine different origins were analyzed under optimized extraction conditions. Compounds related to MA such as benzaldehyde, benzyl alcohol, amphetamine, benzyl methyl ketone, cis- and trans-1,2-dimethyl-3-phenylaziridine, dimethylamphetamine, N-acetylamphetamine, N-acetylmethamphetamine and N-formylmethamphetamine were detected in the chromatograms. Trace amounts of ethanol, diethyl ether and acetic acid were also detected in some of the chromatograms. The numbers and intensities of the peaks detected were different, depending on the sample. After the areas of the eight principal peaks were converted to their square root and logarithm, similarities among the samples were evaluated by Euclidian distance, cosine distance and correlation coefficient. The results showed that a combination of logarithmic conversion and cosine distance was the most suitable for discriminating and classifying the samples. HS-SPME/GC-MS is a simple and effective method for the extraction and identification of impurities. The present method, in combination with an appropriate statistical analysis, would be useful for developing a profile of impurities in MA.     

A validated method for the analysis of cannabinoids in post-mortem blood using liquid-liquid extraction and two-dimensional gas chromatography-mass spectrometry

Phenazepam is a long-acting benzodiazepine that, unlike other benzodiazepines, is currently not scheduled as a narcotic in Finland, most other European countries or the USA. It is used as an anxiolytic, sedative-hypnotic and anti-epileptic, mainly in Russia. In Finland, as well as in some other countries, an increase in the unauthorized use of phenazepam has been observed in recent years. In the one year period between July 1, 2010 and June 30, 2011 the prevalence of phenazepam in Finland was assessed among drivers apprehended for driving under the influence of drugs (DUID), in medico-legal autopsy cases and in police confiscations of illicit drugs. In DUID cases an LC-MS/MS method preceded by solid phase extraction was used for the determination of phenazepam. In the post-mortem investigations the sample preparation consisted of liquid-liquid extraction followed by derivatization and the determination was carried out by GC-MS. The police confiscations were analysed by GC-MS. There were 141 positive phenazepam cases among apprehended drivers, representing approximately 3.5% of all confirmed drug cases (n=4007) in this time period. The median (range) phenazepam blood concentration in DUID cases was 0.061 mg/L (0.004-3.600 mg/L). The median phenazepam concentration in cases with no concomitant stimulant use was significantly higher than the overall median concentration. Phenazepam was found in 17 medico-legal autopsy cases and the median (range) blood concentration was 0.048 mg/L (0.007-1.600 mg/L). Phenazepam was not considered by the medico-legal team to be the sole cause of death in any of the cases, the majority of them being accidental opiod overdoses. There were 26 seizures of phenazepam by the Police in the time period studied, some of the batches consisted of a mixture of phenazepam and stimulant designer drugs. The data show that phenazepam abuse is a widespread phenomenon in Finland. A typical user was a male multi-drug user in his 30s. The concentration range of phenazepam among apprehended drivers and medico-legal autopsy cases was wide and the drug was usually found along with other psychoactive drugs. Therefore, although it seems likely that phenazepam contributed to impairment of driving in some DUID cases, the extent of its effect remains unclear and further studies are needed to define the concentrations causing impairment and toxicity.     

血中精神药物的气相色谱-质谱分析

目的建立人血中精神药物的GC-MS测定方法。方法样品在pH12条件下用乙醚萃取,SKF_525A为内标。以DB-5MS石英毛细管柱、EI源、不分流进样测定人血中四种精神药物。结果人血中四种精神药物与内标物分离良好,血药浓度在0.2-1.0μg,／ml范围内呈线性关系,R2≥0.9728,最低检出限为0.01μg(S／N≥3),血中精神药物的最低检出浓度为0.05μg／ml(S／N≥3),提取率72.5％～89.3％,RSD≤5.17％。四种精神药物日内差RSD≤3.7％(n=5)。结论本法可用于精神药物的血药浓度监测。     

Differentiation of ballpoint pen inks by thermodesorption and gas chromatography-mass spectrometry

Differentiation and classification of ink entries with dated samples of a reference collection are important aspects in the examination of questioned documents. Classification of writing inks is presently achieved by analysis of dyes and colorants contained in the ink. This technique has its limitations in newly developed ink formulations with identical dye composition but differing in their solvents and binder resins. This paper introduces a method for the determination of solvents and binder resins of an ink sample directly from paper without sample preparation. This aim is accomplished by thermodesorption of the sample followed by gas chromatography/mass spectroscopy. The method was tested on numerous samples of ballpoint pen inks, which were subsequently grouped into several solvent and resin subgroups. A case study shows the applicability of the newly developed method.     

Detection of the calcium antagonist nicardipine and its metabolites by gas chromatography-mass spectrometry

An 89-year-old male patient, hospitalized with Parkinson's syndrome, suddenly died shortly after an intravenous drug injection. The conditions indicated that an overdose of nicardipine (1.3 mg/(mlkg)) may be given to the patient. At the autopsy, no pathological changes were noted. With a capillary gas chromatograph with mass spectrometer (GC-MS), nicardipine (4.97 microg/ml) and its pyridine metabolite (M-5, 5.0 microg/ml) were detected in the heart blood of the deceased. This result indicated that an overdose of intravenous nicardipine caused a sudden death of a patient in a poor condition.     

Highly sensitive analysis of methamphetamine and amphetamine in human whole blood using headspace solid-phase microextraction and gas chromatography-mass spectrometry

A simple and highly sensitive method for analysis of derivatized methamphetamine (MA) and amphetamine (AM) in whole blood was developed using headspace solid-phase microextraction (HS-SPME) and gas chromatography-mass spectrometry electron impact ionization selected ion monitoring (GC-MS-EI-SIM). A whole blood sample, deuterated-MA (d(5)-MA), as an internal standard (IS), tri-n-propylamine and pentafluorobenzyl bromide were placed in a vial. The vial was heated and stirred at 90 degrees C for 30min. Then the extraction fiber of the SPME was exposed at 90 degrees C for 30min in the headspace of the vial while being stirred. The derivatives adsorbed on the fiber were desorbed by exposing the fiber in the injection port of a GC-MS. The calibration curves showed linearity in the range of 0.5-1000ng/g for both MA and AM. The time for analysis was about 80min per sample. In addition, this proposed method was applied to two autopsy cases where MA ingestion was suspected. In one case, MA and AM concentrations in the mixed left and right heart blood were 165 and 36.9ng/g, respectively. In the other case, MA and AM concentrations were 1.79 and 0.119 microg/g in the left heart blood, and 1.27 and 0.074 microg/g in the right heart blood, respectively.     

Validation of a method to detect cocaine and its metabolites in nails by gas chromatography-mass spectrometry

The objective of the present work was to compare previously published methods and provide validation data to detect simultaneously cocaine (COC), benzoylecgonine (BE) and norcocaine (NCOC) in nail. Finger and toenail samples (5mg) were cut in very small pieces and submitted to an initial procedure for external decontamination. Methanol (3 ml) was used to release analytes from the matrix. A cleanup step was performed simultaneously by solid-phase extraction (SPE) and the residue was derivatized with pentafluoropropionic anhydride/pentafluoropropanol (PFPA/PFP). Gas chromatography-mass spectrometry (GC-MS) was used to detect the analytes in selected ion monitoring mode (SIM). Confidence parameters of validation of the method were: recovery, intra- and inter-assay precision, as well as limit of detection (LOD) of the analytes. The limits of detection were: 3.5 ng/mg for NCOC and 3.0 ng/mg for COC and BE. Good intra-assay precision was observed for all detected substances (coefficient of variation (CV)<11%). The inter-assay precision for norcocaine and benzoylecgonine were <4%. For intra- and inter-assay precision deuterated internal standards were used. Toenail and fingernail samples from eight declared cocaine users were submitted to the validated method.     

The determination of clozapine in blood and urine by gas chromatography-mass spectrometry]

A method for measuring closapine in the blood and urine by gas chromatography-mass spectrometry as a trifluoroacetic derivative is proposed. The threshold level for closapine detection is 25 ng/ml in the blood and 30 ng/ml in the urine. Calibration curves are linear in the range 0.025-5 mcg/ml for the blood and 0.03-50 mcg/ml for the urine. The method can be used in forensic chemical and clinical toxicological analysis.     

Determination of elemental sulfur in explosives and explosive residues by gas chromatography-mass spectrometry

A new method for the positive identification of elemental sulfur in explosives and explosive residues is developed. Following a carbon disulfide wash of explosives or explosive residues, a sample of the extracted material is injected onto a gas chromatography (GC) column, then analyzed via mass-selective (MS) detection. A positive identification of elemental sulfur is based on both retention time and fragmentation pattern. The GC-MS method is demonstrated to be useful in detecting and positively identifying elemental sulfur from both burned and unburned explosive mixtures. With a detection limit of 2.5 ng (2.5 x 10(-9) grams) of elemental sulfur on the column, it is shown to be 400 times more sensitive than the presumptive chemical color test that is currently the method employed for detection of small amounts of sulfur.     

固相微萃取-气相色谱质谱法测定血浆中的氯氮平浓度

目的建立固相微萃取-气相色谱质谱法测定人血浆中氯氮平浓度的方法。方法以固相微萃取法提取血浆中的氯氮平,萃取头为100μm聚二甲基硅氧烷,洛沙平作内标,用气相色谱质谱选择离子法进行检测。结果本文建立的方法在5~2000 ng/ml浓度范围内呈线性关系,检测限为0.1 ng/ml(信噪比>3),低、中、高浓度(100、500、1000 ng/ml)平均相对回收率分别为98.6%、94.6%和94.6%,日内、日间RSD分别小于7.4%和7.1%。结论本文建立的固相微萃取-气相色谱质谱法灵敏度高、准确度好、操作简便,适用于氯氮平急性中毒案件的检测。     

Quantitative analysis of tropane alkaloids in biological materials by gas chromatography-mass spectrometry

A simple and rapid method for quantitation of tropane alkaloids in biological materials has been developed using an Extrelut column with gas chromatography-mass spectrometry (GC-MS). Biological materials (serum and urine) were mixed with a borate buffer and then applied to an Extrelut column. The adsorbed tropane alkaloids were eluted with dichloromethane before a GC-MS analysis. Atropine-d(3) was used as an internal standard. The extracted tropane alkaloids were converted to trimethylsilyl derivatives prior to GC analysis, to improve the instability of tropane alkaloids from heating and the property of them for a GC column. The recoveries of the compounds, which had been spiked to biological materials, were more than 80%. The GC separation of the derivatives from endogenous impurities was generally satisfactory with the use of a semi-polar capillary column. Tropane alkaloids showed excellent linearity in the range of 10-5000 ng/ml and the limit of detection was 5.0 ng/ml for biological materials. The present method is simple and more rapid than those previously reported, and was applied to a poisoning case. It is useful for the routine analysis of tropane alkaloids in cases of suspected tropane alkaloids poisoning.     

Identification and quantification of p-hydroxyethylamphetamine as a novel metabolite of ethylamphetamine in rat by gas chromatography-mass spectrometry

Ethylamphetamine and two major metabolites in urine, obtained after intraperitoneal administration of the drug to rats, have been isolated by gas chromatography-mass spectrometry. We have also synthesized an authentic sample of p-hydroxy-N-ethylamphetamine by a simple method. In rat, the metabolic pathway of ethylamphetamine is similar to that of amphetamine and methylamphetamine according to quantitative analysis of the major metabolites using a selected ion monitoring (SIM) method.     

Characterization of ballpoint pen inks by thermal and desorption and gas chromatography-mass spectrometry

The characterization of ink on paper is of importance for dating and comparing questioned ink entries in forensic document examination. Inks are commonly characterized by their colorant profile that is identified by well-established analytical methods. Numerous ink formulations show identical colorant profiles, though. In order to differentiate inks that are not distinguishable by colorant analysis, a method for the characterization of colorless ink ingredients, namely binders, solvents and additives is necessary. In this paper, we propose a technique for the analysis of colorless compounds in ballpoint inks using direct thermal desorption of the ink on paper followed by chemical analysis of the desorbed volatile compounds by gas chromatography-mass spectrometry. As compared to liquid extraction and subsequent analysis of the extracts, the technique avoids possible contamination risks. Sensitivity is very high due to the enrichment of volatile components by thermal desorption. Even from old samples, the chromatograms obtained by the method enable the determination of binder polymers, solvents and additives. Pure binders as used by ink manufacturers were analyzed for unambiguous assignment of analytical results to specific polymers. To prove the practical applicability, we analyzed 121 ballpoint pens, not all having the same colorant profile, and grouped the pens into resin and solvent categories.     

The development and application of a rapid gas chromatography-mass spectrometry method to monitor buprenorphine withdrawal protocols

There are several drug therapies that can be used to treat opiate abuse. One such treatment that is currently gaining wide acceptance is the use of the combined agonist/antagonist drug buprenorphine. As with all long-term treatments, there is a potential for compliance issues to arise, which establishes the need for a technique to facilitate the monitoring of individuals prescribed buprenorphine. One such method has been developed and applied to the routine monitoring of buprenorphine and its primary metabolite in urine. The method was found to be sensitive (limits of detection of 1.0 ng/mL for both buprenorphine and norbuprenorphine), reproducible and linear up to 2000 ng/mL. This article describes the application of this method to the analysis of specimens collected from subjects prescribed a reducing low-dose buprenorphine regimen (10.0-0.4 mg per day) for acute opiate detoxification. A significant relationship between the daily dose and the mean creatinine-corrected concentration of buprenorphine in the urine was observed, together with a relatively stable relationship between the ratio of the urinary concentrations of norbuprenorphine to buprenorphine across the dose range studied.     

Solid-phase microextraction for the determination of cocaine and cocaethylene in human hair by gas chromatography-mass spectrometry

A method for the simultaneous determination of cocaine (COC) and cocaethylene (CE) in human hair was developed, using solid-phase microextraction (SPME) and gas chromatography-mass spectrometry (GC-MS) as analytical technique to identify and quantify the drugs. Selected ion monitoring (SIM) mode was used to obtain higher sensitivity. The deuterated-labeled analogues were used as internal standards. The detector response was linear for the drugs studied over the range 0.4-15 ng/mg, with correlation coefficients higher than 0.995. The coefficients of variation oscillated between 0.65% and 14.18% and the accuracy was in the range from 0.73% to 11.20%. The limits of quantitation and detection were found to be acceptable. Finally, this method was applied to 15 hair samples from cocaine users, obtaining positive results in all cases. The mean concentrations were 5.39 ng/mg (range: 0.43-8.98 ng/mg) for cocaine and 1.11 ng/mg (range: 0.42-2.23 ng/mg) for cocaethylene.     

Impurity profiling of ecstasy tablets seized in Hong Kong by gas chromatography-mass spectrometry

In Hong Kong, ecstasy tablets are more commonly known as "Fing Tau Yuen", literally meaning "Shake Head Pills". The tablets contain mainly amphetamine-type stimulants (ATS) including 3,4-methylenedioxymethamphetamine (MDMA), 3,4-methylenedioxyamphetamine (MDA), methamphetamine (MA) and/or ketamine. Adulterant such as caffeine was also detected in the tablets. This paper reports a study on the impurity profiles of ecstasy tablets from 89 seizures in Hong Kong from 2002 to early 2004. Tablet samples were extracted by diethyl ether under alkaline condition and then analyzed by gas GC-MS. The chromatograms obtained were compared. A total of 19 identified impurities were selected as markers for impurity profiling. They are different precursors, intermediates and by-products. The data matrices were examined by hierarchical cluster analysis (HCA), and then the ecstasy tablets were classified into different groups. Cluster analysis of ecstasy tablets is shown to be capable of providing intelligence on clandestine laboratory networks.