On-line trace enrichment — column liquid chromatography of polar pollutants in surface water using bifunctional membrane-based extraction-disk cartridges

Summary An on-line trace-enrichment system, using a bifunctional membrane extraction-disk cartridge, has been combined with a column liquid chromatography separation for the simultaneous determination of basic, neutral and acidic pollutants in surface water. The enrichment device consisted of a specially constructed holder containing both C-18 and cation-exchange disks. The holder can contain up to 25 disks of 0.5 mm thickness and 4.6 mm diameter. Before trace enrichment of 20 ml of surface water (pH 3.0), calcium ions were removed from the sample by means of an oxalic acid precipitation. Desorption of the cartridge was at elevated temperature using reversed-phase gradient elution; detection was performed with a diode-array UV absorbance detector. The detection limits for the test compounds in surface water are typically 0.5–2 g/l; the calibration graphs are linear from the lower limit of determination up to 50 g/l.     

CN chemiluminescence in N2 + CH4 Flowing afterglow at low temperatures

The spectra of flowing microwave post-discharge excited in N₂ and N₂ + CH₄(N₂ + C₂H₂) gas mixtures have been studied at low temperature (77 K). The molecular spectra of CN emitted by the collision-induced N + C and N + CH chemiluminescent reactions in the low-temperature afterglow system have been thoroughly investigated. The intensity of different CN (B²⁺-X²⁺) vibrational bands is very sensitive to low hydrocarbon concentration in nitrogen used as the working gas. Detection of hydrocarbon species has been demonstrated from concentrations of CH₄ and C₂H₂ in N₂ greater than 10¹⁰ molecules · cm^–3.     

广州老人进食中国营养平衡米的营养调查

介绍了广州老人进食中国营养平衡米（简称平衡米）的效果。营养调查发现，广州老人Ca,P,Fe,Zn和Se摄入量分别为403，807，17，14mg/d/人和46μg/d/人，说明老人Ca,Zn,Se不足，原因是主食籼米矿物质营养不平衡，进食平衡米后。老人Ca,P,Fe,Zn和Se摄入量分别提高到1153，863，45，45mg/d/人和111μg/d/人。结果说明，进食平衡米可以提高广州老人矿物质营养水平，使老人健康长寿。     

探索《高分子物理》教学新路

《高分子物理》课程具有内容多、要求高、学科新、发展快、社会需求不断变化等特点,教学面临严峻的挑战。本文介绍了作者在教学过程中的一些方法。在教材建设方面,提出向双语和案例分析方面进行改革,在教学过程中牢牢把握“结构与性能关系”主线,突出“柔顺性”这一重点,注重表达的方式、加强互动、结合科研、以及运用教具和多媒体课件等辅助教学手段,以收到良好的教学效果。     

Trace analysis of gallium arsenide by selective evaporation of the matrix with bromine vapours

Gallium arsenide samples are analyzed by graphite furnace AAS after the selective evaporation of the matrix elements as bromides with bromine vapours in a simple apparatus. The evaporation step is carried out at 280–300 ° C and it is accomplished for 0.5 g sample within 1 h. Reproducibilities of 5 to 20% were obtained. Detection limits (3 s, in ng/g) are 20 (Fe), 5.0 (Ca), 3.0 (Mg), 2.0 (Ni, Cu), 1.0 (Al), 0.5 (Pb, Co), 0.2 (Mn, Cr).     

成年男性精液中19种元素含量的测定及影响因素研究

运用ICP-MS和ICP-AES方法同时分析丹东某硼矿周围工人组及对照组精液中19种元素的含量水平。样品经过双氧水-纯化硝酸体系消解,采用稀释分析及双内标铑(Rh)和铼(Re)进行校正。该法最低检出限、加标回收率及分析精密度能满足精液样品的分析要求。按照95%置信区间进行数据筛选,选出118人的数据统计分析成年男性精液中元素含量水平,并与国内其它研究结果进行比较。分析精液元素含量影响因素表明,硼(B)作业暴露对精液中的B含量具有显著影响;吸烟能显著影响精液中的Cd含量;饮酒对工人组精液中的Cu和Mn的含量具有显著影响。     

深圳市宝安区儿童头发中微量元素含量与儿童眼病关系的研究

通过对2001～2003年深圳市宝安区独生子女(0～14岁)近20000例体检情况统计，结合测定头发中微量元素锌、铁、铜、钙、锰、硒六种元素含量，对照健康人微量元素测定，发现缺锌、缺铜、缺硒儿童较健康儿童更易患近视，这一结论与相关报道一致。     

自然流产孕妇体内微量元素含量的变化

为了解自然流产孕妇体内微量元素的变化,检测了50例正常妊娠妇女和50例自然流产妇女（其中忆查明流产原因的33例,不明原因流产17例）头发中微量元素。结果显示,查明原因流产组发锌、铜、铁、钙和不明原因流产组发锌、铜、铁含量均明显低于正常妊娠组;而发铅含量则明显高于正常妊娠组,经统计学处理分析,差别有显著性。提示妊娠期微量元素平衡与否,对宫内胎儿的发育乃至安危均有一定的影响。     

微量元素与病毒性肝炎

微量元素参与机体各种酶及活性物质的代谢，从多方面影响着人的生命过程。肝脏是人体的重要代谢脏器，对微量元素的代谢关系更为密切。病毒性肝炎患者血清硒，锌均明显降低，铜元素高于正常。因此测定患者机体内的微量元素含量，为诊断及治疗提供新的途径和措施，可及时纠正患者体内微量元素的盈缺，有助于改善肝细胞功能及增强机体免疫力。     

Trace enrichment of polar pollutants from water and the influence of humic substances

Summary A practical liquid chromatographic early-warning system for polar pollutants in water ought to have detection limits at a level below a microgram per litre. Using ultraviolet absorbance detection this normally necessitates trace enrichment of the samples. In this study ten different sorbents have been tested with respect to their enrichment capacity. The hydrophobic polymeric PLRP-S material, in combination with a C-18 modified analytical column, proved to be the best choice. The influence of humic substances, present in surface water, was also studied. Lowering of the sample pH, resulted in a significant increase in the interferences due to the humic substances.