人工神经网络-分光光度法同时测定废水中的金和钯

贵金属金和钯都能与新试剂5-（2-羟基-3,5-二甲基苯偶氮）罗丹宁（HD—PAR）形成稳定的红色络合物,由于二者吸收峰严重重叠,采用化学计量学中的人工神经网络方法实现了金和钯的同时测定,方法可用于废水中金和钯的同时测定。     

FAAS determination of palladium after its selective recovery by silica modified with hydrazone derivative

Amino propyl silica (APS) gel reacts immediately with benzyl monopyridyl hydrazone (BMPH) to produce a new effective and selective derivative (BMPH-APS) for the separation and preconcentration of traces of Pd(II) in aqueous solution. Factors affecting the sorption and desorption of Pd ions have been investigated. Acidic aqueous solution of 0.5% thiourea in 0.5 mol L^?1 HCl has been used as eluent for the desorption of Pd(II). The stripped metal ion was determined by flame AAS. The modified silica quantitatively sorbed Pd(II) at pH 2–4 with a sorption capacity of 0.65 mmol g^?1 and preconcentration factor of 250 fold in less than one minute (t_1/2). Common other ions did not interfere except Co(II) which was eliminated by EDTA . The limit of detection (LOD) is 0.1 ng mL^?1 and the relative standard deviation (R. S. D.) for 10 replicate measurements at 20 ng mL^?1 Pd level was 1.51%. The method was successfully applied for Pd preconcentration in highly concentrated salt solutions and in spiked clay, road dust, scrap and water samples.     

金纳米粒子富集-高效液相色谱同时测定人血浆中三种氨基硫醇

建立了金纳米粒子富集-高效液相色谱-紫外检测(HPLC-UVD)同时测定人血浆中3种氨基硫醇(半胱氨酸(Cys)、高半胱氨酸(Hcys)、谷胱甘肽(GSH))的新方法。以Tween 20修饰的金纳米粒子作为选择探针萃取富集氨基硫醇。经二硫苏糖醇脱附后,采用SpursilTM C18柱(250 mm×4.6 mm, 5 μm)分离氨基硫醇,以60 mmol/L磷酸盐缓冲溶液(pH 2.0)等度洗脱,检测波长为200 nm。3种氨基硫醇的浓度分别在0.025～350 μmol/L、0.02～60 μmol/L、0.01～50 μmol/L内与峰面积具有良好的线性关系,相关系数均高于0.99。方法检出限(信噪比为3)分别为5.0、6.0和2.5 nmol/L,回收率为92.8%～106.0%。该方法能显著降低血浆样品中内源性物质的干扰,提高HPLC-UVD的选择性和灵敏度。将该方法应用于心血管病人血浆中上述氨基硫醇的分离测定,结果显示: 与对照组相比,疾病组血浆中的Hcys和GSH水平存在显著性差异,Cys不存在显著性差异。     

Simultaneous determination of palladium and rhodium using on-line column enrichment and electrothermal atomic absorption spectrometric detection

Flow injection on-line micro-column pre-concentration was coupled with electrothermal atomic absorption spectrometry (ETAAS) for the simultaneous determination of Rh and Pd in environmental samples. The micro-column contained 1,5-Bis(2-pyridyl)-3-sulphophenyl methylene thiocarbonohydrazide (PSTH) immobilised on an anion-exchange resin (Dowex 1 × 8–200). The sorbent was tested in a micro-column, placed in the auto-sampler arm, at the flow rate 3.1 mL/min. Elution was performed with 2 M HNO₃ and the system was optimised with a 60 s pre-concentration time.     

Simultaneous neutron activation determination of palladium,gold, platinum and iridium in some natural materials

A method for rapid simultaneous neutron activation determination of Pd, Au, Pt and Ir in USGS standard rocks, ores and minerals has been developed based on selective extraction of determined elements. Results of determination of noble metals in standard rocks are discussed.     

Separation and enrichment of palladium and gold in biological and environmental samples, adapted to the determination by total reflection X-ray fluorescence

The reductive co-precipitation of trace and ultra-trace elements together with mercury followed by complete evaporation of the mercury makes it possible to determine palladium and gold by total reflection X-ray fluorescence. Both elements can be detected without interferences at optimal sensitivity in the pg range. Thus, detection limits of, e.g., 2.5 ng L-1 for palladium and 2.0 ng L-1 for gold, in urine, were obtained. The precision was determined to 0.04 at a palladium concentration of about 200 ng L-1 urine and to 0.19 at a gold concentration of only 18 ng L-1. The recovery for a urine sample spiked with known amounts of palladium and gold amounted to > 95%. Results of the combined procedure are given for the determination of palladium and gold in the urine of non-exposed and occupationally exposed persons and in some other environmentally relevant samples.     

Determination of ultra-trace gold in natural water by graphite furnace atomic absorption spectrophotometry after in situ enrichment with thiol cotton fiber

A simple method of determining ultra-trace Au in natural water was presented by using graphite furnace atomic absorption spectrophotometry (GFAAS) after in situ enrichment with thiol cotton fiber (TCF). The sample solution was adjusted to pH 1.5-2.0 with HCl, then the water sample was passed through a column packed with 0.10-0.20 g TCF and the flow rate was controlled at 20-40 ml min⁻¹. The effects of interferences, such as complexing and oxidizing agents and other elements adsorbed on TCF were overcome by chemical treatments prior to the desorption of Au. The adsorbed Au was adsorbed with 2.0 ml hot acid, then it was extracted with 1.00 ml methyl isobutylketone (MIBK). For a 5 l water sample, the detection limit of Au is 0.02 ng l⁻¹. The relative standard deviation (R.S.D.) for the determination of 1.44 ng l⁻¹ Au was 9.4%.The method was applied to determine ultra-trace Au both in suspended phase and soluble phase in natural water, the concentrations of total Au in natural water samples range from 0.51 to 67.82 ng l⁻¹. The recovery of added 0.50-6.00 ng l⁻¹ Au was 80-95%. The method is useful in prospecting for Au deposits by means of hydrogeochemical methods. The enrichment is carried out in the field, and then the determination of Au is completed later in the laboratory.     

Simultaneous determination of palladium, platinum and rhodium by on-line column enrichment and HPLC with 5-(2,4-dihydroxyphenylazo)-rhodanine as pre-column derivatization reagent

In this paper, a new method for the simultaneous determination of palladium, platinum and rhodium ions was developed using a rapid column high performance liquid chromatography equipped with on-line enrichment technique. The palladium, platinum and rhodium ions were pre-column derivatized with DHAR to form colored chelates. The Pb-DHAR, Pt-DHAR and Rh-DHAR chelates could be absorbed onto the front of the enrichment column when they were injected into the injector and sent to the enrichment column [ZORBAX Stable Bound, 4.6 x 10 mm, 1.8 microm] with a 0.05 mol L(-1) of phosphoric acid solution as mobile phase. After enrichment, and by switching the six ports switching valve, the retained chelates were back-flushed by mobile phase and traveling towards the analytical column. The separation of these chelates on the analytical column [ZORBAX Stable Bound, 4.6 x 50 mm, 1.8 microm] was satisfactory with 54% acetonitrile (containing 0.05 mol L(-1) of phosphoric acid and 0.1% of tritonX-100) as mobile phase. Palladium, platinum and rhodium were separated completely within 2 min. By on-line enrichment technique, the enrichment factor of 100 was achieved, and the detection limits (S/N = 3) of palladium, platinum and rhodium reaches 1.4 ng L(-1), 1.6 ng L(-1) and 2.0 ng L(-1), respectively. This method was applied to the determination of palladium, platinum and rhodium in water, urine and soil samples with good results.     

The determination of gold,platinum, palladium and rhodium by atomic absorption spectrophotometry with an ultrasonic nebulizer and a multi-element high-intensity hollow-cathode lamp with selective modulation

The use of a multi-element high-intensity hollow-cathode lamp with selective modulation and a 2-MHz ultrasonic nebulizer for the determination of Au, Pt, Pd and Rh by atomic absorption spectroscopy is described. The sensitivities for the various elements in aqueous and organic media were studied. Only some organic solutions could be nebulized satisfactorily; a solution containing 95% acetone proved to be the best. For aqueous solutions, the detection limits (concn. giving 0.004 O.D.) were as follows: Au, 0.03 p.p.m.; Pd, 0.02 p.p.m.; Pt. 0.3 p.p.m.; and Rh, 0.09 p.p.m. For a 95% acetone solution the detection limits were: Au, 0.009 p.p.m.; Pd, 0.012 p.p.m.; Pt, 0.20 p.p.m. and Rh, 0.06 p.p.m. The coefficients of variation for aqueous and organic media were satisfactory.     

Simultaneous determination of gold and copper by reversed-phase high-performance liquid chromatography using online column enrichment as their syn-phenyl-2-pyridylketoximate chelates.

Gold and copper ions react with syn-phenyl-2-pyridylketoxime (PPKO) at 40 degrees C to form neutral chelates. Metal-PPKO chelates subsequently become preconcentrated on a minicolumn packed with a divinylbenzene-methacrylate copolymer. By switching the valve, these chelates are separated on the silica-based phenyl column and detected with a photometric detector. These processes occur automatically except for chelation. The results of the chelation, preconcentration, and separation conditions studies are presented. Calibration curves for Au and Cu ions are linear from nanograms per milliliter (parts per billion) to micrograms per milliliter (parts per million) in the original solution. The precision for 0.5-ppm standards of Au and Cu is 2.1 and 0.9 relative standard deviation (%), respectively. The accuracy of the present method is verified for Au and Cu based on the analysis of a standard alloy of the National Institute of Standards and Technology (NIST). The limits of detection for Au and Cu are 16.7 and 0.6 ppb, respectively. The effects of foreign ions on the determination of Au and Cu are discussed.     

Simultaneous determination of mercury and gold in bismuth by neutron activation analysis

After adding mercury as carrier, trace amounts of mercury and gold were simultaneously separated from bismuth by coprecipitating with sulfur produced by the decomposition of bismuth sulfide. The sulfur was filtered on a membrane filter, and the γ-activities were measured with a Ge(Li) detector. The recoveries were quantitative and the measurement of chemical yield was unnecessary. 123 ppm of mercury and 8 ppb of gold in a bismuth sample were determined simultaneously.     

The rapid isolation and determination of iridium after simultaneous liquid-liquid extraction and determination of platinum,palladium, rhodium and gold

The proposed method provides a rapid isolation of iridium form the other noble metals, as well as from Ni, Cu, Fe, Cr, Co and Na. The scheme comprises an initial removal of ruthenium and osmium by volatilization of their tetroxides followed by the simultaneous extraction of platinum, palladium, rhodium and gold as their 2-mercaptobenzothiazole—tin(II) chloride complexes into chloroform. Iridium in the raffinate is complexed by the same reagent system, after boiling, and extracted into chloroform. The extracts after evaporation of the solvent are converted to hydrochloric acid solutions and the noble metals are determined by atomic absorption spectrometry. Satisfactory results are obtained for various noble metal solutions, and for a solid platiniferous sample.     

Sorption-spectrometric determination of palladium and gold using silica chemically modified with dipropyl disulfide groups

It has been found that silica chemically modified with dipropyl disulfide groups (DPDSS) quantitatively extracts palladium(II) from solutions in the acidity range from 4 M HCl to pH 4 and gold(III) in the range from 1 M HCl to pH 2 with a partition coefficient at the level of n × 10⁴ cm³/g. The adsorption of palladium(II) and gold(III) at room temperature is highly selective, whereas non-ferrous and other platinum metals are not adsorbed. Sorption-atomic absorption, sorption-ICP-atomic emission, and sorption-photometric methods for the determination of palladium and gold have been developed using DPDSS. The accuracy of the methods was tested by the analysis of certified reference samples.     

Spectrophotometric determination of traces of palladium after coprecipitation with tellurium

A spectrophotometric method for the determination of microgram amounts of palladium in the présence of much iron, copper, nickel, cobalt and other common elements (~ 0.5 g) is described. Palladium is separated by stannous chloride precipitation with tellurium as collector. p-Nitroso-diphenylamine is used as the colorimetric reagent, and diethyl oxalate as extradant for the palladium complex (sensitivity = 0.0015 μg $\text{Pd}\text{cm}{}^2$ ≡ log {I₀/I} = 0.001). Silver, selenium and tungsten lead to low results and should not exceed ~ 0.1 mg. The weight ratio Au/Pd should not exceed 10, else results for palladium are high. For Pd > 1 μg, recoveries average 90% or. better.     

The express simultaneous neutron activation determination of gold,palladium and platinum

The method of express neutron-activation (NA) determination of Au, Pd and Pt has been developed. The method is based on the quantitative isolation of¹⁹⁸Au+¹⁹⁹Au and¹⁰⁹Pd activities by extraction with organic sulfides. The radiation of¹⁰⁹Pd is measured on a thin NaI(Tl) crystal and that of¹⁹⁸Au and¹⁹⁹Au on a Ge(Li) detector. The calculations of interferences from gold have been performed for various neutron fluxes and various cadmium ratios. Some interferences introduced by other competitive nuclear reactions into the determination of Pt by its daughter isotope¹⁹⁹Au are discussed.     

Solid-phase extraction in the determination of gold, palladium, and platinum

A simple classification of various sorbents and solid-phase extraction procedures used for preconcentration of trace levels of Au, Pd, and Pt from different sample types is proposed in this review article. The large variety of available sorbents/procedures has been organized according to expected mechanisms of sorption process (complex formation; ion exchange; adsorption; ion-imprinted or molecularly imprinted polymers); according to the kind of monomeric units of the polymer matrix as well as on the basis of the kind of functional group responsible for main performance characteristics (selectivity, capacity) of the sorbent. Advantages of chemically modified sorbents, sulfur-containing sorbent extractants, and ion-imprinted polymers, together with rational pretreatment by means of microwave treatments, scaling down of enrichment, and quantification by means of flow and flow injection approaches are given. Preferred instrumental techniques for quantification of ppb levels of Au, Pd, and Pt in prepared concentrates/column eluates are multielement instrumental techniques: inductively coupled plasma optical emission spectrometry (ICP-OES), and inductively coupled plasma mass spectrometry (ICPMS). Excellent limits of detection at picogram levels of these analytes are provided by electrothermal atomic absorption spectrometry (ETAAS), generally in single-element mode and the neutron activation analysis (NAA), while X-ray fluorescence spectrometry and flame AAS are rarely applied because of lack of sensitivity at sub-ppm levels of Au, Pd, and Pt. Some problems of atomic spectrometric quantification techniques and their representative limits of detection are given. Recent applications to geological, industrial, pharmaceutical, biological, and other materials are tabulated. References have been selected mostly from the period 1995 to 2010.     

Flame atomic absorption spectrometric determination of trace amounts of palladium,gold and nickel after cloud point extraction

In this article, a sensitive cloud point extraction procedure for the preconcentration of trace amounts of palladium, gold and nickel prior to their determination by flame atomic absorption spectrometry has been developed. The cloud point extraction method is based on the complexation of Pd(II), Au(II), and Ni(II) ions with 1-(2-pyridylazo)-2-naphthol and entrapping in non-ionic surfactant Triton X-114. The main factors affecting cloud point extraction efficiency, such as pH of sample solution, concentration of 1-(2-pyridylazo)-2-naphthol and Triton X-114, equilibration temperature and time, were investigated in detail. Under the optimized conditions, calibration curves were constructed for the determination of palladium, gold and nickel according to the general procedure. Linearity was maintained from 0.01 to 1.0 μg/mL for palladium, 10.0 μg/mL to 1.5 μg/mL for gold, and 10.0 μg/mL to 0.5 μg/mL for nickel. Detection limits based on three times the standard deviation of the blank divided by the slope of analytical curve (3Sb/m) for Pd(II), Au(III), and Ni(11) ions were 3.4, 3.9, and 2.4 μg/mL, respectively. Seven replicate determination of a mixture of 0.5 μg/mL palladium and gold and 0.2 μg/mL nickel gave a mean absorbance of 0.174, 0.150, and 0.201 with relative standard deviation ±1.5, ±1.3, and ±1.8%, respectively. The high efficiency of cloud point extraction to carry out the determination of analytes in complex matrices was demonstrated. The proposed method has been applied for determination of trace amount of palladium, gold and nickel in certified reference material and water samples with satisfactory results.     

Simultaneous determination of cyanobacterial hepato-and neurotoxins in water samples by ion-pair supported enrichment and HPLC-ESI-MS-MS

Summary Cyanobacterial neurotoxins, such as anatoxin-a and saxitoxin, as well as hepatotoxins including microcystins and nodularin were simultaneously determined in water samples by ion-pair supported, solid phase extraction (SPE) and reversed-phase liquid chromatography coupled to UV and tandem mass spectrometry (RP-LC-UV; MS-MS). With quantification limits in water samples of approximately 50 ng L⁻¹ for the microcystins (MC-LR,-YR,-RR,-LA), nodularin, and anatoxin-a and 630 ng L⁻¹ for saxitoxin the method is well suited for surveillance of the proposed WHO guidelines for cyanobacterial toxins. MS detection permits, unlike the commonly used UV detection, unambiguous identification and accurate quantification of cyanobacterial toxins even in highly matrix-polluted, water samples.     

Determination of palladium in different samples by neutron activation after selective preconcentration with α-benzildioxime

A procedure is described for the determination of submicrogram quantities of palladium in sea water, biological and geological materials. Palladium is preconcentrated by coprecipitation with α-benzildioxime at pH 2 in the presence of citric acid followed by neutron activation. The method is highly selective and only traces of other metals are adsorbed on the surface of the precipitate. The instrumental variant of counting of long-lived ¹⁰⁹Pd (t$\text{1}\text{2}$ = 13.6 h) after 16-h irradiation gives a detection limit of 10 ng. A further decrease of the detection limit to 1 ng can be attained by removal of radioactive impurities (mainly ²⁴Na, ⁵⁶Mn and ⁸²Br) after washing the dichloromethane extract of dissolved precipitate with an aqueous solution of citric acid containing inactive carriers of bromide, manganese and sodium ions. Palladium (¹⁰⁹Pd) is finally measured by a NaI(Tl) well type scintillation detector. The method can be applied to most environmental samples.