Absolute quantification of superoxide dismutase in cytosol and mitochondria of mice hepatic cells exposed to mercury by a novel metallomic approach

In the last years, the development of new methods for analyzing accurate and precise individual metalloproteins is of increasing importance, since numerous metalloproteins are excellent biomarkers of oxidative stress and diseases. In that way, methods based on the use of post column isotopic dilution analysis (IDA) or enriched protein standards are required to obtain a sufficient degree of accuracy, precision and high limits of detection. This paper reports the identification and absolute quantification of Cu,Zn-superoxide dismutase (Cu,Zn-SOD) in cytosol and mitochondria from mice hepatic cells using a innovative column switching analytical approach. The method consisted of orthogonal chromatographic systems coupled to inductively coupling plasma-mass spectrometry equipped with a octopole reaction systems (ICP-ORS-MS) and UV detectors: size exclusion fractionation (SEC) of the cytosolic and mitochondrial extracts followed by online anion exchange chromatographic (AEC) separation of Cu/Zn containing species. After purification, Cu,Zn-SOD was identified after tryptic digestion by molecular mass spectrometry (MS). The MS/MS spectrum of a doubly charged peptide was used to obtain the sequence of the protein using the MASCOT searching engine. This optimized methodology reduces the time of analysis and avoids the use of sample preconcentration and clean-up procedures, such as cut-off centrifuged filters, solid phase extraction (SPE), precipitation procedures, off-line fractions insolates, etc. In this sense, the method is robust, reliable and fast with typical chromatographic run time less than 20 min. Precision in terms of relative standard deviation (n = 5) is of 3–5% and detection limits is 0.21 ng Cu g⁻¹.     

混凝土中重金属元素溶出量的质谱分析

利用带八极杆碰撞/反应池和屏蔽炬技术的电感耦合等离子体质谱直接测定混凝土中Cr,Mn,Ni,Cu,Zn,As,Cd,Sn,Sb,Pb等多种重金属元素的溶出量。通过向碰撞池中引入氢气和氦气消除多元素分子离子的干扰,以50μg/L的Ge,In,Tb为内标元素校正基体干扰和漂移。10种待测元素的检出限为0.001～0.033μg/L,相对标准偏差为0.85%～2.8%,样品的加标回收率在91.1%～103.9%之间。     

Comparison of no gas and He/H2 cell modes used for reduction of isobaric interferences in selenium speciation by ion chromatography with inductively coupled plasma mass spectrometry

Inductively coupled plasma mass spectrometry (ICP-MS) used for the detection of most common selenium isotopes ⁷⁸Se (23.8%, abundance) and ⁸⁰Se (49.6%, abundance) is interfered in the presence of ³⁸Ar⁴⁰Ar⁺ and ⁴⁰Ar⁴⁰Ar⁺ in argon (Ar) gas. To address this issue, ICP-MS with an octopole reaction system (ORS) was explored for the detection of selenite and selenate, which was separated by anion-exchange chromatography. Results indicate that it was possible to detect ⁷⁸Se using no collusion gas, while to detect ⁸⁰Se a H₂ as the collusion/reaction gas was recommended since the background and noise were significantly reduced using H₂ as the gas. The selenium speciation interested was separated on a new column (G3154/101A, Agilent technologies) within 5 min using a mobile phase containing 10 mM NH₄H₂PO₄ and 20 mM NH₄NO₃ at pH 6.5. Linear plots were obtained in a concentration range of 1–200 μg/L with detection limits less than of 0.4 μg/L for ⁸⁰Se (IV) and 0.6 μg/L for ⁸⁰Se (VI) using H₂ as the reaction gas. Finally, the proposed method was used in the determination of selenium in water and soil.     

电感耦合等离子体质谱法测定食品级磷酸盐中杂质元素

建立了电感耦合等离子体质谱(ICP-MS)法测定食品级磷酸盐中Mg,Ti,V,Cr,Fe,Co,Ni,Cu,Zn,As,Cd,Pb等12种杂质元素的分析方法。样品经硝酸消解后直接进行分析,应用碰撞/反应池(ORS)技术有效地消除了多原子离子对待测元素的干扰,选用Sc,Y,In,Bi等元素为内标混合液校正基体干扰和漂移。研究结果表明,该方法对12种待测元素的检出限在0.004～0.362 μg·L-1之间。本法简便,快速,能满足食品级磷酸盐中多种杂质元素同时测定的分析需求。     

电感耦合等离子体质谱法测定甜味剂中重金属元素

采用微波消解-八极杆碰撞/反应池(ORS)-电感耦合等离子体质谱仪(ICP-MS)测定甜味剂中Cr,Co,Ni,Cu,As,Cd,Sn,Sb,Hg,Pb等十种重金属元素的含量。样品用硝酸+双氧水消解后,试液直接用ICP-MS法进行测定。应用ORS技术,有效地消除了多原子离子对待测元素的干扰,选用45Sc,89Y,115In和209Bi等元素为内标混合液校正基体效应和信号漂移,确定了实验的最佳测定条件。结果表明,该方法对十种待测元素的检出限在0.003～0.038 μg·L-1之间,加标回收率在93.0%～106.6%之间,相对标准偏差(RSD)≤3.4%。方法简便、快速、准确,可以用于食品甜味剂质量控制和安全评价。     

ORS-ICP-MS测定工业废水中La系稀土元素

用 ORS- ICP- MS法测定工业废水中的 L a系稀土元素 ,优化了 ICP- MS测定条件 ,利用动态反应池技术 ,可降低基体干扰 ,提高灵敏度。分析方法的检出限为 0 .8— 8.2 5 ng/ L,加标回收率为 92 %— 99%。     

八极杆碰撞/反应池-ICP-MS测定纯铜中的磷

利用ORS-ICP-MS测定纯铜中的磷. 对ICP-MS测定条件进行了最佳化的选择, 利用动态反应池技术(ORS)和在线内标加入技术, 可降低基体干扰, 提高灵敏度. 分析方法的检出限为0.33 ng/mL, 加标回收率为94%～97%.     

The potential of mass spectrometry to study iron-containing proteins used in clinical diagnosis

Many proteins contain iron as metal ion either within their own structures or bound to their active sites. These iron-containing proteins are involved in numerous biological processes and some of them serve as biomarkers of clinical pathologies, not only related to iron homeostasis but also to other physiological disorders. Thus, a variety of analytical strategies have been developed over the last years in order to conduct studies on Fe-containing proteins. Among them, mass spectrometric (MS) methods still remain as preferred tools since they provide the capabilities of structure elucidation together with quantitative possibilities. Therefore, in this work we have tried to summarize the most recent applications of elemental and molecular mass spectrometric-based methods for the characterization (mostly qualitative but quantitative in some cases) of the high abundant Fe-containing proteins used for clinical diagnosis.     

应用普通ICP-MS和八极杆碰撞/反应池(ORS)技术测定动植物样品中的As和Se的比较

使用普通电感耦合等离子体质谱法(ICP MS)测定一些标准参考物质中多种元素的浓度,该方法不仅可测定常规的有毒元素如As,Pb ,Hg,Cd ,还可以测定常量元素包括P ,Ca,Fe ,K ,Na等。实验研究了消解样品的方法、回收率和方法的检测限等,证明ICP MS的EPA2 0 0 8标准干扰校正方法用于测定食品和植物样品中多元素浓度是可行的。应用ICP MS的八极杆碰撞反应池(ORS)技术测定As ,Se等元素,比较了配置ORS系统与不配置ORS系统的ICP MS仪器对这两种元素测定的结果,讨论了ArCl和ArAr干扰的消除,发现ORS系统可以有效地消除样品基体产生的ArCl,ArAr等分子离子对样品中超痕量的As,Se的干扰。