Determination of cadmium and lead in biological samples by Zeeman ETAAS using various chemical modifiers

The electrothermal atomic absorption spectrometric determination of cadmium and lead in biological certified reference materials (CRMs) has been carried out by using NH(4)H(2)PO(4), Ni, Pd, Ni+NH(4)H(2)PO(4), Pd+NH(4)H(2)PO(4) and Ni+Pd+NH(4)H(2)PO(4) as chemical modifiers. A comprehensive comparison was made among the modifiers in 1% Triton X-100 plus 0.2% nitric acid as diluent and without modifier. Zeeman background correction and graphite tubes inserted with platforms were used. Comparison was made in terms of pyrolysis and atomization temperatures, atomization and background absorption profiles. Ni+Pd+NH(4)H(2)PO(4) modifier mixture was found to be preferable for the determination of Cd and Pb. Pyrolysis temperatures of analytes were increased up to 900 degrees C for Cd and 1250 degrees C for Pb by using Ni+Pd+NH(4)H(2)PO(4) in 1% Triton X-100 plus 0.2% nitric acid diluent solution. Biological CRMs were analyzed to verify the accuracy and precision of this method. Depending on the biological sample type, the percent recoveries were increased from 62 to 102% for Cd and from 58 to 106% for Pb by using the proposed modifier mixture. The detection limits of Cd and Pb were found to be 0.04, 0.92 mug l(-1), respectively.     

采用钯基体改进剂石墨炉原子吸收法测定纺织品中的可萃取铅

纺织品标准中对铅的限量极为严格,但萃取汗液基体成分复杂,背景吸收干扰强烈,为解决纺织品中的可萃取铅检测的困难,建立了一种采用基体改进剂的石墨炉原子吸收光谱法,测定纺织品中的可萃取铅。通过比较两种基体改进剂,优化实验条件,确定了以钯-硝酸镁为基体改进剂、灰化温度1 200℃、原子化温度2 300℃的实验条件。结果表明,以钯-硝酸镁为基体改进剂更能有效降低纺织品可萃取铅的基体干扰,并且具有良好的精密度(2.6%~3.3%)和准确度(加标回收率94.3%~105.6%)。     

Direct sample introduction of wines in graphite furnace atomic absorption spectrometry for the simultaneous determination of arsenic, cadmium, copper and lead content

A multi-element graphite furnace atomic absorption spectrometry (GFAAS) method was elaborated for the simultaneous determination of As, Cd, Cu, and Pb in wine samples of various sugar contents using the transversally heated graphite atomizer (THGA) with end-capped tubes and integrated graphite platforms (IGPs). For comparative GFAAS analyses, direct injection (i.e., dispensing the sample onto the IGP) and digestion-based (i.e., adding oxidizing agents, such as HNO(3) and/or H(2)O(2) to the sample solutions) methods were optimized with the application of chemical modifiers. The mixture of 5 microg Pd (applied as nitrate) plus 3 microg Mg(NO(3))(2) chemical modifier was proven to be optimal for the present set of analytes and matrix, it allowing the optimal 600 degrees C pyrolysis and 2200 degrees C atomization temperatures, respectively. The IGP of the THGA was pre-heated at 70 degrees C to prevent the sputtering and/or foaming of sample solutions with a high organic content, dispensed together with the modifier solution, which method also improved the reproducibility of the determinations. With the digestion-based method, the recovery ranged between 87 and 122%, while with the direct injection method it was between 96 and 102% for Cd, Cu, and Pb, whereas a lower, compromise recovery of 45-85% was realized for As. The detection limits (LODs) were found to be 5.0, 0.03, 1.2, and 0.8 microg l(-1) for As, Cd, Cu, and Pb, respectively. The characteristic mass (m(0)) data were 24 pg As, 1.3 pg Cd, 13 pg Cu, and 35 pg Pb. The upper limits of the linear calibration range were 100, 2, 100, and 200 microg l(-1) for As, Cd, Cu, and Pb, respectively. The precisions were not worse than 4.8, 3.1, 3.7, and 2.3% for As, Cd, Cu, and Pb, respectively. For arsenic, a higher amount of the modifier (e.g., 20 microg Pd plus 12 microg Mg(NO(3))(2)) could be recommended to overcome the interference from the presence of sulphate and phosphate in wines. Although this method increased the sensitivity for As (m(0)=20 pg), it also enhanced the background noise, thus only a slight improvement in the LOD of As (3.9 microg l(-1)) was realized. For the 35 red and white wine samples studied, the highest metal contents were observed for Cu ranging from 20 to 640 microg l(-1) (average: 148 microg l(-1)), followed by Pb from 6 to 90 microg l(-1) (average: 32.3 microg l(-1)), and Cd from 0.05 to 16.5 microg l(-1) (average: 1.06 microg l(-1)), whereas the As content was below the LOD. This wide fluctuation in the trace metal content could be associated with the origin of wines from various regions (i.e., different trace metal level and/or quality of soil, and/or anthropogenic impact), and with diverse materials (e.g., additives and containers) involved in the wine production processes. The Cu content of wine samples was significantly correlated with Pb, whereas its weak anti-correlation was found with Cd. Interestingly, the level of Pb was anti-correlated with the year of production of the wines. This is likely due to the gradual decrease in the Pb content of soils of vineyards by time, which certainly causes less Pb-uptake of the grape plant, thus a decrease in the Pb content of wines as well.     

Phosphorous acid and urea: valuable sources of phosphorus and nitrogen in the hydrothermal synthesis of ammonium-thorium phosphates

Microcrystals of the first ammonium-thorium phosphates, (NH 4) 2Th(PO 4) 2.H 2O (tetragonal, I4 1/ amd, a = 7.0192(4) A, c = 17.9403(8) A) and NH 4Th 2(PO 4) 3 (monoclinic, C2/ c, a = 17.880(6) A, b = 6.906(1) A, c = 8.152(2) A, beta = 104.39(2) degrees ) were hydrothermally obtained from a Th(NO 3) 4-CO(NH 2) 2-H 3PO 3-H 2O system ( T = 180 degrees C). In both cases, the structure consists of a three-dimensional framework with PO 4 tetrahedra coordinated to Th atoms (ThO n polyhedra, where n = 8 or 9, for the tetragonal or monoclinic phase, respectively). The ammonium ions (and water molecules) are located in the tunnels.     

Determination of cadmium in hair and blood by tungsten coil electrothermal atomic absorption spectrometry with chemical modifiers

Three chemical modifiers ((NH(4))(2)HPO(4), NH(4)H(2)PO(4), and Pd as Pd(NO(3))(2)) were evaluated for the determination of Cd in acid-digested solutions of hair and blood using electrothermal atomic absorption spectrometry in a tungsten coil atomizer (TCA). All modifiers caused some thermal stabilization of Cd when compared to the behavior observed in nitric acid medium. The best effects were observed in 15 mug ml(-)(1) Pd medium; the characteristic mass of Cd was 0.3 pg and the method detection limits were 0.009 mug g(-)(1) in hair and 0.2 mug l(-)(1) in blood. In addition to a slight thermal stabilization effect, Pd also increased the sensitivity for Cd by ca. 40% and the tungsten coil lifetime by 20% (i.e. from 300 to 360 heating cycles), reduced background signals, and eliminated condensed phase interferences caused by concomitants. The accuracy (3.2% as mean relative error in the Pd modifier) was checked for the determination of Cd in acid-digested solutions of certified reference materials of human hair and blood and by recoveries of Cd in spiked hair and blood samples by both TCA and a graphite furnace procedure. All results obtained in chemical modifiers are in agreement at a 95% confidence level.     

多步斜坡升温——恒温平台石墨炉法直接测定葡萄酒中微量铅

研究了一种直接测定葡萄酒中微量铅的方法，以硝酸－磷酸二氢铵体系为基体改进剂，采用多步斜坡并温，恒温平台石墨炉技术，测定了四个国家五种类别葡萄酒中微量铅，回收率９７％～１０４％，精密度优于３．９％。     

不同基体改进剂对石墨炉原子吸收法测定土壤和沉积物中铊的影响

应用Pd(NO3)2-抗坏血酸(Vc)基体改进剂,建立了石墨炉原子吸收法(GFAA法)测定土壤和沉积物样品中铊。针对土壤和沉积物复杂基体,GFAA法测定铊元素主要受到氯离子的干扰,文中研究了常见基体改进剂(包括NH4NO3,(NH4)2SO4,La(NO3)3,Mg(NO3)2,Vc,Pd(NO3)2,Pd(NO3)2-Vc)对氯离子的抑制效果。通过研究不同基体改进剂测定含氯铊标准溶液的吸收曲线,探讨出基体改进剂测定铊的作用机理。以土壤或沉积物标准物质为研究对象,优化了应用Pd(NO3)2-Vc测定铊的灰化温度、基改剂浓度以及原子化温度。在最佳实验条件下,通过比较有无基体改进剂条件下,采用GFAA法测定不同土壤和沉积物中铊的精密度和准确度,实验结果表明,应用Pd(NO3)2-VC基体改进剂,测定土壤和沉积物标准物质中铊的测定结果都在标准值范围之内,6次平行测定的相对标准偏差范围为2.8%~8.4%,用于测定实际土壤和沉积物样品加标回收率为128.0%和92.9%。     

Periodic trends in hexanuclear actinide clusters

Four new Th(IV), U(IV), and Np(IV) hexanuclear clusters with 1,2-phenylenediphosphonate as the bridging ligand have been prepared by self-assembly at room temperature. The structures of Th(6)Tl(3)[C(6)H(4)(PO(3))(PO(3)H)](6)(NO(3))(7)(H(2)O)(6)·(NO(3))(2)·4H(2)O (Th6-3), (NH(4))(8.11)Np(12)Rb(3.89)[C(6)H(4)(PO(3))(PO(3)H)](12)(NO(3))(24)·15H(2)O (Np6-1), (NH(4))(4)U(12)Cs(8)[C(6)H(4)(PO(3))(PO(3)H)](12)(NO(3))(24)·18H(2)O (U6-1), and (NH(4))(4)U(12)Cs(2)[C(6)H(4)(PO(3))(PO(3)H)](12)(NO(3))(18)·40H(2)O (U6-2) are described and compared with other clusters of containing An(IV) or Ce(IV). All of the clusters share the common formula M(6)(H(2)O)(m)[C(6)H(3)(PO(3))(PO(3)H)](6)(NO(3))(n)((6-n)) (M = Ce, Th, U, Np, Pu). The metal centers are normally nine-coordinate, with five oxygen atoms from the ligand and an additional four either occupied by NO(3)(-) or H(2)O. It was found that the Ce, U, and Pu clusters favor both C(3i) and C(i) point groups, while Th only yields in C(i), and Np only C(3i). In the C(3i) clusters, there are two NO(3)(-) anions bonded to the metal centers. In the C(i) clusters, the number of NO(3)(-) anions varies from 0 to 2. The change in the ionic radius of the actinide ions tunes the cavity size of the clusters. The thorium clusters were found to accept larger ions including Cs(+) and Tl(+), whereas with uranium and later elements, only NH(4)(+) and/or Rb(+) reside in the center of the clusters.     

NH4NO3 extractable trace element contents of soil samples prepared for proficiency testing--a stability study.

In view of its intended use as a sample for proficiency testing or as a reference material the stability of the extractable trace element contents of a soil from an irrigation field was tested using the extraction with 1 mol/L ammonium nitrate solution according to DIN 19730. Therefore, changes of the extractability of sterilized and non sterilized soil samples stored at different temperatures were evaluated over a period of 18 months. Sets of bottles were kept at -20 degrees C, +4 degrees C, about +20 degrees C and +40 degrees C, respectively. The NH4NO3 extractable contents of Cd, Cr, Cu, Ni, Pb and Zn were determined immediately after bottling and then after 3, 6, 12 and 18 months with ICP-AES or ETAAS. Appropriate storage conditions are of utmost importance to prevent deterioration of soil samples prepared for the determination of NH4NO3 extractable trace element contents. Temperatures above +20 degrees C must be avoided. The observed changes in the extractability of the metals (especially for Cr and Cu) most likely could be related to thermal degradation of the organic matter of the soil. There is no need to sterilize dry soil samples, because microbiological activity in soils with a low moisture content appears to be negligible with regard to trace element mobilization.     

Simultaneous determination of cadmium and lead in wine by electrothermal atomic absorption spectrometry

A method has been developed for the direct simultaneous determination of Cd and Pb in white and red wine by electrothermal atomic absorption spectrometry (ET-AAS) using a transversely heated graphite tube atomizer (THGA) with longitudinal Zeeman-effect background correction. The thermal behavior of both analytes during pyrolysis and atomization stages were investigated in 0.028 mol l⁻¹ HNO₃ and in 1+1 v/v diluted wine using mixtures of Pd(NO₃)₂+Mg(NO₃)₂ and NH₄H₂PO₄+Mg(NO₃)₂ as chemical modifiers. With 5 μg Pd+3 μg Mg as the modifiers and a two-step pyrolysis (10 s at 400°C and 10 s at 600°C), the formation of carbonaceous residues inside the atomizer was avoided. For 20 μl of sample (wine+0.056 mol l⁻¹ HNO₃, 1+1, v/v) dispensed into the graphite tube, analytical curves in the 0.10–1.0 μg l⁻¹ Cd and 5.0–50 μg l⁻¹ Pb ranges were established. The characteristic mass was approximately 0.6 pg for Cd and 33 pg for Pb, and the lifetime of the tube was approximately 400 firings. The limits of detection (LOD) based on integrated absorbance (0.03 μg l⁻¹ for Cd, 0.8 μg l⁻¹ for Pb) exceeded the requirements of Brazilian Food Regulations (decree #55871 from Health Department), which establish the maximum permissible level for Cd at 200 μg l⁻¹ and for Pb at 500 μg l⁻¹. The relative standard deviations (n=12) were typically <8% for Cd and <6% for Pb. The recoveries of Cd and Pb added to wine samples varied from 88 to 107% and 93 to 103%, respectively. The accuracy of the direct determination of Cd and Pb was checked for 10 table wines by comparing the results with those obtained for digested wine using single-element ET-AAS, which were in agreement at the 95% confidence level.     

The Effects of Grape Polysaccharides Extracted from Grape By-Products on the Chemical Composition and Sensory Characteristics of White Wines

There is an increasing interest in the valorization of wine waste by-products. Grape pomace/marc can be an important source of polyphenols but also of polysaccharides (PSs). Therefore, the aim of this work was to extract PSs from grape pomace and musts and incorporate them into wines to improve their quality and valorize these residues. Two white wines were elaborated and treated with four different PS extracts obtained from white grape pomace, white must, a wine purified extract rich in RG-II, and commercial inactivated yeasts. In general, the use of grape PSs extracted from grape pomace or must improve some characteristics of wine, increasing the polysaccharide and volatile concentrations. These PS extracts can be useful to modulate some taste attributes such as an excess of acidity and bitterness and can also prevent the loss of volatile compounds associated with fruity and floral notes over time. This is the first study that shows the effects of grape polysaccharides on the chemical composition and sensory characteristics of white wines. Considering the obtained results, the grape pomace and surplus of musts can be considered valuable sources to obtain polysaccharide-rich products, opening a new opportunity to take advantage of by-products from the wine industry.     

COMPLEX SALTS [Pd(NH3)4][Pd(NH3)3NO2] [CrOx3]·H2O AND [Pd(NH3)4][Pd(NH3)3NO2] [CoOx3]·H2O AND SOLID SOLUTIONS [Pd(NH3)4] [Pd(NH3)3NO2][CoOx3]x[RhOx3]1–x·H2O : PROMISING PRECURSORS FOR POROUS NANOALLOYS

Journal of Structural Chemistry - New complex salts [Pd(NH3)4][Pd(NH3)3NO2][CrOx3]·H2O I, [Pd(NH3)4][Pd(NH3)3NO2][CoOx3]·H2O II, and a series of solid solutions...     

The determination of low lead levels in the bone of lead-depleted mice by graphite furnace atomic absorption spectrometry

Low lead levels in the femurs of mice fed with a lead-depleted diet have been determined by use of electrothermal atomic absorption spectrometry with Zeeman-effect background correction. The method is based on the use of Mg(NO3)2/Pd as matrix modifier which enables significant reduction of the spectral interferences prevalent if chemical modifiers based on NH4H2PO4 with either Ca or Mg are used for samples rich in Ca3(PO4)2 matrix. The method was developed and validated by use of the NIST standard reference material 1486 bone. Bones were decomposed in a pressurized microwave-heated system using 70% nitric acid. Forty-three mice femurs, with a mass of 74.62 +/- 12.54 mg, were dissolved in concentrated nitric acid. The lead results found in SRM 1486 (1.25 +/- 0.15 microg g(-1), n = 9) were in good agreement with the certificate (1.335 +/- 0.014 microg g(-1)). Recoveries of 200 ng lead added to the SRM before or after digestion were 99.0 +/- 1.4% and 98.5 +/- 1.6%, respectively. The lead detection limit in bone samples is 0.06 microg g(-1) dry mass. This method is, therefore, suitable for the determination of very low lead levels (0.06-0.20 microg Pb kg(-1) bone) in the femurs of mice fed a diet with lead level of < 20 microg kg(-1).     

Simultaneous uptake of Ni2+, NH4+ and PO4(3-) by amorphous CaO-Al2O3-SiO2 compounds

Simultaneous uptake of Ni2+, NH4+, and PO4(3-) by amorphous CaO-Al2O3-SiO2 (C-A-S) compounds was investigated using batch and column methods. Fifteen different C-A-S samples with systematically varied chemical compositions were prepared by coprecipitation from ethanol-water solutions containing Ca(NO3)2.4H2O, Al(NO3)3.9H2O, and Si(OC2H5)4, using NH4OH as the precipitating agent. The resulting precipitates were dried and heated at various temperatures to produce the C-A-S samples, which were then characterized by XRD, FTIR, solid state MAS NMR, DTA-TG, and N2 adsorption. All the C-A-S samples prepared at 600-900 degrees C were amorphous, apart from the CaO-rich samples. Simultaneous uptake of Ni2+, NH4+, and PO4(3-) was determined by a batch method using a solution with an initial concentration of 2 mM. In these experiments, the uptake abilities of the C-A-S samples for Ni2+ and PO4(3-) were high, but were relatively low for NH4+. The uptake abilities for Ni2+ and PO4(3-) increased but that for NH4+ decreased as the silica content in the C-A-S decreased, suggesting that similar uptake mechanisms (ion substitution and/or precipitation) are operating for Ni2+ and PO4(3-), but the uptake mechanism for NH4+ is different (physical adsorption). The column experiments indicate that the order of uptake ability of C-A-S for the three ions is NH4+ < PO4(3-) < Ni2+. Although the silica content of the C-A-S does not have the expected influence on the uptake of these three ions, for NH4+ it plays an important role in the formation of the amorphous phase and also in the suppression of Ca2+ and/or Al3+ release from the C-A-S during the uptake experiments. The optimum uptake properties of the C-A-S can thus be controlled by adjusting the chemical compositions and heating conditions under which the samples are prepared.     

Single, binary and multi-component adsorption of some anions and heavy metals on environmentally friendly Carpobrotus edulis plant

A low-cost adsorbent and environmentally friendly adsorbent from Carpobrotus edulis plant was used for the removal of NO(3)(-), H(2)PO(4)(-), Pb(2+) and Cd(2+) ions from single, binary and multi-component systems. The efficiency of the adsorbent was studied using batch adsorption technique under different experimental conditions by varying parameters such as pH, initial concentration and contact time. In single component systems, the dried C. edulis has the highest affinity for Pb(2+), followed by NO(3)(-), Cd(2+) and H(2)PO(4)(-), with adsorption capacities of 175mg/g, 125mg/g, 28mg/g and 26mg/g, respectively. These results showed that the adsorption of NO(3)(-) and H(2)PO(4)(-) ions from single and binary component systems can be successfully described by Langmuir and Freundlich isotherms. Freundlich adsorption model, showed the best fit to the single and binary experimental adsorption data. These results also indicated that the adsorption yield of Pb(2+) ion was reduced by the presence of Cd(2+) ion in binary metal mixture. The competitive adsorption of NO(3)(-), H(2)PO(4)(-), Pb(2+) and Cd(2+) ions on dried C. edulis plant shows that NO(3)(-) and H(2)PO(4)(-) anions are able to adsorb on different free binding sites and Pb(2+) and Cd(2+) cations are able to adsorb on the same active sites of C. edulis particles. The dried C. edulis was found to be efficient in removing nitrate, phosphate, cadmium and lead from aqueous solution as compared to other adsorbents already used for the removal of these ions.     

Structure and properties of a novel 3D straight-channel polyoxovanadate and an unexpected trimeric barbiturate obtained by hydrothermal reactions

The hydrothermal reaction of NaVO(3).H(2)O, barbituric acid, NH(2)NH(2).2HCl, H(3)PO(4), and H(2)O gave a novel heteropolyoxovanadate Na(6)[(P(V)O(4))V(V)(6)V(IV)(12)O(39)](2).H(3)PO(4).31H(2)O (1) and an unexpected phase Na(2)[C(12)H(6)N(6)O(9)].7H(2)O (2). The basic building blocks in 1 are the six-capped sphere-shaped heteropoly anion [(P(V)O(4))V(V)(6)V(IV)(12)O(39)](3-) with framework similar to that of the reported polyoxovanadates possessing [V(18)O(42)] clusters encapsulating VO(4) or other ions. These heterpoly anionic units are linked via V[bond]O[bond]V bridges into an interesting 3D straight-channel structure. The structure of 2 consists of novel organic anions ([C(12)H(6)N(6)O(9)](2-), 5,5-bis(2',4',6'-trioxopyrimidyl)barbital, representing the first oxidized barbituric acid trimer) linked via sodium ions into 1D hollow tubes with diameter of 4.49 x 6.86 A and further connected into a three-dimensional framework via hydrogen bonds.     

A hydrothermal investigation of the 1/2V2O5-H2C2O4/H3PO4/NH4OH system: synthesis and structures of (NH4)VOPO(4).1.5H2O, (NH4)0.5VOPO(4).1.5H2O, (NH4)2[VO(H2O)3]2[VO(H2O)][VO(PO4)2](2).3H2O, and (NH4)2[VO(HPO4)]2(C2O4).5H2O

The 1/2V2O5-H2C2O4/H3PO4/NH4OH system was investigated using hydrothermal techniques. Four new phases, (NH4)VOPO(4).1.5H2O (1), (NH4)0.5VOPO(4).1.5H2O (2), (NH4)2[VO(H2O)3]2[VO(H2O)][VO(PO4)2]2.3H2O (3), and (NH4)2[VO(HPO4)]2(C2O4).H2O (4), have been prepared and structurally characterized. Compounds 1 and 2 have layered structures closely related to VOPO(4).2H2O and A0.5VOPO4.yH2O (A = mono- or divalent metals), whereas 3 has a 3D open-framework structure. Compound 4 has a layered structure and contains both oxalate and phosphate anions coordinated to vanadium cations. Crystal data: (NH4)VOPO(4).1.5H2O, tetragonal (I), space group I4/mmm (No. 139), a = 6.3160(5) A, c = 13.540(2) A, Z = 4; (NH4)0.5VOPO(4).1.5H2O, monoclinic, space group P2(1)/m (No. 11), a = 6.9669(6) A, b = 17.663(2) A, c = 8.9304(8) A, beta = 105.347(1) degrees, Z = 8; (NH4)2[VO(H2O)3]2[VO(H2O)][VO(PO4)2]2.3H2O, triclinic, space group P1 (No. 2), a = 10.2523(9) A, b = 12.263(1) A, c = 12.362(1) A, alpha = 69.041(2) degrees, beta = 65.653(2) degrees, gamma = 87.789(2) degrees, Z = 2; (NH4)2[VO(HPO4)]2(C2O4).5H2O, monoclinic (C), space group C2/m (No. 12), a = 17.735(2) A, b = 6.4180(6) A, c = 22.839(2) A, beta = 102.017(2) degrees, Z = 6.     

Nitrosyl induces phosphorous-acid dissociation in ruthenium(II)

The trans-[Ru(NO)(NH(3))(4)(P(OH)(3))]Cl(3) complex was synthesized by reacting [Ru(H(2)O)(NH(3))(5)](2+) with H(3)PO(3) and characterized by spectroscopic ((31)P-NMR, δ = 68 ppm) and spectrophotometric techniques (λ = 525 nm, ε = 20 L mol(-1) cm(-1); λ = 319 nm, ε = 773 L mol(-1) cm(-1); λ = 241 nm, ε = 1385 L mol(-1) cm(-1); ν(NO(+)) = 1879 cm(-1)). A pK(a) of 0.74 was determined from infrared measurements as a function of pH for the reaction: trans-[Ru(NO)(NH(3))(4)(P(OH)(3))](3+) + H(2)O ? trans-[Ru(NO)(NH(3))(4)(P(O(-))(OH)(2))](2+) + H(3)O(+). According to (31)P-NMR, IR, UV-vis, cyclic voltammetry and ab initio calculation data, upon deprotonation, trans-[Ru(NO)(NH(3))(4)(P(OH)(3))](3+) yields the O-bonded linkage isomer trans- [Ru(NO)(NH(3))(4)(OP(OH)(2))](2+), then the trans-[Ru(NO)(NH(3))(4)(OP(H)(OH)(2))](3+) decays to give the final products H(3)PO(3) and trans-[Ru(NO)(NH(3))(4)(H(2)O)](3+). The dissociation of phosphorous acid from the [Ru(NO)(NH(3))(4)](3+) moiety is pH dependent (k(obs) = 2.1 × 10(-4) s(-1) at pH 3.0, 25 °C).     

石墨炉原子吸收法测定绿色食品农田腐殖土中的铅、铬、镉

提出了用石墨炉原子吸收法测定绿色食品农田腐殖土中Pb、Cr、Cd ,以PdCl2 和NH4H2 PO4作为基体改进剂 ,经国家标准物质测定证明本法可行 .     

Hydrothermal synthesis of the first organically templated open-framework uranium phosphate

[(C2H5)2NH2]2[(UO2)5(PO4)4] was prepared from U3O8, HONEt2 and phosphoric acid under hydrothermal conditions (180 degrees C, 5 days) and represents the first three-dimensional open-framework uranium phosphate prepared to date.