Application of photoluminescent CdS/PAMAM nanocomposites in fingerprint detection

Uniform and well-dispersed photoluminescent semiconductor CdS (cadmium sulfide) QDs (quantum dots) were in situ prepared inside Generation 4.0-NH(2) PAMAM (polyamidoamine) dendrimers in methanol, methanol and water mixed solutions of volume ratio 1:9, respectively. The prepared solutions containing photoluminescent semiconductor CdS QDs were utilized for detection of cyanoacrylate ester fumed fingerprints on tinfoil. The results show that fumed latent fingerprints treated with prepared CdS/PAMAM nanocomposites in methanol, 1:9 methanol:water mixed solutions emit pale yellow-green and orange luminescence respectively under ultraviolet excitation of 365 nm from an UV LED. Fumed fingerprints were successfully detected with good resolving rate and the mechanism was studied in detail.     

Diimide-enhanced fingerprint detection with photoluminescent CdS/dendrimer nanocomposites

The chemical development of latent fingerprints by nanocomposites that involve photoluminescent cadmium sulfide nanoparticle aggregates with Starburst dendrimer is demonstrated. The dendrimer bonds to fingerprint residue via its terminal functional groups. When these are amino groups (generation 4 dendrimer), the binding is enhanced by fingerprint pre-treatment with diimide. The diimide converts carboxylic acid moieties of the fingerprint residue to esters that then react with the dendrimer amino groups to form amide linkages. The cadmium sulfide/generation 4 dendrimer development of fingerprints is enhanced by elevated temperature also. Finally, fingerprint development with carboxylate-functionalized cadmium sulfide/generation 3.5 dendrimer nanocomposites is examined. Here, diimide treatment of the dendrimer itself aids the subsequent fingerprint labeling, which involves amino acid of the figerprint residue. Nanocomposite fingerprint detection is compatible with time-resolved imaging for background fluorescence elimination.     

Investigation into the temporal stability of aqueous standard solutions of psilocin and psilocybin using high performance liquid chromatography.

This paper reports an investigation into the temporal stability of aqueous solutions of psilocin and psilocybin reference drug standards over a period of fourteen days. This study was performed using high performance liquid chromatography utilising a (95:5% v/v) methanol: 10 mM ammonium formate, pH 3.5 mobile phase and absorption detection at 269 nm. It was found that the exclusion of light significantly prolonged the useful life of standards, with aqueous solutions of both psilocin and psilocybin being stable over a period of seven days.     

同时裂解甲基化气相色谱法快速鉴别人体脂肪及动植物油脂

采用同时裂解甲基化气相色谱法（SPM－GC），首次分析人体脂肪，并且观察人体脂肪、猪、鸡、牛、羊脂和豆油中7种脂肪酸的组份含量变化。根据7种主要脂肪酸（肉豆蔻酸、棕榈酸、棕榈油酸、硬脂酸、油酸、亚油酸和亚麻酸）甲酯的百分含量可有效地进行鉴别。结果表明：通过SPM－GC法分析油脂，可将传统的油脂酯化法时间由2个多小时缩短到1分钟左右。数据C．V．％＜4％，最小检测量为1．Oμg。最佳比例四甲基氢氧化按（TMAH）甲醇液（TMAH：甲醇＝1：10，V／V），可消除油脂中多不饱和脂肪酸的异构化和降解。     

Study of TATP: stability of TATP solutions

Stability of raw TATP (3,3,6,6,9,9-hexamethyl-1,2,4,5,7,8-hexoxonane) samples in solutions of common solvents was studied to highlight problems faced by forensic labs in identification and analysis of organic peroxide samples. The TATP samples were prepared by reaction of acetone and hydrogen peroxide (30%) with the aid of following catalysts: hydrochloric, sulfuric, nitric, perchloric and methanesulfonic acid. Acetone, acetonitrile, methanol and acetonitrile/water solutions of TATP samples were prepared and stored at 50°C. Various degrees of stability were observed for particular combination of catalyst and solvent ranging from totally unstable (catalyst-H(2)SO(4)/any solvent) to very stable (catalyst-HCl/solvent acetonitrile). Purification of crude TATP by re-crystallization results in product stable in all investigated solvents. Stability of solution prepared from re-crystallized DADP (3,3,6,6-tetramethyl-1,2,4,5-tetroxane) was found to be on the same level as the stability of solution of re-crystallized TATP.     

Photoluminescent semiconductor nanocrystals for fingerprint detection

The concept of utilizing photoluminescent semiconductor nanocrystals for latent fingerprint detection, especially in concert with phase-resolved imaging for background fluorescence suppression, is reduced to practice with CdS nanocrystals that are capped with dioctyl sulfosuccinate. The nanocrystals are dissolved in heptane or hexane and are applied in much the same way as staining with fluorescent dye, on articles that have been pre-fumed with cyanoacrylate ester and also on the sticky side of electrical tape without pre-fuming. Since CdS can form a photoluminescent nanocomposite with dendrimers, a feasibility examination of dendrimer tagging of fingerprints has also been conducted.     

Automated headspace solid-phase microextraction and capillary gas chromatography analysis of ethanol in postmortem specimens

Solid-phase microextraction (SPME) is a relatively new solventless sample preparation technique that allows simultaneous sampling, extraction, pre-concentration, and introduction of analytes from a sample matrix in a single procedure. This methodology has been used for the analysis of several drugs of forensic toxicology interest including volatile compounds. This paper describes a methodology for analysis of ethanol and other volatile compounds using automatic headspace solid-phase microextraction (HS-SPME) and capillary gas chromatography in postmortem specimens. The methodology was initially developed using standard solutions of acetaldehyde, acetone, methanol, and ethanol. Isobutanol was used as internal standard. Postmortem samples of blood, urine, and vitreous humor were obtained during medico-legal autopsies. To date, there are no published paper regarding alcohol analysis in vitreous humor specimens using HS-SPME and limited literature analyzing blood and urine samples. HS-SPME analysis showed that, under optimized conditions, ethanol and isobutanol (internal standard) were well-separated from other volatile compounds such as acetaldehyde, acetone, and methanol considered to be potential interferents in ethanol analysis. The calibration curves for each volatile compound demonstrated good linearity throughout the concentration range from 0.001 to 1.0 g/dl and the detection limit of ethanol in the studied specimens was approximately 0.0001 g/dl.     

Methanol intoxication: distribution in postmortem tissues and fluids including vitreous humor

A 44-year-old man was found unconscious beneath an elevated rapid transit right-of-way. On admission to the emergency room, the patient was comatose in metabolic acidosis with high anion and osmolal gaps. The serum methanol was 583 mg/dL. The serum ethanol and ethylene glycol were negative. The patient was treated with ethanol, bicarbonate, and hemodialysis. He expired 40 h after admission. The postmortem methanol concentrations in body fluids were as follows: bile 175 mg/dL, vitreous humor 173 mg/dL, and blood 142 mg/dL. Urine was not available for analysis. Postmortem methanol concentrations in body tissues are given in decreasing order: brain 159 mg/100 g, kidney 130 mg/100 g, lung 127 mg/100 g, spleen 125 mg/100 g, skeletal muscle 112 mg/100 g, pancreas 109 mg/100 g, liver 107 mg/100 g, and heart 93 mg/100 g. The total amount of methanol in the gastric contents was 73 mg. Methanol determinations were performed on a Hewlett-Packard 5840A gas chromatograph with flame ionization detection using a glass column packed with 0.2% Carbowax 1500 on Carbopack C. The internal standard used was n-propyl alcohol.     

5-(4-Nitrophenyl)-2,4-pentadien-1-al (NPPD) used as a tracer by nonscientists at a simulated crime scene

5-(4-Nitrophenyl)-2,4-pentadien-1-al (NPPD) was used as a tracer by nonscientists at a simulated crime scene. A card with both a plastic-coated smooth surface and a porous cellulose matrix paper surface was coated with a methanol solution containing 0.5mg/mL of NPPD. The card was touched with bare fingers and fingers covered by a cotton glove. A color-change protocol was then used to detect the presence of NPPD. The bare fingers or the fingers of gloves were swabbed with a cotton swab, or the parts of the glove that had touched the card were cut out. The swabs or the cloth pieces were dipped in methanol, a 0.1% methanol solution of naphthoresorcinol was added, and then concentrated hydrochloric acid was added. The observation of a red color at this point indicated a positive test. NPPD was easily observed in the experiments involving bare fingers, but no color change was observed from the swabbing of the cotton glove. However, when the cloth pieces cut from the fingers of the glove were subjected to the test, the red color was observed. In an attempt to enhance the sensitivity of the test, the volumes of the reagent solutions were reduced, but no improvement in sensitivity was obtained.     

Rapid isolation with Sep-Pak C18 cartridges and capillary gas chromatography of triazine herbicides in human body fluids.

A simple and rapid method, for the isolation of eight triazine herbicides from human serum and urine, using Sep-Pak C18 cartridges is presented. After mixing with distilled water, serum and urine samples containing the herbicides, were loaded on Sep-Pak C18 cartridges and eluted with either chloroform only or chloroform/methanol (9:1). The herbicides were detected by capillary gas chromatography with both flame ionization detection (FID) and nitrogen-phosphorus detection (NPD). Separation of eight triazine herbicides from each other and from impurities was generally satisfactory with the use of a non-polar DB-1 capillary column. Recovery of most compounds was excellent for both chloroform and chloroform/methanol (9:1) as elution solvents. Backgrounds were cleaner and evaporation time was shorter for the chloroform only than for the chloroform/methanol (9:1). The NPD gave sensitivity more than 10-20 times higher than that of FID.     

Detection of latent fingerprints by the use of silver nitrate

Silver nitrate has been an established agent for the detection of latent fingerprints for some 120 years, and it was one of the few reagents suitable for use on porous surfaces until ninhydrin was introduced in forensics. The method is based on the reaction of silver ions with chlorides in the fingerprints, which are visualized in brown, violet or black. The literature describes many variations of the procedure, but the information provided is often vague and imprecise. The purpose of this study was to show whether this method can also be used on modern types of paper and how it should be applied. The results of the tests showed that silver nitrate solutions do work also on modern papers, but that they cannot be recommended as a standard, because the appearance of the prints and the paper background can strongly change in the course of time. The findings also do not justify the use of methanol-containing silver nitrate solutions in contrast to the variations based on water. For reasons of occupational safety, methanol, which is classified as poisonous, should not be used. The silver nitrate method may be taken into consideration, however, e.g. after the application of ninhydin, if there are hints that the potential fingerprints are not too old, have not been affected by moisture and if there are clues that the perpetrator perspired strongly while causing the prints.     

Diagnosis of chronic alcohol consumption. Hair analysis for ethyl-glucuronide

This paper describes a procedure for the detection and quantification of ethyl-glucuronide (EtG) in hair samples. During method development the efficacy of extraction of EtG from hair was compared in four extraction methods: (a) methanol; (b) methanol:water (1:1); (c) water; and (d) water:trifluoroacetic acid (9:1). In addition, three derivatizing agents were compared as well: N,O-bistrimethylsilyl-trifluoroacetamide (BSTFA): trimethylchlorosilane (TMCS) (99:1), pentafluoropropionic anhydride (PFPA) and heptafluorobutyric anhydride (HFBA). Water was found to be the best extracting solvent and PFPA the best derivatizing agent. Both provided the highest recoveries, with cleaner extracts and more stable derivatives. The final method is as follows: about 100mg of hair are sequentially washed with water and acetone. The decontaminated sample is finely cut with scissors, then the deuterated internal standard (EtG-d5) and 2 mL of water are added. After sonication for 2 h, the sample is maintained at room temperature overnight. Derivatization is performed with PFPA. Derivatives are injected into a GC-MS system in the electronic impact mode. The method shows linearity over the range of concentrations from 0.050 to 5 ng/mg. Detection and quantification limits are 0.025 and 0.050 ng/mg, respectively. Mean recoveries for the three studied concentrations (low, medium and high) are higher than 87%. The coefficients of variation in intra- and inter-assay precision are always lower than 7%. The method is being routinely applied in our lab for the diagnosis of chronic alcohol consumption.     

薄层色谱法鉴别口红

本文报道利用薄层色谱鉴别口红的方法.实验选用95%乙醇作溶剂提取口红中的色料,乙酸乙酯一甲醇—水(3.6:2.2:1.2)作展开剂进行色谱分离,观测色谱斑点的颜色、数量、比移值和荧光性,综合分析和比较这些色谱信息,可以确定口红的品牌和生产厂家.     

Fatal methanol intoxication with different survival times--morphological findings and postmortem methanol distribution

Three corresponding cases of fatal methanol intoxication with different survival times were investigated ante-mortem and postmortem. Ante-mortem serum methanol concentrations were determined during treatment in hospital for 4 days. Furthermore, postmortem distribution of methanol in various tissues and fluids was measured after autopsy. Morphological and toxicological findings are discussed based on the literature. The morphological findings correlated with the different survival times. The results of the toxicological analyses were partly in keeping with previously published data. Interestingly, very high methanol levels were determined in brain with very low concentrations in femoral venous blood. These results may have implications for postmortem toxicological analysis, brain death diagnosis and organ explanation for transplantation.     

Simultaneous identification/determination system for phentolamine and sildenafil as adulterants in soft drinks advertising roborant nutrition

An easily available, simultaneous identification/determination procedure for phentolamine (PHE) and sildenafil (SIL) in adulterated dietary supplements was established by using a combination of three different analytical methods; thin-layer chromatography (TLC), liquid chromatography-mass spectrometry (LC/MS) and a high-performance liquid chromatography (HPLC)/photo-diode-array. The sample solution for TLC was applied to silica gel 60 F(254) plates with chloroform/ammonia solution (28)/methanol (70:5:3, lower layer) and chloroform/diethylamine/methanol (15:3:2) as the developing solvent. Spots were located under UV radiation at 254 nm. Mass spectra of PHE and SIL by LC/MS were investigated with electrospray ionization (ESI) interface, under both positive and negative ion mode. The HPLC analysis was performed on a column of Wakosil 5C18 (4.6 mm x 150 mm, 5 microm) with water/methanol/acetonitrile/triethylamine (580:250:170:1) adjusted with phosphoric acid to pH 3.0 as the mobile phase, and the effluent was monitored with a photo-diode-array detector. Quantitative HPLC analysis of PHE and SIL were detected at 280 nm. When this procedure was applied to commercial soft drinks, PHE and SIL were identified and determined at a concentration of 17 mg PHE and 44 mg SIL per bottle, respectively. The procedure described here is available for the screening of PHE and SIL in adulterated supplements.     

薄层色谱法鉴别黑色中性笔色痕的种类

黑色中性笔墨水主要由溶剂、色料、增稠剂、稳定剂和其他添加剂等组成,不同厂家或同厂家不同牌号中性笔墨水的成分不同,尤其是色料差别较大,这为中性笔墨水的种类鉴别提供了依据。本文利用数理统计中的均匀设计法和正交设计法安排试验,建立了一种可用于黑色中性笔色痕种类鉴别的方法:用N,N-二甲基甲酰胺作为黑色中性笔色痕的提取剂,四氢呋喃:甲醇:1,2-二氯乙烷:氯仿=30:15:5:7为展开剂的薄层色谱分析法。     

Severe necrosis of oesophageal and gastric mucosa in fatal methanol poisoning

Methanol is a potent neurotoxic substance that causes severe metabolic acidosis and serious neurological disorders. Most of the cases are accidental exposures to drinking beverages contaminated with methanol. There are few articles reporting pure methanol intoxication; however, it is well known that small quantities of pure methanol causes blindness and death, the minimum lethal dose being 50-100 ml.A case report is presented of a 67-year-old woman, who committed suicide by ingestion of 500 ml of absolute methanol. Despite symptomatic and supportive intensive care, the woman died 23 h after hospital admission due to metabolic acidosis and multiple organ dysfunction syndrome. A complete medico-legal autopsy was performed. Grossly, there was complete detachment of the oesophagus mucosa and brownish discolouration of the gastric mucosa. Histological findings showed diffuse haemorrhagic necrosis of the stomach mucosa and intense acute inflammatory infiltration of the lamina propria. To our knowledge, this is the first autopsy report of such severe digestive injuries. A discussion and review of the recent literature on the subject are given.     

Simultaneous identification/determination system for phentolamine and sildenafil as adulterants in soft drinks advertising roborant nutrition

An easily available, simultaneous identification/determination procedure for phentolamine (PHE) and sildenafil (SIL) in adulterated dietary supplements was established by using a combination of three different analytical methods; thin-layer chromatography (TLC), liquid chromatography–mass spectrometry (LC/MS) and a high-performance liquid chromatography (HPLC)/photo-diode-array. The sample solution for TLC was applied to silica gel 60 F₂₅₄ plates with chloroform/ammonia solution (28)/methanol (70:5:3, lower layer) and chloroform/diethylamine/methanol (15:3:2) as the developing solvent. Spots were located under UV radiation at 254 nm. Mass spectra of PHE and SIL by LC/MS were investigated with electrospray ionization (ESI) interface, under both positive and negative ion mode. The HPLC analysis was performed on a column of Wakosil 5C18 (4.6 mm×150 mm, 5 μm) with water/methanol/acetonitrile/triethylamine (580:250:170:1) adjusted with phosphoric acid to pH 3.0 as the mobile phase, and the effluent was monitored with a photo-diode-array detector. Quantitative HPLC analysis of PHE and SIL were detected at 280 nm. When this procedure was applied to commercial soft drinks, PHE and SIL were identified and determined at a concentration of 17 mg PHE and 44 mg SIL per bottle, respectively. The procedure described here is available for the screening of PHE and SIL in adulterated supplements.     

甲醇中毒机制的研究进展

甲醇经口或皮肤吸收入血后造成中毒者双目失明甚至死亡等严重后果的案件时有发生。甲醇及其代谢产物甲醛、甲酸均可对机体产生严重毒性作用,引起代谢性酸中毒、视力障碍及神经症状。目前对于甲醇中毒机制的研究主要集中在甲醇氧化代谢过程中形成的甲醛、甲酸及大量自由基直接或间接地造成组织细胞缺氧,结构及生物特性改变,自由基及抗氧化系统、蛋白酶及蛋白酶抑制系统平衡被打破,而造成体内一系列中毒改变。     

A case of death after ingestion of an agrochemical spreading agent

An agrochemical spreading agent was found near the slightly decomposed corpse of a deceased female. The appearance of the stomach contents suggested that ingestion of a surfactant had occurred before death. The spreading agent was found to contain nonionic nonylphenol ethoxylates (NPEO(n)) and anionic sulfonated naphthalene-formaldehyde condensates (SNFC(n)). A solid phase extraction cartridge containing a mixed reversed phase-weak anion exchange sorbent (Oasis WAX, Waters) was used to successfully extract both NPEO(n) and SNFC(n) from the blood. The cartridge was preconditioned with methanol and acetic acid (AcOH). After the dilute blood sample was applied to the cartridge, it was washed with AcOH, and then NPEO(n) and SNFC(n) were eluted with methanol/dichloromethane (7:3, v/v) and 5% NH(3)/80% methanol, respectively. The concentrations of NPEO(n=2-9) and SNFC(n=0) in the blood sample were 7.7μg/mL and 1.8mg/mL, respectively. It is possible that postmortem changes increased the concentration of SNFC(n=0) monomer by breaking down the polymer. However, the behavior of these compounds in the human body is unclear and further case studies are needed to investigate this result.