Analysis of ecstasy with a monolithic reversed-phase column

Summary A new, rapid, and precise liquid chromatographic method has been developed for simultaneous identification and quantification of amphetamine,N-methyl-3,4-methylenedioxymetamphetamine,N-ethyl-3,4-methylenedioxymetamphetamine, andN-methyl-1-(3,4-methyl-enedioxyphenyl)-2-butanamine in the presence of other constituents. The compounds were separated on a monolithic column with a gradient prepared from acetonitrile and 20mm monobasic potassium buffer at a flow rate of 1.5 mL min⁻¹. Quantitation was performed with metoclopramide as internal standard. Use of different flow rates was investigated and enabled reduction of the separation time from 11 to 3.5 min for seven substances. The method was then applied to ten seized tablets to identify and quantify their active ingredients.     

Poly(methacrylic acid-ethylene glycol dimethacrylate) monolith in-tube solid-phase microextraction applied to simultaneous analysis of some amphetamine derivatives in urine by capillary zone electrophoresis

A method based on in-tube solid-phase microextraction and capillary zone electrophoresis (CZE) was proposed for simultaneously determining four amphetamines (amphetamine, methamphetamine, 3,4-methylenedioxyamphetamine, and 3,4-methylenedioxymethamphetamine) in urine. A poly(methacrylic acid-ethylene glycol dimethacrylate) monolithic capillary column, which can provide sufficient extraction efficiency, was introduced for the extraction of amphetamines from urine samples. The hydrophobic main chains and acidic pendant groups of the monolithic column make it a superior material for extraction of basic analytes from aqueous matrix. After extraction, the samples were analyzed by CZE. The best separation was achieved using a buffer composed of 0.1 M disodium hydrogen phosphate (adjusted to pH 4.5 with 1 M hydrochloric acid) and 20% methanol v/v, with a temperature and voltage of 25 degrees C and 20 kV, respectively. By applying electrokinetic injection with field-amplified sample stacking, detection limits of 25-34 microg/L were achieved. Excellent method of reproducibility was found over a linear range of 0.1-5 mg/L. Determination of these analytes from abusers' urine sample was also demonstrated.     

人尿中苯丙胺和甲基苯丙胺的酰基衍生化及电子捕获气相色谱分析法检测

本文研究了苯丙胺和甲基苯丙胺的三氟乙酰、五氟丙酰、七氟丁酰、二氯乙酰、一氯二氟乙酰、五氟苯甲酰和3,5-二硝基苯甲酰的衍生化反应条件。在此基础上,建立了人尿中苯丙胺和甲基苯丙胺的酰基衍生化的气相色谱-电子捕获检测分析方法。以五氟苯甲酰衍生化法分析尿中苯丙胺的灵敏度最高,其检出限为2.0 ng/mL;采用3,5-二硝基苯甲酰衍生化分析尿中甲基苯丙胺时的灵敏度最高,检出限为5.8 ng/mL。本法简便、快速。     

动态液相微萃取GC/MS-SIM方法检验毛发中的苯丙胺类毒品

建立了动态液相微萃取GC/MS-SIM方法检测毛发中4种苯丙胺类毒品的方法.毛发样品首先用1 mol/L NaOH溶液消解,然后用50μL氯仿涡旋提取1min,离心后用注射器直接抽取有机相,提取液进行GC/MS-SIM方法检测.毛发样品的测出限(S/N=3)分别为苯丙胺1 ng/mg,甲基苯丙胺、3、4-(亚甲二氧基)苯丙胺、3、4(亚甲二氧基)-甲基苯丙胺500 pg/mg.在毛发中添加上述4种苯丙胺毒品的质量分数为5 ng/mg时,5次测定的RSD分别为苯丙胺8.3%,甲基苯丙胺8.2%,3、4-(亚甲二氧基)苯丙胺2.0%,3、4(亚甲二氧基)2.7%.该方法可用于毛发中低含量苯丙胺类毒品的分析.     

Monolithic silica spin column extraction and simultaneous derivatization of amphetamines and 3,4-methylenedioxyamphetamines in human urine for gas chromatographic-mass spectrometric detection

A simple, sensitive, and specific method with gas chromatography-mass spectrometry was developed for simultaneous extraction and derivatization of amphetamines (APs) and 3,4-methylenedioxyamphetamines (MDAs) in human urine by using a monolithic silica spin column. All the procedures, such as sample loading, washing, and elution were performed by centrifugation. APs and MDAs in urine were adsorbed on the monolithic silica and derivatized with propyl chloroformate in the column. Methamphetamine-d₅ was used as an internal standard. The linear ranges were 0.01-5.0 μg mL⁻¹ for methamphetamine (MA) and 3,4-methylenedioxymethamphetamine (MDMA) and 0.02-5.0 μg mL⁻¹ for amphetamine (AP) and 3,4-methylenedioxyamphetamine (MDA) (coefficient of correlation ≧0.995). The recovery of APs and MDAs in urine was 84-94%, and the relative standard deviation of the intra- and interday reproducibility for urine samples containing 0.1, 1.0, and 4.0 μg mL⁻¹ of APs and MDAs ranged from 1.4% to 13.6%. The lowest detection limit (signal-to-noise ratio ≧ 3) in urine was 5 ng mL⁻¹ for MA and MDMA and 10 ng mL⁻¹ for AP and MDA. The proposed method can be used to perform simultaneous extraction and derivatization on spin columns that have been loaded with a small quantity of solvent by using centrifugation.     

Application of micellar electrokinetic capillary chromatography to the analysis of illicit drug seizures

The application of micellar electrokinetic capillary chromatography (MECC) to the analysis of illicit drug seizures is presented. Areas investigated include general screening and qualitative and, in some instances, quantitative analysis of various drugs, including heroin, opium, cocaine, amphetamines, LSD and anabolic steroids. Due to its high efficiency, high selectivity and general applicability, MECC is well suited for forensic drug analyses.     

Determination of amphetamines in human urine by liquid chromatography with fluorimetric detection using a solid-phase extraction procedure

A precise and feasible HPLC method has been developed for the analysis of amphetamine (AMPH), methamphetamine (MAMPH) and methylenedioxymethamphetamine (MDMA, ecstasy) in human urine. A chromatographic run on a C8 Genesis (150 mm x 4.6 mm, 5 microm) column maintained at 30 degrees C lasts about 17 min, using a mobile phase composed of ACN (12%) and a pH 2.5 phosphate buffer (88%) containing 0.3% triethylamine. Mirtazapine was used as the internal standard. Good linearity was found in the 100-2000 ng/mL concentration range for AMPH and MAMPH and in the 12-2000 ng/mL concentration range for MDMA. The pretreatment of urine samples was carried out by means of a careful SPE procedure on C2 cartridges. The extraction yields were very satisfactory for all analytes, with average values greater than 97%. The leading conditions allowed the determination of AMPH, MAMPH and MDMA with satisfactory precision and accuracy. The method has been successfully applied to the determination of the analytes in urine of AMPH users.     

The Henry reaction: spectroscopic studies of nitrile and hydroxylamine by-products formed during synthesis of psychoactive phenylalkylamines

A clandestine two-step route to psychoactive racemic phenylalkylamines utilises the Henry reaction. In the first step an aromatic aldehyde reacts with a nitroalkane to give the nitrostyrene intermediate. In the second step the nitrostyrene is reduced to the phenylalkylamine. An impurity profile of both steps was evaluated through the synthesis and analysis of common street derivatives. The formation of nitrile impurities in the nitroaldol reaction and hydroxylamine impurities in the reduction step were shown by NMR spectroscopy and GC-MS. A selection of reducing agents has been used to give the phenylalkylamines, together with variable quantities of the partially reduced hydroxylamine product. GC-MS analysis of the hydroxylamines showed heat-induced disproportionation which led to the detection of the corresponding oximes.      

Class identity assignment for amphetamines using neural networks and GC–FTIR data

An exploratory analysis was performed in order to evaluate the feasibility of building of neural network (NN) systems automating the identification of amphetamines necessary in the investigation of drugs of abuse for epidemiological, clinical and forensic purposes. A first neural network system was built to distinguish between amphetamines and nonamphetamines. A second, more refined system, aimed to the recognition of amphetamines according to their toxicological activity (stimulant amphetamines, hallucinogenic amphetamines, nonamphetamines). Both systems proved that discrimination between amphetamines and nonamphetamines, as well as between stimulants, hallucinogens and nonamphetamines is possible (83.44% and 85.71% correct classification rate, respectively). The spectroscopic interpretation of the 40 most important input variables (GC–FTIR absorption intensities) shows that the modeling power of an input variable seems to be correlated with the stability and not with the intensity of the spectral interaction. Thus, discarding variables only because they correspond to spectral windows with weak absorptions does not seem be not advisable.     

Simultaneous quantification of amphetamines, caffeine and ketamine in urine by hollow fiber liquid phase microextraction combined with gas chromatography-flame ionization detector

A method of hollow fiber (HF) liquid phase microextraction (LPME) combined with gas chromatography (GC)-flame ionization detection (FID) was developed for the simultaneous quantification of trace amphetamine (AP), methamphetamine (MA), methylenedioxyamphetamine (MDA), methylenedioxymethamphetamine (MDMA), caffeine and ketamine (KT) in drug abuser urine samples. The factors affecting on the extraction of six target analytes by HF-LPME were investigated and optimized, and the subsequent analytical performance evaluation and real sample analysis were performed by the extraction of six target analytes in sample solution containing 30% NaCl (pH 12.5) for 20 min with extraction temperature of 30 °C and stirring rate of 1000 rpm. Under such optimal conditions, the limits of detection (LODs, S/N = 3) for the six target analytes were ranged from 8 μg/L (AP, KT) to 82 μg/L (MDA), with the enrichment factors (EFs) of 5-227 folds, and the relative standard deviations (RSDs, n = 7) were in the range of 6.9-14.1%. The correlation coefficients of the calibration for the six target analytes over the dynamic linear range were higher than 0.9958. The application feasibility of HF-LPME-GC-FID in illegal drug monitoring was demonstrated by analyzing drug abuser urine samples, and the recoveries of target drugs for the spiked sample ranging from 75.2% to 119.3% indicated an excellent anti-interference capability of the developed method. The proposed method is simple, effective, sensitive and low-cost, and provides a much more accurate and sensitive detection platform over the conventional analytical techniques (such as immunological assay) for drug abuse analysis.