电感耦合等离子体质谱法测定茶叶中的16种稀土元素

采用微波消解和干法灰化两种前处理方法,电感耦合等离子质谱(ICP-MS)测定了茶叶中的16种稀土元素.外标法绘制校准曲线,分析了国家标准物质茶叶GBW07605和GBW10016,测定值与标准值吻合,样品测定的精密度在0.6%-6.3 %,方法检出限为0.04-0.43 μg·kg-1.用加标回收的方法评价了该方法的准确性,回收率为96.0%-108.0%之间.     

吹扫捕集/气相色谱-原子荧光光度法测定土壤和沉积物中烷基汞

本文将原子荧光光谱检测技术与吹扫捕集/气相色谱检测技术联用,结合优化的碱性法消解前处理技术,建立了碱性法消解-吹扫捕集/气相色谱-原子荧光光谱(PT-GC-AFS)联用技术测定土壤和沉积物中烷基汞含量的方法,能够在一次分析中同时获得样品中甲基汞和乙基汞的含量.本文分别用酸性法和碱性法处理了沉积物标准样品ERM-CC580、沉积物实际样品和土壤实际样品,重点比较了本方法提出的碱性法消解和使用率较高的酸性法消解两种前处理方式.采用本方法处理实际样品进行了色谱分离研究,对低浓度的实际土壤样品进行了检出限实验,用3种不同浓度的沉积物和3种不同浓度的土壤样品验证了精密度,对沉积物标准参考物质ERM-CC580进行了测定,并用两种实际土壤样品和两种实际沉积物样品进行了加标回收率试验.实验表明,碱性法消解精密度和准确度优于酸性法消解,且步骤少、耗时短,使用的试剂种类少、毒性小,方法稳定性高、可操作性强,适用于分析测试实验室大量土壤/沉积物样品的烷基汞测定.采用碱性法消解土壤/沉积物样品,目标物实现完全分离,甲基汞、乙基汞的线性相关系数分别为0.9999、1.0000,最低检出限分别为0.02μg·kg~(-1)、0.10μg·kg~(-1)(取样量为0.50 g),样品分析甲基汞、乙基汞的RSD范围分别为1.0%—4.7%、2.5%—6.0%,加标回收率范围分别为85.1%—109%、90.3%—96.3%.     

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.     

微波消解/ICP-MS法测定粮食中的18种痕量元素

对小麦、大米、玉米等粮食中铍、锌、砷等18种痕量元素,建立了微波消解/ICP-MS测试分析方法.讨论了粮食样品制备粒径与微波消解样品称样量、加酸类型和消解过程;同时结合理论、实验及样品特点,各元素质量数、分析模式、内标元素的选择,以降低质谱干扰和非质谱干扰.结果表明,该分析方法具有较好的准确度和精密度,适合粮食样品批量、快速消解和分析.     

石墨炉分光光度法测定土壤和沉积物中铊

针对石墨炉原子吸收法测定土壤和沉积物中铊的消解要求高,干扰严重等问题展开研究,考察了消解体系、灰化温度、原子化温度、基体改进剂以及干扰因素,建立了检出限、精密度和准确度均能满足环境管理要求的方法.所建立的方法条件为:灰化温度600℃,原子化温度2100℃,以硝酸-氢氟酸-双氧水为消解体系,以硝酸钯+抗坏血酸为基体改进剂抑制氯离子等的干扰和提高测定的稳定性.所建立的方法检出限为0.1 mg·kg~(-1),测定下限为0.4 mg·kg~(-1).采用电热板消解法,该方法测定土壤和沉积物中铊的精密度在3.3%—8.1%之间,准确度在0.6%—9.9%之间;采用微波消解法,该方法测定土壤和沉积物中铊的精密度在4.5%—9.3%之间,准确度在1.1%—8.6%之间.     

在土壤及底泥重金属测定中不同前处理和分析方法的比较

采用硝酸-高氯酸-氢氟酸、硝酸-双氧水和王水3种酸消解体系,电热板和全自动石墨消解仪两种方式对样品进行前处理,原子吸收和ICP-MS两种测定方法对土壤和底泥国家标准样品以及实际样品中重金属进行测定.结果表明,硝酸-高氯酸-氢氟酸体系可以使样品完全分解,王水浸提土壤和底泥样品的效率在60.6%—87.7%之间,是硝酸-双氧水浸提率的1.3倍.全自动石墨消解仪和电热板相比受热均匀、操作简单,原子吸收和ICP-MS均可对前处理后的土壤和底泥样品进行准确测定,不同实验室可根据硬件条件选用不同的分析方法.     

测定废弃线路板中重金属的酸消解方法比较

重金属含量一般采用原子吸收光谱仪(AAS)、电感耦合等离子体发射光谱仪(ICP-MS,ICP-AES)等方法测定.测定前需要对固体样品进行预处理.目前,常用的预处理方法有直接加热酸消解法、微波消解法和高压釜消解法等.而直接加热酸消解法是目前相对最常用的方法.     

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%.     

微波消解-电感耦合等离子体质谱法测定8类化妆品中23种元素

建立了微波消解-电感耦合等离子体质谱,同时测定8类化妆品中23种元素的方法.根据化妆品不同基质,选用硝酸-双氧水或硝酸-双氧水-氢氟酸对样品进行微波消解,采用在线内标校正基体效应,外标法定量进行ICP-MS测定.方法检出限为0.03～6.2μg·kg-1,线性相关系数均大于0.999,RSD为1.3%～6.8%,加标回收率为88.6%～109.1%.实验结果表明,该方法简便、快速、灵敏度高、准确度好,适用于8类化妆品中23种元素的同时测定.     

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.     

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.     

A comparative evaluation of wet digestion and dry ashing methods for the determination of some major and minor nutrients in composted manure

The analytical results of 53 manure samples determined by wet digestion and dry ashing procedures were compared in order to evaluate their relative suitability for recovering different nutrient elements in manure and manure compost. Wet digestion recovered greater amounts of phosphorus (P), potassium (K), calcium (Ca), manganese (Mn), and zinc (Zn) in more samples than dry ashing. Nutrient contents in the samples were highly variable, with coefficients of variation (CV) ranging from 38% for magnesium (Mg) to 161% for copper (Cu) analyzed by the wet digestion procedure, and from 47% to 138% for Mg and Cu analyzed by the dry ashing procedure. The mean values of P, K, Ca, Mn, and Zn averaged for the 53 samples were significantly higher using wet digestion than dry ashing procedure, but both procedures recovered comparable amounts of iorn (Fe), Mg, and Cu. Correlations analysis between both procedures for each element showed reasonable to fair agreements for Ca (R ²?=?0.93), K (R ²?=?0.93), P (R ²?=?0.90), Mg (R ²?=?0.84), Fe (R ²?=?0.87), Mn (R ²?=?0.73), and Cu (R ²?=?0.66), but poor agreement for Zn (R ²?=?0.44). The low agreement between procedures for Zn suggests that wet digestion, which gave a higher recovery, should be a preferred procedure for analyzing Zn in manures.     

Chemical composition of plant silica phytoliths

Silica phytoliths are a subgroup of biogenic opal. Silica phytoliths are formed in many plant species and remain preserved in soil and sediments after plant decay. The chemical composition of fossil phytoliths may reveal ancient plant taxa, soil composition and climate. However, actually detailed knowledge on silica phytolith composition is scarce. Here we present result of instrumental neutron activation analysis of barley awns, stems and leaves, and barley phytoliths. The elements of interest were Na, Mg, Al, Si, Cl, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Zn, As, Br, Rb, Sb, Cs, Ba, La, Ce, Sm, Eu, Tb, Dy, Yb, Hf, Ta, W, Th, and U. We compared three phytolith extraction methods: dry ashing, acid digestion, and acid digestion followed by incineration. We found that sole acid digestion is inefficient to remove organic matter. By contrast both dry ashing and acid digestion followed by incineration are suitable for phytolith analysis. Comparison of phytoliths with their source plant material shows that phytoliths are enriched in terrigenous elements such as Al, Sc, Ti, V, Cs, Fe, rare earth elements, and depleted in the major inorganic constituents of plants such as K, Ca, Mg, Mn, Cl and Br.     

Acid dissolution methods for heavy metals determination in pine needles

Microwave digestion procedures using HNO₃, HNO₃+H₂O₂, HNO₃+HClO₄, HF mixtures and dry ashing with HF were investigated for heavy metals analysis by either inductively coupled plasma-optical emission spectroscopy (ICP-OES) or ICP-mass spectrometry (ICP-MS) in pine needles. The HF digestion procedures gave about 1.5 times higher values than a mixture of HNO₃+H₂O₂ alone. For Ti determination in needles, the HF procedure using dry ashing is thus recommended. The mean concentrations amounted to 900 mg/kg for Fe and 21.8 mg/kg for Ti in needles collected at an area polluted by a stainless steel works. Those concentrations were 10.6 and 4.3 times higher than in needles collected at an area nearby a pulp mill complex (84.5 mg/kg Fe and 5.0 mg/kg Ti).     

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     

Levels and patterns of polychlorinated biphenyls in residues from incineration of established source-classified MSW in China

Municipal solid waste (MSW) source-classified collection represents an advancement in resource cycling and secondary pollution control in China. Comparative experiments were performed to assess the levels and patterns of polychlorinated biphenyls in bottom ash, fly ash from boiler, and fly ash from bag filter from an MSW incineration plant with source-classified collection of MSW. Polychlorinated biphenyls were concentrated in the bag filter fly ash and in the bottom ash. The total amount of polychlorinated biphenyls was much lower than in fly ashes and bottom ash from traditional mixed waste incineration. Total concentration of coplanar polychlorinated biphenyls and toxic equivalent quantities were also reduced. Due to variations of feed waste, complete combustion, including continuously high incineration temperature, low CO concentrations and high air excess ratio were observed. Incineration temperature showed a negative correlation, while CO concentration showed a positive correlation with total and coplanar polychlorinated biphenyls, indicating that the latter can be reduced by controlling combustion conditions related to properties of feed waste.     

The role of sample preparation in interpretation of trace element concentration variability in moss bioindication studies

Trace element concentrations in plant bioindicators are often determined to assess the quality of the environment. Instrumental methods used for trace element determination require digestion of samples. There are different methods of sample preparation for trace element analysis, and the selection of the best method should be fitted for the purpose of a study. Our hypothesis is that the method of sample preparation is important for interpretation of the results. Here we compare the results of 36 element determinations performed by ICP-MS on ashed and on acid-digested (HNO₃, H₂O₂) samples of two moss species (Hylocomium splendens and Pleurozium schreberi) collected in Alaska and in south-central Poland. We found that dry ashing of the moss samples prior to analysis resulted in considerably lower detection limits of all the elements examined. We also show that this sample preparation technique facilitated the determination of interregional and interspecies differences in the chemistry of trace elements. Compared to the Polish mosses, the Alaskan mosses displayed more positive correlations of the major rock-forming elements with ash content, reflecting those elements’ geogenic origin. Of the two moss species, P. schreberi from both Alaska and Poland was also highlighted by a larger number of positive element pair correlations. The cluster analysis suggests that the more uniform element distribution pattern of the Polish mosses primarily reflects regional air pollution sources. Our study has shown that the method of sample preparation is an important factor in statistical interpretation of the results of trace element determinations.     

Anaerobic digestion and recycling of kitchen waste: a review

About 1.6 billion tons of food are wasted worldwide annually, calling for advanced methods to recycle food waste into energy and materials. Anaerobic digestion of kitchen waste allows the efficient recovery of energy, and induces low-carbon emissions. Nonetheless, digestion stability and biogas production are variables, due to dietary habits and seasonal diet variations that modify the components of kitchen waste. Another challenge is the recycling of the digestate, which could be partly solved by more efficient reactors of anaerobic digestion. Here, we review the bottlenecks of anaerobic digestion treatment of kitchen waste, with focus on components inhibition, and energy recovery from biogas slurry and residue. We provide rules for the optimal treatment of the organic fraction of kitchen waste, and guidelines to upgrade the anaerobic digestion processes. We propose a strategy using an anaerobic dynamic membrane bioreactor to improve anaerobic digestion of kitchen waste, and a model for the complete transformation and recycling of kitchen waste, based on component properties.

     

从净化含银废水的水生植物残体中提取和回收白银

本文介绍了从凤眼莲等水生植物体中回收废水中白银的方法.第一种方法是将植物残体直接打捞、晒干、灰化、HNO_3浸取,氯化法沉淀直至火法冶炼(加入碳酸钠和硼砂)出银;第二种方法是将植物残体全部集中,晒干,最后由贵稀金属提炼厂专门处理.根据上述方法已成功地从净化含银废水的水生植物残体中提炼和回收白银561.7g.     

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%.