微波消解-ICP-AES/ICP-MS测定大米中微量元素

采用微波消解技术,电感耦合等离子体光谱(ICP-AES)和电感耦合等离子体质谱(ICP-MS)测定了分别产自辽宁、四川、湖南三地的大米中21种元素B、Ba、Ca、Cd、Cu、Fe、K、Mg、Mn、Na、P、S、Sr、Zn、Co、Ni、Cr、Mo、Pb、Li、Cs。所有元素标准曲线回归方程线形系数均大于0.999,各元素相对标准偏差(RSD)均小于5.31%(测定次数n=4),加标回收率为96.6%～110.6%,方法检出限:ICP-AES为0.0048～0.33μg·mL-1,ICP-MS为0.022～0.192ng·mL-1。用国家一级标准物质大米(GBW10010)验证了方法的准确性,测定值与推荐值相符,实验表明,P、S、K、Mg、Ca、Na、Zn、Mn、Fe、Cu在大米中含量较高。此方法简便、快速,适用于大米等粮食作物中微量元素的测定。     

微波消解-电感耦合等离子体-质谱(ICP-MS)测定木制食品接触材料中有害重金属

采用微波消解法处理木制食品接触材料,优化电感耦合等离子体质谱检测参数,建立木制食品接触材料中Sb、As、Cd、Cr金属元素的微波消解-电感耦合等离子体质谱的分析方法.对所测定元素,标准曲线相关系数为0.9999,方法的检出限为0.08～0.22μg/L,RSD＜5%,平均加样回收率84.9%～97.2%.方法准确可靠,可用于实际样品分析.     

微波消解-电感耦合等离子体质谱(ICP-MS) 同时测定塑料包装材料中有毒有害元素

采用硝酸-过氧化氢消解体系,及高压密闭微波技术处理塑料包装材料,建立了电感耦合等离子体质谱法同时测定塑料包装材料中铅、镉、砷、铬、锑、汞、硒、钡、镍、锡、锶、铊多种有毒有害元素的方法。方法的检出限为0.02~0.20μg/L,相对标准偏差(RSD)小于10%,加标回收率为88.0%~117.0%。该方法简单、快速、灵敏、准确度好。     

ICP-MS法检测中药材中7种重金属元素含量

目的:应用电感耦合等离子体质谱(ICP-MS)仪,建立辽五味子、人参、关龙胆、辽细辛、柴胡中铅(Pb)、镉(Cd)、铬(Cr)、砷(As)、硒(Se)、镍(Ni)、铜(Cu)7种重金属元素的测定方法。方法:样品经微波消解,以锗(72Ge)、铟(115In)、铋(209Bi)为内标,采用ICP-MS法同时测定上述7种元素的含量。结果:对于各测定元素,标准曲线的相关系数r≥0.9995,回收率为85.7%-96.2%,相对标准偏差为1.9%~6.5%。结论:该方法简便、快速、准确,可用于中药材中这7种重金属元素的含量测定。     

微波消解-ICP-MS测定花草茶中金属元素含量

采用微波消解法对花草茶样品进行前处理,利用电感耦合等电子体质谱仪(ICP-MS)同时测定了样品中As、Cd、Cr、Pb、Sr、Mn、Cu、Zn等8种金属元素的含量。结果表明,采用微波消解-ICP-MS法的测得加标回收率为92.6~101.3%,实验结果满足检验要求,适用于花草茶中多种元素的同时快速确证检测。且该前处理方法相比干化法,检测时间更短,结果更准确。     

微波消解ICP-AES测定海绵铁中杂质元素含量的研究

运用微波消解处理海绵铁试样,结合ICP—AES测定钙、镁、硅、铝、磷、钾、钠等7种杂质元素。加标回收率在92．4％-101．8％,精密度为0．55％-3．85％,方法准确,分析速度快,效率高,在日常快速分析检测中有重要意义。     

微波ICP-MS联用快速测定小麦中砷、镉和铅

提出微波消解-电感耦合等离子体质谱法测定小麦中As、Cd、Pb的检测方法。样品经HNO3微波消解,分别采用Rh、In、Tb作为内标元素和碰撞池技术以及干扰方程校正来消除基体干扰和质谱干扰;通过小麦粉标准物质和加标回收率验证了检测方法的准确度和可靠性。结果显示:标准物质测试结果均在质控范围,As、Cd、Pb的回收率和相对标准偏差分别为As:87.5%~108%,2.1%~4.9%;Cd:93.0%~106%,2.0%~2.3%;Pb:113%~122%,5.2%~5.3%。该方法快速、准确,适合小麦中有害元素As、Cd、Pb的同时测定。     

微波消解ICP-MS法测定土壤中的十种金属元素

本文采用微波消解ICP-MS法测定土壤中的十种金属元素。用HNO3-HF-H2O2消解土壤样品,选用30.0ug/L的Rh和Re的混合元素作为内标,用测标准土壤样品的方式来验证方法的准确度,元素的检出限在0.001 mg/kg-0.16 mg/kg,方法的精密度≤6.5%,方法重复性与准确性良好。此方法快速、高效,分析过程简单,适用于土壤样品的快速分析。     

微波消解-电感耦合等离子体质谱法同时测定土壤样品中八种重金属元素

本文以Ge、In、Re内标校正体系,采用微波消解-电感耦合等离子体质谱（ICP—MS）对土壤样品中砷、铅、铜、锌、镉、铬、汞、镍八种重金属元素进行同时测定,通过加标回收试验,建立了土壤样品中砷、铅、铜、锌、镉、铬、汞、镍八种重金属元素ICP—MS分析方法,各元素检出限均小于1．0ng／mL,测定8种元素的相对标准偏差均小于10％,各元素的加标回收率在86．3％～101．0％。实验表明：该法操作简单、快速,灵敏度高,重现性好,而且能够对八种重金属元素进行同时测定,大大提高了检测效率。     

微波消解-冷原子吸收法测定纸巾纸中的汞含量

采用微波消解技术处理样品,冷原子吸收法测定纸巾纸中的汞含量。对样品前处理中消解体系和消解条件进行讨论,确定了最佳使用条件。结果表明,该方法的回收率达到91.64%~102.66%,适用于纸巾纸中汞含量的检测。     

大米中镉含量的测量不确定度评定

分析了石墨炉原子吸收光谱法测定大米中镉含量不确定度的各分量,对其测量不确定度进行合理的评定,结果表明:大米样品中镉的含量为0.18 mg/kg时,其扩展不确定度为0.01 mg/kg(k=2),不确定度主要是最小二乘法拟合标准工作曲线求得样品浓度过程和测试过程随机效应引入的。     

Microwave near-field reflection property analysis of concrete formaterial content determination

One of the most important parameters associated with concrete is its compressive strength. Currently, there is no reliable nondestructive testing technique that is capable of robust determination of this parameter. Concrete is a heterogeneous mixture composed of water, cement powder, sand (fine aggregate), rocks of various size or grade (coarse aggregate), and air (porosity). Water and cement powder chemically combine into a cement paste binder which, in due curing time, produces concrete with its specified compressive strength. Compressive strength of concrete is strongly influenced by its water-to-cement (w/c) ratio as well as its coarse aggregate-to-cement (ca/c) ratio. Therefore, if these two parameters are determined using a nondestructive testing technique, then they may be correlated to the compressive strength. Near-field microwave nondestructive testing techniques, employing open-ended rectangular waveguide probes, have shown tremendous potential for evaluating concrete constituent make-up. In this paper, the results of an extensive set of measurements, using these probes, are presented. The results demonstrate that the statistical distribution of the multiple measurements of the magnitude of reflection coefficient of concrete specimens with various constituent make-ups follows two well-known distributions as a function of frequency. It is shown that for the specimens investigated this distribution is Gaussian at 10 GHz and uniform at 3 GHz. Furthermore, the standard deviation of the measured magnitude of reflection coefficient at 10 GHz is shown to correlate well with ca/c ratio, whereas, the mean of this parameter at 3 GHz is correlated well with w/c ratio. Subsequently, these parameters may be used in conjunction with well established formulae or a look-up table to determine the compressive strength of a given concrete specimen     

Microwave resonator technique for moisture content determination insingle soybean seeds

A rectangular waveguide cavity in the H₁₀₅ and H₁₀₇ modes at 4.8 and 6.0 GHz, respectively, was used to measure the resonant frequency shift and the change in the Q-factor caused by seeds of various dimensions and different hydration levels, located in the center of the cavity. Significant statistical correlations were found between measured parameters and the amount of water in the seeds and their dry mass. An empirical approach consists of relating the ratio of these two cavity parameters with the seed moisture content by a curve fitting method. With either of these techniques, the moisture content of soybeans, Glycine max L., in the range from 7 to 16% can be determined with an uncertainty lower than 1% at the 95% confidence level     

微波消解-钼锑抗光度法测定蔬菜中总磷

采用微波消解-钼锑抗光度法测定蔬菜中的总磷,为获得最佳试验条件,对微波消解条件中的酸的种类、消解时间和消解温度等影响因素进行优化,结果表明:硝酸和过氧化氢(体积比7∶1)为最佳消解酸系,最高消解温度180℃,保持时间20 min。对紫外-可见光波长和显色时间对试验结果的影响进行探讨,结果表明710 nm和20 min为最佳试验条件。为评价该方法的可靠性,选用两种蔬菜标准物质GBW 10048和GBW 10049对该方法进行分析验证,测定值与标准值相符,相对标准偏差(RSD)分别为0.884%和0.938%,添加回收率大于89.93%,表明该方法拥有良好的准确性和精密度。微波消解-钼锑抗光度法具有简单、省时省力、试剂用量少等优点,能够满足蔬菜中总磷的测定。     

Microwave digestion of environmental and natural waters for selenium speciation

A microwave preparation procedure is proposed for selenium speciation in natural and drinking waters. Different chemical reagents were tested, and the conditions for Se speciation were optimized. The effect of the different reagents on various oxidation states of selenium under microwave digestion conditions was investigated. Most of the Se(-II) was converted to selenite when digested with HNO3 and <20% to selenate. The digestion with H2O2/H2SO4 can change most Se species into Se(IV). The concentration of Se(IV) in the samples was then determined by HPLC with a fluorescence detector after derivatization with 2,3-diamino-naphthalene (DAN). The microwave preparation procedure allows Se speciation in water samples. Se(IV) was determined after concentrating the sample under nitrogen protection. The amount of Se(IV) and Se(VI) was measured by adding an equal volume of concentrated hydrochloric acid to water sample to reduce Se(VI) to Se(IV). Then the amount of Se(VI) can be calculated by subtraction. The total selenium can be determined after digestion with H2O2/H2SO4, or after digestion with HNO3 followed by reduction with concentrated hydrochloric acid. Selenium (-II, 0) was calculated by subtracting inorganic Se(IV+VI) from the total. Detection limits of 0.0066 ng and 0.0096 ng Se were obtained for HNO3 and H202/H2SO4 as digestion reagents, respectively. The total Se in the four water samples tested range from 0.20 to 0.90 microg L(-1). Among them the dominant form was Se(VI) with the exception of pond waters where Se(-II) predominated.     

Oxygen content determination in perovskite-type cobaltates

Three oxygen content determination methods (iodometric titration, gas volumetric analysis and thermogravimetric hydrogen reduction) have been evaluated for the case of rare earth cobaltates LnBCo₂O_5+δ (were Ln-rare earth, B-alkali earth elements). All the methods are based on oxidation properties of both Co⁴⁺ and Co³⁺ cations but different instrumentation was used for each of the method. We have obtained good agreement within ±0.02 in δ for both the iodometric titration and the gas volumetric analysis, whereas the thermogravimetric hydrogen reduction was found to be less credible.     

Foliar application of two silica sols reduced cadmium accumulation in rice grains

In the present study, pot experiments were conducted to investigate the effects of foliar application of two silica (Si) sols on the alleviation of cadmium (Cd) toxicity in contaminated soil to rice. Results showed that the foliar application of Si sols significantly increased the dry weight of grains (without husk) and shoots in rice grown in Cd contaminated soil, whereas the Cd concentration in the grains and shoots decreased obviously. The total accumulation of Cd in rice grains also decreased with the application of both of the Si sols, but no significant effect was found on the Cd accumulation in the shoots. For the optimal effect, Si-sol-B should be foliar applied at the tillering-stage during rice growth. The mechanism of Si foliar application to alleviate the toxicity and accumulation of Cd in grains of rice may be related to the probable Cd sequestration in the shoot cell walls.     

阳极溶出伏安法水体镉污染快速测定方法研究

建立一种快速测定水体中镉、铅、汞、砷的阳极溶出伏安法。对现场快速测定影响因素进行探讨,并主要对镉的检出限、精密度和准确度进行研究,将该方法运用到广西龙江镉污染事故应急监测中,并与多种其他方法进行比对。结果表明:该方法运用最优温度为5~40℃,水样最佳p H范围为4~9。便携式阳极溶出伏安法测定污染水样中的镉,检出限为0.1μg/L,加标回收率在80%~110%间;在实际样品质量浓度在2~110μg/L范围内准确度均满足要求,实际样品测定精密度2%~5%;与在线监测结果的相对偏差≤4%,与石墨炉原子吸收测定结果相对偏差≤1%。该方法稳定、快速,灵敏度高,准确度好,可广泛用于重金属污染事故应急监测。