Electrospun Nanofibers of Poly(methylmethacrylate)/Polystyrene Blend as a Microcolumn Extraction Sorbent Followed by Corona Discharge Ion Mobility Spectrometry for Analysis of Tramadol in Biological Fluids

Electrospun nanofibers from poly(methylmethacrylate) (PMMA) and polystyrene (PS) blend were used as a sorbent to extract tramadol from urine and plasma samples. Then, the tramadol concentration was determined by corona discharge ion mobility spectrometry. The hydrophilic (PMMA) and hydrophobic (PS) properties of the blend polymer improved extraction efficiency of the analyte. The scanning electron microscopy images of the PMMA/PS nanofibers showed a diameter range of 130–600 nm with a smooth morphology. Parameters affecting extraction efficiency were optimized and under the optimized conditions, the dynamic ranges and detection limit of tramadol were found to be 30–500 and 10–200 ng mL^?1, and 9.4 and 1.6 ng mL^?1 in plasma and urine samples, respectively.     

Negative Corona Discharge Ion Source Under Ambient Conditions with Mini Line-cylinder Electrodes

A novel ambient negative corona discharge ion source with mini line-cylinder electrodes is designed. The diameters of inner and outer electrode are 0.16 and 4 mm respectively. With a special assembly method, a perfect coaxiality of the two electrodes is obtained. An injection system utilizing a temperature control technique, achieves a constant and stable concentration of the sample, which is critical to the experiment. The formulas of the corona onset voltage of line-cylinder electrodes are also introduced. The experiment results show that negative substances such as formic acid and acetic acid can be ionized under ambient conditions. When combined with micro electrical mechanical system fabricationprocess, the volume of the ion source can be reduced dramatically, but there is an undesirable surface discharge. To solve the surface discharge problem, an improved structure was designed and tested. The simplicity of the interface of the ion source makes it suitable for mass spectrometer, micro mass spectrometer, ion mobility spectrometer, and high-field asymmetric waveform ion mobility spectrometer applications.     

Analysis of dextromethorphan and pseudoephedrine in human plasma and urine samples using hollow fiber-based liquid–liquid–liquid microextraction and corona discharge ion mobility spectrometry

We report on the use of hollow fiber liquid-liquid-liquid microextraction (HF-LLLME) followed by corona discharge ion mobility spectrometry for the determination of dextromethorphan and pseudoephedrine in urine and plasma samples. The effects of pH of the donor phase, stirring rate, ionic strength and extraction time on HF-LLLME were optimized. Under the optimized conditions, the linear range of the calibration curves for dextromethorphan in plasma and urine, respectively, are from 1.5 to 150 and from 1 to 100 ng mL^?1. The ranges for pseudoephedrine, in turn, are from 30 to 300 and from 20 to 200 ng mL^?1. Correlation coefficients are better than 0.9903. The limits of detection are 0.6 and 0.3 ng mL^?1 for dextromethorphan, and 8.6 and 4.2 ng mL^?1 for pseudoephedrine in plasma and urine samples, respectively. The relative standard deviations range from 6 to 8%.

Analysis of testosterone in human urine using molecularly imprinted solid-phase extraction and corona discharge ion mobility spectrometry

Analysis of testosterone was accomplished using corona discharge ion mobility spectrometry. Molecular imprinted polymer was used for the extraction and pre-concentration of testosterone. Analytical parameters including precision, dynamic range and detection limit were obtained. The linear dynamic range was from 10 to 250 ng/mL and the limit of detection was 0.9 ng/mL. The proposed method was used for analysis of testosterone in urine samples. A urine sample from a 3-year-old girl was used as the blank. The RSD was below 10%. The obtained results from the method were also compared with the standard method for analysis of testosterone using SPE-HPLC analysis. The results demonstrate the accuracy of the method.     

一种用于高场非对称波形离子迁移谱系统的新型敞开式化学离子源

根据高场非对称波形离子迁移谱(FAIMS)系统的要求, 本文提出了一种新型敞开式直流电晕放电化学离子源. 该离子源主要由内线电极、外筒电极和牵引电极组成, 内、外电极半径分别是0.08、2 mm. 筒壁电极上开有对称的4个槽, 用于通入样品和牵引离子. 质谱实验结果表明, 该离子源能够在敞开环境下很好地离子化丙酮、乙醇、苯胺、N,N-二甲基甲酰胺、甲基磷酸二甲酯(DMMP)、乙酸乙酯、甲酸、乙酸、苯酚等正、负电性物质. 静电计测试实验结果说明该离子源能够稳定地产生离子电流. 通过分析不同时刻的谱图发现, 在不同时间点上产生的主要离子相同, 具有很好的稳定性. 利用感应耦合等离子体(ICP)工艺在硅片上加工了该离子源, 从而验证了该结构可以由微机电系统(MEMS)加工技术实现. 该离子源具有体积小、结构简单、无辐射、工作稳定等特点, 不仅可以满足FAIMS系统的要求, 还可用于敞开式质谱、微型质谱仪、离子迁移谱(IMS)等仪器.     

Determination of aflatoxins B1 and B2 using ion mobility spectrometry

This paper describes total determination of aflatoxins B1 and B2 in pistachio samples using corona discharge ion mobility spectrometry (IMS). A new injection port was designed to introduce liquid samples into the IMS. Using this port, the liquid solvent (methanol) containing standard aflatoxins or an extracted sample was directly introduced into the injection port. Calibration curves resulting from experimental analyses were linear within two orders of magnitude and relative standard deviations (R.S.D.) were less than 10%. The limit of detection (LOD) was found to be 0.25 ng for both aflatoxins. Addition of ammonia as the dopant to the carrier gas improved the LOD by a factor of 2.5. Pistachio samples were analyzed to demonstrate the capability of the proposed method in detecting aflatoxins in real samples.     

超高效液相色谱-串联质谱法测定血浆与尿液中14种麻痹性贝类毒素北大核心CSCD

人体生物基质中麻痹性贝类毒素的检测对其引起的食物中毒诊断和救治具有重要意义。研究建立了超高效液相色谱-串联质谱法测定血浆、尿液中14种麻痹性贝类毒素的分析方法。实验比较了不同固相萃取柱的影响,优化了前处理条件和色谱条件,血浆样品采用0.2 mL水、0.4 mL甲醇、0.6 mL乙腈提取后直接上机测定,尿液样品采用0.2 mL水、0.4 mL甲醇、0.6 mL乙腈提取,聚酰胺(PA)固相萃取柱净化后上机测定。采用Poroshell 120 HILIC-Z色谱柱(100 mm×2.1 mm,2.7μm)对14种贝类毒素进行分离,流动相为含0.1%(v/v)甲酸的5 mmoL/L甲酸铵缓冲溶液和0.1%(v/v)甲酸乙腈溶液,流速为0.50 mL/min。在电喷雾模式(ESI)下进行正负离子扫描,采用多反应监测(MRM)模式检测,外标法定量。结果表明,对于血浆和尿液样品,14种贝类毒素分别在0.24~84.06 ng/mL范围内线性关系良好,相关系数均大于0.995。尿液检测的定量限为4.80~34.40 ng/mL,血浆检测的定量限为1.68~12.04 ng/mL。尿液和血浆样品在1、2和10倍定量限加标水平下平均回收率为70.4%~123.4%,日内精密度为2.3%~19.1%,日间精密度为4.0%~16.2%。应用建立的方法对腹腔注射14种贝类毒素小鼠血浆和尿液进行测定,20份血浆样本中检出含量分别为19.40~55.60μg/L和8.75~13.86μg/L。该方法操作简便,样品取样量少,方法灵敏度高,适用于血浆和尿液中麻痹性贝类毒素的快速检测。     

Determination of MTBE in drinking water using corona discharge ion mobility spectrometry

Methyl tertiary-butyl ether (MTBE) is an organic compound which is used as a gasoline additive. Contamination of ground and surface water can occur due to large scale use of MTBE and its high solubility in water. According to United State Environmental Protection Agency (USEPA), MTBE is a possible human carcinogen at high doses and its detection and measurement in the water is important as concerned about human health. In this work, ion mobility spectrometry (IMS) equipped with a corona discharge ionization source was used for determination of MTBE in drinking water. Both pure and aqueous solutions of MTBE were studied and their ion mobility spectra were obtained at different temperatures. Using a calibration curve for detection of MTBE in drinking water, a detection limit (LOD) of 1 mg/L was obtained by IMS. This work proved that, IMS with corona discharge can be used for fast and direct detection of MTBE in water sample without any sample preparation.     

Adsorption of gaseous formaldehyde and carboxylic acids by ammonium-ion-exchanged alpha-zirconium phosphate

Ammonium-ion-exchanged alpha-Zr(HPO(4))(2)H(2)O (alpha-ZrP) was obtained as a single phase with the interlayer distance of 9.4 A by the ion-exchange of proton with ammonium ion. The ammonium ion-exchanged alpha-ZrP could adsorb ill-smelling gases, such as formaldehyde and carboxylic acids (formic acid, acetic acid, propionic acid, and butyric acid). The adsorption amounts of carboxylic acids increased in the order, butyric acid相似文献   

Optimization of dispersive liquid-liquid microextraction and improvement of detection limit of methyl tert-butyl ether in water with the aid of chemometrics

Dispersive liquid-liquid microextraction (DLLME) coupled with gas chromatography-mass spectrometry-selective ion monitoring (GC-MS-SIM) was applied to the determination of methyl tert-butyl ether (MTBE) in water samples. The effect of main parameters affecting the extraction efficiency was studied simultaneously. From selected parameters, volume of extraction solvent, volume of dispersive solvent, and salt concentration were optimized by means of experimental design. The statistical parameters of the derived model were R(2)=0.9987 and F=17.83. The optimal conditions were 42.0 μL for extraction solvent, 0.30 mL for disperser solvent and 5% (w/v) for sodium chloride. The calibration linear range was 0.001-370 μg L(-1). The improved detection limit with the aid of chemometrics was 0.3 ng L(-1). The relative standard deviation (RSD) with n=9 for 0.1 mg L(-1) MTBE in water with and without internal standard was 2.7% and 3.1%, respectively. Under the optimal conditions, the relative recoveries of spiked MTBE in different water samples were in the range of 100-105%.     

Highly sensitive method for the determination of JI-101, a multi-kinase inhibitor in human plasma and urine by LC-MS/MS-ESI: method validation and application to a clinical pharmacokinetic study

A highly sensitive, rapid assay method has been developed and validated for the estimation of JI-101 in human plasma and urine using LC-MS/MS-ESI in the positive-ion mode. The assay procedure involves extraction of JI-101 and alfuzosin (internal standard, IS) from human plasma/urine with a solid-phase extraction process. Chromatographic resolution was achieved on two Zorbax SB-C(18) columns connected in series with a PEEK coupler using an isocratic mobile phase comprising acetonitrile-0.1% formic acid in water (70:30, v/v). The total run time was 2.0 min. The MS/MS ion transitions monitored were 466.20 → 265.10 for JI-101 and 390.40 → 156.10 for IS. The method was subjected to rigorous validation procedures to cover the following: selectivity, sensitivity, matrix effect, recovery, precision, accuracy, stability and dilution effect. In both matrices the lower limit of quantitation was 10.0 ng/mL and the linearity range extended from ~10.0 to 1508 ng/mL in plasma or urine. The intra- and inter-day precisions were in the ranges 1.57-14.5 and 6.02-12.4% in plasma and 0.97-15.7 and 8.66-10.2% in urine. This method has been successfully applied for the characterization of JI-101 pharmacokinetics in cancer patients.     

单向气流负电晕放电离子迁移谱的研究及其在爆炸物检测中的应用

基于离子迁移谱的爆炸物探测仪多采用放射性电离源,发展非放射性电离源一直是该技术的研究热点。本研究基于电晕放电原理设计了一种新型负电晕放电电离源结构,结合自行研制的离子迁移谱仪,应用于痕量爆炸物的快速、高灵敏检测。单向气流模式下,对此电离源的气流、放电电压等运行参数进行了系统优化,得到最佳实验条件为：电晕放电电离源结构的电极环孔直径为3 mm,针-环距离为2 mm,放电电压为2400 V,漂气流速为1200 mL/min。在此条件下,避免了放电副产物氮氧化物和臭氧等引发的一系列复杂反应,得到了单一的反应试剂离子O-2(H2O)n。将其应用于爆炸物,如2,4,6-三硝基甲苯(TNT)、硝酸铵(AN)、硝化甘油( NG)、太安( PETN)、黑索金( RDX)等的高灵敏快速直接检测,对TNT的检测限达到200 pg/μL。结果表明,此负电晕放电电离源具有灵敏度高、结构简单、无辐射性、反应试剂离子单一等优点,在爆炸物快速高灵敏检测、公共安全保障等方面具有广阔的应用前景。     

Comparison of the performance of three ion mobility spectrometers for measurement of biogenic amines

The performance of three different types of ion mobility spectrometer (IMS) devices: GDA2 with a radioactive ion source (Airsense, Germany), UV-IMS with a photo-ionization source (G.A.S. Germany) and VG-Test with a corona discharge source (3QBD, Israel) was studied. The gas-phase ion chemistry in the IMS devices affected the species formed and their measured reduced mobility values. The sensitivity and limit of detection for trimethylamine (TMA), putrescine and cadaverine were compared by continuous monitoring of a stream of air with a given concentration of the analyte and by measurement of headspace vapors of TMA in a sealed vial. Preprocessing of the mobility spectra and the effectiveness of multivariate curve resolution techniques (MCR-LASSO) improved the accuracy of the measurements by correcting baseline effects and adjusting for variations in drift time as well as enhancing the signal to noise ratio and deconvolution of the complex data matrix to their pure components. The limit of detection for measurement of the biogenic amines by the three IMS devices was between 0.1 and 1.2 ppm (for TMA with the VG-Test and GDA, respectively) and between 0.2 and 0.7 ppm for putrescine and cadaverine with all three devices. Considering the uncertainty in the LOD determination there is almost no statistically significant difference between the three devices although they differ in their operating temperature, ionization method, drift tube design and dopant chemistry. This finding may have general implications on the achievable performance of classic IMS devices.     

超高效液相色谱-三重四极杆/复合线性离子阱质谱法同时快速测定血浆和尿液中84种有毒植物成分

采用超高效液相色谱-三重四极杆/复合线性离子阱的质谱联用技术,建立了同时快速测定血浆和尿液中84种有毒植物成分的方法。血浆样品经乙腈沉淀去蛋白和除磷脂、尿液样品经甲醇稀释后直接进样,以含0.1%（体积分数,下同）甲酸和2 mmol/L甲酸铵的97%乙腈水溶液、含0.1%甲酸的2 mmol/L甲酸铵水溶液作为流动相进行梯度洗脱,在Acquity BEH C₁₈色谱柱上实现分离,在电喷雾正离子多离子监测触发的增强子离子扫描（MRM-IDA-EPI）模式下检测,基质工作曲线内标法定量。血浆和尿液中84种待测物在相应的浓度范围内线性关系良好,相关系数均大于或等于0.9911,血浆和尿液中的检出限（S/N=3）分别为0.01~1和0.03~2 μg/L,准确度（平均加标回收率）为70.6%~124.5%,日内和日间精密度分别为0.7%~18.4%和1.1%~18.5%。该法简单、快速、灵敏、准确,可用于血浆和尿液中84种有毒植物成分的中毒检测。     

Fast high-performance liquid chromatographic determination of R(+)[(5,6-dichloro-2,3,9,9a-tetrahydro-3-oxo-9a-propyl-1-H-fluoren-7-yl)oxy]acetic acid in human plasma and urine

A simple and rapid high-performance liquid chromatographic method for the determination of R[(5,6-Dichloro-2,3,9,9a-tetrahydro-3-oxo-9a-propyl-1-H-fluoren-7-yl)oxy]acetic acid (I) in human plasma and urine is described. The method utilizes Bond-Elut® cartridge facilitate the drug extraction. Analysis is performed on a short reversed-phase column with a mobile phase consisting of acetonitrile and phosphate buffer and quantification is carried out by ultraviolet detection with a wave-length set at 340 nm. The method is linear and reproducible for both plasma and urine analyses (0.25–50) μg/mL) with the detection limit of 125 ng/mL of plasma and urine. Plasma and urine concentrations of / at selected time intervals following I.V. administration of single rising doses are presented.     

Direct determination of ammoniacal nitrogen in water samples using corona discharge ion mobility spectrometry

In this study, direct determination of ammoniacal nitrogen residues in water samples using corona discharge ion mobility spectrometry (CD-IMS) was investigated. Pyridine was used as an alternate reagent gas to enhance selectivity and sensitivity of the method. The results indicate that the limit of detection (LOD) was about 9.2x10(-3)mugmL(-1) and the linear dynamic range was obtained from 0.03 to 2.00mugmL(-1). The relative standard deviation was about 11%. Furthermore, this method was successfully applied to the direct determination of ammoniacal nitrogen in river and tap water samples and the results were compared with the Nessler method. The comparison of the results validates the potential of the proposed method as an alternative technique for the analysis of the ammoniacal nitrogen in water samples.     

Rapid monitoring and sensitive determination of DDT and its metabolites in water sample using solid-phase extraction followed by ion mobility spectrometry

Dichlorodiphenyl trichloroethane (DDT) as an organochlorine compound has been globally used as a pesticide for controlling soil-dwelling insects and treating diseases such as malaria and typhus. The degradation products of DDT and its metabolites have also negative effects on the environment. The present study has investigated the determination of DDT and its metabolites in water sample using ion mobility spectrometry (IMS) as a rapid and sensitive detection technique. For this purpose, DDT and its metabolites were extracted using reverse phase solid-phase extraction (SPE) from water samples. The samples were then recovered by eluting with methanol and finally, quantified using the corona discharge IMS technique. Injection and oven temperatures and the effect of dopant were optimized as experimental parameters influencing both detection and determination efficiencies. Degradation of DDT in IMS drift tube was studied and reduced mobility values of DDT and its metabolites were calculated. The developed method was validated using water sample to obtain good results for the determination of DDT at low levels (1 ng ml^?1) while spiked recoveries were obtained to be between 95.0–96.7%. The proposed method based on IMS proved to be a simple, inexpensive, rapid and sensitive procedure for the fast monitoring and determination of DDT and its main metabolites in water sample.     

A pulsed corona discharge switchable high resolution ion mobility spectrometer-mass spectrometer

A pulsed corona discharge ionisation source, a candidate replacement for 63Ni ionisation sources for ion mobility spectrometry, is described along with a new design of ion mobility spectrometer-mass spectrometer. Preliminary research on the characterisation of the reactant ion peaks associated with the use of this ionisation source was undertaken by assembling a pulsed corona discharge ionisation switchable high-resolution ion mobility spectrometer-mass spectrometer to enable the mobility spectra, atmospheric chemical ionisation mass spectra and selected-mass mobility spectra to be obtained. With ammonia doping at 2.39 mg m(-3) in air and a water content of approximately 80 mg m(-3) in the positive mode the observed response was attributable to the formation of 1(H2O)(n)NH4]+ and [(H2O)n(NH3)NH4]+ in the reaction region. The observed responses in the negative mode were more complex with evidence for the formation [(H2O)(n)O2]-, [(H2O)(n)CO3]-, [(H2O)(n)HCO3]-, [(H2O)(n)CO4]- and [(H2O)(n)NO3]-. The responses due to these species were clearly discernible in the resultant mobility spectra, with enough oxygen-based species formed to support analytically useful responses.     

阀切换-离子色谱法测定1,2-环氧丁烷产品中有机酸

建立了阀切换-离子色谱法测定1,2-环氧丁烷（1,2-BO）产品中有机酸（甲酸、乙酸和丙酸）的方法。样品经乙醇稀释后,通过阀切换技术,有机酸被IonPac TAC-ULP1捕集柱捕集,然后进入IonPac AS11分析柱分离,并由电导检测器检测。结果表明：甲酸、乙酸和丙酸均能实现较好地分离,在各自的范围内其色谱峰面积呈现良好的线性关系。实际样品的加标回收率为92.5%~111.8%,相对标准偏差小于5.6%（n=3）,检出限为0.60~4.80 μg/L。该方法具有前处理简单、快速、准确等特点,适用于不溶于水的有机体系中有机酸的分析。     

A rapid MCM‐41 dispersive micro‐solid phase extraction coupled with LC/MS/MS for quantification of ketoconazole and voriconazole in biological fluids

A rapid dispersive micro‐solid phase extraction (D‐μ‐SPE) combined with LC/MS/MS method was developed and validated for the determination of ketoconazole and voriconazole in human urine and plasma samples. Synthesized mesoporous silica MCM‐41 was used as sorbent in d ‐μ‐SPE of the azole compounds from biological fluids. Important D‐μ‐SPE parameters, namely type desorption solvent, extraction time, sample pH, salt addition, desorption time, amount of sorbent and sample volume were optimized. Liquid chromatographic separations were carried out on a Zorbax SB‐C₁₈ column (2.1 × 100 mm, 3.5 μm), using a mobile phase of acetonitrile–0.05% formic acid in 5 mm ammonium acetate buffer (70:30, v /v). A triple quadrupole mass spectrometer with positive ionization mode was used for the determination of target analytes. Under the optimized conditions, the calibration curves showed good linearity in the range of 0.1–10,000 μg/L with satisfactory limit of detection (≤0.06 μg/L) and limit of quantitation (≤0.3 μg/L). The proposed method also showed acceptable intra‐ and inter‐day precisions for ketoconazole and voriconazole from urine and human plasma with RSD ≤16.5% and good relative recoveries in the range 84.3–114.8%. The MCM‐41‐D‐μ‐SPE method proved to be rapid and simple and requires a small volume of organic solvent (200 μL); thus it is advantageous for routine drug analysis.