赛丹农药的检验研究

将TLC法、GC/FPD-S法用于赛丹农药的检验研究,检材回收率达到80%,TLC最低检出最4μg,为此类案件的检验提供了科学依据.     

The discrimination potential of ultraviolet-visible spectrophotometry, thin layer chromatography, and Fourier transform infrared spectroscopy for the forensic analysis of black and blue ballpoint inks

The knowledge of the discriminating power of analytical techniques used for the differentiation of writing inks can be useful when interpreting results. Ultraviolet-visible (UV-VIS) spectrophotometry, thin layer chromatography (TLC), and diffuse reflectance Fourier transform infrared spectroscopy (FT-IR) were used to examine a population of 21 black and 12 blue ballpoint writing inks. Based on corroborative results of these methods, the discrimination power for UV-VIS, TLC, and FT-IR was determined to be 100% and 98% for the black and blue inks, respectively. Generally, TLC and UV-VIS can be used to differentiate the colorant components (i.e., dyes and some pigments) found in inks. As FT-IR can be utilized to identify some of the noncolorant components, it was determined to be an excellent complementary technique that can be implemented into an analytical scheme for ink analysis.     

Colchicine Extract Suicidal Lethal Poisoning Confirmation Using High‐Resolution Accurate Mass Spectrometry: A Case Study

A case of suspected acute and lethal intoxication caused by colchicine has been reported. The woman was hospitalized after her suspicion of suicidal poisoning by a rare autumn crocus (Colchicum autumnale). Suspected colchicine poisoning was confirmed using a novel UHPLC method with a modern reversed‐phase stationary phase with a sub 2‐micron superficial porous particle size combined with a QTOF mass spectrometer. Sample preparation procedure included the addition of propiverine as internal standard, protein precipitation using methanol and solid phase extraction. High‐resolution MS only and targeted MS/MS modes are reported for the qualitative analysis and screening of other potential drugs of abuse in blood samples. All Ion MS mode was used for quantitative determination of colchicine afterward. The concentration of colchicine in the blood sample was approximately 41 ng/mL, and more than 200 μg/mL of the plant extract used for the suicide.     

Study of the Behaviors of Gunshot Residues from Spent Cartridges by Headspace Solid‐Phase Microextraction–Gas Chromatographic Techniques

Gunshot residues, produced after shooting activity, have acquired their importance in analysis due to the notoriety of firearms‐related crimes. In this study, solid‐phase microextraction was performed to extract the headspace composition of spent cartridges using 85‐μm polyacrylate fiber at 66°C for 21 min. Organic compounds, that is, naphthalene, 2,6‐dinitrotoluene, 2,4‐dinitrotoluene, diphenylamine, and dibutyl phthalate were detected and analyzed by gas chromatography‐flame ionization detection technique. Evaluation of chromatograms for diphenylamine, dibutyl phthalate, and naphthalene indicates the period after a gunshot was discharged, whether it was 1 days, 2–4 days, <5 days, 10 days, 20 days, or more than 30 days ago. This study revealed the potential effects of environmental factors such as occasional wind blow and direct sunlight on the estimation of time after spent cartridges were discharged. In conclusion, we proposed reliable alternative in analyzing the headspace composition of spent cartridges in a simulated crime scene.     

Investigation of Postmortem Absorption and Redistribution After the Application of a Fentanyl Patch

Fentanyl deaths have increased with availability of transdermal patches. Interpretation of postmortem fentanyl levels may be complicated by postmortem redistribution and absorption of fentanyl from a patch. We applied an unused 100‐μg/h fentanyl patch onto the lower abdomen of a decedent with no premortem fentanyl exposure. Ocular fluid, blood, and urine were collected prior to placement, and the decedent was refrigerated for 23 h. Prior to the autopsy, urine, subcutaneous tissue under the patch, and samples from the same anatomic sites were obtained. We observed no fentanyl in any postpatch placement samples (LOD: 0.1 ng/mL for blood and vitreous fluid, 1.0 ng/mL urine, 2.0 ng/g for tissues). Although we observed no postmortem absorption of fentanyl, this was only a single case; therefore, we recommend that patches be removed after receipt of a cadaver before initiation of an autopsy, with the location of removed patch documented.     

Blowfly Larval Tissues as a Secondary Detector for Determining Paraquat-Related Death in Rabbit Carcass

Paraquat poisoning is commonly associated with suicide or homicide in Malaysia. In a case involving advanced body decomposition, pathological analysis regarding the cause of death may become difficult or almost impossible. Insects serve as common alternative matrix for poison detection in forensic analysis. Paraquat detection via secondary bioaccumulation in fly larvae tissue has never been reported. In this study, tissues from blowfly larvae collected from a rabbit carcass with paraquat poisoning were analyzed for secondary bioaccumulation. Larvae samples were collected and analyzed using liquid–liquid extraction. The detection was performed via reduction of quaternary ammonium presence in paraquat and analyzed using gas chromatography–mass spectrometry (GC-MS) with selected ion monitoring mode (SIM mode). GC-MS showed the elution of reduced paraquat was at retention time 12.8 min. Blowfly larvae tissue has proven useful as a secondary detector in paraquat-related deaths.     

Suicidal Fatality from Azide Ingestion

A 35-year-old man ingested an unknown amount of sodium azide and died within 2 h. The postmortem interval was 3 days. No alcohol or drugs were found in the blood and urine. Azide was derivatized in the peripheral blood, urine, and vitreous fluid with propionic anhydride. A portion of the headspace was injected onto a gas chromatograph with a nitrogen–phosphorus detector. Azide was quantitated in the peripheral blood (1.1 μg/mL), urine (7.5 μg/mL), and vitreous (43 μg/mL). The vitreous appears to be a better fluid for azide screening because of slower degradation.     

Ink Dating Using Thermal Desorption and Gas Chromatography/Mass Spectrometry: Comparison of Results Obtained in Two Laboratories

An ink dating method based on solvent analysis was recently developed using thermal desorption followed by gas chromatography/mass spectrometry (GC/MS) and is currently implemented in several forensic laboratories. The main aims of this work were to implement this method in a new laboratory to evaluate whether results were comparable at three levels: (i) validation criteria, (ii) aging curves, and (iii) results interpretation. While the results were indeed comparable in terms of validation, the method proved to be very sensitive to maintenances. Moreover, the aging curves were influenced by ink composition, as well as storage conditions (particularly when the samples were not stored in “normal” room conditions). Finally, as current interpretation models showed limitations, an alternative model based on slope calculation was proposed. However, in the future, a probabilistic approach may represent a better solution to deal with ink sample inhomogeneity.     

Simultaneous Screening for 45 Poisonous Alkaloids in Blood by LC-MS/MS

Objective To develop a liquid chromatography-tandem mass spectrometry(LC-MS/MS) screening method for 45 poisonous alkaloids in blood. Methods Identification was based on the compound’s retention time and two precursor-to-production transitions. The method involved a liquid-liquid extraction(LLE) followed by LC-MS/MS with multiple-reaction monitoring(MRM). When 1 m L of blood was extracted with diethyl ether at p H=9.2 with SKF525 Aas the internal standard, the target compounds were analyzed with LC-MS/MS in the positive ionization mode. Results The target alkaloids had good linearity(r>0.995 1), both the intra-day precision and inter-day precision being less than 14.77%. The limits of detection ranged from 0.05 to 25 ng/m L in blood. Conclusion The method is selective and sensitive in detecting poisonous alkaloids with a total running time of 12 minutes; therefore it was successfully applied to some actual cases of suspected alkaloids poisoning.     

Nails as useful materials for detection of methamphetamine or amphetamine abuse

Methamphetamine and amphetamine could be demonstrated in nail clippings obtained from methamphetamine users by sensitive gas chromatography/chemical ionization mass spectrometry with N-methylbenzylamine as an internal standard. The methamphetamine levels in fingernails were comparable to those in hair. Both stimulants were more concentrated in toenails than in fingernails. The detection of methamphetamine and amphetamine in nails provides an alternative informatian to that in hair on their past abuse.