首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 109 毫秒
1.
王喜全 《干旱环境监测》1998,12(4):199-200,235
用石墨炉原子吸收分光光度法测定环境废水中的痕量镉时,Mn、Cr、Ni、Cu、Co、Zn等共存元素干扰严重。用100mg/L的铁作为基体改进剂可消除上述共存元素的干扰,测定结果令人满意。  相似文献   

2.
于2011—2017年在江苏省南京环境监测中心办公楼顶开展PM_(2.5)监测采样,分析其样品中OC、EC、水溶性离子和20余种无机元素等组分演变特征。结果表明,NO3-、SO24-、NH4+、OC、EC等是PM_(2.5)的主要组分,且大部分组分值随ρ(PM_(2.5))降低呈下降趋势; OC在2016—2017年成为占比最大的组分;ρ(NO_3~-)/ρ(SO_4~(2-))由0. 9上升至1. 3,ρ(OC)/ρ(EC)由3. 2上升至3. 6,均呈持续上升趋势;机动车污染和有机碳污染明显加重,南京大气污染类型从传统煤烟型污染向煤烟型与氧化型污染共同主导的复合型污染转变; K~-、Cl~-、SO_4~(2-)等水溶性离子和痕量元素K、Al、Ca、Na、Mg等值持续下降,说明工业污染减排、燃煤总量控制和污染治理、扬尘管控和秸秆禁烧效果显著。  相似文献   

3.
采用国产001 ×7 (732)强酸性阳离子交换树脂,在PH5—7条件下分离Cr(Ⅲ)与Cr(Ⅵ)收集流出液,定量加入2%KHSO_4干扰抑制剂,用火焰原子吸收分光光度法测定Cr(Ⅵ)含量。方法简便快速、稳定。几种常见金属离子对测定无显著影响。适合于测定冶金工业废水中的Cr(Ⅵ)。  相似文献   

4.
对昆山市区域7个点位夏秋季的5中水溶性无机阴离子(SO2-4、NO-3、NO-2、Cl-、F-)的污染特征进行了调查,结果表明,昆山市夏季大气PM2.5中5种离子平均值排序为:ρ(SO2-4)ρ(Cl-)ρ(NO-3)ρ(F-)ρ(NO-2);秋季平均值排序为:ρ(SO2-4)ρ(NO-3)ρ(Cl-)ρ(F-)ρ(NO-2)。SO2-4、NO-3和Cl-3者的总量在PM2.5中占比20%。除F-以外各区域离子的平均值秋季比夏季要高。ρ(NO-3)/ρ(SO2-4)表明,固定污染源在昆山市大气颗粒物污染中仍然占很大比重,但大部分测点的比值接近1,说明移动源也是昆山大气颗粒物的重要污染源。  相似文献   

5.
用金属涂层石墨管原子吸收法直接测定天然水中痕量锡   总被引:1,自引:0,他引:1  
本文在研究金属Ta、W、V、Mo、La涂层石墨管对Sn测定灵敏度影响的基础上,选择能提高灵敏度一个数量级的涂La石墨管、在天然水中加入抗坏血酸和(NH_4)_2HPO_4消除共存元素的干扰,直接测定了ppb级含量的Sn。  相似文献   

6.
提出了以磷酸三丁酯 (TBP)萃淋树脂分离富集六价铬的方法 ,对 TBP萃淋树脂为柱填料分离富集 Cr( )的介质、酸度、洗脱条件及干扰行为等进行了详细研究。结果表明在 1 %的盐酸介质中 ,TBP萃淋树脂能定量吸附 Cr( ) ,配以石墨炉原子吸收法测定达到分别测定 Cr( )和 Cr( )之目的。方法快速简便 ,试样无需经过复杂的前处理 ,方法检出限为 2 μg L,对含铬 5μg L的试样测得方法的变异系数为 5 5% ,标准回收率为 95%~ 1 0 5%。  相似文献   

7.
将表 1贴在分光光度计上对照使用可避免忙中出错或眈误时间。表 1 分光光度计常用元素、波长对照表元素 (项目 )分析方法波长 ( nm)As Ag-DDC 51 0S2 -对氨基二甲基苯胺 665Cr6 +总 Cr 二苯碳酰二肼 540CN-异烟酸 -巴比妥酸 60 0CN-吡啶 -巴比妥酸 580C6 H5 OH 4 -氨基安替比林 4 60Th 偶氮胂 660U TRPO-偶氮氯膦 665U TRPO-5Br-PADAP 578SO2 盐酸付玫瑰苯胺 (甲醛 ) 577NOx 盐酸萘乙二胺 540HCl Hg( SCN) 2 比色法 4 60NH3、NH3-N 纳氏试剂 4 2 0Cl2 甲基橙褪色法 51 5P2 O5 磷钼兰 680总 P 磷钼兰 70 0Mn 高碘…  相似文献   

8.
微量Pb、Cd的测定多采用原子吸收方法。土壤、岩石中的Pb的测定,由于受到Al、Mg、Ca、Fe等共存元素的干扰,所以采用DDTC或双硫腙/MIBK萃取。也有的用APDC/MIBK、双硫腙/CCl_4萃取后,用0.02NHCl反萃取。在萃取时,要首先在8 NHCl介质中用异丙  相似文献   

9.
天津地区两大排污河是天津市区及郊县数百家工厂、乡镇企业向渤海排放的含有重金属类金属、有机物、放射性物质、植物营养物和需氧废弃物等成份异常复杂的工业废水.本文在废水样品经酸充分消化有机物后用标准加入法与标准曲线进行比较,检验废水样品中共存元素对Fe、Mn的干扰.通过试验认为Ni、Co、Al、Cu等共存基体元素对Fe的吸光度的干扰只需改变燃烧器高度即可消除,而无需加任何其他试剂.  相似文献   

10.
我们曾对镀铬泥渣中铬的原子吸收测定进行了研究,本文重点研究镀铬泥渣中Fe、Ni、Cu、Zn、Pb测定时共存元素的干扰及其消除方法。 实验证明,大量Ni、Si的存在严重干扰铁的测定,大量Cu的存在严重干扰Ni的测定。采用标准加入法以消除Ni对Fe的干扰;采用沉淀法,萃取法分离铁与镍;在标液中加入等量铜来消除大量铜对测定镍的干扰,都难免繁琐费时。本文采用加入十二烷基硫酸钠或柠檬酸作干扰抑制剂,消除了大量铜对镍及大量硅对铁、锌测定的干扰;用降低乙炔流量,提高火焰温度的方法消除了二倍量的镍对铁测定的干扰,拟定了用火焰原子吸收法,不经分离直接测定镀铬废水处理后的泥渣中铁、镍、铜、锌、铅的测定程序。样品分析精密度均小于±4%,铁、镍、铜、铅的标准加入回收率为96—106%,锌为90—115%,用于实际样  相似文献   

11.
以含锌废盐酸为原料制备磷酸锌[Zn3(PO4)2],探讨含锌废盐酸中Zn、Fe、Cr、Ni等重金属质量分数、TOC质量浓度、磷酸体积分数和反应时间等典型因素对Zn3(PO4)2纯度及化学组成结构的影响,并用XRD及SEM表征Zn3(PO4)2的物相结构。结果表明,含锌废盐酸可制备纯度较高、结构较为稳定的Zn3(PO4)2产品,制备过程中废盐酸中的Fe对Zn3(PO4)2产出纯度的影响较大;Zn3(PO4)2的产出纯度随TOC质量浓度的升高而下降;当磷酸体积分数低于85%时,对Zn3(PO4)2产出纯度总体呈正相关趋势,而高于85%后,产出纯度则有所降低;反应时间为5 h时制备Zn3(PO4)2的效率最高。  相似文献   

12.
An ion selective electrode (ISE) for the measurement of Cr(VI), using supported liquid membranes (SLMs), containing tricaprylmethyl ammonium chloride (Aliquat336), was investigated in this study. Aliquat336, as a carrier, had a high selectivity for Cr(VI) in the presence of interfering ions, in the order SO4(2-) > CO3(2-) > Cl(-) > NO2(-) > NO3(-) > I(-) > SCN(-). The composition of the SLM for the detection of Cr(VI) was optimized at 0.169 mL Aliquat336 mL(-1) NPOE (o-nitrophenyl octyl ether) 0.5 g Poly (vinyl chloride), for the preparation of a 19.6 cm2 sheet. The Cr(VI) concentrations were measured, using the SLM prepared in the study, in the range 2.023 x 10(-5) to 0.1 M (1.052 to 5200 ppm). It seemed that the Cr(VI) was transported as a negatively charged monovalent ion, as indicated by the slope of the electromotive force (emt) response. The selectivity coefficients and detection limits for the Cr(VI). against the interfering ions, were determined experimentally using the fixed interference (FIM) and the separate solution methods (SSM).  相似文献   

13.
Incineration has become one of the principal methods for municipal solid waste disposal particularly in all large cities throughout the world. Currently, the municipal solid waste incinerator fly ashes (MSWIF) are disposed of by landfill. The metal speciation of cadmium (Cd), chromium (Cr), copper (Cu), lead (Pb), and zinc (Zn) in MSWIF after been extracted with water at different pH values were examined using a sequential extraction procedure. The extraction sequence was as follows: (1) Exchangeable (NaOAc, pH 8.2), (2) Bound to Carbonates (NaOAc, pH 5.0), (3) Bound to metal oxides (HONH3Cl), (4) Bound to organic matters (HNO3, H2O2), and (5) Residual (HNO3, HCl, H2O2, HF, 1:3:1:3). The heavy metal contents in the extraction solutions were determined by inductively coupled plasma atomic emission spectrometry. The heavy metal concentrations in the different fractions obtained by sequential extraction show distinct distribution trends. The extractable fraction ranges from 25.5 to 88% of the total element content. With the pH of the extractant fall below the neutral and acidic ranges, the concentrations of heavy metals rise substantially due to the released of metals bound to carbonate fraction.  相似文献   

14.
15.
In this work we present the results of extensive characterization and optimization of the Ambient Ion Monitor-Ion Chromatograph (AIM-IC) system, an instrument developed by URG Corp. and Dionex Inc. for simultaneous hourly measurements of the water-soluble chemical composition of atmospheric fine particulate matter (PM(2.5)) and associated precursor gases. The sampling assembly of the AIM-IC consists of an inertial particle size-selection assembly, a parallel-plate wet denuder (PPWD) for the collection of soluble gases, and a particle supersaturation chamber (PSSC) for collection of particles, in series. The analytical assembly of the AIM-IC consists of anion and cation IC units. The system detection limits were determined to be 41 ppt, 5 ppt, and 65 ppt for gas phase NH(3(g)), SO(2(g)), and HNO(3(g)) and 29 ng m(-3), 3 ng m(-3), and 45 ng m(-3) for particle phase NH(4)(+), SO(4)(2-), and NO(3)(-) respectively. From external trace gas calibrations with permeation sources, we determined that the AIM-IC is biased low for NH(3(g)) (11%), SO(2(g)) (19%), and HNO(3(g)) (12%). The collection efficiency of SO(2(g)) was found to strongly depend on the composition of the denuder solution and was found to be the most quantitative with 5 mM H(2)O(2) solution for mixing ratios as high as 107 ppb. Using a cellulose membrane in the PPWD, the system responded to changes in SO(2(g)) and HNO(3(g)) within an hour, however for NH(3(g)), the timescale can be closer to 20 h. With a nylon membrane, the instrument response time for NH(3(g)) was significantly improved, becoming comparable to the responses for SO(2(g)) and HNO(3(g)). Performance of the AIM-IC for collection and analysis of PM(2.5) was evaluated by generating known number concentrations of ammonium sulfate and ammonium nitrate particles (with an aerodynamic diameter of 300 nm) under laboratory conditions and by comparing AIM-IC measurements to measurements from a collocated Aerosol Mass Spectrometer (AMS) during a field-sampling campaign. On average, the AIM-IC and AMS measurements agreed well and captured rapid ambient concentration changes at the same time. In this work we also present a novel inlet configuration and plumbing for the AIM-IC which minimizes sampling inlet losses, reduces peak smearing due to sample carryover, and allows for tower-height sampling from the base of a research tower.  相似文献   

16.
氯化铵-火焰原子吸收光谱法测定地表水中的总铬   总被引:4,自引:0,他引:4       下载免费PDF全文
应用原子吸收法测定水样中的总铬,在不同条件下对空白样品、标准样品和实际样品进行试验分析,进一步验证了方法的准确度和精密度,加标回收率在96.8%-103%之间,相对标准偏差为2.1%。试验表明,该方法准确可靠,实际操作具有可行性,适用于工业废水和受污染地表水中总铬的测定。  相似文献   

17.
以海口市美舍河市区河段为研究对象,于2020年雨季分别采集降雨径流以及降雨径流汇入后的河流瞬时水样,测定并分析主要重金属元素的浓度及其变化规律,探讨其对降雨径流的动态响应。研究结果表明:降雨径流对河流可溶态污染元素质量浓度的贡献不突出,对可溶态锌(Zn)、砷(As)、镉(Cd)、硒(Se)具有一定稀释作用,排水口下游 3 m处是可溶态铬(Cr)、锰(Mn)、钴(Co)对降雨径流响应最显著区域;降雨径流对各悬浮态元素质量浓度贡献较大,排水口下游7 m处是绝大多数悬浮态元素对降〖JP〗雨径流响应最显著区域;Mn、Zn、Cr、镍(Ni)、As、Co、Cd 7种元素的总质量浓度对降雨径流的动态响应表现为先上升后下降。其中,排水口下游3 m处是Cr、As总质量浓度对降雨径流响应最显著区段,排水口下游7 m处是Mn、Co、Ni、Zn及Cd总质量浓度对降雨径流响应最显著区段。降雨径流对河流主要污染元素年输入总量估算结果表明,海口市建成区降雨径流向美舍河等受纳水体直接年输入量最大的是Mn和Zn,其次是Cr、As、Ni,Se与Cd的年输入量最小。  相似文献   

18.
We describe the design, optimization, and application of a small, lightweight, deployable monitoring instrument for accurately measuring parts-per-billion levels of hexavalent Cr in surface waters at hourly intervals. The monitor quantifies Cr(vi) using a standard molecular absorbance spectroscopic method, i.e. by formation of a complex with 1,5-diphenylcarbazide (DPC). The continuous flow analysis (CFA) design uses narrow conduits (0.90 mm) that are hot-forged onto poly(methyl methacrylate) ('Plexiglas') plates based on the method of Jannasch et al.(Anal. Chem., 1994, 66, 3352). The sample stream is drawn through the manifold at 25 microl min(-1) using a mini-peristaltic pump; osmotic pumps (10 microl h(-1)) are used to continuously inject reagent (2.0 mM DPC, 0.60 M HNO(3), 5.0% w/v acetone, and 0.10% w/v Brij-35) and to periodically introduce quality control standards and a cleaning solution (0.50 M HNO(3)). The 'Z-type' optical cell uses a liquid-core waveguide (10 mm) to collimate the light-emitting diode source beam (lambda(max) 574 nm) to a broadband photodiode detector. Figures of merit are: 7 min cycle time, response within 28 min and clear-down within 31 min, low waste generation (<40 ml d(-1)), detection limit (3sigma) of 48.4 microg l(-1) as Cr(vi) or 0.411 microM as chromic acid, 1.54% relative standard deviation at 100 microg l(-1), and selectivity for dissolved Cr(vi) in authentic surface water samples containing moderate levels (>0.21% w/v) of total particulate matter. Using a test chamber containing Milwaukee Harbor water that was periodically fortified with Cr(vi) standards, continuous testing over a 15 day period (354 h) yielded results that were in excellent agreement (<5% variation) with measurements made using an ICP-MS reference method. Drift in the calibration model over the test period was 1.23% and the variation in a 0.50 mg l(-1) Cr(vi) standard was 3.8%(n= 11). Known interferences to the DPC chemistry (Mo, V, and Hg at >5 mg l(-1)) were undetected in the harbor water by ICP-MS.  相似文献   

19.
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。  相似文献   

20.
为了研究在线离子色谱法测定大气PM2.5中NH4^+、NO3^-、SO4^2-的不确定性来源,探讨了标准曲线的浓度范围及浓度梯度设置对离子浓度结果的影响,并对标准曲线设定方案进行了优化。结果表明:不同浓度范围的标准曲线对于NH4+的浓度结果有较大的影响,存在1. 87%~14. 91%的偏差,对于NO3^-、SO4^2-的影响较小,相对偏差分别为2. 94%和2. 82%;非均匀布点和均匀布点标准曲线定量NH4+的结果存在4. 15%~4. 25%的偏差,对于NO3^-和SO4^2-,相对偏差分别为0. 10%和5. 99%。对于二次拟合的NH4^+,在样品浓度波动较大时,可以将样品划分为低浓度范围和高浓度范围,分别选用低浓度段标准曲线和高浓度段标准曲线,以期得到更合理的浓度结果。  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号