热分解-冷原子吸收法测定土壤中汞

采用热分解处理土壤样品,用冷原子吸收法测定样品中的汞,通过优化固体测汞仪的分析条件、确定校准曲线的线性范围和样品的称样量,使该方法在0.025 mg/kg~1.50 mg/kg范围内线性良好。当取样量为0.2 g时,方法检出限为0.000 9 mg/kg,有证标准物质的测定结果在保证值范围内,高、低浓度标准物质6次测定结果的RSD分别为4.6%和4.8%。用热分解法与国标法同时处理样品并测定,其测定结果无显著差别。     

氢化物发生-原子荧光光谱法测定土壤中镉

采用氢化物发生-原子荧光光谱法测定土壤中的镉,优化了试验条件,讨论了共存元素的干扰及消除办法。方法在0μg/L～120μg/L范围内线性良好,检出限为0.003 mg/kg（按取样0.600 g定容至45 mL计）,土壤标准样品测定的RSD≤3.7%,加标回收率为94.8%,与石墨炉原子吸收分光光度法的测定结果相吻合。     

碱提取-丙基化衍生法同时测定土壤中的甲基汞和乙基汞

建立了碱提取-丙基化衍生方式同时测定土壤中甲基汞和乙基汞的方法。优化了仪器分析条件，研究了碱提取温度、提取时间、缓冲溶液加入量和衍生化试剂加入量对测定结果的影响。应用本方法对5种实际土壤样品进行测定，甲基汞和乙基汞的方法检出限分别为0.5 μg/kg和0.3 μg/kg，相对标准偏差分别为1.3%~17%和0.94%~16%，平均回收率分别为88.2%~110%和66.1%~110%。该法适用于批量土壤样品中甲基汞和乙基汞的分析测定。     

全自动消解-石墨炉原子吸收法测定土壤中镉的探讨

探讨全自动消解-石墨炉原子吸收法测定土壤中镉的方法。选用硝酸-氢氟酸-高氯酸作为消解体系,采用全自动消解仪对土壤样品进行消解,通过研究干燥、灰化和原子化温度对吸光度的影响,优化出最佳的石墨炉升温程序,依据国标方法 (GB/T17141-1997)石墨炉原子吸收分光光度法测定土壤样品中的镉元素含量。该方法检测土壤国家标准物质GSS-8、 GSS-22、GSS-24等,所得结果与标准值相吻合。方法简便、快速、重现性好、灵敏度高,适用于批量土壤样品中Cd的测定。     

高效液相色谱-二极管阵列检测器测定邻苯二甲酸酯色谱条件优化

采用高效液相色谱-二极管阵列检测器对6种PAEs类物质进行测定,并对梯度洗脱条件、流速、检测波长等影响化合物色谱响应的关键参数进行优化。综合考虑样品测试效率、分析精度、实际样品中存在杂质干扰等因素,确定以乙腈-水为流动相进行梯度洗脱,洗脱0~11 min流动相乙腈-水梯度比例为50∶50,11 min后流动相调整为100%乙腈,各化合物均能完全分离;色谱分析流速为0.8 m L/min;PAEs的最佳吸收波长为225 nm。在优化的色谱条件下,6种PAEs的线性良好,相关系数均大于0.999 8,仪器检出限为0.08~0.12 mg/L,保留时间、峰面积的相对标准偏差分别为0.02%~0.60%、0.13%~0.86%。方法灵敏度较高,适合土壤等邻苯二甲酸酯含量较高基质样品的快速分析。     

固体进样-冷原子吸收法直接测定土壤中总汞

应用固体测汞仪,采用多标准土壤样品(n20)绘制校准曲线法和单一标准土壤样品绘制校准曲线法,分别对土壤中的汞进行测定。结果表明,两者的方法检出限分别为0.30、1.49 ng,平行样(n=6)的相对标准偏差分别为3.6%~4%、5.4%~9.0%,90 d内的重复性精密度为4.1%,对国家土壤标样进行测定,结果与标准值相符。表明与单一标准土壤样品绘制校准曲线法相比,多标准土壤样品绘制标准曲线法具有更好的精密度、更低的检出限,更强的适用性,并且由于校准曲线长期稳定性,有效缩短土壤中汞的检测周期。     

热分解齐化原子吸收光度法测定土壤中汞

固体测汞仪采用热分解齐化原子吸收光度法,此方法可以直接测定土壤中汞的含量。通过实验分析表明:此方法相关系数r≥0.999,检出限为0.01 ng,精密度为6.0%~9.1%,准确度为0%~6.7%,加标回收率为95%~107%。本方法具有简便、快速、准确、干扰少、成本低等优点,适合大批量土壤样品的测定。     

石墨炉原子吸收分光光度法测定饮用水中钡的实验研究

文章通过实验研究优化了一种石墨管原子吸收法测定饮用水中钡的方法。分别采用普通石墨管和ELC石墨管,通过优化灰化温度和原子化温度以及实际样品检测验证了方法的可行性。结果表明,采用普通石墨管检出限为4.69μg/L,相对标准偏差为9.5%,实际样品加标回收率为92%~100%;采用ELC石墨管检出限为1.90μg/L,相对标准偏差为8.7%,实际样品加标回收率为98%~101%,两种方法均可满足实验室饮用水中钡的测定要求。     

水溶剂加速萃取-超高效液相色谱串联质谱测定土壤中全氟羧酸

采用水溶剂加速萃取-超高效液相色谱串联质谱法（UPLC-MS/MS）建立了土壤中6种全氟羧酸（PFCs）的分析方法,并对色谱分析条件、水溶剂萃取条件、固相萃取柱净化条件及实验材料选择等进行了优化。结果表明,以ACQUITY UPLC BEH C18色谱柱为分离柱,2.0 mmol/L乙酸铵水溶液为流动相A,甲醇为流动相B,梯度洗脱下可在9 min内完成6种PFCs的测试,检出限为0.03~0.4 μg/kg。对实际土壤样品进行测定,加标回收率为90.7%~118%,相对标准偏差为5.6%~18.0%,精密度和准确度均较好。该方法前处理过程简单、易操作,仪器检测效率高、结果准确,能够满足土壤中PFCs的检测要求。     

顶空-气相色谱-质谱法测定土壤中卤代烃

建立顶空-气相色谱-质谱法同时测定土壤中挥发性及半挥发性卤代烃的方法。实验优化顶空平衡温度、顶空平衡时间及盐度条件,并对优化后方法的线性、检出限、精密度及回收率进行分析。结果表明:29种目标化合物在线性范围内线性良好,相关系数均大于0.997,方法检出限为2.2~5.9μg/kg,样品不同浓度水平加标回收率范围为80.0%~120%,相对标准偏差小于20%。该方法适用于土壤样品中挥发及半挥发性卤代烃的测定。     

On-line solid phase extraction with polyurethane foam: trace level spectrophotometric determination of iron in natural waters and biological materials

This paper reports the development of a simple and accurate on-line procedure for preconcentration and determination of dissolved iron in waters and biological materials using unloaded polyether-type polyurethane foam as solid extractor. In the developed flow injection system, the analyte was preconcentrated from acidic aqueous medium as iron-thiocyanate complex with post-elution with ascorbic acid solution and spectrophotometric measurement with 1,10-phenanthroline as colorimetric reagent. In order to improve the performance of the system several chemical and flow variables were investigated as well as the effect caused by the presence of possible interferents. The method was validated by the analysis of two certified reference materials. Application of the methodology was carried out by the determination of dissolved iron content in eight natural water samples with different characteristics. The results were compared with those obtained by electrothermal atomic absorption spectrometry (ETAAS) and no statistical difference was observed. The detection limit was 0.75 microgram l-1 and the RSD was 1.2% for 2 min preconcentration time. At this condition, a productivity of 20 samples h-1 was achieved. Increasing the preconcentration time up to 3 min, a detection limit of 0.45 microgram l-1, an RSD of 1.5% and an analytical throughput of 15 h-1 were verified.     

自动石墨消解-石墨炉原子吸收法测定土壤中铅和镉

本文建立了一种自动石墨消解仪消解土壤样品,石墨炉原子吸收法测定土壤中的铅、镉的方法。铅、镉元素在标准曲线范围内线性良好,相关系数均大于0.999,检测限分别为0.02、0.007 mg/kg,加标回收率在90.8%~104.0%,方法重复性RSD(n=7)低于3%。实验结果表明,该方法操作简单、准确度高、精密度好、检测限低,可用于大批量土壤中铅、镉的测定。     

连续流动注射间接测定空气中的五氧化二磷

建立连续流动注射间接测定空气中五氧化二磷的方法。空气中的五氧化二磷用过氯乙烯滤膜或滤筒采样,加入去离子水反应生成正磷酸,过滤、洗涤、定容后运用连续流动注射仪进行测定。优化了抗坏血酸浓度、硫酸浓度、钼酸盐浓度以及恒温室温度等影响显色的因素。最佳条件下,实际样品五氧化二磷加标回收率为96.0%~102%,相对标准偏差在4%以下;采样体积为300 L时,方法检出限为0.001 6 mg/m~3。t检验结果表明,所建方法与现行国标法的测定结果无显著性差异。方法分析速度快、重现性好、灵敏度高,适用于空气中五氧化二磷的测定。     

石墨炉原子吸收法测定空气中铬酸雾

采用石墨炉原子吸收法对空气中铬酸雾进行测定,方法在待测液中铬质量浓度为1~10μg/L范围内线性良好,r=0.999 6,检出限为0.001 mg/m~3,测定结果的相对标准差为1.64%~4.53%,样品加标回收率为91.0%~95.4%,且用该方法与《固定污染源排气中铬酸雾的测定二苯基碳酰二肼分光光度法》(HJ/T 29—1999)分别测定实际样品中铬的质量浓度,结果无明显差异。     

Application of nanoclay for preconcentration of ultra trace amounts of palladium in environmental samples prior to its determination by ETAAS

In the present work, a batch preconcentration technique using nanoclay with 5-(4-dimethylaminobenzylidene)rhodanine coupled with electrothermal atomic absorption spectrometry was developed for the separation and determination of trace amounts of palladium. In this method, the sample solution was stirred with nanoclay as an adsorbent. Then, adsorbed palladium was subsequently eluted with HCl in acetone (1.5 mol L^?1) and, finally, this eluate was injected to electrothermal atomic absorption spectrometry. Under the optimum conditions, the limit of detection and linear dynamic range were found to be 2.6 and 10.0–133 ng L^?1 (in original solution), respectively. Furthermore, the enrichment factor and relative standard deviation of seven replicate determinations were 148 and ±5.1 %, respectively. This suggested method is simple, selective and sensitive and can be applied to the extraction and determination of palladium in water, tea leaves, synthetic sample and certified reference material with satisfactory results.     

Determination of ultra-trace amounts of cadmium by ET-AAS after column preconcentration with a new sorbent of modified MWCNTs

The present research reports on the application of modified multiwalled carbon nanotubes as a new, easily prepared, and stable solid sorbent for the column preconcentration of ultra-trace amounts of cadmium in aqueous solution. Multiwalled carbon nanotubes were oxidized with concentrated HNO₃ and modified with 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol and then were used as a solid phase for the column preconcentration of Cd(II). Elution was carried out with 0.5 mol?L^?1 HNO₃. The amount of eluted Cd(II) was measured using electrothermal atomic absorption spectrometry. Various parameters such as pH, sample and eluent flow rate, eluent concentration, breakthrough volume, and interference of a great number of anions and cations on the retention of analyte on sorbent were studied. Under the optimized conditions, the calibration graph was linear in the range of 0.67 ng?L^?1 to 5.0 μg?L^?1 and the detection limit (3S_b, n?=?7) was 0.14 ng?L^?1 in initial solution. A preconcentration factor of 300 and relative standard deviations of ±3.6 % for seven successive determinations of 3 ng of Cd(II) were achieved. The column preconcentration was successfully applied to the analysis of river water, waste water, and Persian Gulf water sample.     

石墨炉原子吸收光谱法测定空气中四乙基铅

采用一氯化碘的盐酸溶液吸收光谱法和三氯甲烷萃取-石墨炉原子吸收光谱法测定空气中四乙基铅,优化了试验条件。此方法对测定空气中四乙基铅的灵敏度、准确度都有很大的提高,方法的最低检出浓度为0.70μg/L,当采样体积为60 L,四乙基铅最低检出浓度为0.000 1 mg/m3。对实际样品进行分析,四乙基铅的加标回收率为89.1%~105.9%。     

空气颗粒物中铅、镉超声浸取-原子吸收测定方法研究

用超声波震荡方法对大气滤膜样品进行前处理,提取待测元素。研究了浸取液种类、酸度、浸取时间和干扰因素等,确定了颗粒物样品溶液制备的最佳条件,与流动注射在线富集——原子吸收技术结合,建立了大气颗粒物样品测定Pb、Cd方法。结果表明,方法快速、准确,标准样品测定回收率在97％以上,6次测定方目对标准偏差小于2.6％。     

Direct electrothermal atomic spectrometric determination of Ag in aqua regia extracts of soils, sediments, and sewage sludge with matrix modification

Silver is subject to significant interferences caused by high chloride concentrations in electrothermal atomic absorption spectrometry, thus its direct determination in aqua regia leaches from soils, sediments, and sludges is very difficult, especially when using instrumentation equipped with deuterium-lamp background correction (D₂). In this study, the interference of the aqua regia medium was successfully eliminated using Pd–citric acid chemical modifier. This chemical modifier was found to be the most advantageous in comparison with Pd mixture with ascorbic acid, tartaric acid, or citric acid–Li based on its ability to suppress the interference originating from different chloride matrix. Palladium increases the analyte stability; citric acid serves as a reducing reagent, and furthermore, it helps to remove the interfering chlorides by forming HCl, in the drying step of the electrothermal program. In the presence of the modifier, the pyrolysis temperature can be adjusted up to 1,000 °C with no loss of the analyte. The obtained limit of detection and characteristic mass were 5 ng g^?1 and 1.7 pg, respectively. The accuracy of the method was verified by means of six different reference samples and by comparing the results of the analysis of real samples with those obtained by inductively coupled plasma orthogonal acceleration time-of-flight mass spectrometer. The proposed method was applied to the Ag determination in soils, sediments, and sewage sludge samples from the Pardubice region in Czech Republic.     

固体废物氰化物总量和浸出毒性测定方法的比较

中国现行的固体废物氰化物总量和氰化物浸出毒性的分析方法存在缺陷，不便于广泛指导监测工作，笔者优化了固体废物氰化物测定的前处理方法，明确了固体废物氰化物总量、氰化物浸出毒性测定时的样品粒径、浸提方法和消解方法，建立了容量法、分光光度法、流动注射法测定固体废物氰化物总量和浸出毒性的方法，并与标准方法（离子色谱法）进行比较。实验结果表明：容量法、分光光度法、流动注射法测定结果与离子色谱法无显著差异，3种方法测定固体废物氰化物总量加标回收率为80.5%~102%，平行样测定相对标准偏差为3.0%~6.9%，3种方法测定固体废物氰化物浸出毒性加标回收率为80.1%~107%，平行样测定相对标准偏差为7.8%~9.5%，3种方法测定结果精密度和准确度良好，均能够满足固体废物氰化物总量和氰化物浸出毒性的测定要求。其中容量法、分光光度法由于其仪器设备简单、操作简便，可用于突发环境事件应急监测等情况下固体废物氰化物的测定。但容量法检出限较高，不能满足评价标准较低的分析测试工作要求，离子色谱法、分光光度法和流动注射法检出限均能满足一般分析测试要求。