ICP-MS法测定酸枣仁中微量元素及重金属

采用微波消解电感耦合等离子体质谱(ICP-MS)建立酸枣仁中锂(Li)、钙(Ca)、钡(Ba)、锰(Mn)、铍(Be)、铋(Bi)、钒(V)、铁(Fe)、钴(Co)、锶(Sr)、铜(Cu)、锌(Zn)、钛(Ti)、镍(Ni)、镉(Cd)、锡(Sn)、镁(Mg)、汞(Hg)、铅(Pb)和砷(As)共20种元素的测定方法。结果表明,各元素的线性关系良好,各元素的检出限在0.001~0.246μg·kg~(-1)之间,加样回收率在91.50%~105.51%之间,相对标准偏差RSD≤3.0%(n=3)。酸枣仁中元素钙、铁和镁含量较其他元素高,其中钙含量最高,为79.988 1~81.638 4 mg·kg~(-1)。重金属含量符合国家标准。该方法快速、简便、准确,可以用于酸枣仁中多元素的质量控制。     

卷烟纸特性参数对烟气中重金属迁移率的影响

为考察卷烟纸特性参数对主、侧流烟气中重金属迁移率的影响,采用单因素设计方案制备了13种试验卷烟,考察了卷烟纸透气度、定量和助燃剂含量对主、侧流烟气中铬(Cr)、镍(Ni)、砷(As)、硒(Se)、镉(Cd)和铅(Pb)6种元素迁移率的影响。结果表明:1卷烟纸透气度在20~80 CU时,与侧流烟气中Cd元素迁移率有显著正相关性;在20~50 CU时,与主流烟气中As,Cd和Pb 3种元素迁移率有显著负相关性。2卷烟纸定量与侧流烟气中Cd元素的迁移率有显著正相关性,与其他元素的迁移率无明显相关性。3助燃剂含量与主流烟气中Cr,As元素和侧流烟气中As元素的迁移率有显著负相关性。卷烟纸特性参数对主、侧流烟气中6种元素的迁移率有一定影响,但对各元素迁移率的影响并不完全一致。     

电感耦合等离子体发射光谱测定食用植物油中的重金属元素北大核心CSCD

研究快速准确测定食用植物油中重金属元素的方法。采用微波消解对食用植物油样品进行预处理,在多模式进样系统(MSIS)的双重模式下,采用电感耦合等离子体发射光谱(ICP-OES)测定其中可形成蒸气重金属元素As、Sb、Hg和不可形成蒸气重金属元素Ni、Cd、Pb的含量。选择盐酸对样品进行酸化并还原氧化态元素,通过在线加入L-半胱氨酸/酒石酸提高可形成蒸气元素的蒸气发生效率,利用快速自动曲线拟合技术(FACT)消除光谱干扰。方法的检出限(LOD)为0.63~20.60μg/kg,加标回收率为97.0%~104%,相对标准偏差(RSD)为1.5%~2.6%。该方法在分析可形成蒸气元素和不可形成蒸气元素时无需切换不同进样系统,能满足食用植物油中微量重金属元素的高通量分析需要。     

一种新型补充矿物元素的载体——脱铁铁蛋白的研究进展

铁蛋白(ferritin)经脱铁处理后,内部空腔可装载多种矿物元素。鉴于这种蛋白可经胞饮作用,完整地被小肠上皮细胞吸收,因此有望作为新型矿物元素载体而发展。脱铁铁蛋白(apoferritin)的脱铁及矿物元素的装载过程可利用透射电镜(TEM)、能谱分析(EDS)、X射线粉末衍射(X-Ray)、质谱(MS)、核磁共振(NMR)、动态光散射(DLS)、紫外分光光度法(UV)等技术研究分析。本文综述了目前国内外利用铁蛋白装载矿物元素的成果及其在营养方面的应用。     

六堡茶中稀土元素及矿质元素含量特征分析

目的 探究六堡茶以及六堡茶原料毛茶中无机元素的含量特征。方法 以26个六堡茶成品茶和6个原料茶为研究对象, 采用电感耦合等离子质谱法测定稀土元素, 采用电感耦合等离子发射光谱法测定矿质元素。结果 六堡茶成品茶中稀土元素总量范围[(0.72~2.79) mg/kg]，原料茶中稀土元素总量范围[(0.42~0.71) mg/kg]，其中含量较高的稀土元素为铈(Ce)、镧(La)、钪(Sc)、钕(Nd)、钇(Y)，这5种元素含量之和分别占16种稀土元素总量的82.3%(六堡茶成品茶)和89.6%(原料茶)；六堡茶成品茶的矿质元素总量范围[(22655.48~37517.18) mg/kg]，原料茶中矿质元素总量范围[(22083.48~35647.29) mg/kg], 其中含量较高的矿质元素为钾(K)、磷(P)、钙(Ca)、镁(Mg)，这4种元素含量之和分别占19种矿质元素总量的95.6%(成品茶)和95.9%(原料茶)。结论 研究表明六堡茶成品茶中稀土元素含量显著高于原料茶(P<0.05)，而矿质元素含量在二者间差异不显著(P>0.05)。     

微波消解-ICP-MS法测定水产罐头食品中12种元素

试验旨在建立微波消解-电感耦合等离子体质谱(ICP-MS)同时测定水产罐头食品中铅、砷、镉、铬、汞、钒、镍、锰、铜、锡、铁、铝共12种元素的分析方法。样品以硝酸-过氧化氢作为消解体系,经微波消解处理后用ICP-MS检测,以钪(~(45)Sc)、锗(~(74)Ge)、铟(~(115)In)、铋(~(209)Bi)作为内标元素校正基体效应,采用标准曲线法定量。结果表明, 12种元素的线性相关系数均大于0.999,检出限为0.000 63～0.065 mg/kg,定量限为0.002 1～0.22 mg/kg。各元素加标浓度在0.01～8 mg/kg范围内,加标回收率在89.6%～101.6%之间,相对标准偏差(RSD)为1.03%～5.36%(n=6)。国家标准物质中各元素的测定值与标准值均相吻合。该方法操作简单,分析速度快,测量灵敏度高,结果准确、可靠,适用于大批量水产罐头食品中多元素的同时测定。     

茶饮料中矿物元素的分析与评价

本文应用赛曼原子吸收光谱仪、723可见分光光度计等仪器,检测了茶饮料中铜、铅、锌、铁、钠等五种元素在茶饮料中的含量,并对其进行分析与评价。结果表明,茶饮料中矿物元素的平均含量依次为钠元素79.443(mg/L)铁元素0.099(mg/L)锌元素0.089(mg/L)铜元素0.013(mg/L)铅元素1.131(ug/L)。进一步对各类茶饮料中的五种元素进行分析与比较,结果表明:乌龙茶类饮料矿物质的含量相对较少,其品质不如其他种类的茶饮料,而红茶类饮料中矿物元素的含量相较于其他茶饮料要高。通过对茶饮料中铜、锌、铁、铅、钠的含量进行分析与评价,为人们评价茶饮料的营养价值、安全性及性价比提供了理论数据和参考。     

北京地区六种主产水果矿质元素含量分析及初步膳食风险评估

采用电感耦合等离子体质谱法(inductively coupled plasma mass spectrometry,ICP-MS)测定了北京地区主要生产的6种水果中9种矿质元素含量,并以膳食矿物质推荐摄入量或适宜摄入量(RNI/AI)和可耐受最高摄入量(UL)为评价标准,对不同年龄段人群每日从6种水果中摄入矿质元素的量进行初步的膳食风险评估。结果表明:各元素线性回归方程的相关系数均大于0.9990,其检出限在0.125~125 μg/L之间,加标回收率在81.25%~110.46%之间,相对标准偏差均小于8%,且标准物质大米的测定值在国家参考标准值范围内,表明该方法具有较好的准确度和精密度,适用于水果中矿质元素含量的测定。9种矿质元素的平均含量由高到低依次为:Mg(92.58 mg·kg-1) > Zn(6.03 mg·kg-1) > Fe(4.75 mg·kg-1) > Mn(0.97 mg·kg-1) > Cu(0.61 mg·kg-1) > Cr(49.41 μg·kg-1) > Ni(38.19 μg·kg-1) > Co(4.03 μg·kg-1) > Se(1.47 μg·kg-1),各元素之间差异显著(P<0.05),变异系数范围为51.22%(Cu)~99.58%(Ni)。通过对6种水果中元素含量的水平分析和水果之间的纵向比较,得到9种矿质元素在水果中的含量状况和排序规律,但尚未发现富硒样品。水果中矿质元素满足人体需求的程度随着年龄增长而持续降低。桃、葡萄和梨满足人体每日膳食矿物质摄入需求的程度较高。各类人群从6种水果中摄入矿质元素的量是安全的,Mn和Zn的风险指数高于其它元素,应重点关注。     

云南野生与栽培茯苓中矿质元素含量研究

建立微波消解-电感耦合等离子体质谱法(ICP-MS)测定云南15个产地野生与栽培茯苓菌核中Fe、Mn、Cu、Zn、Co、Li、V、Ba、Cr、As、Cd、Pb等12种矿质元素,探讨茯苓中矿质元素的含量分布特征。采用SPSS 21.0进行主成分分析和相关性分析。结果显示,线性回归方程相关系数r均大于0.9990,检出限范围在0.009~1.035μg/L之间,参考物菠菜(GBW10015)和灌木枝叶(GBW07603)测定值在国家参考标准值范围内,表明该方法准确、可靠。所测样品中含有丰富的矿质元素,栽培种Fe、Mn、Co、V、Cr等元素含量高于野生;野生和栽培菌核中Fe元素含量范围分别为31.8~108.3、49.7~805.6 mg/kg,Mn元素含量分别为5.59~35.6、12.9~67.7 mg/kg;Cu、Zn和Ba元素平均含量在1~10 mg/kg之间;Co、Li、V、As、Cd、Pb、Cr等均小于1 mg/kg,其中As(0.16 mg/kg)、Cd(0.03 mg/kg)、Pb(0.35 mg/kg)等有毒重金属均低于食品安全国家标准、世界卫生组织(WHO)和《中国药典》(2015版)最高限量。第一主成分解释原始数据变量的49.060%,Mn、Fe、V、Li、As、Cr等元素载荷值较大,茯苓中特征元素为Mn、Fe、V、Li、As、Cr。相关性分析显示14对矿质元素呈现显著相关(p0.05)或极显著相关(p0.01)。元素在茯苓生长过程中存在内在的相关关系,不同产地样品中元素含量差异显著,可能与降水、温度、生长的土壤环境和生长方式有关。     

粘结剂(或钎料)中活性元素的选择

具强烈形成碳化物倾向性的金属在熔化时能使金刚石润湿,因而可采用含有活性元素(强碳化物形成元素)的合金或单活性元素金属作为金刚石工具的粘结剂(或钎料)。文中重点探讨了在“常规”制造条件下能对金刚石实现良好包镶的“活性元素”选择。     

碾米机离散元模拟参数测定

目的:解决碾米机操作不便及碾米机滚动摩擦系数与滑动摩擦系数概念混淆的问题.方法:使用EDEM软件对碾白加工过程进行离散元模拟.以MNAW18型碾米机为参照,取丰两优系列糙米为样品,通过自主搭建实验台并结合模拟标定,建立一套测取碾米机离散元模拟参数的方法.结果:使用自制碰撞系数试验装置,并结合视频运动处理软件得到糙米与糙米、碾辊和筛网间的碰撞恢复系数分别为0.34,0.24,0.43;利用斜面倾角与静摩擦系数的关系,设计静摩擦试验,测得糙米与糙米、碾辊和筛网间的静摩擦系数分别为0.467,0.881,0.550;通过糙米堆积角试验、糙米斜面滚落试验与离散元模拟试验相结合对滚动摩擦系数进行标定,得到糙米与糙米、碾辊和筛网间的滚动摩擦系数分别为0.013,0.101,0.159.结论:通过二次模拟,仿真模拟结果与实测结果误差在合理范围内,表明参数标定的数据是可靠.     

Near Infrared Spectroscopic Measurement of Protein Content in Oil/Water Emulsions

The regression coefficient (slope) of the calibration for determination of the protein content decreased as oil content increased. A corrected equation for the effect of oil was derived using optical intensities at 2170 nm (protein) and 2306 nm (oil). The accuracy of the corrected calibration was tested against separate data sets with each oil content. Standard errors of the corrected calibration were comparable to the standared regression equation over a wide range of oil content, suggesting that this corrected calibration is useful for determination of the protein content in oil/water emulsions.     

基于中红外光谱技术的甘氨酸铁螯合物判别研究

目的研究基于中红外光谱(mid infrared spectroscopy,MIRS)技术定性判别有机微量元素添加剂掺假的可行性。方法以甘氨酸铁螯合物和硫酸亚铁为研究对象,分析样品的中红外光谱,解析不同样品光谱的特异性;建立偏最小二乘判别(partial least squares discriminant analysis,PLS-DA)校正模型对掺假样品进行判别,并比较不同预处理方法、全光谱与特征波段对校正模型判别效果的影响。结果甘氨酸铁螯合物与硫酸亚铁光谱差异显著,主要分布在(3500～3000) cm~(-1)、(1600～1300) cm~(-1)、(1300～1000) cm~(-1)、(660～550) cm~(-1),通过采用平滑(smoothing,SM)、归一化(normalization,Norm)与一阶导数(first derivative,FD)相结合的方法对光谱进行预处理,结合1300 cm~(-1)～1000 cm~(-1)波段建立的PLS-DA校正模型判别效果最优,校正集的判别正确率为97.5%,验证集的判别正确率为100.0%,对外部样品的判别正确率达到92.7%。结论中红外光谱技术结合化学计量学方法能够对甘氨酸铁螯合物的掺假进行准确判别。     

Time resolved characterization of diesel particulate emissions. 1. Instruments for particle mass measurements

The measurement of diesel vehicle exhaust particulate mass is currently accomplished using filter collection methods according to the Code of Federal Regulations (CFR). Such filter methods limit time resolution to a minimum of several minutes, making it impossible to study emissions during transient operating conditions. Extensive testing of five different measurement methods has demonstrated that fast response measurements of diesel exhaust particulate mass concentrations, consistent with CFR filter measurements, are feasible using existing technology. The measurement principles of choice are the real time weighing of exhaust samples as implemented in the tapered element oscillating microbalance (TEOM) and the measurement of light scattering from exhaust particles as implemented in the DustTrak nephelometer. Each of these two instruments has distinctive strengths. The TEOM excels in the area of constant calibration, independent of vehicle. For the DustTrak, this calibration varies by vehicle. On the other hand, the DustTrak has an excellent signal-to-noise ratio, freedom from interference due to other exhaust sample properties, good time resolution, and simplicity. The strengths of the two measurement methods are complimentary, so an obvious suggestion is to integrate them. The nephelometer would obtain a fast response signal, with near real time calibration provided by the microbalance.     

应用激光诱导离解光谱自由定标法测定黄金首饰成分初探

利用激光诱导离解光谱自由定标法对一系列高纯度黄金样品进行定量分析与研究,初步证明了将此方法应用于黄金首饰成分测定的可行性。采用波长1 064nm的Nd∶YAG脉冲激光器激发黄金样品,波长范围为200～760nm的4CCD光纤光谱仪采集发射光谱,对Au元素质量分数范围为85.0%～99.6%的6件黄金标准样品进行激光诱导离解光谱测试。对所得黄金样品光谱中的Au,Cu,Ag三种元素分别选择合适的原子(离子)谱线代入自由定标法模型,通过所得参数拟合得到了所有元素原子(离子)的二维波尔兹曼平面曲线,并以此为基础进行元素的质量分数计算。激光诱导离解光谱自由定标法定量分析黄金样品中Au元素的质量分数与标准值的相对误差<3%。     

混合标准溶液在乳粉检测中的应用

目的为了去除乳粉检测时共存元素的基体效应和干扰问题，提高测试效率。方法将钾、钠、钙、镁、铁、锌、铜、锰、磷的单元素标准溶液配制成多元素混合标准溶液，用于乳粉中常量元素的检测。分析混合标准溶液对于乳粉中常量元素检测时的优势。阐述应用混合标准溶液进行测定时有哪些关键点。采用电感耦合等离子体发射光谱法（ICP-OES）进行标准溶液稳定性研究。结果 采用混合标准溶液测定，能解决基体效应的问题。不同日期该混合标准溶液系列的校准曲线回归方程相关系数均大于0.999；并对质控样品进行分析，使用保存12个月的混合标准溶液进行测定结果仍在标准值的范围内。结论混合标准溶液在乳粉检测时能提高乳粉中常量元素检测的准确性和测试效率。能在常温下稳定保存12个月。     

火焰原子吸收光谱法测定薏苡仁中的微量元素

运用火焰原子吸收光谱法直接测定了薏苡仁中Fe、Cu、Zn、Mn、Ca、Mg六种微量元素的含量.用浓硝酸微波消解样品,采用标准曲线法测定.结果所测定的薏苡仁中含有丰富的人体必需微量元素.本方法简单、准确,回收率在99.10%～105.50%之间,相对标准偏差(RSD)小于2.602 8%,结果令人满意.     

电感耦合等离子质谱法测定母乳中10 种矿物元素

建立电感耦合等离子体质谱（inductively coupled plasma-mass spectrometry,ICP-MS）的同时测定母乳中K、Ca、Na、Mg、P、Cu、Mn、Zn、Fe、Se共10 种矿物元素的分析方法。以浓硝酸和双氧水为混合试剂,采用密闭高压消解技术对母乳样品消解后,用ICP-MS检测,利用动态反应池技术有效地消除了分析过程中质谱的干扰,选取Rh作为内标元素校正基体效应和信号漂移。标准曲线用外标法定量,以相对标准偏差考察方法的重复性,以标准物质考察方法的准确性。实验测定的10 种元素线性回归方程的相关系数均大于0.999 0,回收率范围为80.00%～118.19%,对照分析的奶粉成分分析标准物质（GBW10017）和脱脂奶粉成分分析标准物质（GBW08509）的K、Ca、Na、Mg、P、Cu、Mn、Zn、Fe、Se测定值均在标示值范围内,相对标准偏差均小于10.0%。结果表明,实验方法具有较好的准确度和精密度,适用于测定批量母乳的矿物元素。     

Lipolysis and proteolysis of modified and producer milks used for calibration of mid-infrared milk analyzers

Our objective was to determine if lipolysis or proteolysis of calibration sets during shelf life influenced the mid-infrared (MIR) readings or calibration slopes and intercepts. The lipolytic and proteolytic deterioration was measured for 3 modified milk and 3 producer milk calibration sets during storage at 4°C. Modified and producer milk sets were used separately to calibrate an optical filter and virtual filter MIR analyzer. The uncorrected readings and slopes and intercepts of the calibration linear regressions for fat B, fat A, protein, and lactose were determined over 28 d for modified milks and 15 d for producer milks. It was expected that increases in free fatty acid content and decreases in the casein as a percentage of true protein of the calibration milks would have an effect on the MIR uncorrected readings, calibration slopes and intercepts, and MIR predicted readings. However, the influence of lipolysis and proteolysis on uncorrected readings was either not significant, or significant but very small. Likewise, the amount of variation accounted for by day of storage at 4°C of a calibration set on the calibration slopes and intercepts was also very small. Most of the variation in uncorrected readings and calibration slopes and intercepts were due to differences between the optical filter and virtual filter analyzers and differences between the pasteurized modified milk and raw producer milk calibration sets, not due to lipolysis or proteolysis. The combined impact of lipolysis and proteolysis on MIR predicted values was <0.01% in most cases.     

The evaluation of the uncertainty of the research method on the geometrical parameters of the embroidery elements

The indirect measurement method of the contour width deformation of the embroidery element is presented in the work. The square-shaped, directly measured, embroidery element is compared to its digital image. Together with the used test methods steps, the reliability criteria for this method are presented as well. The reliability of the method of measuring the geometrical parameters of a closed contour element of an embroidered square shape is evaluated by analyzing its systematic and random errors and by calculating the total standard uncertainty. In assessing the accuracy of the measurement method, there is also a talk about a comprehensive assessment of measurement uncertainty. Measurement uncertainties are considered to be one of the most important parameters of the ability of a method to determine the possibilities of using and applying the method. When measuring the parameters of real samples, the components of total uncertainty related to the characteristics of the specimen (weave, surface density, filling characteristics, direction of the fabric yarn), their variation within certain limits and possible correlation among these components, influence of the standard means, data processing, digital image calibration were evaluated. It has been determined during the research that a negative error ～2.4% with expanded uncertainty ～3.3% complying with the requirements of the reliability of the method is typical for the deformation measurement method applied for the measurement of the five (6, 10, 14, 18, and 22?mm) elements of different contour widths. Because of that the evaluation of the uncertainty according its components is useful while analyzing the factors which have an impact on the deformation.