碱液提取-电感耦合等离子体质谱法快速准确测定土壤中的六价铬

建立碱液提取-电感耦合等离子体质谱法快速准确测定土壤中六价铬的方法。以碳酸钠-氢氧化钠溶液提取，经恒温水浴振荡后离心的方式提取土壤中的六价铬。对提取方式、提取时间、提取温度、振幅的选择等条件进行了优化，用电感耦合等离子体质谱仪测定土壤中的六价铬，使用内标元素Sc进行干扰校正。标准曲线线性系数为0.999 9，检出限为0.2 mg/kg。土壤六价铬标准物质测定结果的相对偏差为1.12%～5.56%(n=6)，回收率为97.81%～104.00%。与传统方法比较，该方法检测时间缩短了6 h，适合批量土壤样品中六价铬的分析，且检出限更低，重现性好，测量结果满足日常生产需要。     

碱消解-电感耦合等离子体发射光谱法(ICP-OES)测定土壤中六价铬的研究

采用碱消解—电感耦合等离子体发射光谱(ICP-OES)检测方法对土壤中六价铬含量进行分析。土壤样品以碳酸钠-氢氧化钠为消解液,加入氯化镁和磷酸氢二钾-磷酸二氢钾缓冲溶液,经90-95℃消解溶出六价铬,用电感耦合等离子体发射光谱仪测定消解液中六价铬含量。在选定的测定条件下,方法的检出限为0.24 mg/kg,测定下限为0.96 mg/kg,加标回收率在99.6 %～104.1%之间,相对标准偏差2.53%-7.48%。该方法简便快速,稳定性好,结果准确可靠,适用于土壤中六价铬含量的分析。     

碱消解-火焰原子吸收法测定土壤和固体废物中六价铬

建立了一种碱消解-火焰原子吸收法测定土壤和固体废物中六价铬的方法,讨论了碱消解过程缓冲剂用量、消解液用量以及氯化镁用量对六价铬测定的影响以及考察了三价铬共存条件下对六价铬测定的干扰情况。采用碱消解-火焰原子吸收法测定土壤和固体废物中六价铬,具有操作简单、干扰少、精密度和准确度好等优点。当取样量为1.25 g样品,消解后定容至50 m L,方法用于测定土壤和固体废物中六价铬的检出限为4.0 mg/kg,实际样品的加标回收率范围为100.4%~105.5%。     

钙、镁、铁、铝离子对土壤中总氟化物检测干扰的消除

建立钙、镁、铁、铝离子对离子选择电极法检测土壤总氟化物干扰的消除方法。通过对含不同浓度水平钙、镁、铁、铝离子的土壤样品中总氟化物进行测试,明确了在总离子强度调节缓冲溶液共存下钙、镁、铁、铝离子对土壤提取液中总氟化物检测结果存在负干扰。通过测试10种土壤样品总氟化物提取液中干扰最强的背景铝含量,对其中土壤提取液中铝离子质量浓度大于10.0 mg/L的3种土壤样品进行加标回收试验,结果表明了土壤总氟化物含量为327～926 mg/kg范围内,当样品提取液中的铝离子含量为50～100 mg/L时,通过减少提取液取样体积为5.00 mL并增加柠檬酸三钠总离子强度缓冲溶液体积至15.0 mL的方法可将加标回收率由56.4%～78.3%优化至94.7%～104.0%;当加入Ca~(2+),Mg~(2+),Fe~(3+)质量浓度为200～300 mg/L,加标回收率由63.1%～77.6%优化为92.4%～105.0%。用优化后的方法测定土壤总氟化物含量为246～2 240 mg/kg的5种标准样品,测试结果与标准值一致。该方法能有效地消除土壤样品总氟化物测定中含钙、镁、铁离子质量浓度为200～300 mg/L,铝离子质量浓度为50～100 mg/L而产生的干扰,具有良好的适用性。     

液相色谱-电感耦合等离子体质谱法测定水嘴中六价铬和三价铬析出量

采用硝酸和氨水体系为流动相,等度洗脱方式,建立了液相色谱-电感耦合等离子体质谱(LC-ICP-MS)同时测定水嘴浸泡液中超痕量六价铬和三价铬的方法。考察了不同p H值、质谱条件等因素对实验体系的影响,使用动态反应技术(DRC)消除离子干扰。通过优化实验,实现了六价铬和三价铬的分离,避免了高含量三价铬对低含量六价铬出峰的干扰。测得六价铬和三价铬的检出限分别为0.013,0.028μg/L,线性范围分别0.02~10μg/L和0.04~20μg/L,加标回收率为76.0%~116.4%,相对标准偏差(RSD)分别为1.8%和2.8%。该方法样品用量小、检出限低、快速、准确,能够满足水嘴产品的检测需求。     

柱后衍生-离子色谱法测定土壤和沉积物中的六价铬

为了提高土壤和沉积物中六价铬测定的灵敏度、精密度和正确度,建立了柱后衍生-离子色谱法测定六价铬的分析方法。样品经过预处理后,使用仪器进行定量分析。样品中的六价铬经过Prin-Cen Cr（VI）Spec Column型阴离子分析柱分离出来,分别使用硝酸铵体系溶液和二苯碳酰二肼溶液作为流动相和柱后衍生液,并使用TLD检测器进行六价铬的定量分析。结果表明,六价铬质量浓度在5～100 μg/L范围内线性关系较好,相关系数为1.0000,检出限为0.02 mg/kg。该方法在实际土壤和沉积物样品中的加标回收率为84.0%～94.0%,相对标准偏差为2.34%～11%。本方法与火焰原子吸收分光光度法（HJ1082-2019）相比,六价铬的测定不受试样盐分、pH值及三价铬影响,而且该方法具有灵敏度高、精密度好、正确度高和稳定性强的优点,适用于测定土壤和沉积物中的六价铬。     

ICP－OES测定含钒尾渣中钒的含量

以氢氟酸、硝酸消解样品,然后加入硫酸络合钛避免其在低酸度介质中水解,并且加热至产生三氧化硫烟以驱赶氢氟酸,以水稀释定容后采用电感耦合等离子体原子发射光谱法(ICP-OES)直接测定含钒尾渣中钒的含量。试验考察了在共存含有铁、钛、铝、铬、锰、钒等元素的含钒尾渣复杂基体中,基体效应、光谱干扰以及背景噪音等影响因素对钒测定的干扰,方法通过优选元素分析谱线、背景校正区域以及光谱仪工作条件,并且采用基体匹配法和同步背景校正法相结合方式,消除了构成复杂且变化无常的样品基体对测定的影响。结果表明：方法可用于测定0.01～6.0%范围的钒,并且样品基体在铁20～40%、钛5～30%、铝铬锰钠硅钙镁各1～10%的范围变化对测定无影响;检测下限可达0.0009%; 精密度：RSD<3%;回收率94%～106%;方法与高锰酸钾氧化－硫酸亚铁铵滴定化学分析法的测定结果对照一致。     

电热原子吸收光谱法测定水中总钼

建立电热原子吸收法测定水中总钼的含量。样品采用硝酸–过氧化氢消解,热解涂层石墨管减小记忆效应,塞曼背景校正消除背景噪声。检测了27种共存离子的干扰影响。经6家实验室对标准物质和实际样品检测验证,方法检出限为0.6μg/L,能够满足微量检测要求。钼测定结果相对误差最大值为–6.2%,实验室内相对标准偏差为4.5%~7.6%(n=6),实验室间相对标准偏差为4.3%~5.7%(n=6),加标回收率为91.8%~104.0%。该方法精密度和准确度满足我国地下水和废水监测技术规范的质控要求。     

王水消解-冷原子吸收光谱法测定土壤中汞

为了寻求一种更加适宜测定土壤中汞含量的测试方法,将检出限低、精密度高的冷原子吸收光谱法与便捷、高效的王水水浴消解土壤处理方式相结合,建立了王水消解-冷原子吸收光谱法测定土壤中汞。通过测定方法的线性相关性、方法检出限、准确度、精密度、加标回收率,并与原子荧光光谱法进行对比实验来评价该方法的有效性。王水消解-冷原子吸收光谱法在汞质量浓度0.0～1.0μg/L范围内线性良好,相关系数可以达到0.999 9,方法检出限为0.000 75mg/kg,土壤标准样品测试的相对标准偏差为4.0%～10.7%,实际样品加标回收率分别为93%～104%。采用原子荧光光谱法进行对比测试,原子荧光光谱法的方法检出限为0.002 5 mg/kg,相对标准偏差为4.8%～13.5%,加标回收率为104%～107%。结果表明,对于王水水浴消解土壤的方法不仅适用于原子荧光光谱法测定汞含量,同样可以应用于冷原子吸收光谱法中。所建立的王水消解-冷原子吸收光谱法具有更低的检出限,更优的准确度和精密度,有利于提高土壤样品测试的工作效率,值得推广。     

动态三磁场塞曼背景校正技术应用于石墨炉原子吸收光谱法测定血样中铅

在石墨炉原子吸收光谱法测定血样中铅时,采用动态三磁场塞曼背景校正技术,使血样中铅测定的线性范围由0～100μg.L-1扩增到0～800μg.L-1。动态模式下,质量浓度在80μg.L-1范围以内选择二磁场背景校正模式,特征量为29.4pg。在80～800μg.L-1范围内选择三磁场背景校正模式,特征量为10.7pg。应用此法测定高浓度铅的样品时无需稀释,同时解决了高浓度样品测定时出现塞曼反转,及吸收信号出现双峰的问题。     

碱消解-离子色谱与电感耦合等离子体质谱(IC-ICP-MS)法测定土壤中的六价铬

采用碱消解土壤溶液提取土壤溶液中的六价铬,用离子色谱(IC)进行分离,有效避免了高盐及焰色反应的干扰,电感耦合等离子体质谱(IC P-M S)法进行检测.研究了消解液使用量、消解温度、消解时间等因素,测定结果和火焰原子吸收光谱(FAAS)法进行对比.结果表明,当称样量为5.0 g,消解液40.0 mL,磷酸缓冲溶液0....     

超痕量六价铬分析仪检测制革场地中六价铬

为解决制革等污染场地中Cr(III)-有机络合物会干扰六价铬测定的问题,通过优化仪器色谱条件、在现有行标基础上改进前处理方式,使用超痕量六价铬分析仪检测六价铬,并通过在土壤中投加低、中、高浓度的三价铬、六价铬以及Cr(III)-有机络合物考察三价铬、色度和Cr(III)-有机络合物对六价铬测定的影响。结果表明仪器的最佳色谱条件为：流动相浓度为0.1 mol/L、流动相pH为9、浓硫酸用量为5 mL、流动相流速为1.2 mL/min,衍生试剂流速为0.7 mL/min。样品预处理方式由抽滤提取改进为离心提取,上机前样品pH无需调节,可提高检测效率;该方法与现行行标相比操作简便、耗时短且不受三价铬、样品色度及Cr(III)-有机络合物的干扰。方法精密度和正确度均显著提高,相对标准偏差为1.7%~5.2%,回收率均在94.6%~103%之间。通过与液相色谱-电感耦合等离子体质谱仪对实际样品测定结果的统计学检验发现,结果无显著性差异。该方法适用于制革、电镀等富含Cr(III)-有机络合物场地中六价铬的测定。     

电感耦合等离子体原子发射光谱法(ICP-OES)测定含钒尾渣中钒的含量

以氢氟酸、硝酸消解样品,然后加入硫酸络合钛避免其在低酸度介质中水解,并且加热至产生三氧化硫烟以驱赶氢氟酸,以水稀释定容后采用电感耦合等离子体原子发射光谱法（ICP-OES）直接测定含钒尾渣中钒的含量。实验考察了在共存含有铁、钛、铝、铬、锰、钒等元素的含钒尾渣复杂基体中,基体效应、光谱干扰以及背景噪音等影响因素对钒测定的干扰,方法通过优选元素分析谱线、背景校正区域以及光谱仪工作条件,并且采用基体匹配法和同步背景校正法相结合的方式,消除了构成复杂且变化无常的样品基体对测定的影响。结果表明,方法可用于测定0.01%~6.0%的钒,并且样品基体在含20%~40%铁,5%~30%钛时,铝、铬、锰、钠、硅、钙、镁各元素1%~10%的变化对测定无影响,检测下限可达0.0009%;精密度RSD〈3%,加标回收率94%~106%,与高锰酸钾氧化-硫酸亚铁铵滴定化学分析法的测定结果对照一致。     

Methods for separation of trace amounts of platinum and investigation of the influence of interfering elements during platinum determination in copper ores and copper concentrates by graphite furnace atomic absorption spectrometry

A THGA graphite furnace with Zeeman background correction has been used to determine platinum content in copper ore and copper concentrate at the part per billion (ppb) concentration level. Two different procedures for the separation of trace platinum have been applied: (i) use of an ion exchange resin; and (ii) a two-stage method based on platinum separation on inorganic carriers. The influence of interfering elements in the matrix (Cu, Pb, Fe, Ti, V, Au, Pd, Ir, Rh and Al) has been examined using a graphite furnace. It was found that the presence of Cu (12.5–100 mg l⁻¹), Pb (100–500 mg l⁻¹), Fe (100–2000 mg l⁻¹), Ti (25–100 mg l⁻¹), V (25–100 mg l⁻¹), Au (25–300 mg l⁻¹), Pd (20–250 mg l⁻¹), Ir (0.5–3.5 mg l⁻¹) and Rh (0.025–1 mg l⁻¹) in the samples analyzed has no effect on the platinum absorption signal when using a recommended temperature program (T_pyr=1300°C, T_at=2450°C). Spectral interference was observed, which was due to aluminum, as a result of the close neighborhood of the Pt 265.945-nm and Al 266.039-nm lines. This interference could not be eliminated by the Zeeman background correction.     

Determination of lead in waters and sediments from the wetland Tablas de Daimiel National Park (Spain)

Electrothermal atomic absorption spectrometry (ETAAS) has been used for lead control in waters and sediments of the wetland Tablas de Daimiel National Park. The lead determination in the wetland water is hindered by an enhanced salt content, so matrix interference was evaluated. The use of stabilized temperature platform atomization technique, Zeeman background correction and palladium nitrate as matrix modifier were found advisable. For the sediments a closed-vessel microwave dissolution method has been proposed using a mixture of HCl-HNO₃-HF and a heating time of 90 s. With subsequent ETAAS using platform atomization and Zeeman background correction, no chemical modification was necessary. Using these conditions, the interferences were completely removed for both waters and sediments and the calibration curve in ultrapure water (1% nitric acid) was linear up to 30 μg/L. The detection limits for waters and sediments were 0.95 μg/L and 0.78 μg/g, respectively. The accuracy of the proposed method for sediments was validated by analyzing certified reference materials (obtained values were within the certified ones) and spiked wetland sediments (mean recovery of 99.0%). Received: 11 October 1998 / Revised: 3 December 1998 / Accepted: 11 March 1999     

Determination of lead in waters and sediments from the wetland Tablas de Daimiel National Park (Spain)

Electrothermal atomic absorption spectrometry (ETAAS) has been used for lead control in waters and sediments of the wetland Tablas de Daimiel National Park. The lead determination in the wetland water is hindered by an enhanced salt content, so matrix interference was evaluated. The use of stabilized temperature platform atomization technique, Zeeman background correction and palladium nitrate as matrix modifier were found advisable. For the sediments a closed-vessel microwave dissolution method has been proposed using a mixture of HCl-HNO₃-HF and a heating time of 90 s. With subsequent ETAAS using platform atomization and Zeeman background correction, no chemical modification was necessary. Using these conditions, the interferences were completely removed for both waters and sediments and the calibration curve in ultrapure water (1% nitric acid) was linear up to 30 μg/L. The detection limits for waters and sediments were 0.95 μg/L and 0.78 μg/g, respectively. The accuracy of the proposed method for sediments was validated by analyzing certified reference materials (obtained values were within the certified ones) and spiked wetland sediments (mean recovery of 99.0%). Received: 11 October 1998 / Revised: 3 December 1998 / Accepted: 11 March 1999     

Determination of As in environmental solid matrix

In line with recent European environmental guidelines on biomasses, one of the most important parameters to take into account is the As concentration, especially when present in biomasses and complex matrices. The goal of the present study is to give information about possible technical-analytical problems during the determinations of such elements by means of different instrumental spectroscopy techniques, in particular inductively coupled plasma atomic emission (ICP-AES) and atomic absorption (AAS), using two different wavelengths, 188.98 nm and 193.70 nm.In the Laboratory of Hygiene of National Institute of Health in Italy, a specific study has been carried out concerning the determination of As contents in environmental solid matrices, using as reference material BCR 141 R, represented by a calcareous soil. In particular, whereas recovery tests did not show particular drawbacks, difficulties were met in the As detection in reference material. Spectral interference was seen during determination by ICP-AES and matrix interference during determination by AAS, in particular using ETAAS with deuterium background correction and HAAS. Using ETAAS with Zeeman background correction at 193.70 nm, the As line did not show particular matrix interference during the reading of samples.A ring test involving two more laboratories and another certified reference material (IAEA-356 in marine sediment matrix) produced important information about problems of under/over estimation of data. Two different instrumental techniques, ICP-MS and HAAS, confirmed previous data, i.e., overestimation for inductively coupled plasma mass spectrometry and that As values achieved by HAAS were of the same order as the references, but affected by considerable standard deviation.In the light of this study, data achieved on the environmental matrices investigated suggest that the critical step in As determination is the instrumental reading, rather than the mineralization process. Further, each of the methods proposed, apart from ETAAS with Zeeman background correction, presents its own peculiar drawbacks and no particular advantage over other techniques.     

Spectral interferences and background overcompensation in inverse zeeman-corrected atomic absorption spectrometry : Part 2. The effects of cobalt,manganese and nickel on 30 elements and 53 elements lines

The background compensation performance of a transversal alternating-current Zeeman corrector system with the magnet acting on the graphite atomization cell was assessed for 30 elements and 53 element lines in the presence of relatively large amounts of cobalt, manganese or nicke. The study reveaaled three cases of background overcompensation, all being caused by a cobalt line adjacent to the analytical line. When the magnetic field is on (and the background is measured), a σ-component of the cobalt lines overlaps the emission lines of boron (249.7 nm), mercury (253.7nm) and gold (267.6 nm). The interfering effect on boron is small, but mercury and gold are more seriously affected; for both elements a serious negative systematic error is introduced. Manganese and nickel did not give any overcompensation effects on the elements and lines studied. When gold and mercury were measured with the use of the same experimental parameters and a conventional deuterium-arc background corrector, only mercury suffered from spectral interference. The spectral interference of cobalt on mercury, with either type of background correction, can be avoided by selecting a proper furnace program. When gold is tobe measured in the presence of cobalt and with the present Zeeman background-correction system, the 267.6.-nm line should not be used; the more sensitive 242.8 nm line is recommended.     

电感耦合等离子体发射光谱(ICP-OES)法测定水泥熟料中铬的干扰研究

电感耦合等离子体发射光谱法（ICP-OES）测定重金属时常面临干扰问题。为提高ICP-OES测定水泥熟料中铬的准确度,研究选取了Cr205.560、Cr267.716和Cr283.563三条谱线,根据水泥熟料中主量元素（铁、铝、钙和镁）含量,设计不同浓度单元素干扰试验,结果表明：铁对Cr283.563谱线测定有较大的正干扰,钙对三条谱线均有较大的负干扰,两者导致的相对误差（RE）均在±10%以上,其他一般为负干扰,RE在±10%以内。进一步线性回归分析发现,除铝外,其他干扰元素的干扰大小与浓度呈强线性相关性。通过多元素复合干扰试验发现干扰导致的RE约为-18%~11%,同单元素干扰加和结果比较,两者相差约为8%~10%。实际样品检测结果表明实际干扰同多元素复合干扰试验基本相同,Cr283.563谱线测定结果误差可能更小,三条谱线的实际样品加标回收率大致相当,约为80%,经回收率修正,Cr205.560和Cr267.716谱线结果满意,而Cr283.563谱线误差较大。以多元素复合干扰试验溶液作为基体,采用基体匹配法测定可基本消除干扰影响。以钙溶液作为基体的简化基体匹配法同样有效,但仅可选用Cr205.560和Cr267.716谱线。本研究从实际干扰问题出发,通过系统分析问题,找到干扰的原因,并据此提出消除干扰方法,提高了测定铬的准确度,也为检测人员解决相关干扰问题提供借鉴。     

Detection of Natural Cr(VI) with Computer Screen Photo-assisted Technology

The combined use of a computer screen and a webcam has been demonstrated in several cases to provide a platform for measuring optical properties of liquid and solid samples. Here the method is utilized to measure the absorbance change in an analytical procedure aimed at determining the amount of hexavalent chromium (Cr(VI)) in water. The method calibrated on standard solutions was tested on-field on naturally contaminated spring waters. Results show a sufficient resolution to measure Cr(VI) concentration down to 5 ppb. World Health Organization recommends a maximum concentration of 0.05 mg/l (50 ppb) for chromium (as hexavalent) in drinking waters.