流动注射-电感耦合等离子体质谱法的基体效应

研究了流动注射小体积进样,电感耦合等离子体质谱法的在体效应,并与连续进样作了比较,流动注射小体积（１００μＬ）进样时,电离电位较高的Ａｓ和Ａｕ基体对分析元素的信号表现为增强效应,分析元素的质量数越大,所受增强效应越小。了电位较低的Ｃｕ、Ｉｎ、Ｌｉ、Ｎａ和Ｐｂ基体对分析元素的信号则表为抑制效应,基体元素的质量数越大,对分析元素的抑制效应也越大;质量数较大的分析元素,所受的抑制效应较;对质量数相近的分析元素,电离电位较高者受的抑制较大,与连续进样相比,流动注射小体积进样时,基体元素对分析元素的抑制效应较弱,而增强效应较强。     

微流动注射-等离子体质谱直接测定白酒中铅和镉

研制了多采样体积的微流控芯片, 结合普通的八通阀实现了等离子体质谱(ICP-MS)亚微升级样品的进样. 研究了白酒基体[52%(体积分数)乙醇]引入量对ICP的稳定性和裂解后所产生碳干扰的情况, 考察了进样体积与灵敏度的关系, 并优化了载流流速. 实验结果表明, 当进样量低于0.8 μL时, ICP-MS能长时间正常运行, 未出现积碳现象; 进一步将进样量降到0.3 μL以下, 可消除白酒基体中的碳所引入的质谱干扰. 在此基础上建立了用微流动注射ICP-MS直接测定白酒中Pb和Cd的方法, 每小时可分析45个样品, Pb和Cd的检出限分别为12和42 ng/L. 以水标准溶液直接测定了6个白酒样品中的Cd和Pb含量, 结果与微波消解-常规进样系统ICP-MS的分析结果一致.     

流动注射进样-火焰原子吸收光谱法测定钴镍基体中钙

提出了火焰原子吸收光谱法直接测定钴镍基体中钙的方法,用流动注射微量进样系统有效降低了大量基体元素对测定的影响,并用邻菲啰啉乙醇溶液和镧释放剂消除大量钴镍基体及硫酸根对其测定的干扰。对释放剂浓度、采样时间、干扰情况及其消除进行了研究。线性回归方程为A=0.000 9+0.024 1C(mg.L-1),相关系数为0.999 9。方法检出限(3σ)为0.09 mg.L-1,RSD为1.1%,样品加标回收率为95%~105%。     

通过柱切换技术与高效液相色谱联用的限进性柱对盐酸贝那普利的在线富集性能

以自制的限进性填料柱为预处理富集柱,Luna C₁₈柱为分析柱,通过柱切换技术将限进性填料柱与高效液相色谱联用(RAM-HPLC),研究了盐酸贝那普利的在线富集效果。考察了进样体积与峰面积、系统总压力的关系,以及常规进样与大体积进样的差别。当进样体积在100 μL以内时,峰面积随进样体积的增加而增加;当进样体积大于80 μL时,系统总压力变化明显。考虑对整个系统的保护,选择80 μL作为最大进样体积。同一浓度的样品进样20 μL与进样80 μL所得峰面积之间的线性关系良好。RAM柱对盐酸贝那普利具有良好的富集作用,能够有效提高HPLC的灵敏度,而且具有简单、经济的特点。     

氨水密闭消解-电感耦合等离子体质谱法测定植物样品中碘的含量

为解决在电感耦合等离子体质谱法(ICP-MS)测定碘时易出现分解效率不高、碘记忆效应强、多原子离子干扰及基体效应等问题,进行了题示研究。粮食类、豆类样品(干样)去除杂物后,用水洗净,于60℃烘干;蔬菜、水果类样品(鲜样)用水洗净,晾干,取可食用部分,制成匀浆。取上述样品0.500 0 g置于高压密闭聚四氟乙烯内罐中,加入15 mL 10%(体积分数)氨水溶液,于200℃密封消解过夜。冷却后,用水将溶液转移至聚四氟乙烯比色管中,定容至25 mL,经0.45μm混合纤维素滤膜过滤,采用ICP-MS测定滤液中碘的含量。选择与碘质量数最为接近的碲作为内标元素,以氦气碰撞模式进行分析,并通过优化氦气流量,降低了空白值,有效消除了基体效应及多原子离子产生的质谱干扰。碘的质量浓度在50.0μg·L^-1内与对应的信号强度呈线性关系,检出限(3s)为0.005 mg·kg^-1。方法用于国家一级标准物质分析,测定值的相对标准偏差(n=12)为2.7%～6.2%,相对误差为-7.5%～6.9%。     

微量待测元素的富集(综述)

一、前言当分析方法的相对检出限高于样品中微量待测杂质的浓度(或含量)时,可以采用预富集法。富集能够确保除去基体或者大部分基体,有时还可除去一系列微量干扰组分。得到的富集物中微量杂质的浓度,通常均比原来样品中相应微量杂质的浓度高。此外,采用富集步骤时,称样量可以增大,待测元素的绝对量增加,因此,可降低(改善)微量待测元素的检出限,而且可能改善几百倍、甚至几千倍,有时改善相当可观。这正是广泛采用预富集法的主要原因,但不     

一步酸稀释-电感耦合等离子体质谱法测定全血中17种元素的含量

鉴于经典方法(原子吸收光谱法)存在过程繁琐、引入污染风险高、样品量大、耗时较长等缺点,进行了题示研究。采用含0.1%(体积分数)硝酸、0.1%(体积分数)曲拉通、1%(体积分数)异丙醇的稀释液一步稀释全血样品(样品量最低为50μL),所得溶液直接进电感耦合等离子体质谱仪分析。以Sc、Rh、In、Tb、Bi作为内标元素,碰撞模式选择氦(He)模式。结果显示：一步酸稀释法过程简单,引入污染风险小,且低、高浓度水平样品不会相互干扰,样品中17种元素可在45s内完成同时检测;各目标元素的质量浓度分别在0.05～30mg·L^-1(Ca、Mg、Fe)和0.5～300μg·L^-1(Cr、Co、Cd、Cu、Mn、Mo、Ni、Pb、Se、V、Zn、Rb、Sr、Cs)内与对应的质谱响应值比值呈线性关系,检出限(3s)为0.3ng·L^-1～0.22μg·L^-1;对全血痕量元素标准物质L-1、L-2进行准确度试验,测定值均在认定值的95%置信区间内;对质控样品进行日内(n=10)、日间(n=15)精密度试验和方法比对试验,...     

微量乙醇对59种无机元素ICP-MS行为的影响

探讨了在相同测试条件下,不同含量乙醇(0.4%~2.0%)作为基体改进剂对59元素ICP-MS信号的影响,测定了最大增敏效果下各元素的检出限。结果表明,微量乙醇对元素ICPMS行为的影响随元素种类或乙醇浓度不同而不同。相同乙醇浓度下,大多数元素的抑制效应随元素质量数增加而减弱,增敏趋势随质量数增加而增强,尤其对电离能大于8 eV的元素,增敏效果更明显;相同元素质量数下,乙醇浓度愈高,抑制作用趋强或增敏趋弱。乙醇作为基体改进剂不同程度降低了除~7Li,~(27)Al及~(232)Th外其余56种元素的检出限,为扩展ICP-MS应用领域提供了更多可能。     

基体匹配—电感耦合等离子体质谱(ICP-MS)法测定萤石精矿中痕量有害元素

为向萤石精矿质量检测和环境监管提供可靠的数据支撑，采用基体匹配—电感耦合等离子质谱法测试萤石精矿中痕量有害元素铜、锌、砷、镉和铅的含量。利用硝酸溶解分析纯碳酸钙后，经ICP-MS测试溶液中钙元素含量与理论值偏差约6%。钙溶液经不同倍率稀释后配置基体浓度为1000、2000和5000mg/L多元素标准溶液，在ICP-MS测试不同基体浓度混合标准溶液的内标回收率稳定性和IF/BK压降情况后，确定了1000 mg/L的最佳基体浓度。在传统四酸消解法基础上，通过改变加酸顺序、用量和温控水平，实现对萤石精矿的完全消解。消解实验中，同步设置消解加标、过程空白和空白加标实验。萤石精矿在消解定容及适度稀释后，溶液中离子浓度与复杂基体标准溶液的最佳基体浓度接近。在复杂基体标准溶液及样品消解液测试中，采用He模式的碰撞反应池技术，选用72Ge、115In和175Lu作为内标元素。结果显示：各元素标准曲线线性大于0.9995，各样品内标回收率在80%-110%范围波动，表明基体匹配联合内标校正，有效消除了复杂样品测试中的非质谱和质谱干扰。消解实验中未产生过量的元素沉淀或挥发损失，加标样品各有害元素回收率在90%-120%。质控样品各元素含量测试误差在15%以内。此测试方法中铜、锌、砷、镉和铅的检出限分别为4.81、8.65、17.91、0.49和2.84 μg/L，可满足复杂基体样品中痕量元素含量的准确测试需求。     

三重串联电感耦合等离子体质谱法直接测定高纯氧化钕中14种稀土杂质元素

建立了三重串联电感耦合等离子体质谱(ICP-MS/MS)法直接测定高纯钕中的14种稀土杂质元素的方法.采用氧气和氨气反应池在串联质谱MS/MS模式,有效克服了基体对待测元素的干扰.通过优化仪器参数得到Tb,Dy和Ho的背景等效浓度分别为22,40和4 ng/L.在选定的条件下,样品加标0.5 μg/L14种混合稀土标样测得的回收率为88.6％ ～ 98.6％,使用仪器标准配置的耐高盐进样系统(HMI)测得2h信号值的相对标准偏差(RSD)为1.3％-4.1％.本方法简单实用,能够满足纯度为5N (99.999％)及以上的高纯钕中14种杂质元素的直接测定.     

高效液相色谱-四极杆/静电场轨道阱高分辨质谱快速检测6种农产品中96种农药的残留量

利用高效液相色谱-四极杆/静电场轨道阱高分辨质谱快速筛选辣椒、青花菜、脱水土豆、大豆、绿茶和大蒜中96种农药残留。样品经含0.1%醋酸的乙腈提取,分散固相萃取脱水、除色、净化后,以C18色谱柱为分析柱,甲醇和5 mmol/L醋酸铵水溶液作为流动相进行梯度洗脱分离。采用正、负离子切换同时测定96种农药残留,大大提高了检测通量。通过优化分辨率,在全扫描模式下提取目标化合物的精确质量数,有效地去除了基质干扰;采用自动触发采集二级质谱图进一步提高了定性的准确性。在1～200 μg/L范围内,96种农药的线性相关系数均大于0.99。通过实际样品的添加回收试验,回收率范围为58%～105%,相对标准偏差为8.8%～18.3%。该方法的检测低限可以达到5 μg/kg,可以作为蔬菜中多种农药残留高通量筛选和确认检测方法。     

A novel sample introduction system for microwave-induced plasma optical emission spectrometry

A newly developed micro-sampling technique using a discrete sample introduction system (DSIS) has been demonstrated for simultaneous multi-element analysis by microwave-induced plasma optical emission spectrometry (MIP-OES). A microliter volume of sample solution (20 μl) is manually inserted into a Teflon microsampling device and subsequently pumped at low solution uptake rates of <100 μl min⁻¹ to a Meinhard-type concentric nebulizer and then into a 250-W helium plasma. The performance of DSIS-MIP-OES was demonstrated by the determination of major (Na, K, Ca, Mg), minor (Cu, Fe, Zn) and trace (Sr) elements in two clinical standard certified reference materials (serum, hair). Standard microaddition procedures were used to minimize possible matrix interference. The detection limit (3σ) obtained was 10, 30, 50, 100, 10, 5, 20 and 40 ng ml⁻¹ for Ca, Cu, Fe, K, Mg, Na, Sr and Zn, respectively. The method offers relatively good precision (RSD ranged from 5 to 14%) and microsampling capability. Agreement between analytical results and certified values for the test elements was good. The method could be useful as a routine clinical laboratory procedure.     

基体归一定量技术在激光烧蚀-等离子体质谱法锆石原位多元素分析中的应用

探讨了内标法和基体归一法校准的基本原理。基体归一校准法的基本步骤为:先用简单外标法测得样品中尽可能全的主、次、痕量元素含量,氧化物加和后进行100%归一,得到灵敏度校正系数,对所有元素的测定结果进行修正。修正结果的可靠性在很大程度上取决于测定元素是否"完全"。由于锆石的基体元素组成简单且易于测定,很适合用基体归一法校准。在激光剥蚀-电感耦合等离子体质谱法(LA-ICP-MS)微区原位分析中,应用基体归一校准法的最大优点是:可以避免预先用其它微区分析技术对未知样品中的内标元素进行定量。该技术可适用于具有环带结构、难以找到均匀分布的内标元素的地质样品的元素空间分布测定。在高分辨ICP-MS(Element2)和NewWave-UV-213激光系统上,应用基体归一定量技术同时分析了锆石中主、次、痕量共54种元素。对未知锆石样品的分析,基体归一法与内标法结果的一致性令人满意。分析德国蛇纹岩标准玻璃ATHO-G中相对误差<25%的有52个元素,<10%的有36个元素;大多数元素的相对标准偏差<10%。     

Reduction of matrix effects in ICP-MS by optimizing settings of ion optics

The effect of ion optics settings on the degree of suppression of analyte signals due to the presence of different basic elements in a sample solution, such as manganese, copper, indium, lanthanum, hafnium, and lead, was investigated on an example of an XSeries II inductively coupled plasma mass spectrometer. The effect of atomic mass and the concentration of the matrix element on the optimum values of ion optics settings and the change in the analyte signals was studied. It was shown that a decrease in the potential of the extractor lens to ?300 V can significantly reduce the matrix effect. As an example, the results of determining impurity elements in solutions containing up to 1 g/L of lanthanum were obtained using standard settings of the spectrometer with a reduced voltage on the extractor. It was shown that the optimization of ion optics settings enables the use of more concentrated solutions, thus reducing the detection limits for elements by several times.     

-电感耦合等离子体质谱法测定硅锰冶炼渣中8种金属元素

实验采用HCl-HNO₃-HF-HClO₄混合酸为消解体系对样品进行前处理,加入1.0 mL盐酸羟胺溶液(100 g/L)溶解残渣,选择合适的同位素,以¹⁰³Rh为内标测定Cr、Co、Ni、Cu、Zn和Cd,以¹⁹³Ir为内标测定Tl和Pb,建立了电感耦合等离子体质谱(ICP-MS)法测定硅锰冶炼渣中8种重金属元素的方法。实验发现,样品前处理选择HCl∶HNO₃∶HF∶HClO₄=5∶5∶5∶1,并在复溶阶段加入1.0 mL盐酸羟胺溶液(100 g/L)可以完全消解样品,实验采用KED模式和干扰系数校正法消除质谱干扰,样品中待测元素的测定结果不受基体成分的干扰。通过绘制校准曲线及测定流程空白,各元素校准曲线的相关系数均大于0.9999,方法检出限为0.006~0.19 mg/kg,方法定量限为0.018~0.57 mg/kg。对硅锰渣实际样品进行测定,各元素的相对标准偏差(RSD,n=11)在0.83%~4.1%,加标回收率为94.7%~106%;经过人员比对实验,相对偏差为-4.54%~4.24%。测定结果稳定可靠,能满足硅锰冶炼渣中8种微量金属元素含量的分析检测要求。     

基于单颗粒电感耦合等离子体质谱法测定环境基质水样中纳米银颗粒

采用单颗粒电感耦合等离子体质谱法(SP-ICP-MS)同时测定环境水样中纳米银颗粒(AgNPs)的颗粒浓度、质量浓度和粒径分布,并考察了溶液的pH值、溶解性有机质(DOM)浓度以及离子强度等对AgNPs测定的影响。结果表明:SP-ICP-MS方法对60 nm AgNPs标准溶液的测定结果与标准值一致,准确性较好;pH值(5.0～7.0)、离子强度(≤1 mmol/L)和DOM浓度(≤30 mg/L)对测定结果影响较小;当溶液的pH值≤5.0或离子强度1 mmol/L时,AgNPs的颗粒浓度和粒径随pH值的下降或离子强度的增强而减小。采用SP-ICP-MS方法测定河水、染料废水、养殖废水3种水样中AgNPs的加标回收率分别为98.1%、83.3%和93.3%,表明该方法在合适的基质条件下可用于快速准确测定环境水样中AgNPs的颗粒浓度、质量浓度和粒径分布。     

高效液相色谱法测定植物根系分泌物中的有机酸

以小麦为例,建立了植物根系分泌物中有机酸的提取和测定方法。小麦根系分泌物由培根法培育收集,先后经阳离子和阴离子交换树脂提取,旋转蒸发至干后用pH 2.1的稀HClO4溶液溶解、定容,以5 mmol/L H2SO4水溶液为流动相,经Bio-Rad Aminex HPX-87H阳离子交换树脂柱分离,在波长210 nm处紫外检测。在小麦根系分泌物中,有机酸的检测限为1~120 μg/L,日内检测精密度为1.2%~4.7%,日间检测精密度为3.3%~10.6%,不同剂量的加标回收率为82.0%~96.2%,相对标准偏差为0.67%~3.31%。该方法简便快速,灵敏可靠,适用于介质复杂的环境样品中有机酸的测定。     

Intensity of molecular ion peak in electron ionization mass spectra

Compounds from NIST??08 and Wiley 8th databases were considered as a representative subset of the general population of organic compounds which can be analyzed using mass spectrometry with electron ionization. The percentage of organic compounds as a function of intensity of molecular ion (M^+?) peak normalized to the base peak was determined for the first time. It was shown that only 26% compounds have high-intensity M^+? peaks (greater than 50% of base peak). Intensity of M^+? peak is less than or equal to 1 or 5% of base peak for 24 or 37% compounds respectively. It means that in case of trace-level analysis M^+? peak may not be registered for quarter (or even more) of organic compounds. It is well-known that the absence of M^+? peaks in electron ionization mass spectra reduces reliability of unknown compound identification based on library search. Therefore determination of molecular mass by independent technique (e.g., mass spectrometry with chemical ionization) is necessary for increasing the identification reliability.     

Dispersive liquid–liquid microextraction based on solidification of floating organic droplet for the determination of triazine and triazoles in mineral water samples

A simple, rapid, and sensitive method for the determination of atrazine, simazine, cyproconazole, tebuconazole, and epoxiconazole in mineral water employing the dispersive liquid–liquid microextraction with solidification of a floating organic drop with determination by liquid chromatography tandem mass spectrometry has been developed. A mixed solution of 250 μL 1‐dodecanol and 1250 μL methanol was injected rapidly into 10 mL aqueous solution (pH 7.0) with 2% w/v NaCl. After centrifugation for 5 min at 2000 rpm, the organic solvent droplets floated on the surface of the aqueous solution and the floating solvent solidified. The method limits of detection were between 3.75 and 37.5 ng/L and limits of quantification were between 12.5 and 125 ng/L. The recoveries ranged from 70 to 118% for repeatability and between 76 and 95% for intermediate precision with a relative standard deviation from 2 to 18% for all compounds. Low matrix effect was observed. The proposed method can be successfully applied in routine analysis for determination of pesticide residues in mineral water samples, allowing for monitoring of triazine and triazoles at levels below the regulatory limits set by international and national legislations.     

Determination of microcystin-LR in drinking water using UPLC tandem mass spectrometry-matrix effects and measurement

A simple detection method using ultra-performance liquid chromatography electrospray ionisation tandem mass spectrometry (UPLC-ESI-MS-MS) coupled with the sample dilution method for determining trace microcystin-LR (MC-LR) in drinking water is presented. The limit of detection (LOD) was 0.04 μg/L and the limit of quantitation (LOQ) was 0.1 μg/L. Water matrix effects of ionic strength, dissolved organic carbon (DOC) and pH were examined. The results indicate that signal detection intensity for MC-LR was significantly suppressed as the ionic strength increased from ultrapure water condition, whereas it increased slightly with solution pH and DOC at low concentrations. However, addition of methanol (MeOH) into the sample was able to counter the signal suppression effects. In this study, dilution of the tap water sample by adding 4% MeOH (v/v) was observed to be adequate to compensate for the signal suppression. The recoveries of the samples fortified with MC-LR (0.2, 1, and 10 μg/L) for three different tap water samples ranged from 84.4% to 112.9%.