LC-ICP-MS联机技术与同位素稀释质谱法精确测定小麦粉中硒代蛋氨酸

The precise determination of selenomethionine (SeMet) in wheat flour has been performed by species specific isotope dilution mass spectrometric analysis (IDMS) using an inductively coupled plasma mass spectrometer as detector after liquid chromatography (LC-ICP-MS). A labeled ⁷⁶SeMet species-specific isotope enriched spike solution was used for these determinations. The experiment procedure included spiking, extraction, and a simultaneous separation and detection procedure. The method gave yield to good precision (＜2%). The accuracy of the method has been validated on the certified reference materials. The result obtained was in good agreement with the certified reference value. And this method was used to do the international comparison CCQM-K60.     

同位素稀释-液相/气相-电感耦合等离子体质谱联用等方法为鱼肉中甲基汞成分标准物质准确定值

The fish tissue certified reference material is designed and prepared mainly for evaluating the determining accuracy of methyl mercury in sea fish or other seafood, as well as for a quality control standard. The property value was certified by three different methods, including high performance liquid chromatographic -cold vapor atomic fluorescence spectrometry（HPLC-CVAFS）method and species specific isotope dilution mass spectrometric analysis (IDMS) using an inductively coupled plasma mass spectrometer as detector after liquid chromatography (LC-ICP-MS) or gas chromatography (GC-ICP-MS). The experiment included spiking, extraction, derivatization, separation and detection procedures. The ERM 464 tuna fish reference material was used as the analytical quality control standard. The results obtained from three different methods were in good agreement. And the statistic average values were used as certified values of methylmercury in the fish tissue CRM.     

甲胎蛋白纯品的同位素稀释质谱法测定

建立了基于特征肽段的甲胎蛋白的液相色谱-同位素稀释串联质谱检测方法。选取3条同位素标记的甲胎蛋白特征肽段作为内标,准确称其质量后与酶切后的甲胎蛋白样品定量混合,采取Phenomenex Kinetex 2.6 μm C18色谱柱分离,电喷雾三重四极杆串联质谱多反应监测模式（MRM）测定,并对最优酶切条件、酶切效率以及定值结果的不确定度进行了考察和评定,得到的甲胎蛋白标准物质的最终测量结果为（0.329±0.016）mg/g。     

同位素稀释多接收电感耦合等离子体质谱法测定血铅

采用同位素稀释多接收电感耦合等离子体质谱（ID-MC-ICP-MS）法测定血铅。运用同位素稀释法测得整个实验的流程空白Pb的浓度平均值为5.6 ng。对SRM 955b level 1和SRM 955b level 3标准血样进行分析,测得血样浓度分别为40.2、207.8 μg•L^-1,测定值落在血样参考值范围之内,证明该方法有效、可靠。利用建立的血铅分析方法,参加了络合型血铅标准物质的定值,得到3种血铅标准样中铅的浓度分别为（102.7±5.5）、（181.7±4.0）、（304.1±3.9） μg•L^-1。     

高分辨电感耦合等离子体质谱法测定铀矿石浓缩物中的微量元素

A method for determination of trace elements in uranium ore concentrates by high resolution inductively coupled plasma mass spectrometry (HR-ICP-MS) was developed. Results obained by the method can be used to identify origins, processing characteristics and quality of uranium ore concentrates. The sample was dissolved by 2% nitric acid and prepared to matrix concentration of 1 g·L－1, followed by the measurement of HR-ICP-MS with on-line internal standard technique. The contents of multi trace elements from 7Li to 232Th have been determined, giving about 16% of relative deviation over certified reference material. The method has been validated using certified reference material.     

流动注射-电感耦合等离子体质谱联用分析土壤样品中的铀

建立了使用²³³U作为同位素稀释剂,流动注射-电感耦合等离子体质谱联用法分离测量土壤样品中铀的方法。土壤样品经过微波消解后,以UTEVA树脂在线预富集铀,0.2 mol•L^-1 HCl解吸铀,且直接将铀解吸液导入多接收电感耦合等离子体质谱仪测定同位素比,从而得出样品中铀的同位素比及铀的浓度。通过对土壤标准样品的分析,验证了方法的可行性,结果与标称值一致。该方法对²³⁸U和²³⁵U的检测限分别为5.4×10^-9g和5.7×10^-11g。     

同位素稀释-电感耦合等离子体质谱法测定沉积物中铬和汞

采用同位素稀释-电感耦合等离子体质谱法（ID-ICP-MS）测定沉积物中铬和汞,分别以铬、汞单元素溶液标准物质标定⁵³Cr和²⁰²Hg浓缩同位素,将稀释剂与样品混合均匀后,加酸进行消解。对质谱测定过程的数据采集参数进行优化,探究基体效应以及H2和He两种模式对铬测定的影响。为防止汞的记忆效应干扰比值的测定,采用5 mg/L EDTA、2.5 mg/L Au溶液和3%硝酸交替冲洗管路系统,分别测定了²⁰⁰Hg/²⁰²Hg和¹⁹⁹Hg/²⁰²Hg两组比值,并比较测定结果。结果显示：积分时间为0.5 s时,同位素比值的测定精密度较好,对测定样品进行稀释能够消除质谱及基体效应干扰。H₂和He模式均适用于该类样品中铬的测定,²⁰⁰Hg/²⁰²Hg和¹⁹⁹Hg/²⁰²Hg两组比值对汞的测定结果无显著性差异,沉积物中铬和汞含量分别为81.7 mg/kg和0.471 mg/kg,相对标准偏差分别为0.35%和0.99%。采用美国NIST2709a标准物质进行方法验证,验证结果与标准值一致。该方法准确度高、精密度良好,适用于沉积物、土壤等基体样品中铬和汞的高准确度测定。     

甲醇中4-氯甲苯溶液标准样品的研制

介绍了甲醇中4-氯甲苯溶液标准样品的研制。标准样品采用称量法制备,用气相色谱-质谱法进行均匀性检验和稳定性监测,以配制浓度值作为标准值,分析其不确定度来源并进行评估。研究结果表明,甲醇中4-氯甲苯溶液标准样品均匀性和稳定性良好,量值准确,可用于环境监测和科学研究工作。     

铕浓缩同位素全蒸发-1012Ω高阻信号放大器的热电离质谱分析方法

浓缩同位素是校正质谱法、同位素稀释质谱法和双稀释剂法等同位素质谱分析技术的基础,其化学纯度及丰度量值的准确性直接影响着分析结果的准确性。但由于浓缩同位素中低丰度同位素的离子信号较难准确测量,且缺乏合适的标准物质校正,给高精准的同位素丰度分析带来挑战。本文建立了适用于微量铕浓缩同位素样品纯化的锌还原-萃取色层法,纯化后的151 Eu和153 Eu两种浓缩同位素纯度优于99.99%,有效消除了其他稀土元素杂质的干扰。通过采用1012Ω信号放大器的法拉第杯接收样品中的低丰度同位素离子信号,建立了铕浓缩同位素的全蒸发-热电离分析方法。两种浓缩同位素样品的主丰度测量结果分别为151 Eu 0.9683676(11)和153 Eu 0.9876851(21),测量重复性比1011Ω信号放大器的法拉第杯以及文献中校正质谱法的测量结果提高了3倍。     

同位素稀释质谱在化学计量学中的应用

本文扼要地叙述了同位素稀释质谱（IDMS）及其在化学计量学中的应用。用具有天然丰度的国家一级标准物质作稀释剂,借助IDMS标定浓缩同位素溶液的浓度,而后,用被标定过的浓缩同位素作稀释剂,为研制中的化学标准物质定值。对多数复杂的基体样品,用混合酸在微波炉内消解,用离子交换法进行元素分离。试验用水和试剂经石英亚沸蒸馏器或离子交换法进一步纯化,取决于待别样品的性质,样品的装载使用单灯丝组件或双灯丝组件。对高电离电位元素,在用单灯丝组件时,用高纯硅胶和磷酸作热电离时的电离增强剂,便于提高离子的发射效率。多位法拉第筒和二次电子倍增器组成的探测系统,对多同位素元素进行同时多接收测量。完备的测量软件有效地监督和调整离子源的电参数与法拉第筒的位置。因质量岐视而产生的分馏效应,在实验过程中基本被消除。遵照上述方法,完成了Li、K、Mg、Fe、Cu、Ni、Ca、Mo、Pb和Ce、Nd、Sm、Er、Gd、Dy、Er、Yb的IDMS测量。测过的基体有酸雨,奶粉、贻贝、大米粉、高纯试剂、深海沉积物等国家一级标准物质。在CIPM组织的IOMS三次国际比对研究中,取得了好的成绩。