不同酸化体系测定中国不同地区土壤重金属的比较研究

本文采用硝酸-氢氟酸-盐酸-过氧化氢(5∶1∶1∶1)的消解体系和硝酸-过氧化氢(6∶2)消解体系,均通过微波消解法和电感耦合等离子体质谱法(ICP-MS)测定土壤中的铬、镍、铜、锌、砷、镉、铅等7种元素.分析了来自全国不同地区的9种土壤与水系沉积物的质控样品,研究了全量微波消解酸体系对土壤中7种重金属测定的影响.结果表明,对于Cr和Pb元素,硝酸-过氧化氢消解体系可溶态元素的结果显著低于元素全量的结果,未加入氢氟酸,难以将硅晶格中的Cr和Pb析出.对于As元素,硝酸-氢氟酸-盐酸-过氧化氢消解体系的回收率略有偏高,推测其原因为盐酸引入的氯离子对ICP-MS的测定产生了质谱型干扰,因此消解体系应尽量避免引入氯.对于Ni、Cu和Zn的结果,硝酸-过氧化氢消解体系的回收率在75%—110%的范围,两种消解体系结果的偏差较小,硝酸-过氧化氢法测定的可溶态元素的结果可以较好的反映元素全量的水平.对比不同地区土壤的结果发现,除水系沉积物和砖红壤中的Pb及砖红壤中的Cr,土壤中部分Cr和Pb难以被硝酸-过氧化氢体系消解出来,在环境中处于稳定的状态,因此采用硝酸-过氧化氢体系能更准确地评估Cr和Pb对环境的危害.     

土壤/沉积物中14种金属元素的ICP-MS准确测定方法

建立了微波和湿法两种消解方式的不同条件下土壤/沉积物中V、Cr、Co、Ni、Cu、Zn、Se、As、Sr、Mn、Pb、Cd、Ba和Fe共14种金属元素的ICP-MS准确测定方法.比较了微波消解不同称样量及湿法不同消解体系、温度对不同金属元素的消解效果.以103Rh和195Pt作为ICP-MS测定时的内标元素,针对不同测定元素选择合适的监测质量数及碰撞/反应模式.结果表明,微波消解称样量为0.10 g、消解体系为硝酸-盐酸-氢氟酸时,除Mn、Sr、Ba、Fe等半金属外大部分金属元素消解效果良好;湿法消解采用硝酸-盐酸-高氯酸-氢氟酸(5∶1∶1∶5)体系、消解最高温度为180℃时消解效果最佳,14种金属元素测定结果均在标准值范围内,但需防止少数易挥发元素如As、Se、Pb等在蒸酸过程中挥发损失.分别采用上述两种消解体系对湖底沉积物和两种国际比对土壤样品进行了前处理,并以ICP-MS进行了准确测定,14种金属元素的RSD均在0.10%—3.32%范围之间,国际比对中As、Cd、Pb、Mn的测定结果与初步公布结果一致.该方法重复性好、准确度高,适用于常规土壤/沉积物样品的准确测定.     

混酸微波辅助萃取ICP-MS测定不同性质土壤中的重金属元素

比较了硝酸(HNO3)、硝酸-盐酸(HNO3∶HCl=3∶1)、硝酸-盐酸-双氧水(HNO3∶HCl∶H2O2=3∶1∶1)和硝酸-盐酸-高氯酸(HNO3∶HCl∶HCl O4=3∶1∶1)等4种消解液对土壤中铅(Pb)、镉(Cd)、砷(As)、铬(Cr)、镍(Ni)、铜(Cu)和锌(Zn)等7种重金属元素的萃取效率.结果表明,硝酸-盐酸-高氯酸混合液的萃取效果最好,硝酸-盐酸混合液次之.通过对6种土壤标准物质的分析发现,除了Cr之外,其他重金属元素在土壤中的混酸微波可提取态含量与总含量接近.土壤中的Cr有一部分是以铬铁矿的形式存在,在环境中相对较为稳定,采用混酸微波可提取态的Cr来评估其对环境的危害能够获得更加准确的结果.重金属与土壤的结合强弱与成土母质相关,冲积母质的土壤中Pb、Zn和Cu的结合较强,萃取相对较难,Cd、Ni和As与土壤的结合强弱则与成土母质关系不大.采用最优的消解液萃取矿区河流底泥和土壤中的重金属,ICP-MS分析结果表明,底泥中重金属含量较高,应为尾砂冲积而成,矿区周边的土壤也受到不同程度重金属的污染.     

干法灰化和微波消解-火焰原子吸收法测定铅锌冶炼厂废旧除尘布袋中重金属

采用干法灰化和微波消解两种样品分解方法处理广东省某铅锌冶炼厂布袋试样,用火焰原子吸收光谱法测定样品中Cu、Zn、Pb、Cr、Ni、Cd 6种重金属元素含量.同时用两种前处理方法对国家一级标准物质进行测定,与标准值比对,验证两种方法的准确度和精密度.结果表明,不同的样品分解方法对各重金属元素的测定结果会产生不同程度的影响.微波消解法相对于干法灰化法的准确度高,试剂利用率高,有利于元素的分析.干法灰化和微波消解两种前处理方法的精密度（RSD,n=11）均小于5%.     

永定河上覆水、间隙水和沉积物中重金属的分布特征

采集了永定河及其支流清水河水样和表层沉积物各11个,并通过高速离心获得间隙水样10个.利用ICP-MS检测了上覆水中可溶性重金属(Cd、Cr、Cu、Hg、Mn、Ni、Pb、Zn)、间隙水中可溶性重金属(Cd、Cr、Cu、Mn、Ni、Pb、Zn)的含量以及沉积物中重金属(Cd、Cr、Cu、Hg、Mn、Ni、Pb、Zn)的总量;检测了样品的理化性质;分析了水体及沉积物间重金属的分配系数.结果表明,上游采样点水化学类型主要为Ca~(2+)-Mg~(2+)-HCO_3~--SO_4~(2-),而下游采样点水化学类型则主要为Na~+-Mg~(2+)-Cl~--SO_4~(2-),上游和下游的水化学类型呈现明显的差异性;上覆水中Mn在位于下游的7号采样点含量超出生活饮用水卫生标准;间隙水中的重金属普遍高于上覆水含量;采用间隙水标准毒性单位(IWCTU)对间隙水重金属进行评价,发现Zn在大部分采样点(除2、5、11)及Pb在采样点6、7、8存在一定程度的毒性风险;Cd、Pb、Ni等3种重金属在附近有煤矿分布的采样点的上覆水和沉积物中含量都较高,需要特别注意的是Hg的分布也可能与煤矿开采有关.Pb、Cr、Mn等3种重金属在沉积物与上覆水中的分配系数比较大,而Hg、Cd、Zn则分配系数比较小;重金属在上覆水间隙水及沉积物中的分布关系为沉积物间隙水上覆水;分别对上覆水间隙水和沉积物中的重金属进行相关性分析及沉积物的主成分分析,发现Cd和Pb在间隙水和沉积物中均存在显著的相关性,沉积物中的Cd、Pb、Ni、Hg、Cu、Cr在第一主成分中具有较高的载荷值,推断这几种重金属具有相同的来源.     

硅藻土和膨润土对重金属离子Zn~（2＋）、Pb~（2＋）及Cd~（2＋）的吸附特性

以硅藻土和膨润土作为吸附剂,考察微波加热与否条件下,不同吸附时间、不同吸附剂用量和不同pH值对硅藻土和膨润土分别吸附Zn2＋、Pb2＋、Cd2＋重金属离子的影响.实验结果表明,硅藻土和膨润土对3种重金属离子均有很好的吸附效果,吸附时间对去除率影响不大,数分钟即可达到吸附平衡,微波加热、增加吸附剂用量和提高pH值,都有利于提高3种重金属离子的去除率.     

沉积物中酸挥发硫对上覆水中重金属含量的影响

在实验室条件下,利用装有新鲜河流沉积物和上覆水且可控制环境参数的模拟体系及参比体系,通过定时定量投放重金属溶液,研究了富含酸挥发硫的河流沉积物对上覆水中重金属（铜,镉,铅,锌）含量的影响,并观察了模拟体系更换为清洁上覆水后沉积物中重金属的静态释放;随后考察了同一沉积物样品经酸化后对上覆水重金属含量的影响能力的变化及在更换为清洁上覆水后沉积物的静态释放。研究结果表明：水相金属迅速转移到沉积物中,被其     

消解方法对煤矸石中砷含量测定的影响

选择山西不同地区不同硅铝含量的4种煤矸石,通过实验得到湿法消解和微波消解的优化条件,采用配置氢化物发生器的电感耦合等离子体发射光谱法(HG-ICP-AES)对消解液中的砷含量进行测试,对比了微波消解(酸解液:4 mL HNO3、2 mL HF、1 mL H3PO4)和湿法消解(酸解液:5 mL HNO3、1 mL HF、1 mL HClO4、1 mL H3PO4)对煤矸石中砷含量测定的影响,以确定适合测定煤矸石中砷含量的前处理方法.结果表明,微波消解耗时短、体系密闭,可有效防止砷的挥发与样品间的交叉污染,结合HG-ICP-AES测试,测试结果精密度高、回收率良好,可以满足煤矸石中砷含量准确测定的要求.     

微波消解ICP-AES法测定土壤及植物中的重金属

建立了微波消解、电感耦合等离子体发射光谱法(ICP-AES)同时测定赣南钨矿区尾砂库的土壤和植物中重金属的测试方法.结果表明:土壤和植物分别经HNO3-HF-HClO4(4∶ 5∶ 2)和HNO3-HClO4(8∶ 2)消解后完全分解,适当增加RF功率和雾化速率有利于提高重金属的信噪比,采用内标法有效地改善了检测结果的准确度和精密度.土壤和植物分析方法的加标回收率分别为96.0%-113.6%和97.2%-107.0%,RSD分别为1.31%-4.16%和1.59%-4.17%.     

铅锌矿区河谷沉积物的磁学特征与重金属污染的关系

以流经中国铅锌矿储量最大的兰坪金顶铅锌矿区的澜沧江支流--沘江的河谷冲积物为研究对象,通过实地调查采样、室内实验测定和统计分析等方法,测定并分析了沘江河谷沉积物的磁化率特征与重金属Pb、Zn、Cd的含量,以探讨矿产开发对河谷沉积物重金属含量的影响,并试图为其监测提供一种简单有效的手段.研究表明:(1)沘江沉积物磁化率因受到兰坪铅锌矿产开发活动的影响表现出明显的分段性,且与重金属污染状况的分段性基本吻合,呈现上游污染段沉积物的重金属含量和磁化率均高于下游的特征,且单因子污染指数较高的河段磁化率也高;(2)回归分析显示,沉积物磁化率与重金属含量显著相关;(3)可以利用磁性测试监测矿区河流沉积物的重金属污染状况.     

Comparison of sample digestion procedures for the determination of trace elements in antarctic krill by GF‐AAS

Two independent digestion procedures for Antarctic krill samples were compared. Dry ashing (DA) and microwave (MW) acid‐assisted digestion were tested for decomposing the samples to determine essential (Cu, Fe, Cr) and toxic elements (Cd, Pb) by graphite furnace‐atomic absorption spectrometry (GF‐AAS). A mixture of HNO₃ and H₂O₂ as digesting agent was used in the microwave procedure. For the dry ashing digestion, the organic matter was oxidated at 480°C in an open system. Both digestion methods were compared in terms of accuracy and applied to the analysis of a certified reference material: MURST‐ISS‐A2 (Antarctic krill).

The detection limits for the five elements analysed ranged from 3 to 150 ng g^‐1. Both digestion procedures are suitable for the decomposition of krill samples. However, dry ashing is not recommended to determine Pb and Cd because losses can occur.     

An evaluation of procedures for the digestion of soils and vegetation from areas with metalliferous pollution

Various digestion or extraction processes are available for the determination of trace metals in environmental samples using diverse analytical techniques. Our research examines the most efficient and reproducible methods of digestion utilising readily available laboratory equipment, reagents and instrumentation. Extraction procedures reported in over 80 recent research works were considered and the most common methods were critically evaluated. Thus nitric acid, nitric acid/perchloric acid, aqua regia, nitric acid/hydrogen peroxide and microwave-assisted methods were investigated using soil and leaf samples collected adjacent to three old metalliferous workings. Analysis was carried out using Flame Atomic Absorption Spectrometry and the results were evaluated. Differences in efficiency of extraction relative to specific metals and different substrates are highlighted and recommendations made for a digestion procedure suitable for environmental samples. Aqua regia produced the most accurate, efficient and reproducible results; we consider methods of improving both of these factors and sample preparation. Our recommended methodology has applications in environmental surveys, environmental geology, environmental toxicology, geochemistry and provides a means of obtaining meaningful and reliable results for the determination of metals present in soils, minerals and vegetation.     

Comparison of extraction methods for polycyclic aromatic hydrocarbon determination in sediments

Different sample preparation methods for the determination of polycyclic aromatic hydrocarbons (PAHs) in lake and river sediments were compared and evaluated. Freeze‐dried sediment materials were extracted using Soxhlet extraction, ultrasonic agitation and digestion with various solvents and solvent mixtures. Similarly, clean‐up methods using various types of sorbents for separation of PAHs tested.

The following method gives the best results for the determination of PAHs: freeze‐dried sediment samples were extracted using Soxhlet extractor with dichloromethane (6 hr, dark), extracts were cleanup using Silica gel and a mixture of n‐hexa‐ne‐dichloromethane was used for the elution of PAHs.

This method was used for the determination of 7 selected PAHs in sediment samples from Finnish lakes and Czech streams.     

油脂去除对餐厨垃圾压滤液厌氧消化的影响

采用常温（25℃）厌氧消化工艺,通过设计两种不同的进料浓度和4个处理方式,研究了油脂的去除对餐厨垃圾压滤液厌氧消化产沼气的影响,并考察了消化过程中典型工艺参数pH值、挥发性脂肪酸（VFA）、CODCr、总磷等的变化规律.试验结果表明油脂对餐厨垃圾压滤液厌氧消化的产气前期有一定的抑制作用,但是整体抑制不明显.处理T1（未隔油餐厨垃圾滤液800 mL）、T2（隔油餐厨垃圾滤液800 mL）、T3（未隔油餐厨垃圾滤液500 mL）、T4（隔油餐厨垃圾滤液500 mL）的产气总量分别为：84357、55539、45031和31033 mL,其中T1的产气总量是T2的1.52倍;T3的产气总量是T4的1.45倍,结果表明餐厨垃圾滤液不需要经过隔油处理而直接可以用于厌氧消化产沼气.同时,当压滤液低浓度（T3、T4）时,产气差异小;高浓度（T1、T2）时,产气差异大.此外,在整个厌氧消化过程中,处理T1、T2、T3和T4的CODCr总去除率分别为80.44%、78.53%、79.67%和80.7%.     

Total and “Selective” Extraction Methods for Trace Metals in Marine Sediment Reference Samples (Mess-1, NBS 1646)

Trace metals (Cd, Cr, Cu, Mn, Pb and Zn) and Fe were analyzed in two sediment reference samples (NBS 1646, MESS-1) with AAS fitted with graphite furnace, using five different (three total and two selective) extraction procedures.

The comparison of the total digestion methods (hot strong acids) with reference materials gave good results for almost all of them, and the “teflon bomb” was preferred for its rapidity and ease of operation. Some non-referenced data on total and organic carbon, total nitrogen and minerals are given. The two selective leaching extractions (nitric and cold hydrochloric) were also compared with reference values.

The use of certified reference materials (CRM) for environmental chemistry is recommended, together with the determination of organic matter and fundamental mineralogical composition.     

食物中营养物及污染物的生物可给性研究进展

随着人们对食物质量关注度的提高,生物可给性的测定结果已逐渐代替物质的总量进行评价,包括有毒物质对人体健康的危害程度和营养物质的被吸收利用程度.因此,在阐述生物可给性意义,概括并介绍生物可给性的不同的测定方法及各自的优缺点的基础上,重点综述了in vitro消化方法的生理基础和实验操作,以及应用于各种食物样品生物可给性检...     

Bestimmung von leicht freisetzbarem Cyanid in Böden und Wässern mit der Mikrodestillation

Easy-liberatable cyanide has to be analysed if soils and waters are contaminated by cyanide. The aim of this study was to determine easy-liberatable cyanide in these environmental samples using a micro-distillation apparatus by means of a modified digestion vessel. Pure aqueous solutions of different cyanide species, five contaminated and uncontaminated soil samples and two water samples were analysed by micro-distillation according to the German standards. Recovery was determined by analysis of spiked samples. When using the modified digestion vessels, the pH of 4 which is demanded by the standard method can be adjusted. The recovery of potassium cyanide and weakly-complexed zinc-cyanide ranged from 93–101% for standards, and from 87–98% for spiked samples. In contrast, the recovery of strong iron-cyanide complexes was below 4% both for pure solutions and spiked samples. The precision of the method expressed as a relative standard deviation was 25% in cases of very low easy-liberatable cyanide contents (< 1 mg CN kg^?1) and below 12% in case of high easy-liberatable cyanide contents (> 1 mg CN kg^?1) for contaminated soils. The determination of easily-liberatable cyanide in soils and waters using micro-distillation combined with the modified digestion sample is an alternative to other distillation methods.     

Element determination in environmental samples using Z-GFAAS with variable magnetic field

Electrothermal atomic absorption spectrometry methods with Zeeman effect background correction (Z-GFAAS) for determination of As, Sb, Se, Ag, Cd, Pb, Cu, Fe, Zn, Cr, and Ni in water and sludge samples were developed. The measurements using Z-GFAAS and variable magnetic field at the three-field dynamic mode permit the sensitivity adaptation for higher analytical concentrations. Calibration ranges were expanded over two orders of magnitude within one measurement run by the applying three-field dynamic mode of this correction system. There are presented calibration data, furnace programs, modifiers, and microwave digestion programs of the obviously monitored elements in the environmental samples. Very low detection limits (3σ criterion) were obtained. Quality assurance was checked by the suitable CRM. The study brings simultaneous determination of the samples with different element concentration range and different sample matrixes, as an important application information for an analyst working in the area of the eco-analytical research.     

两种消化方法对无齿相手蟹重金属含量测定结果的影响

生物样品分别经湿灰法和干灰法消化处理后，测定其Zn,Cu和Pb的含量。结果表明，不同消化方法对样品中Cu含量的测定没有显著的影响，而对Zn和Pb含量的测定都有显著的影响，湿灰法处理后样品中Zn和Pb含量的测定值均普遍高于干灰法处理后相应的测定值。根据本研究结果可知。测定Cu含量的生物样品可用常规灰化温度进行处理，而测定Zn和Pb含量的生物样品宜用低温灰化技术进行处理。图6表1参12     

电感耦合等离子体质谱法分析锰结核中的多种元素含量

本文使用岛津ICPMS-2030电感耦合等离子体质谱仪,采用微波消解法对锰结核样品进行前处理,测定了锰结核样品中32种元素含量.实验结果表明,各元素在1.0—100μg·L^-1范围内线性关系良好,相关系数均大于0.9998,检出限低,各元素检出限都在0.00004—0.73μg·g^-1之间.该方法操作简便、快速,测试结果准确,使用锰结核标准物质GBW07296进行验证,测定值与标准值基本吻合,该方法可适用于锰结核样品中多元素含量的测定.