ICP-MS测定土壤中铅同位素比值及地域差异性比较

建立用HNO_3-H_2O_2-HF体系微波消解前处理样品,利用电感耦合等离子体质谱测定土壤中铅同住素比值的方法,探讨并优化了影响测试结果的两种干扰因素.该方法中~(207)Pb/~(206)Pb和~(208)Pb/~(206)Pb的短期测量稳定性RSD分别达到0.12%和0.13%,长期测量的偏差分别在0.002和0.01以内,样品测量的最佳范围是10～40μg/L.采用标样-样品交叉法测定了湖南、湖北、云南、贵州、河南、福建、辽宁7个省的48个地区土壤中的铅同位素比值,结合聚类分析和主成分分析比较了各省土壤中同位素分布的差异,初步探讨了利用~(207)Pb/~(206)Pb和~(208)Pb/~(206)Pb比较烟叶产区的可能性.     

土壤及其他背景样品中铅同位素比值的测定方法

为给铅同位素示踪技术在判别土壤、大气、水体和人体中铅与相关重金属污染来源,区别汽车尾气铅污染和工业铅污染等方面的应用提供科学依据。通过大量的对比条件实验,拟出了土壤、煤、汽车尾气和气溶胶样品中铅同位素比值的测定方法。利用这三个流程分别测定了采自杭州茶园的土壤及茶园附近的煤、汽车尾气和气溶胶样品的铅同位素比值,其中207Pb/206Pb的精度(2σ)均优于±0.03%。重复样误差优于±0.05%2。08Pb强度一般均在1V以上,有的高达8 V以上。监控分析流程的国际标准物质NBS981的207Pb/206Pb为0.91449±0.00004。全流程本底铅为10-8数量级。     

应用多接收器电感耦合等离子体质谱法测定海洋碳酸盐中稳定铅同位素组成

研究了多接收器电感耦合等离子体质谱仪(MC-ICP MS)测定铅同位素比值时,影响测试结果准确度和精密度的主要因素及其优化过程。在优化条件下,10 h内连续30次测定4 ng/mL NIST SRM 981同位素标准溶液铅同位素比值,获得208Pb/206Pb、207Pb/206Pb和206Pb/204Pb相对标准偏差(RSDs)分别为0.005%、0.004%和0.054%。长期监测208Pb/206Pb、207Pb/206Pb和206Pb/204Pb,标准偏差(2SDs)分别为0.000 06、0.000 05和0.006 7。采用NEPTUNE MC-ICP MS法测定了低铅海洋碳酸盐样品中稳定铅的同位素比值,并对南海橙黄滨珊瑚(Porites lutea)和库氏砗磲(Tridacna gigas)进行了分析,得到全流程空白为8～10 pg,重复样误差优于0.1%。经0.50 mol/L HNO3洗脱之后,得到海南珊瑚样品中208Pb/206Pb、207Pb/206Pb的比值分别为2.086 2±0.001 5、0.849 90±0.001 47(n=16);海南砗磲样品中208Pb/206Pb、207Pb/206Pb的比值分别为2.116 9±0.004 2、0.864 81±0.001 62(n=9)。进一步考察了南海海洋碳酸盐中204Pb的同位素比值。分析结果表明,南海海洋碳酸盐中稳定铅同位素比值与中国气溶胶、珠江三角洲大气沉降、黄土及南海海底玄武岩等具有很好的相关性。方法适用于复杂基体高钙低铅的海洋碳酸盐样品中铅同位素比值的分析。     

基于ICP-MS和机器学习的土壤物证溯源研究

土壤是犯罪现场最常出现的物证,对现场土壤进行地理溯源能够为认定犯罪事实提供有力证据。本研究收集了来自五座城市、20个取样点的土壤样本,用ICP-MS测定了样本中钠(Na)、铝(Al)、钙(~(43)Ca、~(44)Ca)、铬(Cr)、锰(Mn)、铁(Fe)、钴(Co)、镍(Ni)铜(Cu)、锌(Zn)、砷(As)、银(Ag)、镉(Cd)、钡(Ba)和铅(~(206)Pb、~(207)Pb、~(208)Pb)18种元素及同位素的含量,使用机器学习方法对土壤来源进行区分,SVM的识别准确率可达99%。依据元素与人类活动的相关性,又筛选出8种重金属元素作为特征,对土壤城市来源进行识别,其中SVM识别准确率为100%,贝叶斯模型识别准确率为97%。结果表明基于ICP-MS多元素测定和机器学习方法能够实现对土壤来源的准确识别。     

火焰原子吸收光谱法测定高锑烟尘中的银、铅、镉

建立了火焰原子吸收光谱法测定高锑烟尘中的银、铅、镉的分析方法。试样经王水、高氯酸溶解后,利用四价锑的溴化物沸点较低的性质,将锑挥发除去,以消除基体锑对测定的干扰,在盐酸-高氯酸-硫脲介质中实现了银、铅、镉的连续测定。方法检出限:Ag为0.003 7μg/mL,Pb为0.019 8μg/mL,Cd为0.001 6μg/mL。相对标准偏差(RSD,n=11):Ag为0.92%~1.04%,Pb为1.29%~2.21%,Cd为1.99%~2.22%。加标回收率:Ag为99.30%~101.8%,Pb为98.60%~102.5%,Cd为98.40%~104.0%。方法准确、可靠、简便、快速,完全适用于高锑烟尘中银、铅、镉的测定。     

活性炭吸附及离子交换富集分离-分光光度法测定水中痕量银

建立了用活性炭对水中痕量银进行预富集的新方法。结果表明,pH=1.0时,活性炭能对水中被抗坏血酸还原后的痕量银进行吸附富集,而Cu(Ⅱ)、Fe(Ⅲ)、Co(Ⅱ)、Ni(Ⅱ)、Pb(Ⅱ)、Zn(Ⅱ)、Mn(Ⅱ)、Al(Ⅲ)、Bi(Ⅲ)和Sb(Ⅲ)等常见阳离子不被吸附,用K2S2O8将吸附在活性炭上的单质银氧化解脱后,用Mg(NO3)2辅助置换洗脱,可用分光光度法测定。该法在8～50μg/L银(Ⅰ)范围内加标回收率为93.2～97.1%。同时还研究了活性炭对银的吸附行为,提出了活性炭表面上被氧化的Ag(Ⅰ)和Mg(Ⅱ)有离子交换作用。应用该法测定自来水中痕量银,结果令人满意。     

火焰原子吸收法测定植物叶片中Pb、Cd、Cu、Zn含量

对八种植物叶片 (糖胶树、榕树、红花羊蹄甲、银合欢、垂叶榕、白玉兰、蟛蜞菊、大花紫薇 )中Pb、Cd、Cu、Zn的测定方法进行了研究 ,采用炭化—灰化—硝酸溶解方法进行样品处理 ,火焰原子吸收法测定Pb、Cd、Cu、Zn四种重金属元素。结果表明 ,该法准确 ,回收率高。各元素的回收率分别为 :铅 88%～ 1 0 5 %、镉 90 %～ 1 0 3 %、铜 90 %～ 1 0 5 %、锌 91 %～ 1 0 5 %。     

毛细管电泳-电感耦合等离子体质谱联用测定海藻中铅形态化合物

建立了毛细管电泳( CE)与电感耦合等离子体质谱( ICP-MS)联用技术测定铅离子( PbⅡ)、三甲基铅(TML)和三乙基铅(TEL)3种不同形态铅化合物的方法,以及海藻中不同形态铅化合物的提取技术,实现了海藻中3种铅形态化合物的定性定量分析。结果表明：以70 mmol/L H3BO3-17.5 mmol/L Na2B4O7(pH 8.90)为缓冲溶液,在最佳CE-ICP-MS条件下3种铅化合物20 min内可实现有效分离,重现性较好,迁移时间RSD﹤4%,峰面积的RSD﹤5%;在10~200μg/L 范围内3种铅化合物线性较好,相关系数大于0.90; PbⅡ、TML和TEL的CE-ICP-MS检出限(3S/N,以Pb计)分别为0.091,0.023和0.030μg/L;采用分步提取海藻中Pb元素,提取率高达80%以上,以藻体为基底 PbⅡ, TML 和 TEL 回收率分别为103.6%,95.7%和90.6%;通过检测紫菜和海带中铅含量,结果显示藻体内Pb主要以PbⅡ形式存在。本方法具有简单、高效、样品消耗量少等优点,可为海藻及其它海产品的质量控制提供技术支撑。     

原位微区同步辐射X射线荧光和近边吸收谱研究铅耐受细菌吸附-转化铅机理

为了从微观水平研究细菌生物吸附及转化铅机理,利用原位微区同步辐射X射线荧光(μ-SRXRF)及X射线吸收近边结构谱( XANES)研究云南兰坪铅锌矿区农田土壤样品中筛选的铅耐受性细菌吸附铅的分布特征及铅形态转化规律。土壤中具有铅耐受性的菌株主要为Arthrobacter sp.属(节杆菌属),采用μ-SRXRF对其吸附铅的含量进行快速简单直接分析,部分细菌吸附铅的含量高达5925μg/g,富集系数达14.8。XANES结果表明,细菌吸附 Pb 后存在形态为 PbS、(C17 H35 COO)2Pb 和 Pb5(PO4)3Cl 分别占58.0％,22.2％和19.8％,与培养基本身以有机态为主的Pb形态有明显差异,表明培养基中铅被细菌吸附后有向硫化物转化的趋势,这为研究重金属生物有效性的影响因素提供了实验参考。     

高效液相色谱-电感耦合等离子体质谱法测定烟草及其制品中3种铅形态

建立了高效液相色谱-电感耦合等离子体质谱法(HPLC-ICP-MS)测定烟草及其制品中无机铅[Pb(Ⅱ)]、三甲基铅(TML)和三乙基铅(TEL)含量的方法。将烟草样品粉碎后,加入体积比为60∶40的1 mmol·L~(-1) 1-戊烷磺酸钠溶液和甲醇的混合溶液(流动相) 15 mL,于40℃超声萃取20 min,离心,上清液过0.22μm滤膜,用HPLC-ICP-MS测定滤液中3种铅形态含量。在烟草样品中加入硝酸和30%过氧化氢溶液,在程序升温条件下微波消解,消解液用水稀释后,用ICP-MS测定其中的铅总量。在HPLC分析中,在1.0 mL·min~(-1)流量下用流动相等度洗脱吸附在ZORBAX Eclipse Plus C_(18)反相色谱柱上的3种铅形态,8 min即可实现高效分离。在ICP-MS分析中,同步监测~(206)Pb、~(207)Pb和~(208)Pb等3种铅同位素,用三者含量和进行定量。结果显示:3种铅形态的质量浓度在0.5～50.0μg·L~(-1)内与其对应的质谱响应值呈线性关系,检出限(3S/N)为0.33～0.47μg·L~(-1);对实际样品进行3个浓度水平的加标回收试验,所得回收率为81.9%～96.5%,测定值的相对标准偏差(n=6)为5.3%～9.6%。方法用于烟叶样品和卷烟成品的分析,结果显示:烟叶样品及卷烟成品中均未检出有机铅,其铅形态以Pb(Ⅱ)为主,且含量较低(1.53～5.08μg·g~(-1));下、中、上部烟叶中铅含量呈递减分布;卷烟成品中的铅含量与烟叶样品的基本处于相同水平;检出的3种铅形态含量总和占铅总量的74.3%～84.6%。     

Effect of Rutile on Modulus of Rupture in Ceramic Glaze

The study was focused on the performance of rutile addition in glaze composition for antibacterial application. Rutile powder in micro size (ξηзm) were added in the glaze composition at different weight percentage (5 wt%, 7 wt%, 9 wt%, 10 wt% and 15 wt%). Glazing was performed by dipping technique for 10 seconds. Glazed tile was then sintered at 1200 °C for 1 hour. Characterizations used to observe the properties of produced tiles were physical observation, scanning electron microscopy (SEM) and modulus of rupture. Results show that cracking occurred in glazed tile which could be related to the viscosity of the glaze mixture during dipping. The relation between viscosity and the occurrence of crack depend on the amount of rutile The amount of crack appearance increases with increasing glaze viscosity. However, modulus of rupture increased when the tile was glazed.     

Concise and stereocontrolled syntheses of phosphonate C-glycoside analogues of β-d-ManNAc and β-d-GlcNAc 1-O-phosphates

Diethyl C-(2-deoxy-2-acetamido-β-d-mannopyranosyl)methylphosphonate and dimethyl C-(2-deoxy-2-acetamido-β-d-glucopyranosyl)methylphosphonate were stereoselectively prepared from N-acetyl d-glucosamine. Routes to such compounds starting from d-GlcNAc have been problematic, but we have found short and efficient implementations of this highly desirable transformation.     

Chemistry of tetravalent actinide phosphates—Part II

The chemistry and crystal structure of tetravalent cation phosphates, including that of actinides was reviewed several times until 1985. Later, new compounds were synthesized and characterized. In more recent studies it was found that some of previously reported phases, especially those of thorium, uranium, and neptunium, were wrongly identified. In the light of these new facts, an update review and classification of tetravalent actinides phosphates is proposed in this two-part paper. Their crystal structure and some chemical properties are compared to non-actinide cation phosphates.     

Chemistry of tetravalent actinide phosphates—Part I

The chemistry and crystal structure of phosphates of tetravalent cations, including that of actinides was reviewed several times up to 1985. Later, new compounds were synthesized and characterized. In more recent studies, it was found that some of previously reported phases, especially those of thorium, uranium and neptunium, were wrongly identified. In the light of these new facts an update review and classification of the tetravalent actinide phosphates is proposed in the two parts of this paper. Their crystal structure and some chemical properties are also compared to non-actinide cation phosphates.     

Synthesis and thermal characterization of copper and calcium mixed phosphates

A series of compounds with composition of Ca_1–xCu_xHPO₄, where x varied from 0.05 to 0.5 were synthesized by precipitation method. The compounds were characterized by elemental analysis, X-ray diffraction, infrared spectroscopy, scanning electron microscopy, and thermogravimetry. The chemical stabilities of solids were investigated at several pH. Elemental analysis of copper, calcium and phosphorus are in agreement with the proposed composition. The formation of lamellar phosphates was evidenced. The stability of the set of compounds was better for samples with high copper content.     

Conductivity of Phosphoric Acid, Sodium, Potassium, and Ammonium Phosphates in Dilute Aqueous Solutions from 278.15 K to 308.15 K

Precise conductivity measurements on aqueous solutions of phosphoric acid, sodium dihydrogen phosphate, potassium dihydrogen phosphate, ammonium dihydrogen phosphate, disodium hydrogen phosphate, dipotassium hydrogen phosphate, diammonium hydrogen phosphate, sodium phosphate, and potassium phosphate were performed from 5 to 35°C. Data analysis was executed by the use of the Quint–Viallard equation for unsymmetrical electrolytes. Equations are given for the concentration dependence of electrolyte and single-ion conductivities at all temperatures.     

我国北方古白瓷釉化学组成的能量色散X荧光光谱分析

利用能量色散X荧光光谱分析法（EDXRFS）测定了我国北方的四个窑口——邢窑、定窑、巩窑和宜阳窑所烧制白瓷釉的主量元素和微量元素，通过化学成分分析和多元统计的方法，揭示出不同窑口化学组成的分区特征，并且发现宜阳窑的白瓷与我国北方三个代表性白瓷窑口之一——巩窑之间存在着密切的联系。     

A Novel Method for the Synthesis of Acetyl Phosphate

A facile method for the synthesis of acetyl phosphate by a reaction of 2-hydroxypropylphosphate with acetic acid is described.     

Intercalation of 1,2-alkanediols into Vanadyl and Niobyl Phosphate

Intercalation compounds of VOPO₄and NbOPO₄ with 1,2-alkanediols (from C3 to C16)have been prepared. The diol molecules are placedbetween host layers in a bimolecular way with theiraliphatic chains tilted at an angle of 70°. Itwas found that the intercalates contain 1.5 moleculesof diol per formula unit. Three ways of bonding of thediol molecules to the host layers are proposed. Twomolecules of diol are coordinated to the metal atomsby their first and second oxygen, respectively. Thethird diol molecule is anchored in the interlayerspace by H-bonds.     

Synthesis,Characterization, and Crystal Structures of a New Coordination Polymer of Manganese(II) Containing Dimethyl Phosphate

The reaction of MnCl₂ with TMP (TMP = Trimethyl phosphate) in THF (THF = tetrahydroforan), led to the coordination polymer [Mn₂(μ₃‐DMP)₂(μ‐DMP)₂]_n (1) (DMP = dimethyl phosphate). This complex was characterized by elemental analysis, IR spectroscopy and single‐crystal structure of 1 . Crystal data for 1 at ?173 °C: triclinic, space group , a = 9.7071(11), b = 10.4482(11), c = 10.6242(11) Å, α = 88.892(2)°, β = 80.829(2)°, γ = 87.572(2)°, Z = 2, R1 = 0.0441.