Determination of butaperazine in biological fluids by gas chromatography using nitrogen specific detection system.

A simple and sensitive gas chromatographic method for the quantitative determination of butaperazine in biological fluids is described. The use of a nitrogen specific detector reduces the number of interfering peaks, thereby increasing the number of samples that can be analyzed. When butaperazine is extracted from 2 ml of plasma, the coefficient of variation is 7.4% over the concentration range of 5-180 ng/ml. The method was used to measure the levels in plasma and red blood cells in schizophrenic patients treated with butaperazine. It was also extended to measure butaperazine levels in rat red blood cells, plasma, liver, and brain after intraperitoneal injection (15 mg/kg).     

基于PbS量子点和金纳米颗粒的可卡因适体传感器的研究

本文采用水热法合成了硫化铅量子点,将其与壳聚糖混合后修饰在玻碳电极上,利用PbS与巯基之间的强烈的键和作用,直接将所合成的带巯基的与可卡因适体互补的DNA固定到电极上,将金纳米颗粒标记在可卡因适体作为示踪物检测可卡因,研制了一种新型的用于快速测定可卡因的适体传感器.该适体传感器与不同浓度的可卡因培育时,可卡因适体与可卡...     

Concentration profiles of cocaine, pyrolytic methyl ecgonidine and thirteen metabolites in human blood and urine: determination by gas chromatography-mass spectrometry

When cocaine is smoked, a pyrolytic product, methyl ecgonidine (anhydroecgonine methyl ester), is also consumed with the cocaine. The amount of methyl ecgonidine formed depends on the pyrolytic conditions and composition of the illicit cocaine. This procedure describes detection of cocaine and 10 metabolites--cocaethylene, nor-cocaine, nor-cocaethylene, methyl ecgonine, ethyl ecgonine, benzoylecgonine, nor-benzoylecgonine, m-hydroxybenzoylecgonine, p-hydroxybenzoylecgonine and ecgonine--in blood and urine. In addition, the detection of pyrolytic methyl ecgonidine and three metabolites--ecgonidine (anhydroecgonine), ethyl ecgonidine (anhydroecgonine ethyl ester) and nor-ecgonidine (nor-anhydroecgonine)--are included. The newly described metabolites, ethyl ecgonidine and nor-ecgonidine, were synthesized and characterized by gas chromatography-mass spectrometry (GC-MS). All 15 compounds were extracted from 3 mL of blood or urine by solid-phase extraction and identified by a GC-MS method. The overall recoveries were 49% for methyl ecgonine, 35% for ethyl ecgonine, 29% for ecgonine and more than 83% for all other drugs. The limits of detection were between 0.5 and 4.0 ng/mL except for ecgonine, which was 16 ng/mL. Linearity for each analyte was established and in all cases correlation coefficients were 0.9985-1.0000. The procedure was applied to examine the concentration profiles of analytes of interest in post-mortem (PM) blood and urine, and in urine collected from living individuals (LV). These specimens previously were shown to be positive for the cocaine metabolite, benzoylecgonine. Ecgonidine, the major metabolite of methyl ecgonidine, was present in 77% of PM and 88% of the LV specimens, indicating smoking as the major route of cocaine administration. The new pyrolytic metabolites, ethyl ecgonidine and nor-ecgonidine, were present in smaller amounts. The urine concentrations of nor-ecgonidine were 0-163 ng/mL in LV and 0-75 ng/mL in PM specimens. Ethyl ecgonidine was found only in PM urine at concentrations 0-39 ng/mL. Ethanol-related cocaine metabolites, ethyl ecgonine or cocaethylene, were present in 69% of PM and 53% of cocaine-positive LV specimens, implying alcohol consumption with cocaine use. The four major metabolites of cocaine--benzoylecgonine, ecgonine, nor-benzoylecgonine and methyl ecgonine--constituted approximately 88 and 97% of all metabolites in PM and LV specimens, respectively. The concentrations of nor-cocaine and nor-cocaethylene were consistently the lowest of all cocaine metabolites. At benzoylecgonine concentrations below 100 ng/mL, ecgonine was present at the highest concentrations. In 20 urine specimens, benzoylecgonine and ecgonine median concentrations (range) were 54 (0-47) and 418 ng/mL (95-684), respectively. Therefore, detection of ecgonine is advantageous when benzoylecgonine concentrations are below 100 ng/mL.     

Measurement of unbound cocaine in blood, brain and bile of anesthetized rats using microdialysis coupled with liquid chromatography and verified by tandem mass spectrometry

To investigate the disposition of unbound cocaine in the rat blood, brain and bile, we demonstrate an in vivo multiple sampling microdialysis system coupled with liquid chromatography for cocaine assay and verified by tandem mass spectrometry. Three microdialysis probes were concurrently inserted into the jugular vein, bile duct and brain striatum of each anesthetized rat. After a period of 2 h post-surgical stabilization, cocaine (10 mg kg(-1)) was administered through the femoral vein. Separation of unbound cocaine from various biological fluids was applied to a reversed-phase C(18) column (250 x 4.6 mm I.D., 5 microm). The mobile phase consisted of acetonitrile--10 mm potassium dihydrogen phosphate buffer (25:75, v/v, pH 4.0) and 0.8% diethylamine at a flow rate of 1 mL min(-1). The UV detector wavelength was set at 235 nm. The results indicate that cocaine penetrates the blood--brain barrier with a rapid distribution. However, unbound cocaine in the bile dialysate was not detectable in the UV detection. We therefore use LC--tandem mass spectrometry to detect the bile fluid after cocaine administration (3 mg kg(-1), i.v.). The results indicate that cocaine goes through hepatobiliary excretion.     

Blood Levels of Hexavalent Chromium in Rats. “In Vitro” and “In Vivo” Experiments

Abstract

For the Cr(VI) selective separation from biological materials we have developed a highly rapid extraction-separation method with liquid anion exchanger as Amberlite LA-1 or LA-2. The analytical determination of Cr(VI) in organic phase was carried out using electrothermal atomic absorption spectroscopy (ETA-AAS).

After i.v. administration of 0.5 and 2.5mg/kg b.w. of K₂Cr₂O₇ in male Wistar rats the biological samples, collected at different times, were immediately analyzed. Cr(VI) was not detected in whole blood one minute after administration of the lower dose. In blood of rats receiving higher dose an incomplete reduction of Cr(VI) was observed.

Such data demonstrate a highly rapid but limited metabolic capacity of hematic compartment to reduce Cr(VI) to trivalent status.

These results obtained with a new and specific analytical method, confirmed a trigger role of red cells in Cr(VI) metabolism.

“In vitro” incubation of K₂Cr₂O₇ (4 μM) with rat erythrocytes or plasma at 37°C showed a rapid reduction of Cr(VI) in red cells while plasma samples demonstrated a limited reductive power.     

微波萃取-气相色谱法测定血液中的可卡因及其代谢物爱冈宁甲基酯

建立了血液中可卡因(cocaine, COC)及其代谢物爱冈宁甲基酯(ecgonine methyl ester, EME)的气相色谱-质谱(CG-MS)和气相色谱-氢火焰离子化检测(GC-FID)方法。该方法采用微波萃取提取血液中的COC和EME,优化并确定了最佳提取条件: 以氯仿-异丙醇(体积比为9:1)混合溶液为提取溶剂,用0.05 mol/L Na2CO3-NaHCO3缓冲溶液调节样品溶液的pH至10.0,在40 ℃下微波萃取6 min;采用GC-MS对萃取液中的COC和EME进行定性,采用GC-FID进行定量检测。COC和EME的平均回收率分别为79.91%～99.85%,相对标准偏差(RSD)均小于3.10%,检出限(S/N=3)分别为60 mg/L和40 mg/L。该方法无需衍生化,快速、准确、灵敏,可同时检测血液中的COC和EME。     

High-performance liquid chromatographic determination of cyanide in human red blood cells by pre-column fluorescence derivatization.

A method for the determination of cyanide in human red cells has been developed. Cyanide was extracted from red cells by adding water and methanol, and then derivatized with 2,3-naphthalene-dialdehyde and taurine to give a fluorescent product, which was determined by reversed-phase high-performance liquid chromatography with fluorescence detection. The recovery of cyanide from red cells was ca. 83%, and the limit of detection was 100 pmol/ml. The mean concentrations of red cell cyanide from ten smokers and from ten non-smokers were 705 and 466 pmol/ml, respectively. The method was also applicable to whole blood.     

High-performance liquid chromatographic determination of cicletanide, a new diuretic, in plasma, red blood cells, urine and saliva

A sensitive, selective and easy to use high-performance liquid chromatographic method for the determination of cicletanide, a new diuretic, in plasma, red blood cells, urine and saliva is described. After extraction of cicletanide together with an internal standard with diethyl ether, or diethyl ether-n-hexane (20:80) for urine, the sample extracts are chromatographed with water-methanol-acetic acid (50:50:0.3) as eluent on to a Nucleosil C18 column. Both compounds are detected by their ultraviolet absorption at 280 nm. The calibration graph was linear between 0.2 and 20 micrograms/ml for plasma and between 0.2 and 5 micrograms/ml for the other biological fluids. The sensitivity limit was 20 ng/ml for plasma, red blood cells and saliva and 30 ng/ml for urine. The coefficients of variation of the between-day assays did not exceed 4.6% in plasma, 8.3% in red blood cells, 7.8% in urine and 4.2% in saliva for the lowest concentrations studied. The application of the method to a pharmacokinetic study of cicletanide after a single oral therapeutic dose in humans is reported.     

Phosphorimetric determination of procaine,phenobarbital, cocaine,and chlorpromazine in blood serum,and cocaine and atropine in urine

A new sensitive and rapid method is proposed for the determination of procaine, cocaine, phenobarbital and chlorpromazine in blood serum, and cocaine and atropine in urine. The drug is extracted from the biological fluid using chloroform or ether, the solvent is evaporated and the resulting residue is dissolved in EPA; the EPA solution is measured phosphorimetrically. Recoveries of 100 ± 6% and relative standard deviations of 2–5% are obtained for most drugs.     

Comparison of a novel thin-layer chromatographic-fluorescence detection method with a spectrofluorometric method for the determination of 7-hydroxycoumarin in human urine.

A novel method for the determination of 7-hydroxycoumarin in human urine which combines thin-layer chromatography (TLC) with fluorescence detection (FD) has been devised. The limit of detection (1 ng/ml) enables determination of 7-hydroxycoumarin after both administration of coumarin and environmental exposure to this fragrance material. When compared to a spectrofluorometric method of analysis, the TLC-FD method proved to be more selective for the analysis of 7-hydroxycoumarin in human urine.     

On-line dialysis and weak cation-exchange enrichment of dialysate. Automated high-performance liquid chromatography of pholcodine in human plasma and whole blood.

An automated method for the determination of pholcodine in plasma and whole blood is described. The technique combines dialysis and trace enrichment prior to high-performance liquid chromatography. Dialysis, trace enrichment on a weak cation-exchange column, separation on a cyano column and fluorescence detection was shown to be an extremely selective and sensitive method. The method has been used successfully in the analysis of real samples after administration of pholcodine. The automated method can be used, after minor modification, to determine other basic drugs in whole blood and plasma.     

Examination of the in vitro degradation of [14C] pentaerythritol tetranitrate in rat and human blood with an improved thin-layer radiochromatographic procedure

Improvements were made on a reported thin-layer radiochromatographic assay for the determination of [14C]pentaerythritol tetranitrate (PETN) and its metabolites in whole blood, using methanol instead of dioxane as the extracting solvent. Recovery of total radioactivity for the entire work-up procedure was greater than 90%, and the distribution of PETN and its metabolites in degraded blood samples was found to be reproducible. This modified method appeared simpler and yielded better recovery of radioactivity than the literature method. In vitro metabolism of [14C]PETN in rat and human blood was examined by incubation of the drug with fresh blood at 37 degrees C for 60 min. In rat blood, the half-life of PETN degradation was about 15 min producing the trinitrate, dinitrate and mononitrate metabolites. Human blood was also capable of degrading PETN in vitro, but at a lower rate than rat blood, yielding only the trinitrate metabolite in quantifiable amounts during the incubation period. Equilibrium of PETN between plasma and red blood cells was observed within 1 min after PETN addition to both rat and human blood. The apparent plasma/red blood cells partition ratios of PETN were 1.1 and 1.7 for rat and human blood, respectively. PETN degradation was approximately ten times slower in rat plasma than in rat blood, suggesting that enzymes in erythrocytes are important for PETN metabolism in rat whole blood.     

Quantitation of ribavirin in human plasma and red blood cells using LC–MS/MS

LC–MS/MS has been applied for the rapid determination of the nucleoside analogue ribavirin in human plasma and red blood cells. The incorporation of ribavirin to the erythrocytes has been assayed after in vitro incubation of the cells at different concentrations of the antiviral drug. After protein precipitation, samples were injected into a C₈ column, achieving a complete separation of ribavirin from the endogenous isobaric compound uridine. Calibration ranges varied from 10 to 10 000 ng/mL in plasma and from 0.2 to 200 ng/cell pellet in red blood cells. Precision and accuracy values were always below 10 and 13%, respectively, in all assayed matrices. Ribavirin was demonstrated to remain unchanged after short and long time storage. No matrix effects could be assessed for the analyzed matrices. The developed method has been fully validated. Monitoring of ribavirin concentration in red blood cells in addition to the classic plasma monitoring of the drug could help to explain its efficacy and safety profiles in patients.     

Magnetic dispersive solid‐phase extraction based on modified magnetic nanoparticles for the detection of cocaine and cocaine metabolites in human urine by high‐performance liquid chromatography–mass spectrometry

An easy‐to‐handle magnetic dispersive solid‐phase extraction procedure was developed for preconcentration and extraction of cocaine and cocaine metabolites in human urine. Divinyl benzene and vinyl pyrrolidone functionalized silanized Fe₃O₄ nanoparticles were synthesized and used as adsorbents in this procedure. Scanning electron microscopy, vibrating sample magnetometry, and infrared spectroscopy were employed to characterize the modified adsorbents. A high‐performance liquid chromatography with mass spectrometry method for determination of cocaine and its metabolites in human urine sample has been developed with pretreatment of the samples by magnetic dispersive solid‐phase extraction. The obtained results demonstrated the higher extraction capacity of the prepared nanoparticles with recoveries between 75.1 to 105.7% and correlation coefficients higher than 0.9971. The limits of detection for the cocaine and cocaine metabolites were 0.09–1.10 ng/mL. The proposed magnetic dispersive solid‐phase extraction method provided a rapid, environmentally friendly and magnetic stuff recyclable approach and it was confirmed that the prepared adsorbents material was a kind of highly effective extraction materials for the trace cocaine and cocaine metabolites analyses in human urine.     

Simultaneous determination of cocaine and its metabolites with caffeine in rat serum microsamples by high-performance liquid chromatography

A single, isocratic high-performance liquid chromatographic method is described for the determination of cocaine and three of its metabolites along with caffeine in serum microsamples (50 microliters). The small sample size permits the tracking of pharmacokinetic data over time in individual, small animals. The method also was used to demonstrate that cocaine, benzoylecgonine and norcocaine in rat serum samples were stable for at least a month without the presence of sodium fluoride.     

Rapid and simple pretreatment of human body fluids using electromembrane extraction across supported liquid membrane for capillary electrophoretic determination of lithium

Electromembrane extraction was used for simultaneous sample cleanup and preconcentration of lithium from untreated human body fluids. The sample of a body fluid was diluted 100 times with 0.5 mM Tris solution and lithium was extracted by electromigration through a supported liquid membrane composed of 1-octanol into 100 mM acetic acid acceptor solution. Matrix compounds, such as proteins, red blood cells, and other high-molecular-weight compounds were efficiently retained on the supported liquid membrane. The liquid membrane was anchored in pores of a short segment of a polypropylene hollow fiber, which represented a low cost, single use, disposable extraction unit and was discarded after each use. Acceptor solutions were analyzed using capillary electrophoresis with capacitively coupled contactless conductivity detection (CE-C(4) D) and baseline separation of lithium was achieved in a background electrolyte solution consisting of 18 mM L-histidine and 40 mM acetic acid at pH 4.6. Repeatability of the electromembrane extraction-CE-C(4) D method was evaluated for the determination of lithium in standard solutions and real samples and was better than 0.6 and 8.2% for migration times and peak areas, respectively. The concentration limit of detection of 9 nM was achieved. The developed method was applied to the determination of lithium in urine, blood serum, blood plasma, and whole blood at both endogenous and therapeutic concentration levels.     

High-performance liquid chromatographic determination of cocaine and benzoylecgonine by direct injection of human blood plasma sample into an alkyl-diol-silica (ADS) precolumn

A column-switching high-performance liquid chromatographic method with UV detection for the determination of cocaine (COC) and benzoylecgonine (BZE) in human blood plasma samples is described. The method uses an alkyl-diol-silica ADS-C18 extraction precolumn. A 50- micro L plasma sample was introduced to the ADS precolumn in order to separate the analytes from proteins and endogenous compounds. The fraction containing COC and BZE was back-flushed and transferred to an Alltech mixed-mode C(18)/cation-exchange analytical column for final separation. The validation of the method revealed quantitative recoveries from 95.0 to 99.0% for COC at three different concentrations (0.5, 1.0 and 2.0 micro g mL(-1)), and from 96.0 to 99.0% for BZE at the same concentration levels with coefficients of variation <4.00% (n=5). The detection limit (signal to noise ratio (S/N)>3) was 0.03 micro g mL(-1) for all the compounds with an injection volume of 50 micro L. However, it was possible to enhance the sensitivity further by injecting larger plasma volumes, up to 200 micro L, at the same optimal conditions. The overlap of sample preparation, analysis and reconditioning of the extraction column, increase the overall sample throughput to 5 samples h(-1). The developed method has been applied to human blood plasma samples from subjects suspected of cocaine abuse.     

Indirect Atomic Absorption Determination of Cocaine via Formation and Liquid‐liquid Extraction of the Iron(III)‐cocaine Complex

The principles of metal‐alkaloid ion‐pair formation and liquid‐liquid extraction are applied to the development of a sensitive and convenient atomic absorption spectrophotometery (AAS) method for the indirect determination of cocaine. In an aqueous medium of 5 M hydrochloric acid, cocaine is protonated and is associated with tetrachloro ferrate (III) anion prior to its extraction into 1,2‐dichloroethane. The critical experimental variables were identified and optimized. The method is simple and reproducible with a detection limit (DL) of 0.1 ng cm^?3 cocaine in water, a relative standard deviation of 0.07 (n = 12), and the calibration graph was linear up to 50 ng cm^?3 cocaine.     

Determination of the carotenoid phytoene in blood by high-pressure liquid chromatography

A sensitive and specific high-pressure liquid chromatographic assay was developed for the determination of phytoene in blood with an overall recovery of 86 ± 6.0% and a limit of detection of 50–100 ng per ml of blood. This method provides for rapid and simple quantitation of phytoene using 1 ml or less of blood.

The assay was used in the determination of phytoene blood levels in the dog following intravenous and oral administration of 10-mg/kg doses.     

非靶向代谢组学用于藜芦妨害人参治疗脾气虚的机制研究

采用超高效液相色谱串联四级杆飞行时间质谱( UPLC/Q-TOF-MS)联用技术,通过非靶向代谢组学方法分析大鼠尿液内源性代谢物的变化,研究藜芦妨害人参发挥药效作用的机制。建立脾气虚大鼠模型,连续给药15天,测定力竭游泳时间及血液中白细胞、红细胞、血红蛋白的含量。结果表明,人参可显著提高脾气虚模型大鼠的力竭游泳时间(p﹤0.01),升高白细胞、红细胞及血红蛋白含量(p﹤0.05,p﹤0.01),藜芦对脾气虚模型大鼠各项指标无明显影响(p>0.05),人参与藜芦配伍后对脾气虚模型大鼠各项指标均无显著影响(p>0.05),表明藜芦妨害了人参发挥药效作用。采用UPLC/Q-TOF-MS技术及非靶向代谢组学的方法分析了空白组、模型组、人参组、藜芦组、参藜组对脾气虚模型大鼠的尿液代谢组差异,其中主成分分析( PCA)得分图显示各组代谢轮廓有显著差别,并通过正交偏最小二乘法-判别分析( OPLS-DA)及数据库检索,鉴定出15种人参干预调节脾气虚模型大鼠的潜在生物标志物,从中找出了7种人参藜芦配伍后减弱人参上述干预作用的潜在生物标志物,并对其涉及的代谢通路进行了系统分析。上述研究结果表明,人参藜芦配伍后妨害了人参对脾气虚模型大鼠的治疗作用,其机理可能是影响人参对体内能量代谢、免疫平衡及氧化还原反应等相关代谢的调节。