环境样品的前处理方法

由于基体复杂、干扰物多,环境样品能直接测定的比较少,随着仪器设备的发展和监测分析方法的更新,试样前处理工作越来越重要。本文系统地综述了大气、水体、土壤和底泥等不同形态环境样品的一般前处理过程及常用的分离方法。重点介绍了固相萃取、快速溶剂萃取、超临界萃取以及吹扫捕集等技术方法特点及其在环境样品前处理中的应用。对今后样品前处理技术发展方向作了展望。     

吉尔森自动化固相萃取仪及其在样品前处理中的应用

介绍了吉尔森自动固相萃取仪（ＡＳＰＥＣ）及其在样品前处理中的应用，实践表明ＡＳＰＥＣ可广泛用于体内药物分析，生化分析，环保分析以及食品分析中的自动化样品前处理，它不仅能自动处理各种样品，使分析人员从繁琐的工作中解放出来，更重要的是可以提高分析的准确度和精密度，便于方法的传递和实验室的质量控制。     

常用样品前处理设备的发展与展望

强调了样品前处理在分析化学中的地位,并介绍常用有机样品前处理流程涉及到提取、浓缩、净化等技术,常用无机样品前处理过程涉及到消解、灰化、熔融等技术,进一步阐述了这些技术的原理以及如何发展衍化为自动化设备。对国内外前处理设备发展状况进行了剖析,认为样品前处理设备这一细分行业,目前处于市场成长期,发展潜力巨大。最后,本文作者展望了前处理设备的发展趋势。     

总磷水样采集与前处理的差异性分析与建议

水质中总磷的测定结果与样品采集、前处理等步骤密切相关,不同的方式会得出不同的监测结果。对比水质相关采样规范以及总磷测定标准中的样品采集、前处理方法,从样品采集与前处理角度得出监测结果差异来源。通过实际样品的分析实验,验证了差异的显著性,并提出了水质中总磷测定的样品采集及前处理的相关建议。     

碘的质谱测量方法研究进展

近年来,电感耦合等离子体质谱（ICP-MS）技术的发展着力于应对基质更加复杂的样品和解决测量过程中的干扰问题,同时与进样、分离系统的联用技术也在快速发展,而加速器质谱（AMS）则朝着更加小型化和更高灵敏度的方向发展。ICP-MS测量前需要对样品进行前处理以消解和提取碘,而AMS测量前则还需对样品进一步分离富集和纯化。本文总结了ICP-MS和AMS的发展概况及其在碘测量方面的应用,归纳了ICP-MS和AMS测量含碘样品的前处理方法,综述了国内外总碘、碘同位素及碘形态的质谱测量方法新进展。     

GC-MS分析中的样品制备与前处理技术

综述了气相色谱-质谱联用仪分析样品的几种前处理技术,并对样品制备与前处理技术在今后的发展做了展望。     

基质辅助激光解析电离质谱靶上样

基质辅助激光解析电离飞行时间质谱(MALDI-TOF MS)技术已成为目前蛋白质组学研究中的经典技术。在该技术的成功应用过程中,合适的样品前处理方法起着首要和关键的作用。只有将合适的样品前处理方法与合适的有机基质结合起来,才能成功实现对多肽和蛋白质等生物大分子的准确鉴定。随着质谱分析向高灵敏度、高准确度、高通量的方向发展,出现了许多新的,可直接在MALDI靶上前处理的方法,极大地简化了对生物样本的处理步骤,同时减少了样品的损失。特别是将一些纳米材料用于MALDI靶上进行样品的前处理,为样品前处理方法的研究开辟了广阔的应用前景。     

食品安全检测中样品前处理技术研究进展

本文综述样品前处理技术在食品安全检测中的应用,主要包括食品中农药残留、兽药残留、重金属和环境污染物检测中需要的样品前处理技术,并对样品前处理技术的研究方向进行展望。     

土壤污染分析中样品采集与前处理方法探讨

土壤样品成分复杂，不同污染物需要采用不同的样品采集和前处理方法，本文重点对重金属、VOCs类、农药类、二恶英类和PCBs的前处理及测定方法进行了分析，比较了我国目前各种土壤消解方法的优、缺点，还介绍了日本现行的土壤前处理方法以及有关简易快速前处理和测定方法，以适应不同的环境管理的需求。     

ASE快速溶剂萃取—角决固体、半固体样品前处理的新技术

样品前随着现代化学分析技术的飞速发展 ,分析手段越来越向着快速、微量、准确、自动的方向发展 ,样品的分析时间基本在 2 0～ 30分钟 ,痕量样品的检测可达ｐｐｂ ｐｐｔ,但在样品的前处理方面 ,仍存在很大的问题 ,数小时数十小时的处理时间 ,大量的溶剂消耗和废液的处理 ,其结果造成萃取效率低、人为误差大 ,萃取成本高。有数据表明 ,完成一个实验 70～80 %甚至更多时间用在样品的前处理上 ,而给实验带来的误差有 6 0 %以上出自样品的前处理。样品前处理越来越成为现代分析方法发展的制约 ,已越来越引起人们的重视。美国戴安公司自 1996年…     

Effect of gallium focused ion beam milling on preparation of aluminium thin foils

Focussed ion beam milling has greatly extended the utility of the atom probe and transmission electron microscope because it enables sample preparation with a level of dimensional control never before possible. Using focussed ion beam it is possible to extract the samples from desired and very specific locations. The artefacts associated with this sample preparation method must also be fully understood. In this work, issues specifically relevant to the focussed ion beam milling of aluminium alloys are presented. After using the focussed ion beam as a sample preparation technique it is evident that gallium will concentrate in three areas of the sample: on the surface, on grain boundaries and at interphase boundaries. This work also shows that low-energy Ar ion nanomilling is potentially quite effective for removing gallium implantation layers and gallium from the internal surfaces of aluminium thin foils.     

Surface damage formation during ion-beam thinning of samples for transmission electron microscopy

All techniques employed in the preparation of samples for transmission electron microscopy (TEM) introduce or include artifacts that can degrade the images of the materials being studied. One significant cause of this image degradation is surface amorphization. The damaged top and bottom surface layers of TEM samples can obscure subtle detail, particularly at high magnification. Of the techniques typically used for TEM sample preparation of semiconducting materials, cleaving produces samples with the least surface amorphization, followed by low-angle ion milling, conventional ion milling, and focused ion beam (FIB) preparation. In this work, we present direct measurements of surface damage on silicon produced during TEM sample preparation utilizing these techniques. The thinnest damaged layer formed on a silicon surface was measured as 1.5 nm thick, while an optimized FIB sample preparation process results in the formation of a 22 nm thick damaged layer. Lattice images are obtainable from all samples.     

Site-specific structural investigations of oxidized nickel samples modified by plasma erosion processes

A focused ion beam was employed for local target preparation for EBSD analysis. The volume of the ion‐solid interaction is well below 50 nm at glancing incidence for metallic and transition metal oxide samples. Therefore, focused ion beam can successfully be used for electron backscatter diffraction (EBSD) sample preparation. The sample investigated consists of Ni covered with a NiO layer of ～5 μm thickness. Focused ion beam cross‐sectioning of these layers and subsequent electron imaging in addition to EBSD maps shows a bimodal structure of the oxide layer. In order to test the potential of such oxidized samples as electrode materials, single spark erosion experiments were performed. The erosion craters have diameters up to 40 μm and have a depth corresponding to the thickness of the oxide layer. In addition, a deformation zone produced by thermoshock accompanies the formation of the crater. This deformation zone was further investigated by EBSD analysis using a new way of sample preparation employing the focused ion beam technology. This target preparation routine is called Volume of Interest Transfer and has the potential of providing a full three‐dimensional characterization.     

国标高效液相色谱法测定黄曲霉毒素的不确定度评定

依据GB/T18979-2003《食品中黄曲霉毒素的测定-免疫亲和层洗净化高效液相色谱法和荧光光度法》中的HPLC法,对花生中黄曲霉毒素测量的不确定度进行分析评定,对样品的制备、标准溶液的配制及检测等影响因素进行分析,确定各分量的分布类型,并进行分步计算和整体合成。     

Novel method for the plan-view TEM preparation of thin samples on brittle substrates by mechanical and ion beam thinning

A new preparation method has been developed in order to avoid the breaking of brittle samples for plan-view TEM investigation during and after mechanical and ion beam thinning. The thinning procedure is carried out on a reduced size piece of the sample (about 1.6 x 0.8 mm(2) or about 1-1.6 mm diameter) that is embedded into a 3-mm-diameter Ti disk, which fits the sample holder of the TEM. The small sample size and the supporting metal disk assure the mechanical stability and minimize the possibility of breaking during and after the preparation: The Ti disk is placed on adhesive kapton tape, a cut piece of the sample is put into the slot of the disk, pressed onto the tape and embedded with glue. The tape keeps the parts in place and in the same plane, keeps the sample surface safe from the embedding glue and can be removed easily after the glue solidifies. Subsequently, the embedded sample is thinned from the rear by well-known mechanical and ion beam techniques until electron transparency. This simple solution lowers the risk of failed sample preparation remarkably and makes it possible to reduce the thickness of the sample to about 50 microm by mechanical thinning. As a result, dimpling becomes unnecessary and low angle ion milling gives a large transparent area for TEM. Its efficiency has been proved by successful preparation of numerous thin film samples on Si, sapphire, and glass substrates. The method is compatible with the widespread cross-sectional thinning procedures, and can be easily adopted by TEM laboratories.     

新鲜蔬菜水果的农药多残留快速检测

介绍了一种农药多残留快速检测方法，此方法样品前处理过程简单，快速，采用固相萃取和氮吹仪实现了样品的净化和浓缩；双柱，双检测器的仪器配置提高了检测结果的准确度和精密度。     

Cross-section analysis of organic light-emitting diodes

The 'lift-out' technique using a focused ion beam microscope was applied to prepare cross-sectional specimens of organic light-emitting diodes for use in transmission electron microscopy. The focused ion beam equally thins the organic/inorganic hybrid devices despite the difference in material hardness of the compounds. This allowed to overcome preparation difficulties of conventional techniques such as ion thinning or ultra-microtomy. Two different samples were prepared and studied by both conventional transmission electron microscopy and analytical electron microscopy to display some of the investigation possibilities which become available with this sample preparation method.     

Current mass spectrometry strategies for the analysis of pesticides and their metabolites in food and water matrices

Analysis of pesticides and their metabolites in food and water matrices continues to be an active research area closely related to food safety and environmental issues. This review discusses the most widely applied mass spectrometric (MS) approaches to pesticide residues analysis over the last few years. The main techniques for sample preparation remain solvent extraction and solid‐phase extraction. The QuEChERS (Quick, Easy, Cheap, Effective, Rugged, Safe) approach is being increasingly used for the development of multi‐class pesticide residues methods in various sample matrices. MS detectors—triple quadrupole (QqQ), ion‐trap (IT), quadrupole linear ion trap (QqLIT), time‐of‐flight (TOF), and quadrupole time‐of‐flight (QqTOF)—have been established as powerful analytical tools sharing a primary role in the detection/quantification and/or identification/confirmation of pesticides and their metabolites. Recent developments in analytical instrumentation have enabled coupling of ultra‐performance liquid chromatography (UPLC) and fast gas chromatography (GC) with MS detectors, and faster analysis for a greater number of pesticides. The newly developed “ambient‐ionization” MS techniques (e.g., desorption electrospray ionization, DESI, and direct analysis in real time, DART) hyphenated with high‐resolution MS platforms without liquid chromatography separation, and sometimes with minimum pre‐treatment, have shown potential for pesticide residue screening. The recently introduced Orbitrap mass spectrometers can provide high resolving power and mass accuracy, to tackle complex analytical problems involved in pesticide residue analysis. © 2010 Wiley Periodicals, Inc., Mass Spec Rev 30:907–939, 2011     

离子色谱法与火焰原子吸收法测定钾、钠、钙、镁离子标准样品的实验比对

国家环境标准样品在实验室质量控制与质量保证方面起着关键性的作用，但同时在新方法分析的验证方面也起着重要的步骤。主要是利用火焰原子吸收法与离子色谱法，对钾、钠、钙，镁离子的混合标样分析做了一个比对，认为用离子色谱法同样可以准确分析钾、钠、钙、镁离子。     

High spatial resolution secondary ion imaging and secondary ion mass spectrometry of aluminium-lithium alloys

Samples of aluminium-lithium alloys have been observed by scanning ion microscopy and analysed by secondary ion mass spectrometry. The high signal-to-noise ratio of the positive secondary lithium ion opens up the possibility of both high resolution imaging and microanalysis of lithium distributions in aluminium and other materials. Some of the problems encountered due to sample preparation are discussed and ion images of both the artefacts and the true lithium distribution are shown.