MPT-AES测定奶粉中的Ca和Fe

用微波等离子体(MPT)为激发光源,氩气为等离子体工作气体,用气动雾化进样,采用标准曲线法研究了微波等离子体炬原子发射光谱法(MPT-AES)测定奶粉中Ca、Fe的方法。详细考察了溶液中HCl浓度、HNO3浓度、微波前向功率、载气流量、工作气流量等实验参数对测定的影响,同时考察了共存元素钠、镁、锌对钙和铁发射强度的影响。     

微波消解-微波等离子体炬原子发射光谱法测定合金钢中的铜、锰、钼

用微波等离子体炬 (MPT)为激发光源 ,氩气为等离子体工作气体 ,用气动雾化进样 ,研究了微波消解 微波等离子体炬原子发射光谱法 (MPT AES)测定合金钢中铜、锰、钼的方法。考察了微波功率、载气流量、工作气流量、氧屏蔽气流量等实验参数对测定铜、锰、钼的影响。对微波消解合金钢样品的消解条件进行了考察 ,建立了最佳消解程序。测定铜、锰、钼的检出限分别为 3.3、3.7和 42ng mL ,RSD(n =6)分别为 1 7%、2 .4%、3.8% ,并且测得它们的线性范围分别为0 .0 2～ 5 0 μg mL、0 .0 4～ 5 0 μg mL和 0 .2 0～ 5 0 μg mL。     

低功率微波等离子体炬发子发射光谱法的研究：超声雾化进样测定…

本文提出一种测定贵金属元素的微波等离子体炬原子发射光谱法（ＭＰＴＡＥＳ）。采用自制的超声雾化微量进样装置进样，以氩气为工作气体，探讨了观察高度，微波功率，体系介质，氩气流量和共存元素对被测元素发射信号的影响。选用合适的分析线和ＭＰＴ光源的工作参数，其方法的检出限分别为５．８（Ａｕ），０．５（Ａｇ）１２（Ｐｔ），１．６（Ｒｈ）和ｔ１．０ｎｇ／ｍｌ（Ｐｄ）。实际样品中金和银的测定结果是令人满意的。     

气相色谱用氩微波等离子体炬发射光谱检测器——对Sn,P,Si和B金属有机化合物响应特性的研究

报道了一种气相色谱用氩微波等离子体炬原子发射光谱检测器(GC-MPT-AED),以氩气为载气、等离子体工作气和尾吹气,探讨了不同气体作等离子体清洗气和屏蔽气时对Sn,P,Si,B等元素响应特性的影响.研究了系统对Sn,P,Si,B等元素的检出限、线性范围和精密度,并对乐果乳油中磷元素的含量进行了测定.     

电感耦合等离子体质谱法测定有机肥料中砷、镉、铅、铬、汞的含量

提出了用微波消解-电感耦合等离子体质谱法测定有机肥料中砷、镉、铅、铬、汞等5种元素的方法。有机肥料样品(0.200 0~0.500 0g)加入硝酸10mL和过氧化氢溶液1mL,按程序升温微波消解,将消解液蒸发至2mL,用硝酸(1+99)溶液定容至50mL。用电感耦合等离子体质谱法测定上述样液中的砷、镉、铅、铬、汞等元素。各元素的检出限(3.3s/k)为0.015~0.040mg·kg~(-1),测定值的相对标准偏差(n=6)均小于5.0%。按标准加入法进行回收试验,测得回收率在98.0%~101%之间。     

便携式微波等离子体离子化检测器气相色谱仪用于气体分析的研究

本文使用自制的便携式微波诱导等离子体离子化检测器气相色谱仪对可燃气体中N_2、O_2、H_2和CH_4的测定方法进行了研究。以氩气为载气和工作气体,考察了改进后的微波诱导等离子体离子化检洲器(MIPID)的工作参数对测定的影响。对煤气和乙炔中的O_2、N_2、H_2和CH_4进行了测定,分析结果与热导池检测器(TCD)的气相色谱法一致。讨论了高电离电位(>11.7ev)气体组分在MIPID中响应特性。     

微波消解-电感耦合等离子体质谱法测定鲤鱼、河蚌样品中的铜、镉、铅、铬

建立微波消解–电感耦合等离子体质谱法同时测定鲤鱼、河蚌样品中铜、镉、铅、铬4种重金属元素的含量。以20.0μg/L的Rh作为内标,采用硝酸–过氧化氢消解液,用微波消解仪消解鲤鱼、河蚌等生物样品,在选定的仪器工作条件下测定。铜、镉、铅、铬4种重金属元素的质量浓度在1～100μg/L范围内与其质谱强度呈良好的线性关系,相关系数均为0.999 9,方法检出限为0.01～0.09μg/L。测定结果的相对标准偏差为1.30%～9.95%(n=6),样品加标回收率为91.0%～111%。用所建方法对黄鱼国家标准物质(GBW 08573)进行测定,测定值与标准值基本一致,相对误差均小于7%。该方法简单、快速,灵敏度高,重现性好,适用于大批量生物样品中多种重金属元素的同时测定。     

微波消解-ICP-MS法同时测定木薯淀粉中铅、铜、镉、砷、汞的含量

用硝酸-过氧化氢溶液(3+3)作为消解剂,微波消解法处理木薯淀粉等样品,采用电感耦合等离子体质谱法,选择适合的同位素元素,运用碰撞池技术(CCT)降低元素Cu、As的多原子离子干扰,测定样品溶液中Pb、Cu、Cd、As、Hg等元素的含量,各元素线性相关系数为0.9997 ～0.9999,元素的检出限(3sd)分别为pb...     

微波消解–电感耦合等离子体质谱法测定酱卤肉中铬、砷、镉、铊、铅

建立微波消解–电感耦合等离子体质谱法测定酱卤肉中铬、砷、镉、铊、铅5种元素含量的检测方法。采用微波消解法处理酱卤肉样品,对预处理条件和仪器工作参数进行了优化,以内标校正法降低基体影响。结果表明,铬、砷、镉、铊、铅5种元素的质量浓度在0.1~50.0 μg/L范围内与质谱响应值具有良好的线性关系,相关系数均大于0.999,方法检出限为0.2~6.2 μg/kg。在3种加标浓度水平下平均回收率为72.4%~113.5%,测定结果的相对标准偏差为3.1%~7.7%(n=6)。该方法简便,快速,高效,准确,可为酱卤肉中铬、砷、镉、铊、铅的测定提供技术支持。     

电感耦合等离子体质谱法(ICP-MS)测定化妆品中铍、镉、铊、铬、砷、碲、钕、铅

建立了化妆品中铍、铬、砷、镉、碲、钕、铊、铅8种有害元素的测定方法,样品采用微波消解,以钇、锂、铟、铋为测定的内标元素,用电感耦合等离子体质谱法测定,结果表明,各元素和内标元素在一定浓度范围内的质量数比值均与浓度呈良好的线性关系,线性方程的相关系数均大于0.999 8,平均加标回收率为95%~104%,相对标准偏差(RSD)均小于3%。方法灵敏度高,准确,可为化妆品中上述元素的限量检查提供参考。     

Determination of trace Ag, Au, Ge, Pb, Sn and Te by microwave plasma torch atomic emission spectrometry coupled with an electrothermal vaporization sample introduction system

An electrothermal vaporization (ETV) sample introduction device tantalum filament was combined with microwave plasma torch atomic emission spectrometry (MPT-AES) for determination of several trace elements. Some operating parameters of the system were optimized. The effects of easily ionized elements (EIEs) on the emission intensities of the tested elements were studied in detail. It was revealed that there was no interference resulting from small amount of sample matrix; while with the existence of large amount of sample matrix, the method of standard addition could be used to determine trace elements in samples. So, no modifier was required in this method. The results indicated that ETV-MPT-AES not only has the advantage of micro sample consumption (a volume of 3 mul for each injection), but also offers high sensitivities for the determination of Ag, Au, Ge, Pb, Sn and Te as compared with those obtained with pneumatic nebulization (PN) MPT-AES.     

A facile synthesis and characterization of Ag, Au and Pt nanoparticles using a natural hydrocolloid gum kondagogu (Cochlospermum gossypium)

An environmentally benign method for the synthesis of noble metal nanoparticles has been reported using aqueous solution of gum kondagogu (Cochlospermum gossypium). Both the synthesis, as well as stabilization of colloidal Ag, Au and Pt nanoparticles has been accomplished in an aqueous medium containing gum kondagogu. The colloidal suspensions so obtained were found to be highly stable for prolonged period, without undergoing any oxidation. SEM-EDXA, UV-vis spectroscopy, XRD, FTIR and TEM techniques were used to characterize the Ag, Au and Pt nanoparticles. FTIR analysis indicates that -OH groups present in the gum matrix were responsible for the reduction of metal cations into nanoparticles. UV-vis studies showed a distinct surface plasmon resonance at 412 and 525 nm due to the formation of Au and Ag nanoparticles, respectively, within the gum network. XRD studies indicated that the nanoparticles were crystalline in nature with face centered cubic geometry. The noble metal nanoparticles prepared in the present study appears to be homogeneous with the particle size ranging between 2 and 10 nm, as evidenced by TEM analysis. The Ag and Au nanoparticles formed were in the average size range of 5.5±2.5 nm and 7.8±2.3 nm; while Pt nanoparticles were in the size range of 2.4±0.7 nm, which were considerably smaller than Ag and Au nanoparticles. The present approach exemplifies a totally green synthesis using the plant derived natural product (gum kondagogu) for the production of noble metal nanoparticles and the process can also be extended to the synthesis of other metal oxide nanoparticles.     

Microwave spectra and structures of KrAuF, KrAgF, and KrAgBr; 83Kr nuclear quadrupole coupling and the nature of noble gas-noble metal halide bonding

Microwave spectra of the complexes KrAuF and KrAgBr have been measured for the first time using a cavity pulsed jet Fourier transform microwave spectrometer. The samples were prepared by laser ablation of the metal from its solid and allowing the resulting plasma to react with an appropriate precursor (Kr, plus SF6 or Br2) contained in the backing gas of the jet (usually Ar). Rotational constants; geometries; centrifugal distortion constants; vibration frequencies; and 197Au, 79Br, and 81Br nuclear quadrupole coupling constants have all been evaluated. The complexes are unusually rigid and have short Kr-Au and Kr-Ag bonds. The 197Au nuclear quadrupole coupling constant differs radically from its value in an AuF monomer. In addition 83Kr hyperfine structure has been measured for KrAuF and the previously reported complex KrAgF. The geometry of the latter has been reevaluated. Large values for the 83Kr nuclear quadrupole coupling constants have been found for both complexes. Both the 197Au and 83Kr hyperfine constants indicate a large reorganization of the electron distribution on complex formation. A thorough assessment of the nature of the noble gas-noble metal bonding in these and related complexes (NgMX; Ng is a noble gas, M is a noble metal, and X is a halogen) has been carried out. The bond lengths are compared with sums of standard atomic and ionic radii. Ab initio calculations have produced dissociation energies along with Mulliken populations and other data on the electron distributions in the complexes. The origins of the rigidity, dissociation energies, and nuclear quadrupole coupling constants are considered. It is concluded that there is strong evidence for weak noble gas-noble metal chemical bonding in the complexes.     

水滑石层间阴离子为还原剂原位负载贵金属纳米颗粒

研究了以水滑石为载体原位负载贵金属纳米颗粒(Pd、Ag、Ru、Au)的方法,通过共沉淀合成甲酸根水滑石,以层间甲酸根为还原剂原位还原贵金属前驱体制得高分散水滑石(LDH)负载纳米颗粒。本方法无需载体预处理,操作方便、适用性强,阴离子前驱体(Au)和阳离子前驱体(Pd、Ag、Ru)均可顺利得到纳米颗粒。所得水滑石负载纳米颗粒系一种潜在的纳米催化剂,作为示例,Pd/LDH在Suzuki偶联反应中显示出较高催化活性。     

Pd/ZnO和Ag/ZnO复合纳米粒子的制备、表征及光催化活性

 用焙烧前驱物碱式碳酸锌的方法制备了ZnO纳米粒子，采用光还原沉积贵金属的方法制备了Pd／ZnO和Ag／ZnO复合纳米粒子，并利用ICP，XRD，TEM和XPS等测试技术对样品进行了表征，初步探讨了贵金属在ZnO纳米粒子表面形成原子簇的原因．以光催化氧化气相正庚烷为模型反应，考察了样品的光催化活性以及贵金属沉积量对催化剂活性的影响．结果表明：沉积适量的贵金属，ZnO纳米粒子光催化剂的活性大幅度提高．同时，深入探讨了表面沉积贵金属的ZnO纳米粒子光催化剂活性有所提高的内在原因．     

Enhanced two-photon emission in coupled metal nanoparticles induced by conjugated polymers

Interactions between noble metal (Ag and Au) nanoparticles and conjugated polymers as well as their one- and two-photon emission have been investigated. Ag and Au nanoparticles exhibited extraordinary quenching effects on the fluorescence of cationic poly(fluorinephenylene). The quenching efficiency by 37-nm Ag nanoparticles is ～19 times more efficient than that by 13-nm Au nanoparticles, and 9-10 orders of magnitude more efficient than typical small molecule dye-quencher pairs. On the other hand, the cationic conjugated polymers induce the aggregate formation and plasmonic coupling of the metal nanoparticles, as evidenced by transmission electron microscopy images and appearance of a new longitudinal plasmon band in the near-infrared region. The two-photon emissions of Ag and Au nanoparticles were found to be significantly enhanced upon addition of conjugated polymers, by a factor of 51-times and 9-times compared to the isolated nanoparticles for Ag and Au, respectively. These studies could be further extended to the applications of two-photon imaging and sensing of the analytes that can induce formation of metal nanoparticle aggregates, which have many advantages over the conventional one-photon counterparts.     

Pd/ZnO和Ag/ZnO复合纳米粒子的SPS和XPS研究

用焙烧前驱物碱式碳酸锌的方法制备了ZnO纳米粒子，采用光还原沉积贵金属的方法分别得到了质量分数为0.5％的Pd/ZnO和Ag/ZnO复合纳米粒子，并利用XRD、TEM、XPS和SPS等测试技术对样品进行表征.初步探讨了贵金属在ZnO纳米粒子表面形成原子簇的原因及沉积贵金属对ZnO纳米粒子表面光电压信号的影响.以光催化氧化气相正庚烷为模型反应，考察了沉积贵金属对ZnO纳米粒子光催化活性的影响，并探讨了光催化活性有所提高的内在原因.结果表明， ZnO纳米粒子沉积贵金属后，其表面光电压信号明显下降，而光催化活性却大大地提高，这说明可以通过表面光电压谱的测试来初步的评估纳米粒子的光催化活性，即粒子的表面光电压信号越弱，其光催化活性越高.     

Determination of noble metals in silicate rocks, ores and metallurgical samples by simultaneous multi-element graphite furnace atomic absorption spectrometry with Zeeman background correction

A new method has been developed for rapid determination of mug/g and ng/g amounts of noble metals in silicate rocks, ores and metallurgical samples by attacking with hydrofluoric acid and aqua regia, preconcentration by ion-exchange chromatography and measuring in a simultaneous multi-element graphite furnace atomic absorption spectrometer equipped with a polarized Zeeman background correction device which eliminated interferences from any incompletely separated common elements. The method was tested for Ru, Rh, Pt, Ir, Pd, Ag and Au with three Canadian certified reference materials, and then applied to the determination of ng/g amounts of these elements in four new Canadian candidate reference materials.     

Preconcentration of gold,silver, palladium,platinum, and ruthenium with organophosphorus extractants

Extraction of noble metals in acid media with new tertiary phosphines and phosphine chalcogenides was examined. Tristyrylphosphine, tristyrylphosphine sulfide tris(2-phenylethyl)phosphine oxide, tris-(2-phenylethyl)phosphine sulfide, bis(2-phenylethyl)[2-(propylthio)ethyl]phosphine oxide, bis(2-phenylethyl)-[2-(butylthio)ethyl]phosphine oxide, and tris[2-(butylthio)ethyl]phosphine oxide were used as extractants. The suitability of the extractants for determination of Au, Ag, and Pd in rock and ore samples was elucidated.     

Synthesis of Au, Au/Ag, Au/Pt and Au/Pd nanoparticles using the microwave-polyol method

Gold, Au/Ag, Au/Pt and Au/Pd bimetallic nanoparticles with varying mol fractions were synthesized in ethylene glycol and glycerol, using the microwave technique in the presence of a stabilizer poly(N-vinylpyrrolidone) (PVP). It was found that bimetallic colloids of Au/Ag, Au/Pd and Au/Pt form an alloy either on co-reduction of respective metal ions or on mixing individual sols.