ICP-MS测定小麦中的铅、镉、汞、砷

重金属污染及其测量方法一直以来都是粮食检测部门关注的重点.本文探索采用微波消解结合ICP-MS的方法同时测定小麦中铅、镉、砷、汞含量,并根据此法测量结果评价了江苏小麦重金属污染情况.结果表明,该方法测试铅、镉、砷、汞含量的相关系数(r2,)分别为0.9991、0.9999、0.9999、0.9997;检测限分别为0.05μg/kg、0.01 μg/kg、0.02μg/kg、0.06 μg/kg;精密度分别为3.7％士2.8％、3.8％士2.8％、2.8％士1.9％、3.7％士3.5％;加标回收率分别为99.5％±4.4％、98.2％±4.6％、100.6％±7.1％、97.9％±10.8％;2014年江苏小麦铅、镉、砷、汞含量未见超标.结果认为,微波消解结合ICP-MS是一种高效、准确的小麦铅、镉、汞、砷含量测定方法.     

应用微波消解ICP-MS法同时测定青干草中20种元素的研究

利用高压密闭微波化学工作站消解青干草样品,采用电感耦合等离子体质谱仪(ICP-MS)测定青干草中的主要元素;优化了微波消解样品前处理条件和仪器测定条件;标准曲线的线性范围为0~200.0μg/L,回归方程的相关系数皆大于0.999 6。方法的检出限均小于2.138 2μg/L,试样加标回收率为85.7%~118.8%,精密度RSD<4.42%;西红柿叶国家标准样品(GSBZ 51001-94)和茶叶国家标准物质(GBW07605)的验证分析测定值均在保证值和标准值范围内。该方法具有快速、准确、灵敏度高及多元素同时分析等特点,适用于批量粗饲料样品的多元素检测。     

利用电感耦合等离子体质谱(ICP-MS)同时测定黄土性土壤中多种元素的研究

[目的]探讨利用电感耦合等离子体质谱(ICP-MS)同时测定黄土性土壤中多种元素的可行性.[方法]将标准物质和黄土性土壤进行一次湿法消解,使用ICP-MS同时测定样品中的多种大量和微量元素,计算标准物质中各元素的回收率和相对标准偏差确定方法的准确度和精密度以及黄土性土壤中各元素测定结果的精密度.[结果] ICP-MS法对于黄土性土壤中的多种大量和微量元素测定均具有良好的精密度.[结论] ICP-MS可用于黄土性土壤中多种大量和微量元素的同时测定.     

ICP-MS测定烟草中的重金属及其不确定度分析

[目的]建立烟叶中重金属的电感耦合等离子体质谱法(ICP-MS)的测定方法并分析其不确定度.[方法]烟草样品经微波消解,以Bi、Sc、Ge、In为内标校正体系,采用电感耦合等离子体质谱法(ICP-MS)测定烟草中Cr、Cu、As、Cd、Hg、Pb的含量,并用计量学方法对测量不确定度进行了评定.[结果]分析表明,在0～1.0 μg/ml的线性范围内,6个元素的线性相关系数r为1.0000,相对标准偏差为1.5％ ～ 11.0％.烟叶样品含量测定为:Cr(2.92±0.24) mg/kg、Cu(3.64±0.24) mg/kg、As(0.467±0.025)mg/kg、Cd(3.12±0.15)mg/kg、Hg(0.035±0.006)mg/kg、Pb(4.62±0.36) mg/kg.标准溶液中待测元素的含量和样品重复性是电感耦合等离子体质谱法测定烟叶中重金属含量的主要不确定度来源,而取样量、待测样品溶液的定容等引入的不确定度可以忽略不计.[结论]电感耦合等离子体质谱法测定烟草中重金属具有简便、快速、灵敏度高、重现性好等优点,选择合适的试验方案可保证测定结果的准确可靠.     

ICP-MS法分析10种箬竹属竹叶中矿质元素质量分数

采用ICP-MS法,对10种箬竹属竹叶中矿质元素质量分数进行分析。结果表明,10种箬竹属竹叶中有17种矿质元素被检出,其中K、Ca和Mg的质量分数较高,范围分别为8 770.5~14 270、4 000~8 000、1001.7~1 370 mg·kg-1。而Ag和Cd未检出,Cu、As、Hg质量分数均较低。从矿质元素总体质量分数均值来看,粽粑箬竹竹叶矿质元素质量分数较高,阔叶箬竹则较低。系统聚类分析表明,髯毛箬竹与米箬竹矿质元素质量分数较为相似;元素相关性分析表明,箬竹属竹叶中多种元素之间显著相关,如K和Ca、Na呈显著负相关;Fe、Al除了与Hg呈负相关外,与其他元素均为显著正相关。     

Determination of trace elements in otoliths of chum salmon Oncorhynchus keta by laser ablation-ICP-mass spectrometry

Trace element levels in the otoliths of chum salmon Oncorhynchus keta were examined by means of laser ablation inductively coupled plasma mass spectrometry (LA-ICPMS). A close linear relationship in the Sr/Ca ratios between X-ray analysis with an electron microprobe (EPMA) and LA-ICPMS analysis was found, suggesting that the latter technique could be used to distinguish the marine and freshwater life phases. Mg, Zn, Ba and Sr concentrations of the otoliths differed between the freshwater and seawater growth zones. Mg and Zn concentrations in the freshwater growth zone were significantly higher than those in the seawater growth zone, while Sr and Ba concentration s in the former were significantly lower than in the latter. The relationship between Sr concentration and Mg, Zn, and Ba concentrations at each ablation showed significant correlations. These results suggest that trace element compositions may reflect differences between freshwater and seawater environmental conditions.     

微波消解ICP-MS测定茶叶中稀土元素的不确定度评定

采用微波消解电感耦合等离子体质谱(ICP-MS)法测定茶叶中稀土元素的含量,对样品称量、样品消解、样品定容、标准溶液的配制、标准曲线的拟合、仪器测量重复性等影响不确定的分量进行分析,按JJF1059.1-2012《测量不确定度的评定与表示》的规定进行合成。结果表明:样品称量和定容对测量结果影响不大,标准溶液的配制、标准曲线拟合、重复性测量及样品消解等因素对测定结果准确性影响大,应加以严格控制,以提高稀土元素测定结果的准确性和客观性。     

成都地区膨化食品中铝污染水平评估

[目的]建立ICP-MS测定膨化食品中铝含量的方法,对成都地区销售的膨化食品中的铝污染水平进行测定分析。[方法]在成都地区的商场超市、餐饮店、农贸市场和路边摊点采集各种膨化食品57份,样品经微波湿法消解后,用电感耦合等离子体质谱进行测定其中铝的含量。[结果]试验测得,从农贸市场和路边摊采集的油炸膨化食品铝含量超标严重,超标率达100%,最高含量达872.00 mg/kg。测定方法的最低检出浓度为0.670 mg/kg,相关系数为r=0.999 9,回收率为98.53%~102.01%,测定结果的RSD为6.5%。表明该测定方法的准确度高、方法简便、线性范围广。[结论]建议新的国家食品安全标准中应更加严格控制膨化食品中含铝食品添加剂的使用,加强对农贸市场和路边摊食品安全的监督管理。     

What Constitutes Plant-Available Molybdenum in Sandy Acidic Soils?

Molybdenum (Mo) is critical for the function of enzymes related to nitrogen cycling. Concentrations of Mo are very low in sandy, acidic soils, and biologically available Mo is only a small fraction of the total pool. While several methods have been proposed to measure plant-available Mo, there has not been a recent comprehensive analytical study that compares soil extraction methods as predictors of plant Mo uptake. A suite of five assays [total acid microwave digestion, ethylenediamenetetraaacetic acid (EDTA) extraction, Environmental Protection Agency (EPA) protocol 3050B, ammonium oxalate extraction, and pressurized hot water] was employed, followed by the determination of soil Mo concentrations via inductively coupled mass spectroscopy. The concentrations of soil Mo determined from these assays and their relationships as predictors of plant Mo concentration were compared. The assays yielded different concentrations of Mo: total digest > EPA > ammonium oxalate ≥ EDTA > pressurized hot water. Legume foliar Mo concentrations were most strongly correlated with ammonium oxalate–extractable Mo from soils, but an oak species showed no relationship with any soil Mo fraction and foliar Mo. Bulk fine roots in the 10- to 30-cm soil horizon were significantly correlated with the ammonium oxalate Mo fraction. There were significant correlations between ammonium oxalate Mo and the oxides of iron (Fe), manganese (Mn), and aluminum (Al). Results suggest that the ammonium oxalate extraction for soil Mo is the best predictor of plant-available Mo for species with high Mo requirements such as legumes and that plant-available Mo tracks strongly with other metal oxides in sandy, acidic soils.     

微波消解—电感耦合等离子体发射光谱法（ICP-AES）测定婴儿米粉中的常量和微量元素

采用微波消解—电感耦合等离子体发射光谱法（ICP-AES）测定婴儿米粉中的微量元素。优化微波消解和ICP-AES处理条件;通过分析国家标准物质GBW10010（大米）和GBW10012（玉米）来验证方法的准确度和精密度,结果得出测定值与标准值吻合;相对标准偏差在0.65%～3.70%之间,加标回收率在96.1%～103.2%之间。表明此法具有操作简便、检出限低、线性范围宽、精密度高、准确度好等优点,能同时满足微量元素和常量元素的检测要求。