Determination of 3,4-Methylenedioxymethamphetamine (MDMA) and 3,4-Methylenedioxyamphetamine (MDA) in Urine by High Performance Liquid Chromatography

Abstract

The present study proposes a simple, inexpensive method for the identification and quantification of 3,4-methylenedioxymethamphetamine (MDMA) and its principal metabolite 3,4-methylenedioxyamphetamine (MDA) in samples of human urine utilizing high performance liquid chromatography with a UV detector. The optimized method presented adequate linearity, sensitivity, precision, selectivity, and robustness, thereby demonstrating its feasibility for adoption as a laboratorial option for the confirmation of the presence of the drug in urine samples from users.     

Highly sensitive capillary electrophoresis-mass spectrometry for rapid screening and accurate quantitation of drugs of abuse in urine

The combination of capillary electrophoresis (CE) and mass spectrometry (MS) is particularly well adapted to bioanalysis due to its high separation efficiency, selectivity, and sensitivity; its short analytical time; and its low solvent and sample consumption. For clinical and forensic toxicology, a two-step analysis is usually performed: first, a screening step for compound identification, and second, confirmation and/or accurate quantitation in cases of presumed positive results. In this study, a fast and sensitive CE-MS workflow was developed for the screening and quantitation of drugs of abuse in urine samples. A CE with a time-of-flight MS (CE-TOF/MS) screening method was developed using a simple urine dilution and on-line sample preconcentration with pH-mediated stacking. The sample stacking allowed for a high loading capacity (20.5% of the capillary length), leading to limits of detection as low as 2 ng mL⁻¹ for drugs of abuse. Compound quantitation of positive samples was performed by CE-MS/MS with a triple quadrupole MS equipped with an adapted triple-tube sprayer and an electrospray ionization (ESI) source. The CE-ESI-MS/MS method was validated for two model compounds, cocaine (COC) and methadone (MTD), according to the Guidance of the Food and Drug Administration. The quantitative performance was evaluated for selectivity, response function, the lower limit of quantitation, trueness, precision, and accuracy. COC and MTD detection in urine samples was determined to be accurate over the range of 10–1000 ng mL⁻¹ and 21–1000 ng mL⁻¹, respectively.     

新型宽波束圆极化天线--微带介质天线

通过在微带天线中引入介质天线原理，提出了一种以简单方式展宽微带天线波束和提高低仰角增益的新方法，从而发明了一种新型宽波束天线－微带介质天线。该天线具有极宽的波束、较高的低仰角增益和波束范围内有较好的圆极化性能等特点。文中给出了天线的原理、设计公式和实验结果。     

基于软件通信体系结构的波形组件化开发技术研究

文章简要阐述了软件无线电波形组件化开发的特点,研究实现了一套基于软件通信体系结构（SCA）的波形组件化开发技术,对开发过程各步骤进行了阐述。该技术可以提高组件的开发效率、可重用性和可移植性。     

中国公司债券评级方法应用研究

在国内外债券评级的研究基础之上,选用MDA、Logistic模型、Probit模型以及神经网络四种债券评级方法,结合中国上市公司的风险特征,从变量甄选的角度对债券评级方法进行优化,同时采用中国上市公司数据进行实证分析.实证结论表明:甄选出的评级变量较国外常用的评级指标更好的刻画了中国上市公司的风险特征;Logistic模型、Probit模型和神经网络方法都对中国上市公司的债券有较高的评级分类能力,尤其是Probit模型和神经网络方法对中国公司债券的评级非常准确,误判率接近于0.     

平行因子结合二维荧光光谱相关技术解析丙二醛诱导熟肉糜氧化过程

采用前表面三维同步荧光光谱、平行因子和二维相关技术研究丙二醛诱导熟肉糜氧化过程的荧光特征。发现丙二醛熟肉糜体系有两个特征同步荧光峰,分别是色氨酸残基的荧光特征(Ex292 nm、Δλ50 nm)和丙二醛蛋白结合物的荧光特征(Ex400 nm、Δλ70 nm);平行因子分析表明Δλ为50和70 nm的同步荧光光谱分别为第一、第二主成分,分别对应的是色氨酸残基的荧光特征和丙二醛蛋白结合物的荧光特征;丙二醛诱导熟肉糜氧化过程中,随着时间的延长,色氨酸残基特征同步荧光强度逐渐减弱,丙二醛蛋白结合物特征同步荧光强度逐渐增强;二维相关分析表明,色氨酸残基荧光强度变化速率快于丙二醛蛋白结合物的荧光强度变化速率。     

基于有色Petri网的模型驱动SOA服务模型组合

在模型驱动SOA的框架下,业务流程层的合理创建可验证的流程服务。通过形式化定义了服务组合过程中的5种基本的逻辑结构,采用有色Petri网表示,并将其抽象成为服务的代数运算;在此基础上,提出了经过服务运算后得到的服务性质以及组合服务的构造方法;最后通过实例,说明该建模方法可以保证组合的服务是正确而且可终止的。     

Sensitive determination of MDMA and its metabolite MDA in rat blood and brain microdialysates by HPLC with fluorescence detection

Simultaneous determination of 3,4-methylenedioxymethamphetamine (MDMA) and 3,4-methylenedioxyamphetamine (MDA) in rat blood and brain microdialysates by high-performance liquid chromatography with fluorescence detection (HPLC-FL) was developed. Microdialysates were directly subjected to derivatization with 4-(4,5-diphenyl-1H-imidazol-2-yl)benzoyl chloride (DIB-Cl). The DIB-derivatives of MDMA, MDA and the internal standard, 1-methyl-3-phenylpropylamine (MPPA), were isocratically separated on an ODS column using a mixture of 50 mm phosphate buffer (pH 7.0)-acetonitrile-methanol-2-propanol (50:45:5:2, v/v/v/v %) as an eluent at a flow rate of 1.5 mL/min. The calibration curves of MDA and MDMA spiked to blood and brain microdialysates were linear over the ranges 2.5-500 and 5.0-1000 ng/mL, respectively. The detection limits of MDA and MDMA were 1.2 and 4.2 for blood and 1.3 and 4.8 ng/mL for brain, respectively. Additionally, the intra- and the inter-assay precisions were lower than 5.6% for the blood and brain microdialysates (n = 4). The proposed method was successfully applied for the monitoring of MDMA and its metabolite MDA in rat blood and brain microdialysates, and the pharmacokinetic parameters of MDMA and MDA in the microdialysates after administration of MDMA (5 mg/kg, i.p.) with or without caffeine (20 mg/kg, i.p.) were evaluated.     

Evaluation of the Anticancer Potential of Crude,Irradiated Cerastes cerastes Snake Venom and Propolis Ethanolic Extract & Related Biological Alterations

We aimed to evaluate the anticancer potential of crude venom (CV), γ irradiated Certastes cerastes venom (IRRV), and propolis ethanolic extract (PEE). IRRV showed a higher toxicity than CV, while CV-PEE showed higher toxicity than IRRV and CV against lung [A549] and prostate [PC3] cancer cells. Toxicity to [A549] and [PC3] cells was concentration and cell type dependent. In comparison to controls, apoptotic genes showed a significant upregulation of P53 and Casp-3 and a downregulation of Bcl-2. Also, induced elevated DNA accumulation in the [S] phase post PC3 cell treatment with IRRV and CV, as well as a significant DNA accumulation at G2/M phase after IRRV treatment of A549 cells. In contrast, PC3 cells showed a negligible cellular DNA accumulation after PEE treatment. Glutathione reductase [GR] was reduced in case of PC3 and A549 cell treated with IRRV, CV, and PEE compared with its values in untreated cell control. The Malondialdehyde [MDA] values in both cells recorded a significant elevation post IRRV treatment compared to the rest of the treatment regimen and untreated cell control. Similarly, IRRV and CV-PEE mix showed obviously higher reactive oxygen species [ROS] values than PC3 and A549 cell treatments with CV and PEE.     

硒与维生素E对需谷胱甘肽抗氧化酶的保护作用

观察了微量元素硒和维生素Ｅ对体外培养的仓鼠幼肾成纤维细胞的三种需谷胱甘肽抗氧化酶活性的保护作用。发现：三种促氧化剂,即Ｆｅ－ＡＤＰ、特丁基氢过氧化物（ｔ－ＢＨＰ）和Ｈ２Ｏ２,均显著刺激ＭＤＡ生成,抑制谷胱甘肽过氧化物酶的活性,而对谷胱甘肽还原酶无影响。其中ｔ－ＢＨＰ的作用最强,并可使谷胱甘肽Ｓ－转移酶的活性降低。两种抗氧化剂均对上述过氧化反应及酶活性抑制有明显预防作用,且维生素Ｅ更为有效。说明：ＧＳＨ－Ｐｘ较易受到过氧化反应损伤;维生素Ｅ是更为有效的抗氧化性保护物质。