双硫腙改性氧化石墨烯/壳聚糖复合微球固相萃取在线富集-原子荧光光谱法测定地质样品中痕量汞

汞可以指示矿床或矿化存在,是一种重要的地质过程示踪元素,因此汞的测定是十分重要的。由于汞在地质矿床中丰度较低,直接测定存在困难,需要进行预分离富集处理。目前采用的分离富集手段大多数是离线,自动化程度较低。本文将合成的双硫腙改性氧化石墨烯/壳聚糖复合微球制成固相萃取小柱,考察了溶液pH、吸附剂种类和体积对汞的吸附效果的影响,优化了固相萃取在线采样/洗脱时间和速率对汞的吸附/洗脱效果的影响,建立了固相萃取在线富集-原子荧光光谱法测定地质样品中痕量汞的分析方法。结果表明:溶液pH=3.0时,以5 mL/min的采样速率进样5 min,汞的吸附率大于90%;用20 g/L硫脲-1.0mol/L硝酸混合溶液作洗脱液,以1 mL/min的洗脱速度洗脱1 min,洗脱率大于95%。汞含量在0.050~5.0μg/L范围内线性关系良好,富集因子为22,检出限为0.0019μg/L。采用本方法测定了土壤和沉积物国家标准物质样品,Hg的测定值与参考值的相对误差小于±13%。与离线分析相比,本方法具有灵敏度高、操作简单快速等特点。     

EXPLORATION ON METHOD OF AUTO-CLASSIFICATION FOR MAIN GROUND OBJECTS OF THREE GORGES RESERVOIR AREA

1IN TR O DU C TIO N With thedevelopmentof remotesensingtechnolog,y thestudyandapplicatioonftheautomaticclassifitciaon method usingcomputerhad achievedsatisfyi ndgevel- opment. From spectrumstatisticcallassificatitoonthe neural network classificatimoenthod…     

5—Br—PADAP液珠萃取比色法测定化探样品中的微量铜

目前在野外进行快速测定化探样品中微量铜的方法还不多见，本文报道了一个野外快速测定化探样品微量铜的新方法，该法基于在pH5乙酸缓冲溶液中，铜与5－Br-PADAP形成的有色络合物能够被磷酯原黄丁（TBP）的液珠萃取，形成的液珠灵敏度高，0－0.1ug之间的色阶可明显辨出，采用三酸酯棉富集分离铜^[1]，灰化法解脱，称样0.5g,测定下限为每毫升0.2ug铜，该法操作简单快速，不需要特殊的仪器和通风设备，适用于野外进行化探样品中数量铜的快速测定。     

Phosphorus features in FT-IR spectra of natural organic matter

Fourier-Transform Infrared （FT-IR） spectroscopy has been used extensively to characterize natural organic matter （NOM）. Absorption bands at 1100-1000 cm^-1 in the FT-IR spectra of NOM have been frequently assigned to alcoholic and polysaccharide C-O stretching or to vibrations of SiO2-related impurities. However, these interpretations do not consider that a strong band associated with P-O bonds of phosphate also appears in the same region. We evaluated the correlation between absorbance in this region and P content of 19 NOM samples from terrestrial, aquatic and plant shoot sources. In the spectra of 10 humic and fulvic acid samples, shoulder to minor bands appeared around 1050 cm^-1. Absorbance intensity at 1050 cm^-1 （Y） was linearly related to P content （X） by the following： Y=4.38X＋0.3 l, with R2=0.90. We did not observe such a close correlation between absorbance and P content in two aquatic NOM samples. Apparently, this is because the aquatic NOM samples were concentrated by reverse osmosis, which would have concentrated not only humic and fulvic acids but also other soluble organic solutes present in natural waters. In the FT-IR spectra of seven dissolved organic matter （DOM） samples obtained from dried plant shoots, broad and/or multiple bands around 1075 cm^-1 were observed with a shoulder at 977 cm^-1. These characteristics were more like those of organic phosphate compounds （such as inositol hexaphosphate）. However, solution 31P nuclear magnetic resonance spectroscopic analysis showed no significant amount of organic phosphate present in these samples.     

关于矿源层和成矿物质来源的探讨

"矿源层"的基本概念是富含一种或几种成矿物质的地层或岩石。矿床中的成矿物质主要来源于矿源层,认为岩浆岩的侵位使其中的成矿物质被活化、迁移、沉淀成矿。"矿源层"成矿理论多年来一直被广大地质工作者接受和引用,在一些文献和论文中屡见不鲜。我们认为,富含成矿物质的地层或岩石是客观存在的,但从中萃取成矿物质成矿的机理是值得探讨的,即成矿物质被活化、迁移过程中,为什么从低温处向高温处迁移?为什么从低压区向较大压力区迁移?又为什么从低浓度区向高浓度区迁移?为什么被萃取的"矿源层"没有发生热液蚀变?本文举例说明冀东二十多亿年前生成的铁、金和铅锌矿在经历无数次热事件后,并未发生活化、迁移,生成新的矿体,仍保留原始面貌,证明从围岩(矿源层)萃取成矿物质、迁移富集成矿的机理是不可行的。指出成矿物质是岩浆从地壳深部带上来的,岩浆热液是成矿物质的主要来源。     

二氧化钛表面键合配位体固相萃取填料的制备及其吸附性能研究

有机配位体/无机纳米复合材料作为固相萃取填料用于重金属离子分离富集是当前分析化学研究的热点课题。本文将含有N、S配位原子的氨基硫脲通过缩合反应接枝于纳米二氧化钛表面,制备了一种新型纳米Ti O2/TSC复合固相萃取填料。通过红外光谱、X射线衍射、X射线光电子能谱和扫描电镜表征,此填料与共混法制备的聚合物包覆纳米二氧化钛复合填料相比,二氧化钛粒子(尺寸200~300 nm)分布更均匀,结构更稳定。用该填料制备的固相萃取小柱静态吸附Sb3+、Cd2+和Ba2+在30℃时饱和吸附量分别为13.9mg/g、12.9 mg/g和11.2 mg/g,在优化的实验条件下三种金属离子的吸附回收率分别达到97.94%、95.65%和94.04%,实验数据重现性高(RSD5.5%),吸附性能优于聚苯乙烯-甲基丙烯醛-氨基硫脲包覆纳米二氧化钛和纳米二氧化钛两种填料。本填料结合ICP-MS测定水样中以上三种离子的检出限分别为0.061μg/L、0.013μg/L和0.075μg/L。     

Molecularly Imprinted Polymers for Selective Extraction of Crystal Violet from Natural Seawater coupled with High- Performance Liquid Chromatographic Determination

Molecularly imprinted polymers （MIPs） were prepared by the bulk polymerization using crystal violet as the template molecule, and the methacrylic acid and ethylene glycol dimetheacrylate as functional monomer and cross-linker, respectively. Sys- tematic investigations of synthetic conditions were conducted. The surface morphology and recognition mechanism of the obtained polymers were studied using scanning electron microscope and spectrophotometric analysis. MIPs showed high atTmity to template molecule and were successfully applied as special solid-phase extraction sorbent for selective extraction of crystal violet from natural seawater. An off-line molecularly imprinted solid-phase extraction （MISPE） method followed by high-performance liquid chroma- tography with diodearray detection for the analysis of crystal violet was also established. MISPE columns have good recoveries for crystal violet standard solutions and good linearity was obtained over the concentration range of 0-200 ~tg L-1 （R2 〉 0.99）. Finally, two natural seawater samples were investigated. The recoveries of spiked seawater on the MISPE columns were from 44.47% to 62.34%, the relative standard deviation （n=3） being in the range of 2.89%-5.96%.