理学公司ZSX100e型X射线荧光光谱仪自动进样器故障分析

针对自动进样器复杂的故障现象,根据其控制系统工作原理进行故障原因分析,总结了在无经验情况下进行仪器维修的方法.     

GC–MS法测定水体中甲基汞和乙基汞

用巯基棉富集,四乙基硼化钠衍生,气相色谱–质谱联用法测定水体中的甲基汞和乙基汞,线性范围为10~150 ng/L,线性范围内的重复性相对标准偏差(n=10)甲基汞为4.63%,乙基汞为5.52%,方法回收率甲基汞为99.00%~103.01%,乙基汞为85.49%~97.59%。通过四乙基硼化钠衍生把甲基汞和乙基汞化转化成全烷基化合物,降低了甲基汞和乙基汞的活性,减少甲基汞和乙基汞在色谱柱上的吸附和峰拖尾的现象。方法适合实验室大批量样品的测定。     

Speciation of Mercury in Microalgae by Isotope Dilution-inductively Coupled Plasma Mass Spectrometry

Species-specific stable isotope dilution in combination with gold trap- or gas chromatography (GC)-inductively coupled plasma mass spectrometry (ICP-MS) is reported for the determination of inorganic mercury and methylmercury in diatoms (Chaetoceros curvisetus). The optimum conditions for the separation parameters were established. The isotope dilution analysis was performed using ¹⁹⁹Hg-enriched Hg²⁺ and laboratory-synthesized ²⁰¹Hg-enriched methylmercury. The absolute detection limits obtained with isotope dilution-ICP-MS were 9 pg for total mercury and 0.6 pg for methylmercury. The relative error of 7 Hg isotopic abundances based on the peak area measurements was better than 2.0% for 20 pg of methylmercury (as Hg) and 250 pg of inorganic mercury. The accuracy of the method was validated with a biological certified reference material. The developed method was then applied to investigate the uptake of inorganic mercury and methylmercury by C. curvisetus. Continuous uptake of inorganic mercury and methylmercury was observed during 5 days of incubation.     

土壤及蔬菜中微量汞的同位素稀释电感耦合等离子体质谱测定

建立了微波消解电感耦合等离子体质谱同位素稀释(ID/ICP-MS)测定微量汞的方法。考察了仪器参数及测量条件对汞同位素比值RHg(202Hg/200Hg)测量的影响,根据同位素比值测量误差的传递因子优化了富集同位素稀释剂(202Hg98%)的加入量,并以铊同位素比值(205Tl/203Tl)作为RHg(202Hg/200Hg)测量时发生质量歧视效应的校正因子;通过反同位素稀释法标定了富集汞同位素稀释剂的浓度。利用所建立的ID/ICP-MS方法测定了杨树叶(GBW07604)和湖积物(GBW07423)2种标准参考物中汞的含量,回收率分别为112%和100%。该方法具有准确度高、精密度好等优点,且样品前处理简便,适用于土壤及蔬菜等样品中微量及痕量汞的准确测定。     

In Situ Explosive Detection Using a Miniature Plasma Ion Source and a Portable Mass Spectrometer

A small low-temperature plasma (LTP) ionization probe was coupled to a portable mass spectrometer for the rapid detection of trace explosives on surfaces. Using only a small diaphragm pump to supply ambient air to the LTP source, 100 ng each of pentaerythritol tetranitrate (PETN), 1,3,5-trinitroperhydro-1,3,5-triazine (RDX), and 2,4,6-trinitrophenylmethylnitramine (Tetryl) were detectable on glass in under 1 minute. The main ion signal from these molecules (M) is the [M + NO₃]^? species. While much optimization remains, it is believed that this miniature LTP source will remove the need for external gas cylinders and additional heating for in situ explosives detection using portable mass spectrometers.     

样品处理方法对测定汞的影响

研究了两种样品前处理方法——湿法消解法和微波消解法对汞测定结果的影响。结果表明，用微波消解法测得的结果要比传统的湿法消解法结果较为可靠，特别是对于难分解的样品(如化妆品)，尤其在含量很低时，要尽量使用微波消解。     

Determining Solubility and Diffusivity by Using a Flow Cell Coupled to a Mass Spectrometer

One of the main challenges in metal–air batteries is the selection of a suitable electrolyte that is characterized by high oxygen solubility, low viscosity, a liquid state and low vapor pressure across a wide temperature range, and stability across a wide potential window. Herein, a new method based on a thin layer flow through cell coupled to a mass spectrometer through a porous Teflon membrane is described that allows the determination of the solubility of volatile species and their diffusion coefficients in aqueous and nonaqueous solutions. The method makes use of the fact that at low flow rates the rate of species entering the vacuum system, and thus the ion current, is proportional to the concentration times the flow rate (c?u) and independent of the diffusion coefficient. The limit at high flow rates is proportional to . Oxygen concentrations and diffusion coefficients in aqueous electrolytes that contain Li⁺ and K⁺ and organic solvents that contain Li⁺, K⁺, and Mg²⁺, such as propylene carbonate, dimethyl sulfoxide tetraglyme, and N‐methyl‐2‐pyrrolidone, have been determined by using different flow rates in the range of 0.1 to 80 μL s^?1. This method appears to be quite reliable, as can be seen by a comparison of the results obtained herein with available literature data. The solubility and diffusion coefficient values of O₂ decrease as the concentration of salt in the electrolyte was increased due to a “salting out” effect.     

Determination of Mercury in Urine and Seawater by Flow Injection Vapor Generation Isotope Dilution Inductively Coupled Plasma Mass Spectrometry

A simple and inexpensive laboratory-built vapor generator was used with inductively coupled plasma mass spectrometry (ICP-MS) for the determination of mercury in urine and seawater samples. The applications of vapor generation ICP-MS alleviated the non-spectroscopic interferences and the sensitivity problem of mercury determination encountered when the conventional pneumatic nebulizer was used for sample introduction. The concentration of mercury was determined by isotope dilution method. The isotope ratio of mercury was calculated from the peak areas of each injection peak. The repeatability of the peak areas and isotope ratio determinations of seven consecutive injections of 1 ng mL^?1 Hg solution were 2.3% and 2.2%, respectively. This method has a detection limit of 0.07 ng mL^?1 for mercury. This method was applied to determine mercury in a CASS-3 nearshore seawater reference sample, NASS-4 open ocean seawater reference sample, NIST SRM 2670 freeze-dried urine reference sample and several urine and seawater samples collected from National Sun Yat-Sen University. The results for the reference samples agreed satisfactorily with the reference values. Results for other samples analyzed by the isotope dilution method and the method of standard additions agreed satisfactorily. Precision was better than 10% for most of the determinations.     

小型高分辨电子轰击离子源反射式飞行时间质谱仪的研制

常用的气体分析质谱仪使用四极杆质谱作为分析器,分辨率一般低于300,无法解决同质量数离子带来的干扰问题.本实验自行研制了一种小型高分辨气体分析质谱仪,它采用电子轰击离子源反射式飞行时间质量分析器.仪器腔体总长45 cm,在m/z 28的位置,质量分辨率达到3000(Full width at half maximum,FWHM),实现了CO和N2的半峰谷分离;在m/z 69的位置,仪器分辨率达到5000(FWHM).在直接大气压进样条件下,可以检测到空气中136Xe(含量7.8 μ g/m3)和80Kr(含量2.8 μg/m3).使用ADC采集时,仪器的动态范围为1 06.该仪器将作为高端气体质谱仪,应用于过程监测在线分析、环境有机挥发物研究、热分析质谱及催化反应监测等领域.     

线性离子阱飞行时间质谱仪的研制及性能表征

基于飞行时间质谱技术、线性离子阱技术、大气压电离源等核心技术,自制了一款台式高分辨线性离子阱飞行时间联用质谱仪器(LIT-TOF MS)。以电喷雾离子源对仪器性能进行表征:LIT-TOF MS的质量分辨率超过12 000(利血平m/z 609),质量范围达到33～1 922 amu,灵敏度为1μg/L;能够实现MS3的三级质谱分析效果。对氨基酸进行了定性及定量的初步应用分析,结果表明:LIT-TOF MS可为代谢组学研究中实时、在线、高通量测定生物复杂样品中氨基酸的含量及其变化提供一定依据。该仪器能与多种常压电离技术联用,有望用于药品、环境、食品等领域。     

盐酸消解-原子荧光光谱仪测定土壤中总汞

本研究利用原子荧光光谱仪,探寻适合本实验室测定土壤总汞的方法。实验中对沸水浴消解和电热板消解这两种土壤样品的前处理方法、消解液种类以及仪器检测等因素进行条件试验,结果表明：土壤样品选用(1+1)盐酸溶液在沸水浴下加热消解、在热汞条件下分析待测液中的总汞含量是最佳样品消解及测定方法,该方法标准曲线的相关系数大于0.999,仪器最低检出限为0.006μg/g,精密度为1.2%~4.8%(n=7),样品准确度满足标准土样的要求。该方法快速简单,空白背景低,样品精密度准确度较高,适用于土壤中总汞的测定。     

飞行时间质谱仪固体样品自动进样系统研制

以常规型飞行时间质谱仪为基础,通过配置移动平台、样品杆、工业相机、LED灯源、工业显示屏等部件,研制了一套飞行时间质谱仪用固体样品自动进样系统,实现了固体有机样品的直接进样分析。该装置具有一定的普适性,可为相关实验室设备升级改造提供借鉴和参考。该装置可进行难溶未知有机化合物的结构剖析,实现目标物的快速筛查,且操作人员可实时观测锥孔处样品状态并可软件操控进样位置,实现人机分离的自动化测试。     

静态灼烧氧化法制备有机碳同位素质谱分析样品

针对目前国内大多数实验室采用密封安瓶法制备有机碳同位素质谱分析样品所存在的不足之处，设计了呈套静态灼氧化法制备有机碳同位素质谱分析样品的实验系统，该系统具有实验精度高，操作方便，经济安全等特点，适合于在国内同位素实验室中推广应用。     

A Bulk Resin Bead Procedure To Obtain Uranium And Plutonium From Radioactive Solutions For Mass Spectrometric Analysis

Abstract

A method is described for extracting representative uranium and plutonium samples from highly radioactive solutions for isotopic mass spectrometric analysis. Anion resin beads in the nitrate form are used to effect separation from fission products and other actinides. Conditions required to achieve separation are proper adjustment of the uranium and nitric acid concentrations. Once uranium and plutonium are adsorbed, each bead serves as a sample for mass spectrometric analysis, with plutonium and uranium being run sequentially from the same bead. Quantitative determination of the two elements is effected through the technique of isotopic dilution.     

可移动激光质谱仪的研制与应用

激光质谱法是一种新的环境测污方法,具有高灵敏度、高选择性、多组分同时测量和快速实时的特点。本研究介绍了新近研制的可移动激光质谱仪的系统结构、各部分功能、原理以及主要技术指标。该仪器能在大气压下采样,并在设计过程中解决了记忆效应,使用输出波长248nm的KrF准分子激光器,可以对芳香烃进行多组分同时检测。该仪器对机动车尾气中苯系物含量的实时在线测量结果表明,尾气中含有苯、甲苯、二甲苯、三甲苯、萘、甲基萘等多种芳香烃污染物,检测的灵敏度达0．1mg／m^3,时间响应可达0．1s。     

液相色谱-同位素稀释质谱法测定配方奶粉中的烟酰胺

对复杂基体中微量化合物的准确定量是分析化学的重要目标之一。常规的方法是选择与待测物性质相似的内标物,以抵消样品处理过程的待测物损失。由于待测物的同位素标记试剂与待测物具有最为接近的物理与化学性质,所以是最理想的内标物。该文以氘代烟酰胺为内标物,采用液相色谱-同位素稀释质谱法(LC-IDMS)测定了配方奶粉中烟酰胺的含量。测定结果的相对标准偏差为0.94%。方法的准确性高、特异性高、重复性好,可实现复杂基体中维生素含量的准确测定。参加国际比对实验CCQM-P78,结果与国际实验室的结果等效一致。     

双道原子荧光光谱法测定蔬菜中的砷和汞

采用湿法消解蔬菜样品,用AFS-230E型双道原子荧光光度计测定蔬菜中的As和Hg重金属含量。在最佳实验条件下,As和Hg元素的工作曲线相关系数(r)分别为0.999 2和0.999 6,检出限分别为0.011 9和0.013 9μg/L,加标回收率分别为:91.6%~101.5%和89.8%~97.3%,相对标准偏差(RSD,n=7)分别为1.4%和0.52%,方法可供各地测定各类蔬菜中As和Hg等重金属元素含量作参考。     

质谱在线连续检测系统的建立及应用实例

设计和建立了一种质谱在线连续检测系统。该系统响应迅速,操作灵活。可直接与反应系统或与色谱等联机使用,对所有的气相反应和有可挥发组分的液相反应进行在线检测。在ＺｒＯ２－Ａ１２Ｏ３上进行了ＮＨ３吸脱附和ＣＯ脉冲反应的研究,获得了重现性很好的结果。     

Simulation of the Collisional Cooling Effect in a Quadrupole Ion Trap Mass Spectrometer

Examination of the collisional cooling effect of the buffer gases on ion trapping and detection in an ion trap mass spectrometer has been undertaken by the SIMION 3D program. Computation for the kinetic energy of ions under various conditions was used to account for the effects of collisional cooling of ions. Several parameters that may affect the collisional cooling effects of ions are evaluated including the existence and the variation of pressure of the buffer gas; the temperature of the ion trap; the size of the inner radius of the ion trap electrodes; the mass to charge ratio of ions; the alternative buffer gases and the q_z. values which establish the ion trap trapping environment.     

Modification of Reflectron Time-of-Flight Mass Spectrometer for Photodissociation of Mass-Selected Cluster lons

We introduce a modification of reflectron time-of-flight mass spectrometer for laser photodissociation of mass-selected ions. In our apparatus, the ions of interests were selected by a mass gate near the first space focus point and decelerated right after the mass gate, were then crossed by a laser beam for dissociation. The daughter ions and surviving parent ions were re-accelerated and analyzed by the reflectron time-of-flight mass spectrometer. Compared to the designs reported by other research groups, our selection-deceleration-dissociation-reacceleration approach has better daughter-parent-ions-separation, easier laser timing, and better overlapping between the ion beam and laser beam. We also conducted detailed cal- culations on the parent ion and daughter ion flight times, and provided a simplified formula for the calibration of daughter ion mass.