生物检材中苯丙胺类兴奋剂和氯胺酮的LC-MS/MS分析

目的建立生物检材中苯丙胺类兴奋剂和氯胺酮的液相色谱-串联质谱(LC-MS/MS)分析方法。方法生物检材包括血液、尿液和毛发,采用稀释法和液液提取的前处理方法,应用两个不同的液相柱,优化LC-MS/MS分析方法,并考察了血液和尿液基质的离子抑制作用。结果同时分析苯丙胺和MDA,液相1在3m in内完成,液相2可用于确认分析或复杂基质分离。尿液稀释法检材用量少,前处理简便快速。毛发中苯丙胺类兴奋剂和氯胺酮的最低检测限(LOD)为0.005~0.05ng/mg。对送检案例检材产妇头发和胎毛进行苯丙胺类兴奋剂和氯胺酮的分析。结论本方法可用于生物检材中苯丙胺类兴奋剂和氯胺酮的同时分析,血、尿等生物检材的离子抑制作用是影响本方法灵敏度的主要原因。     

布比卡因在生物样品中的分解动力学

目的研究布比卡因麻醉致死犬的脑组织、血液和尿液在不同保存条件下的布比卡因分解动力学。方法将布比卡因蛛网膜下腔麻醉致死犬的脑组织、血液和尿液分三等份分别置于20℃、4℃和-20℃条件下保存,于死后不同时间点用气相色谱仪检测布比卡因的含量,WinNonlin软件拟合分解动力学方程,计算不同保存条件下脑组织、血液和尿液中布比卡因的分解半衰期。结果脑组织、血液和尿液中布比卡因的分解动力学均符合一级动力学过程,可用lgC=lgCo-kt/2.303表示,式中k为一级分解速率常数。结论 20℃、4℃和-20℃条件下保存的脑组织、血液和尿液中布比卡因均可发生分解,20℃保存时分解较快,其次为4℃,-20℃保存时分解最慢。     

用串联质谱法提高毒鼠强的检测灵敏度

目的建立一种能避免生物样品中杂质的干扰,提高毒鼠强检测灵敏度的方法。方法应用串联质谱法,对生物样品中的毒鼠强进行检验研究。结果在样品无需净化的情况下,以m/z240为母离子,当激活电压在0.8V左右时,毒鼠强二次电离的离子碎片适中,质谱谱图清晰;此时进样量为1.0ng的毒鼠强,其信噪比(s/n)为87,经与全扫描质谱法进行比较灵敏度大为提高。结论该方法能有效提高毒鼠强检测灵敏度,适用于同类案件检验。     

Gas chromatographic-mass spectrometric analysis of buflomedil hydrochloride in biological samples after acute intoxication.

Two cases of acute intoxication of buflomedil hydrochloride are reported. The analysis of this compound was performed by an Extrelut extraction followed by a gas chromatographic-mass spectrometric determination. Analytical parameters of linearity, reproducibility and specificity were satisfactory.     

Disposition of quetiapine in biological specimens from postmortem cases

Quetiapine is a new atypical antipsychotic that was approved in 1997 by the U.S. Food and Drug Administration for the treatment of schizophrenia. It possesses a high affinity for 5-HT2 receptors and a low affinity for D1 and D2 dopamine receptors. Because quetiapine has only been released recently to the U.S. market, little information exists regarding therapeutic, toxic, and lethal concentrations. This study reports the detection of quetiapine in 13 postmortem cases. Following a basic liquid-liquid extraction, quetiapine was identified and quantitated by capillary gas chromatography with nitrogen phosphorus detection. Confirmation was accomplished by full scan electron impact gas chromatography/mass spectrometry. Heart blood quetiapine concentrations ranged from 0.07 to 18.37 mg/L (N = 12, mean +/- SD = 3.42 +/- 5.67, median 0.62) and femoral blood concentrations ranged from 0.06 to 19.25 mg/L (N = 10. mean +/- SD = 3.89 +/- 6.12, median 0.81). The average heart blood/femoral blood ratio was 1.31 (range 0.55 to 2.57, N = 10). Urine, bile, and gastric contents were assayed in all cases in which they were submitted. In three cases, the cause of death was determined to be quetiapine toxicity. In these cases heart blood concentrations ranged from 0.72 to 18.37 mg/L (N = 3). These data may provide a basis for establishing levels associated with quetiapine toxicity as well as therapeutic concentrations in postmortem specimens.     

The detection of cocaine in hair specimens using micro-plate enzyme immunoassay.

The analysis of hair for drugs of abuse is becoming increasingly popular and is under consideration by the Division of Health and Human Services as a possible alternative or adjunct to urinalysis in workplace programs. The detection of cocaine in human hair using a commercially available micro-plate enzyme immunoassay is described for the first time. Sample size and incubation time were the major variables in the optimization of the method. In order to validate the procedure, the method was applied to 105 consecutive hair samples routinely received into our laboratory. The samples were simultaneously analyzed by the Micro-Plate immunoassay (EIA), as well as our current fluorescence polarization immunoassay (FPIA) procedure and gas chromatography-mass spectrometry (GC/MS). The sensitivity of the EIA and FPIA assays were 75% and 67.8% respectively; specificity 97.4% and 80.5% respectively; and efficiency 91.4 and 77.1% respectively. The Micro-Plate EIA was shown to be a valid alternative to other immunoassay screening methods for the detection of cocaine in hair by demonstrating increased sensitivity, specificity and efficiency over our current technique.     

Disposition of citalopram in biological specimens from postmortem cases

Citalopram is a bicyclic phthalate compound approved in 1998 by the U.S. Food and Drug Administration for the treatment of depression. It is a highly selective serotonin reuptake inhibitor that appears to have little effect on noradrenaline or dopamine reuptake. Since this drug has only recently been released on the U.S. market, information regarding therapeutic, toxic, and lethal concentrations is sparse. This study reports the detection of citalopram in 22 postmortem cases. Citalopram was identified and quantitated by capillary column gas chromatography with nitrogen phosphorus detection after basic liquid-liquid extraction. Confirmation was achieved by full scan electron impact gas chromatography/mass spectrometry. In the 22 cases studied, heart blood citalopram concentrations ranged from 0.09 to 1.64 mg/L (n = 22, mean +/- SD = 0.51+/-0.43, median = 0.34); femoral blood concentrations ranged from 0.09 to 0.76 mg/L (n = 14, mean +/- SD = 0.34+/-0.23, median = 0.28); and urine concentrations ranged from 0.05 to 276.00 mg/L (n = 13). Liver was analyzed in three cases with citalopram concentrations ranging from 2.22 to 8.08 mg/kg. The average heart blood/femoral blood ratio was 1.26 (range 0.75 to 1.98, n = 14). In each case, the cause of death was not considered to be related to citalopram toxicity. These data may therefore provide a basis for establishing post mortem citalopram concentrations following therapeutic doses.     

Gas-chromatographic detection of acetic acid in cadaveric specimens

Data on Liquid Gas Chromatographic method for detection of the acetic acid after etherification in the cadaveric organs are presented. The results of quantitative acetic acid determination in the cadaveric organs by LGC method after etherification are influenced upon by its "background" values. Acetic acid concentration in the cadaveric organs of subjects who died from the cause other than acetic acid poisoning is within the limits 0.1-0.21 g (mean value 0.17 g) in 100 g of the stomach and 0.07-0.13 g (mean value 0.11 g) in 100 g of the liver. Method may be used in expert practice to determine acetic acid poisoning with due regard for its "background" concentrations in the organs.     

A fatal dichlorvos poisoning: concentrations in biological specimens

Abstract:  A 54-year-old man was found dead with a bottle containing a brownish fluid near him. A toxicological screening was carried out in blood, urine, and stomach content. Only dichlorvos (2,2 dichlorovinyl O-O dimethylphosphate or DDVP) was found. A simple and rapid method, using DDVP-D₆ as an internal standard, was developed for the determination of DDVP by gas chromatography/mass spectrometry (GC/MS). The method was linear from 1 to 10 mg/L. Intraday and interday precisions were all <15%. DDVP concentration in cardiac blood was approximately four times higher than in peripheral blood. A high concentration was found in the heart showing a cardiac tropism of DDVP, kidney and lung concentrations being much lower. No DDVP was found in liver. DDVP stomach content was 38 g. The amount presumed ingested was 82 g, c . 1000 mg/kg of body. The oral LD₅₀ for DDVP ranges between 20 and 1090 mg/kg in animals but is not known for humans.     

A preliminary study of the analysis of explosives using packed-column supercritical fluid chromatography with atmospheric pressure chemical ionisation mass spectrometric detection

A packed-column supercritical fluid chromatographic (SFC) separation of explosive compounds hyphenated to atmospheric pressure chemical ionisation (APCI) mass spectrometric (MS) detection has been developed. Nitroaromatics, nitramines and nitrate esters can be resolved and identified, with theoretical limits of detection of approximately 100 ng on column. This represents a development over previously described gas chromatography–thermal energy analysis (GC–TEA), gas chromatography– electron capture detection (GC–ECD) and SFC methods for the analysis of explosives due to the molecular identification afforded by the mass spectrometry. Explosives in the combinations expected in commercially available mixtures can be separated and identified. A successful application to a laboratory trial simulating casework is described.     

The detection of nifedipine in biological materials

The objective of the present study was to find optimal conditions for the isolation of nifedipine from biological materials by ethylacetate. It was shown that nifedipine can be purified from co-extracted substances of the biological material on a Silasorb C-18 column with the size of the particles 30 microns. The authors propose to use thin-layer chromatography, IR spectrophotometry, and reverse-phase high performance liquid chromatography for the identification and quantitative determination of nifedipine extracted from cadaveric liver samples.     

Liquid chromatography-mass spectrometric and liquid chromatography-tandem mass spectrometric determination of hallucinogenic indoles psilocin and psilocybin in "magic mushroom" samples

Accurate and sensitive analytical methods for psilocin (PC) and psilocybin (PB), tryptamine-type hallucinogens contained in "magic mushrooms," were investigated using liquid chromatography-mass spectrometry (LC-MS) and liquid chromatography-tandem mass spectrometry (LC-MS-MS). The chromatographic separation on an ODS column and mass spectral information gave complete discrimination between PC and PB without derivatization. The mass spectrometric detection had a high sensitivity, and the tandem mass spectrometric detection provided more specificity and accuracy, as well as high sensitivity. The detection limits ranged from 1 to 25 pg by LC-MS in the selected ion monitoring mode, and the intra- and inter-day coefficients of variation were estimated to be 4.21-5.93% by LC-MS-MS in the selected reaction monitoring mode. By applying the present LC-MS-MS technique to four real samples, the contents of PC and PB were found to vary over a wide range (0.60-1.4 and 0.18-3.8 mg/g dry wt. for PC and PB, respectively) between samples.     

Secondary ion mass spectrometric characterization of nail polishes and paint surfaces

A variety of paint and fingernail polish samples, which were visually similar, but had different chemical compositions and formulations, was analyzed using quadrupole static secondary ion mass spectrometry (SIMS). Coating distinction was easily achieved in many cases because of the presence of dominant ions derived from the components of the coating, which could be observed in the SIMS spectra. In other instances, coating distinction was difficult within a product line because of spectral complexity; for this reason and because of the large numbers of spectra generated in this study, multivariate statistical techniques were employed, which allowed the meaningful classification and comparison of spectra. Partial Least Squares (PLS) and Principal Component Analysis (PCA) were applied to quadrupole SIMS data. PCA showed distinct spectral differences between most spectral groups, and also emphasized the reproducibility of the SIMS spectra. When using PLS analysis, reasonably accurate coating identification was achieved with the data. Overall, the PLS model is more than 90% effective in identifying the spectrum of a particular coating, and nearly 100% effective at telling which coating components represented in the PLS models are not present in a spectrum. The level of spectral variation caused by sample bombardment in the SIMS analysis was investigated using Fourier transform infrared spectroscopy (FT-IR) and quadrupole static SIMS. Changes in the FT-IR spectra were observed and were most likely a result of a number of factors involving the static SIMS analysis. However, the bulk of the sample is unaltered and may be used for further testing.     

The detection of hydromorphone in urine specimens with high morphine concentrations

A previous study suggested that small amounts of morphine are metabolically converted to hydromorphone. In the present study, morphine positive urine specimens obtained from a postmortem laboratory and a random urinalysis program were tested for morphine, codeine, hydromorphone, hydrocodone, oxymorphone, and oxycodone to assess the possibility that small amounts of hydromorphone are produced from the metabolism of morphine. The opioids were analyzed by gas chromatography-mass spectrometry as their respective trimethylsilyl derivatives following solid phase extraction. The limit of detection for hydromorphone was 5 ng/mL. A total of 73 morphine positive urine specimens were analyzed, with morphine concentrations ranging from 131 to 297,000 ng/mL. Hydromorphone was present at a concentration > or =5 ng/mL in 36 of these specimens at concentrations ranging from 0.02% to 12% of the morphine concentration. Hydrocodone was not detected in these specimens at the assay detection limit of 25 ng/mL. These results support earlier work suggesting that the detection of hydromorphone in urine specimens does not necessarily mean that exogenous hydromorphone or hydrocodone was used.     

Evaluation of desorption/ionization mass spectrometric methods in the forensic applications of the analysis of inks on paper.

Fast atom bombardment and laser desorption mass spectrometry (LDMS) provide molecular level information concerning an ink's composition. Two ink-jet printer inks, Ink A containing the cationic dye Methyl Violet 2B, and Ink B containing the anionic dye, Solvent Black, were studied. Both positive and negative ion detection modes of the mass spectrometer were used. LD may be used for the analysis of inks on paper. Once on paper, the ink's solvent system has evaporated, leaving mainly the dyes behind, which are detected using LDMS. An ink fades with time, indicating that the dyes are degrading. Preliminary results from an accelerated aging study of ballpoint pen ink using UV irradiation confirm that dye degradation products are formed. The degradation chemistry follows an oxidative demethylation process for which all products formed are detected using LDMS. Results suggest that LDMS may be developed to determine the relative age of inks.     

Analysis of buprenorphine in urine specimens.

The simultaneous determination of buprenorphine (Temgesic) and its major metabolite, N-desalkylbuprenorphine, in urine samples has been studied. By using reversed-phase high-performance liquid chromatography (HPLC) with electrochemical detection, therapeutic concentrations of unconjugated buprenorphine down to 0.2 ng/mL, and 0.15 ng/mL for the metabolite, can be detected in urine samples. This method has been applied to a variety of urine samples from drug users. The possible analytical interference from several other regulated drugs has been studied. The results were also compared with those obtained from a commercial radioimmunoassay (RIA) test. This test is only capable of detecting buprenorphine concentrations higher than 1 ng/mL.     

Screening and detection of amphetamine derivatives in biological stains

A GC/MS-method is described for the screening, detection and determination of the commonly used drugs amphetamine, methamphetamine, MDA, MDMA and MBDB in small blood samples and bloodstains using solid phase SPE columns and a pipetting robot (Gilson Aspec XL). The detection limits are in the order of 0.03 to 0.08 microgram/L and the correlation factors between 0.9982 and 0.9998. Furthermore the stability was investigated covering a storage time of 64 days. The method has proven useful in forensic cases with only small sample volumes or bloodstains.