二苯碳酰二肼光度法测定微量铬的改进

正以六价铬和三价铬价态存在的铬,在地壳中的含量排序稍靠前,属于自然界中分布较普遍的化学元素之一。其中三价铬参与协作生物体内葡萄糖平衡及脂肪、蛋白质的代谢作用,是人体新陈代谢必不可少的微量元素,但人体或动植物摄入过多的三价铬会对机体产生伤害;毒性较大、对人体表皮肌肤有刺激、有高致癌特性的六价铬更易被人体所吸收,在体内产生蓄积,污染环境又影响人体健康,因此铬是环境监测中的重要监控项目。目前,测定总铬含量     

铬与健康

对铬与人体健康的关系进行了综述，主要内容包括：三价铬的作用、六价铬的作用和环境中的铬。     

火焰原子吸收光谱法测定玩具涂料中总铬

三价铬与六价铬都有毒,但六价铬比三价铬更易被人体吸收蓄积,毒性比三价铬高出100倍[1].因此,对于儿童玩具涂料中总铬的测定是至关重要的.     

铬的危害

铬与其他必需元素一样 ,在体内只能保持一定的数量 ,摄取过量 ,非但无益还有害。而且很多铬的化合物危害健康。其中以六价铬的毒性最大 ,因为六价铬具有强氧化性和腐蚀性 ,又有透过生物体膜的作用 ,能影响体内物质的氧化还原和水解等正常生理过程 ,还可抑制尿素酶的活动 ,影响组织中的磷含量。三价铬的毒性次之 ,二价铬和金属铬的毒性小。体内过量的铬主要积聚在肝、肾、内分泌腺中 ,通过呼吸道进入的则易积存在肺中。有意思的是 ,人体肺中的含铬量随年龄增长而升高 ,而其它器官没有这种现象存在 ,并且人体各器官中只有肺的含铬量高于野生动…     

高效液相色谱-电感耦合等离子体质谱法测定玩具材料中六价铬

正我国是世界最大的玩具出口国,同时也是对欧盟出口玩具的大国。玩具中有害重金属元素会影响孩子的健康[1]。自然界中的铬具有不同的形态,主要是以三价铬[Cr(Ⅲ)]和六价铬[Cr(Ⅵ)]的形式存在。三价铬是人体维持健康的微量元素[2],Cr(Ⅵ)则具有较大毒性。美国环境保护局将Cr(Ⅵ)确定为17种高度危险的毒性物质之一。因     

焦亚硫酸钠处理废水中铬

铬是环境中的一种主要污染物,铬的毒性与其存在的状态有极大的关系,不同价态的含铬物质对生物体和人体的危害大不相同.六价铬是一种致癌物质,对它的处理及测定有着重要的意义.     

用焦亚硫酸钠处理废水中铬

铬是环境中的一种主要污染物，铬的毒性与其存在的状态有极大的关系，不同价态的含铬物质对生物体和人体的危害大不相同。六价铬是一种致癌物质，对它的处理及测定有着重要的意义。     

代铬镀层的研究进展

六价铬会严重破坏环境并危害人类的健康,所以开发无六价铬的代铬镀层电镀工艺具有重要的现实意义。本文主要介绍了几种代铬镀层的研究进展,包括合金代装饰铬镀层、电镀及化学镀合金代硬铬镀层以及复合镀代铬镀层等,重点论述了其特点、典型电镀工艺及其应用,并结合其研究现状对代铬镀层的发展进行了展望。     

催化动力学光度法测定水中痕量铬——应用β-环糊精作增敏剂

医学研究发现，六价铬有致癌的危险。电镀、制革、制铬酸盐或铬酐等工业废水，均可污染水源，使水中含有铬。因此研究铬，特别是环境及人体中铬的测定方法，是十分有意义的。近年来有许多关于催化动力学光度法测铬的报道。试验发现：在环糊精存在下，过氧化氢氧化罗丹明B的褪色反应，铬具有明显的催化作用，据此建立了测定铬的方法。该方法用于水中痕量铬的测定。     

连续流动法测定卷烟主流烟气中的六价铬

正重金属元素铬是卷烟中的有害成分,可能来源于烟草作物在生长过程中从环境中吸收和富集的铬~([1]),也可能来源于卷烟加工过程中用到的香精香料、水基胶、卷烟纸、接装纸等烟用辅助材料的痕量铬~([2-3])。在卷烟抽吸过程中,铬元素会随着主流烟气进入身体,从而对人的健康造成危害。铬元素常见的价态为三价和六价,其中六价铬比三价铬毒性高100倍~([4]),吸入会伤及肺和肾,有强烈致癌作用。因此,准确测定主流烟气中六价铬含量对卷烟危害性评价有重要意义。     

Determination of hexavalent chromium in traditional Chinese medicines by high‐performance liquid chromatography with inductively coupled plasma mass spectrometry

An analytical method that combined high‐performance liquid chromatography with inductively coupled plasma mass spectrometry has been developed for the determination of hexavalent chromium in traditional Chinese medicines. Hexavalent chromium was extracted using the alkaline solution. The parameters such as the concentration of alkaline and the extraction temperature have been optimized to minimize the interconversion between trivalent chromium and hexavalent chromium. The extracted hexavalent chromium was separated on a weak anion exchange column in isocratic mode, followed by inductively coupled plasma mass spectrometry determination. To obtain a better chromatographic resolution and sensitivity, 75 mM NH₄NO₃ at pH 7 was selected as the mobile phase. The linearity of the proposed method was investigated in the range of 0.2–5.0 μg L^?1 (r² = 0.9999) for hexavalent chromium. The limits of detection and quantitation are 0.1 and 0.3 μg L^?1, respectively. The developed method was successfully applied to the determination of hexavalent chromium in Chloriti lapis and Lumbricus with satisfactory recoveries of 95.8–112.8%.     

Sources and toxicity of hexavalent chromium

Chromium exists in oxidation states ranging from ?IV to +VI, inclusively. The compounds exhibit a wide range of geometries including square planar, tetrahedral, octahedral, and various distorted geometries. Ore refining, chemical and refractory processing, cement-producing plants, automobile brake lining, catalytic converters for automobiles, leather tanneries, and chrome pigments contribute to the atmospheric burden of chromium. Hexavalent chromium is known to have 100-fold more toxicity than trivalent chromium, for both acute and chronic exposures because of its high water solubility and mobility, as well as easy reduction. The respiratory tract is the major target organ for hexavalent chromium following the inhalation exposure in humans. Chronic inhalation exposure to hexavalent chromium results in effects on the respiratory tract, with perforations and ulcerations of the septum, bronchitis, decreased pulmonary function, pneumonia, and nasal itching and soreness as reported. Chronic human exposure to high levels of hexavalent chromium by inhalation or oral exposure may produce effects on the liver, kidney, gastrointestinal, and immune systems, and possibly the blood. Dermal exposure to hexavalent chromium may cause contact dermatitis, sensitivity, and ulceration of the skin.     

印制电路板中六价铬测定方法的研究进展

阐述了近年来国内外印制电路板中六价铬Cr(Ⅵ)的测定方法,主要包括分光光度法、柱后衍生法、离子色谱-电感耦合等离子体质谱联用(IC-ICP-MS)等方法,未来印制电路板中六价铬的测定方法一定向着新技术联用方向发展。     

Detection of hexavalent chromium using gold/4-(2-mercaptoethyl) pyridinium surface enhanced Raman scattering-active capture matrices

In this communication, the fabrication of SERS-active capture matrices for the detection of hexavalent chromium is described. The amine groups of amine-modified magnetic microparticles were used to immobilize gold colloidal particles. Once immobilized, the gold was reacted with 4-(2-mercaptoethyl) pyridinium (MEP) hydrochloride to form a self-assembled monolayer (SAM). The MEP SAM exhibits great selectivity for hexavalent chromium. It was shown that calibration curves could be generated by ratioing MEP peaks that increased in intensity upon complexation with chromate with a peak that did not change. Flow experiments, using Au/MEP capture matrices held in place by a magnet, showed instantaneous response to changes in chromate concentration.     

Rapid determination of hexavalent chromium in textiles by a novel ammonium pyrrolidine dithiocarbamate derivatization combined with UHPLC–MS/MS

Hexavalent chromium is mainly determined by traditional spectrophotometry, atomic absorption spectrometry, and ion chromatography methods. In the present work, a reliable ultra high performance liquid chromatography with tandem mass spectrometry method was firstly developed for the determination of hexavalent chromium in textiles. The sample was extracted by acetic acid/sodium acetate buffer solution and followed by derivatization with ammonium pyrrolidine dithiocarbamate. The resulting derivative product was extracted by ethyl acetate, separated on a C18 column, and detected through electrospray ionization source in the positive mode with multiple reaction monitoring conditions. The derivatization reaction conditions were investigated and optimized. The developed method was validated in terms of the sensitivity, linearity range, matrix effects, recovery, accuracy, intra‐ and interday precision. Results showed that the calibration curves of pure solvent and matrix were linear over the selected concentration ranges of 0.1–20.0 μg/L. The achieved instrument and method limit of quantification were 0.1 and 40.0 μg/kg, respectively. Recoveries were calculated at three spiked concentrations and the values were between 92.2 and 103% with relative standard deviation values of 2.7–4.9% for intra‐day precision and 6.1% for inter‐day precision. Successful analysis of hexavalent chromium in practical textiles indicated that there was hexavalent chromium contamination in textiles.     

Determination of Chromium (VI) in Airborne Particulate Matter by Electrothermal Atomic Absorption Spectrometry

Hexavalent chromium Cr(VI) is a well-established carcinogen associated with lung, nasal, and sinus cancer. Cr(VI) threshold limit values in workroom air have been recently lowered. Consequently, the currently available analytical methods are insufficiently sensitive or high cost. In this paper, a simple, cost-effective, sensitive, and reproducible method using solid-phase extraction with electrothermal atomic absorption spectrometry for determination of hexavalent chromium in airborne samples is reported. The method validation included selectivity, linearity, accuracy, and precision. Interferences from other ions likely to be present in airborne samples, including trivalent chromium, were tested and selectivity was demonstrated. The detection and quantification limits were, respectively, as low as 0.1 and 0.4?µg?L^?1. The linearity ranged from 0.5 to 50.0?µg?L^?1, with a regression coefficients exceeding 0.998. The extraction recovery exceeded 98%. The developed method was successfully compared with a reference spectrophotometric method. The performances achieved were similar to ion chromatography and high-performance liquid chromatography approaches. The novel method was tested on airborne samples collected from the workplace. The method’s performance suggests that it may be an alternative to high-cost techniques for monitoring occupational exposure to hexavalent chromium.     

碱消解-火焰原子吸收光谱法测定土壤中六价铬

建立了碱消解-火焰原子吸收光谱法测定土壤中六价铬的方法。讨论了pH值对六价铬测定的影响。干扰实验的结果表明同等含量的三价铬对六价铬测定无干扰。实验对比了无背景校正、氘灯背景校正、塞曼背景校正三种工作方式,分别对低、中、高三个水平土壤六价铬标准物质进行了测定,结果表明,低含量的土壤样品用塞曼背景校正方式测定的结果更准确,最终选择了塞曼背景校正的工作方式。方法的线性范围0.1～2.0mg/L,线性相关系数R为0.999 8,相对标准偏差(RSD)为1.1%;当取样量5g,定容体积100mL时,方法检出限为0.20mg/kg,加标回收率为84.8%～86.9%,能满足日常测定需求。     

微波灰化-液相色谱-电感耦合等离子体质谱联用测定干食用菌中的三价铬和六价铬

建立了干食用菌中三价铬(Cr(Ⅲ))和六价铬(Cr(Ⅵ))的液相色谱-电感耦合等离子体质谱(LC-ICP-MS)检测方法。采用微波灰化技术对食用菌样品进行灰化处理,灰化样品用乙二胺四乙酸(EDTA)二钠盐稳定其中的Cr(Ⅲ),并使其保留在阴离子交换柱(250 mm×4.6 mm,10μm)上;用含有60 mmol/L硝酸(pH 9.3)的流动相分离其中的Cr(Ⅲ)和Cr(Ⅵ),电感耦合等离子体质谱仪测定。标准溶液中Cr(Ⅲ)和Cr(Ⅵ)的质量浓度在0.5~50μg/L范围内呈良好的线性关系,线性回归系数均达到0.999 9。食用菌样品中Cr(Ⅲ)和Cr(Ⅵ)不同加入量的平均回收率为78.0%~90.7%,相对标准偏差小于4%(n=6);定量限均为0.5μg/L。该方法稳定、可靠、灵敏,可满足干食用菌中Cr(Ⅲ)和Cr(Ⅵ)的测定。     

六价铬测定方法的进展

文章阐述了2000-2007年来国内外Cr(Ⅵ)的测定方法,包括分光光度法、原子吸收光谱法、电化学分析法等.引用文献49篇.     

大体积进样离子色谱法检测饮用水中六价铬

建立了离子色谱检测饮用水中的六价铬的分析方法。以AS23柱分离,20mmol／L NaOH为淋洗液,1．0mL／min流量,1mL大体积进样,电导检测。结果表明,方法检测限为0．8μg／L,水样加标回收率在96．0％-102．0％之间,相对标准偏差为4．09％-1．40％;与标准方法二苯碳酰二肼分光光度法结果比对表明,该法检测限低、操作简便、准确快捷,适用于饮用水中六价铬的检测。