电感耦合等离子体原子发射光谱法测定不锈钢食具容器中12种重金属元素的迁移量

经清洗的不锈钢食具容器中加入乙酸(4+96)溶液至规定体积,煮沸30min,冷却,补充乙酸溶液至原体积,在室温浸泡24h,所得溶液用于原子发射光谱法测定其中的12种元素的含量。选择强度相对较高且干扰较少的谱线作为所测定元素的分析线,对3项仪器工作参数进行了优化,结果表明:发生器射频功率1 250W;载气流量0.6L·min-1;观测高度16mm。12种元素的质量浓度均在0.05~1.0mg·L-1范围内与其谱线强度之间呈线性关系,其检出限(3s)在0.001~0.013mg·L-1之间。对方法的回收率进行了试验,测得回收率在98.2%~104%之间,对浸出液平行测定10次,测定值的相对标准偏差均小于3.0%。     

ICP-AES法快速测定不锈钢食具容器中重金属的迁移量

采用ICP–AES法快速测定不锈钢食具容器中的重金属铅、铬、镍、镉和砷的迁移量。样品用4%乙酸溶液浸泡,ICP–AES法测定浸泡液中铅、铬、镍、镉、砷的含量。铅、铬、镍、镉、砷的质量浓度分别在0.03~0.30,1.0~5.0,0.3~2.0,0.015~0.20,0.020~0.30 mg/L范围内与其光谱强度线性相关,相关系数均大于0.999 6。铅、铬、镍、镉、砷的检出限分别为0.009,0.000 5,0.002,0.000 5,0.007 mg/L,加标回收率分别为100.0%~122.5%,100.0%~115.0%,99.0%~117.5%,108.0%~115.0%,60.0%~68.8%,测定结果的相对标准偏差为0.2%~5.0%(n=6)。结果表明,该方法能够满足对不锈钢食具容器中重金属迁移量的快速测定要求,可应用于食品相关产品的监管工作。     

黄芩药材中铅的测定及其水煎过程中铅的浸出率研究

测定了黄芩药材中有害元素铅的含量，并研究了黄芩水煎过程中铅的浸出率。     

茶水中微量元素硒浸出量的研究

研究了茶水中微量元素硒浸出量。采用2,3－二氨基萘荧光法测定茶水中硒的含量。结果表明,富硒茶中硒含量为2．45μg／g。富硒茶3g浸泡于300mL90℃水中浸泡30min,茶水中硒含量0．71μg／100mL,浸泡2－4次的茶水中硒含量0．10－18μg／100mL。富硒茶中含量丰富,常饮茶水有益于人体健康。但茶叶不宜反复冲泡饮用。     

示波极谱法测定金属铅及铅锌矿浸出渣中微量锑

在ｐＨ２．４的邻苯二酚紫－Ｓｅ体系中，Ｓｂ产生一个灵敏的极谱波，其导数峰电位为－０．２８Ｖ，线性范围０．００８－０．４μｇ．ｍｌ＾－１，许多离子不干扰，不用分离和富集，可直接测定金属铅及铅锌矿浸出渣中微量锑。方法具有灵敏，快速，准确的特点。     

ICP-AES测定陶瓷器皿中微量溶出铅、镉的研究

用4%乙酸溶液萃取分离日用瓷表面微量溶出元素Pb和Cd后,采用电感耦合等离子体原子发射光谱(ICP-AES)法进行了分析,对影响其测量的各种因素进行了较详细的研究,确定了实验的最佳测定条件。结果表明,方法的检出限为0.023(Pb)和0.006μg/L(Cd),回收率为98.0%~104.0%,RSD小于3.5%。该法准确、快速、简便,应用于日用瓷中的微量溶出铅、镉的测定,结果满意。     

差分脉冲溶出伏安法测定陶瓷器皿中铅和镉的溶出率

采用4%的乙酸浸泡陶瓷样品24 h,应用同位镀汞差分脉冲溶出伏安法测定了陶瓷样品中微量重金属铅、镉的溶出量。以0.1 mol/L的硝酸溶液做底液,0.1 mol/L的KCl溶液做支持电解质,2 g/L的Hg2+溶液做镀汞液,测得铅的溶出峰电位为-0.5 V(vsSCE),镉的溶出峰电位为-0.7 V(vsSCE),两者含量在5×10-4～1 mg/L和5×10-4～0.5 mg/L范围内峰电流和其含量呈良好的线性关系,检出限分别为2×10-4和4.3×10-3mg/L。     

欧盟新指令提高陶瓷铅、铬限量标准

新指令对仪器分析方法检出的与食品接触瓷器制品铅和镉的限量标准由原来的4．0、0．3mg／L分别修订为0．2、0．2mg／L,提高此类产品进入欧盟市场的门槛。从2010年5月20日起,不符合该指令的瓷器制品将禁止生产和进口。新指令对在欧盟产销的、可能与食品接触的瓷器制品,提出须附由生产商和销售商提供的书面声明,     

DBM-MSA 光度法测定食品包装材料和容器中的铅

研究了新显色剂二溴对甲基偶氮甲磺（ＤＢＭ－ＭＳＡ）与铅的显色反应,在量浓度为０．２４ｍｏｌ／Ｌ的Ｈ３ＰＯ４介质中,铅在ＤＢＭ－ＭＳＡ形成稳定的蓝色配合物,其组成比为ｎ（Ｐｂ）：ｎ（ＤＢＭ－ＭＳＡ）＝１：２,最大吸收波长为６４２ｎｍ,表观摩尔吸光系数达９．５×１０＾４,铅的质量浓度在０－１５μｇ／２５ｍＬ服从比耳定律,测定量浓度为１０μｇ／２５ｍＬ的铅时大多数金属离子的允许量在ｍｇ级,用于食品包装材     

铅对海马LTP的影响

综述了铅对海马“长时程增强”（ＬＴＰ）的影响,海马是学习记忆的关键部位,海马ＬＴＰ是记忆形成的基础。慢性铅暴露可使海马ＬＴＰ的幅度降低甚至抑制其诱导,铅可通过干扰海马ＬＴＰ过程,导致儿童的学习,记忆功能及心理行为异常,这可能是铅神经毒性机制之一。     

Immersion enthalpy of carbonaceous samples in aqueous solutions of monohydroxilated phenols

The immersion enthalpies of modified activated carbons were determined, with commercial Carbochem^TM–PS230 (CAG) as the initial activated carbon, which was modified by: chemical treatment with HNO₃ 7 mol L⁻¹ (CAO) and thermal treatment under flow of H₂ (CAR) in function of the adsorbed quantity of monohydroxilated phenols, catechol, resorcinol and hydroquinone at a pH of 7 in aqueous dissolutions in order to characterize the solid–solution interaction and evaluate the influence of the chemical characteristics of the activated carbon in the phenol adsorption. The results show a variation in the immersion enthalpy in function of the adsorbed quantity of phenol and the initial dissolution concentration; which shows that the intensity of the interaction changes in function of the composition of the liquid phase. The immersion enthalpies present the following arrangement: catechol > resorcinol > hydroquinone, with a −ΔH_inm of 35.7; 30.8 and 24.6 Jg⁻¹, respectively, at a pH of 7 for a 100 mg L⁻¹ phenol monohydroxilated solution.     

32例反复呼吸道感染患儿发铅研究

研究了铅对儿童免疫系统的影响。选择了32例反复呼吸道感染患儿作为研究对象,38例健康儿童为对照。结果表明,患儿发铅含量(26.7±14.1)×10~(-6),高于对照组发铅含量(19.4±9.1)×10~(-6),经统计学处理,两者有显著性差异,t=2.59,P<0.05。证实铅对人体免疫力具有抑制作用,可增加小儿对致病微生物的敏感性。     

68例智力低下儿童发病原因与发铅含量关系探讨

对本院遗传优生门诊１９９４年以来确诊为６８例智力低下儿童进行了发铅测定。其中１２人发铅明显超过正常值,占总数的１７．６％。发铅增高的１２人中,有５人为神经系统病变,１人为射材矮小,另外６例无明显医学原因。本组病例显示,铅对儿童的神经系统损害较明显。讨论了防止胎儿和儿童受铅毒害的措施。     

A Quick Color Test to Detect Lead Release From Glazed Ceramic and Enameled Metalware

Abstract

A color test is presented for the purpose of quickly identifying glazed ceramic and/or enameled metalware which releases excessive Pb. Citric acid solution on filter paper is used to extract Pb from the ware and a Pb-sensitive chromogen indicates the presence of Pb on the paper. The quick color test takes approximately 30 min and is useful for screening ware to determine the need for testing by the 24-h method of the Association of Official Analytical Chemists/American Society for Testing and Materials.     

Determination of the Boron/Lead Ratio in Ceramic Materials Based on Electrochemical Quartz Crystal Microbalance

A method for quantitatively determining the relationship boron/lead in ceramic materials is presented. It is based on the attachment of microsamples of ceramic frits to an electrochemical quartz crystal microbalance (EQCM). After a reductive deposition step in the ?0.25 to ?0.85 V (vs. AgCl/Ag) potential range, well‐defined stripping peaks are recorded in 0.10 M NaCl plus 0.10 M mannitol. The deposition of boron and lead from suspensions of solid materials, and its subsequent oxidative dissolution can be monitorized at the EQCM. The quotient between the maximum mass gain and the corresponding charge passed enables for a direct quantitation of the boron/lead molar ratio in ceramic materials. Addition methods based on the EQCM examination of i) sample plus lead white (2PbCO₃.Pb(OH)₂) and ii) sample plus Li₂B₄O₇ mixtures are also presented. Results for boron‐containing ceramic frits are in excellent agreement with those obtained by reference methods.     

Preparation,Electrochemistry, and Electrocatalytic Activity of Lead Pentacyanonitrosylferrate Film Immobilized on Carbon Ceramic Electrode

Lead pentacyanonitrosylferrate (PbPCNF), a new Prussian blue analog, was immobilized on the surface of a carbon ceramic electrode (CCE) prepared by sol‐gel method. The immobilization process consists of adding a certain amount of metallic lead to the electrode matrix before gelation, and chemical derivatization of Pb on the electrode surface to a PbPCNF solid film by immersing the electrode in a solution of sodium pentacyanonitrosylferrate (PCNF). The composition of the synthesized PbPCNF was characterized by FTIR, scanning electron microscopy (SEM), and energy‐dispersive X‐ray (EDX) techniques. The resulting modified electrode showed electroactivity at two redox centers. The electrochemical behavior of the PbPCNF modified carbon ceramic electrode (PbPCNF|CCE) was studied by cyclic voltammetry. Under optimized conditions the peak‐to‐peak separation is only 39 mV, indicative of a surface reaction. Ion effects of the supporting electrolyte suggest that cations have a considerable effect on the electrochemical behavior of the modified electrode. The transfer coefficient (α) and the charge transfer rate constant at the modifying film|electrode interface (k_s) were calculated. The electrocatalytic activity of the modified electrode toward the electro‐reduction of peroxodisulfate was studied in details.     

广州市天河区1000例城区与工业区儿童发铅分析

抽样调查了天河城区及工业区３￣６岁托幼儿童的发铅,进行分组对照比较。结果表明,生活在城区儿童的发铅异常者占抽样人数的３４．４％,而生活在工业区儿童的发铅异常者则占总抽样人数的５２．２％,把两组儿童的发铅平均含量作比较发现,城区组显著低于工业区组儿童（Ｐ〈０．０１）,提示,生活在工业区的儿童是铅暴露的高危人群。     

Renewable Ceramic (TiN) Ring Electrode in Stripping Voltammetry. Determination of Pb(II) Without Removal of Oxygen

Characteristic features of the process of Pb(II) reduction and oxidation at a renewable ceramic ring electrode (RCRE) were studied by stripping voltammetry. The main constituents of the RCRE are: a specially constructed TiN ring electrode, a silver sheet used as silver counter/quasi‐reference electrode and a silicon O‐ring are fastened together in a polypropylene body. The renovation of this electrode is carried out through mechanical removal of solid contaminants and electrochemical activation in the electrolyte which fills the RCRE body. The optimal measurement conditions, composition of supporting electrolyte and procedures of the electrode activation were selected. The measurements were carried out from nondeaerated solutions. As shown on selected examples, RCRE exhibits good performance in underpotential deposition stripping voltammetry (UPD‐SV) applied for the determination of lead(II) in synthetic solutions with and without surfactants and in certified reference materials. The peak current is proportional to the concentration of lead(II) over the range 2×10^?9–1×10^?7 mol L^?1, with a 3σ detection limit of 1×10^?9 mol L^?1 with an accumulation time of 30 s. The obtained results showed good reproducibility, (RSD=2–5%; n=5) and reliability.