精氨酸插层氧化锰纳米结构材料的制备和表征

应用氧化法水热合成了Na型层状氧化锰[BirMO(Na)], 通过离子交换反应在0.1 mol/L HCl溶液中Na型层状氧化锰转化成H型层状氧化锰[BirMO(H)]. BirMO(H)在四甲基氢氧化铵[(CH3)4NOH]溶液中搅拌处理7 d后, 剥离生成了MnO2纳米层胶体分散液. 剥离的MnO2纳米层胶体分散液在pH＝4.0～11.0的精氨酸溶液中搅拌2 d, 得到了层间距为1.49 nm的精氨酸插层氧化锰纳米结构材料. 通过XRD, DSC-TGA, SEM, IR及元素分析对合成试样进行了分析表征. 结果表明精氨酸在氧化锰层间的插入量及插入形式与重组溶液的pH值密切相关, 其最大插入量为1.80 mmol/g.     

Speciation of antimony by preconcentration of Sb(III) and Sb(V) in water samples onto nanometer-size titanium dioxide and selective determination by flow injection-hydride generation-atomic absorption spectrometry.

A novel method for prevention of the oxidation of Sb(III) during sample pretreatment, preconcentration of Sb(III) and Sb(V) with nanometer size titanium dioxide (rutile) and speciation analysis of antimony, has been developed. Antimony(III) could be selectively determined by flow injection-hydride generation-atomic absorption spectrometry, coexisting with Sb(V). Trace Sb(III) and Sb(V) were all adsorbed onto 50 m g TiO2 from 500 ml solution at pH 3.0 within 15 min, then eluted by 10 ml of 5 mol/l HCl solution. One eluent was directly used for the analysis of Sb(III); to the other eluent was added 0.5 g KI and 0.2 g thiourea to reduce Sb(V) to Sb(III), then the mixture was used for the determination of total antimony. The antimony(V) content is the mathematical difference of the two concentrations. Detection limits (based on 3sigma of the blank determinations, n=11) of 0.05 ng/ml for Sb(III) and 0.06 ng/ml for Sb(V), were obtained.     

Extremely efficient electro-Fenton-like Sb(III) detoxification using nanoscale Ti-Ce binary oxide: An effective design to boost catalytic activity via non-radical pathway

Environmental risks posed by discharge of the emerging contaminant antimony (Sb) into water bodies have raised global concerns recently. The toxicity of Sb has been shown to be species-dependent, with Sb(III) demonstrating much greater toxicity than Sb(V). Here, we proposed an electrochemical filtration system to achieve rapid detoxification of Sb(III) via a non-radical pathway. The key to this technology was an electroactive carbon nanotube filter functionalized with nanoscale Ti-Ce binary oxide. Under an electric field, in situ generated H₂O₂ could react with the Ti-Ce binary oxide to produce hydroperoxide complexes, which enabled an efficient transformation of Sb(III) to the less toxic Sb(V) (τ < 2 s) at neutral pH. The impact of important operational parameters was assessed and optimized, and system efficacy could be maintained over a wide pH range and long-term operation. An optimum detoxification efficiency of> 90% was achieved using lake water spiked with Sb(III) at 500 μg/L. The results showed that Ti/Ce-hydroperoxo surface complexes were the dominant species responsible for the non-radical oxidation of Sb(III) based on extensive experimental evidences and advanced characterizations. This study provides a robust and effective strategy for the detoxification of water containing Sb(III) and other similar heavy metal ions by integrating state-of-the-art advanced oxidation processes, electrochemistry and nano-filtration technology.     

The structure and catalytic activity of anatase and rutile titania supported manganese oxide catalysts for selective catalytic reduction of NO by NH3

The structure and catalytic properties of anatase and rutile supported manganese oxide catalysts prepared by impregnation method have been studied by using X-ray diffraction (XRD), laser Raman spectroscopy (LRS), X-ray photoelectron spectroscopy (XPS), H(2) temperature-programmed reduction (H(2)-TPR) and BET surface area measurements combined with activity testing of selective catalytic reduction (SCR) of NO by NH(3). It has been shown that the manganese oxide loadings on the two TiO(2) supports exert great influences on the SCR activity. For the rutile supported manganese oxide catalysts, increasing manganese oxide loading leads to the increase of reducibility of dispersed manganese oxide species and the rate constant k, which reaches a maximum around 9.6 × 10(-6) mol g(Mn)(-1) s(-1) at 0.5 mmol Mn per 100 m(2) TiO(2). When the manganese oxide loading is beyond this value, the existence of amorphous MnO(x) multiple layers will certainly reduce the ratio of manganese oxide species exposed on the surface and the reducibility of dispersed manganese oxide species, resulting in the rapid decrease of rate constant k. The LRS and XPS results have revealed that for the anatase supported manganese oxide catalysts manganese oxide species exist in Mn(+4) as a major species with Mn(+3) species and partially undecomposed Mn-nitrate as the minor species. Under the SCR reaction conditions, Mn(+3) species on anatase are oxidized to Mn(+4) species, inserting in the surface of anatase and promoting the anatase-to-rutile transformation in the surface layers of the anatase support. Since these Mn(4+) cations are actually dispersed on the support with a rutile shell-anatase core structure and its concentration is very near to that of MnO(x)/TiO(2) (R) catalyst, the relation between the rate constant k and the MnO(x) loading on the anatase support is similar to that on the rutile support, and that the rate constant k values for anatase and rutile supported manganese oxide catalysts are very close at the same MnO(x) loading.     

聚乙撑二氧噻吩/二氧化锰纳米复合物的界面聚合制备及其电化学性能

采用界面聚合法制备聚3,4-乙撑二氧噻吩/二氧化锰(PEDOT/MnO2)纳米复合物. 通过红外(IR)光谱、X射线衍射(XRD)、BET比表面积、扫描电子显微镜(SEM)和透射电子显微镜(TEM)对样品进行表征. 结果表明, 产物是具有丰富的多孔孔道结构的无定型纳米材料, 孔径主要分布在5-25 nm范围内, 比表面积可达98 m2·g-1. 同时用循环伏安(CV)、恒流充放电和交流阻抗(EIS)等电化学测试表明, 在0.5 mol·L-1 Na2SO4溶液中, -0.2 - 0.8 V(vs SCE)的电化学窗口下, PEDOT/MnO2纳米复合物显示出良好的电化学性能, 当电流密度为0.5 A·g-1时, 所制备的PEDOT/MnO2单电极比容量达196.3 F·g-1, 500次循环后样品放电比容量保持90%左右.     

Structure and oxidation state of silica-supported manganese oxide catalysts and reactivity for acetone oxidation with ozone

Silica-supported manganese oxide catalysts with loadings of 3, 10, 15, and 20 wt % (as MnO2) were characterized with use of X-ray absorption spectroscopy and X-ray diffraction (XRD). The edge positions in the X-ray absorption spectra indicated that the oxidation state for the manganese decreased with increasing metal oxide loading from a value close to that of Mn2O3 (+3) to a value close to that of Mn3O4 (+2(2)/3). The XRD was consistent with these results as the diffractograms for the supported catalysts of higher manganese oxide loading matched those of a Mn3O4 reference. The reactivity of the silica-supported manganese oxide catalysts in acetone oxidation with ozone as an oxidant was studied over the temperature range of 300 to 600 K. Both oxygen and ozone produced mainly CO2 as the product of oxidation, but in the case of ozone the reaction temperature and activation energy were significantly reduced. The effect of metal oxide loading was investigated, and the activity for acetone oxidation was greater for a 10 wt % MnOx/SiO2 catalyst sample compared to a 3 wt % MnOx/SiO2 sample.     

Preparation and formation mechanism of a n-butylammonium/MnO2 layered hybrid via a one-pot synthesis under moderate conditions

The preparation of organic/inorganic layered hybrids has relied on multistep processing. Thus, shortening the synthetic procedure is important for possible future applications, but only a few studies report one-pot syntheses. In this work, we established a simple one-pot solution process to synthesize layered alkyl ammonium/MnO(2) hybrids, by stirring MnCl(2) and alkyl amine/H(2)O(2) aqueous solutions at 40 °C; the reaction concept is a chemical oxidation of Mn(II) ions in the presence of alkyl amine in aqueous solution. Furthermore, the formation mechanism of the layered n-butylammonium/MnO(2) hybrid was examined by following the structural and optical changes during the reaction, revealing that the one-pot reaction includes 3 steps; formation of β-MnOOH, topotactic oxidation of β-Mn(III)OOH to form the protonated layered manganese oxide H(x)Mn(III, IV)O(2)·yH(2)O, and ion-exchange of interlayer H(+) (or H(3)O(+)) with n-butylammonium to form layered n-butylammonium/MnO(2).     

Na-Mn-O正极材料的合成及电化学性能

以Mn(CH3COO)2·4H2O为锰源, 以Na2CO3为钠源, 通过溶液-凝胶法合成干凝胶前驱体, 将前驱体在空气气氛中焙烧得到Na-Mn-O正极材料. 并用傅立叶红外光谱(FT-IR), 热重分析(TG), X射线衍射(XRD), 扫描电镜(SEM), 恒流充放电测试等对材料结构和性能进行研究. 结果表明,600 ℃焙烧的样品为结构稳定的层状锰酸钠, 属于六方层状P2结构, 空间群为P63/mmc, 通过PowderX软件计算得到其晶胞参数为a=0.284 nm, c=1.116 nm. Na-Mn-O正极材料在Li+嵌入和脱出过程中, 部分Na+从层状主晶格中脱出, 使得Li+在MnO6层间的嵌/脱阻力减小(由于Na+(0.095 nm)半径比Li+(0.076 nm)大), 电化学性能明显改善. 在充放电电流密度为25 mA·g-1, 电压在2.0-4.3 V范围时, 600 ℃焙烧的样品第二次放电容量高达176 mAh·g-1, 20次循环后, 容量保持率仍有90.9%.     

Speciation of antimony(III) and antimony(V) in cell extracts by anion chromatography/ inductively coupled plasma mass spectrometry

An analytical method for the separation and quantification of Sb(III) and Sb(V) using anion chromatography with ICP-MS is presented. The optimum conditions for the separation of the antimony species were established with 15 mmol/L nitric acid at pH 6 as eluent system on a PRP-X100 column. The retention times for antimony(V) and antimony(III) were 85 s and 300 s with detection limits of 0.06 μg/L and 0.29 μg/L, respectively. The proposed method was applied to cell extracts of Leishmania donovani, which were incubated with antimony(III) and antimony(V). Some metabolism seemed to occur within the cells.     

Inversvoltammetrische spurenbestimmung von Antimon(III) und Antimon(V) in aquatischen umweltproben nach selektiver extraktionStripping Voltammetry of Traces of Antimony(III) and Antimony(V) in Natural Waters After Selective Extraction

The biological activity of antimony depends on the oxidation state. The Sb(III) and Sb(V) states can be distinguished, even in the ng l^?1 range, by coupling extraction with ammonium pyrrlidenedithiocarbamate into methyl isobutyl ketone (APDC/MIBK), or N-benzoyl-N-phenylhydroxylamine (BPHA) into chloroform, with anodic stripping voltammetry (a.s.v.). After complex formation with APDC in acetate-buffered medium, Sb(III), but not Sb(V), is extracted into MIBK and quantified by a.s.v. Antimony(V) is quantified in the aqueous phase after removal of Sb(III) by extraction with BPHA into chloroform from the medium acidified with nitric acid. The applicability of the proposed separation/a.s.v. method is demonstrated for samples of rain, snow and water from a dredging operation. The stability of the two antimony species is examined for natural waters with Sb(III) and Sb(V) added; possibilities of stabilization are described. The precedures should be suitable for speciation of antimony in relatively unpolluted waters.     

Electrodeposition of layered manganese oxide nanocomposites intercalated with strong and weak polyelectrolytes

Multilayered manganese oxide nanocomposites intercalated with strong (poly(diallyldimethylammonium) chloride, PDDA) and weak (poly(allylamine hydrochloride), PAH) polyelectrolytes can be produced on polycrystalline platinum electrode in a thin film form by a simple, one-step electrochemical route. The process involves a potentiostatic oxidation of aqueous Mn2+ ions at around +1.0 V (vs Ag/AgCl) in the presence of polyelectrolytes. Fully charged PDDA polycations are accommodated tightly in the interlayer space by electrostatic interaction with negative charges on the manganese oxide layers, leading to an interlayer distance of 0.97 nm. The layered film prepared with PAH has a larger polymer content (PAH/Mn molar ratio of 0.98) than that (PDDA/Mn molar ratio of 0.43) made with PDDA because of the smaller charging degree of PAH, exhibiting a larger interlayer distance (1.19 nm). The interlayer PAH contains neutral (-NH2) and positively charged (-NH3(+)) amine groups, and the -NH3(+) groups are associated with Cl- (to generate -NH3(+) Cl- ion pairs) as well as the negatively charged manganese oxide layers. Both polyelectrolytes once incorporated were not ion exchanged with small cations in solution. The layered structure of PDDA/MnO(x) was collapsed during the reduction process in a KCl electrolyte solution, accompanying an expansion of the interlayer as a result of incorporation of K+ ions for charge neutrality. On the contrary, the layered PAH/MnO(x) film showed a good electrochemical response due to the redox reaction of Mn3+/Mn4+ couple with no change in the structure. X-ray photoelectron spectroscopy revealed that, in this case, excess negative charges generated on the manganese oxide layers upon reduction can be balanced by the protons being released from the -NH3(+) Cl- sites in the interlayer PAH; the Cl- anions becoming unnecessary are inevitably excluded from the interlayer, and vice versa upon oxidation.     

New considerations about the separation and quantification of antimony species by ion chromatography-hydride generation atomic fluorescence spectrometry

A new method for the speciation of inorganic [Sb(III) and Sb(V)] and organic (Me3SbCl2) antimony species by using a polystyrene-divinylbenzene-based anion-exchange HPLC column (Hamilton PRP-X100) coupled to hydride generation atomic fluorescence spectrometry (HG-AFS) is presented. Several mobile phases were tested for the baseline separation of these three antimony species, investigating in detail experimental parameters such as concentration and pH. The best efficiency and resolution was achieved by using a gradient elution between diammonium tartrate 250 mmol l(-1) pH 5.5 (A) and KOH 20 mmol l(-1) pH 12 (B). The gradient programme used was 100% B for 1.5 min, decreasing to 0% B in 0.1 min and maintained the elution with 100% A for 5.5 min. Analysis time was less than 7 min. Equilibration of the column with the complexing mobile phase was found to be critical in order to avoid Sb(III) double peak formation. Dilution in diammonium tartrate medium was necessary in order to avoid Sb(III) oxidation at microg l(-1) concentration level. Detection limits of 0.06 microg l(-1) for Sb(V), 0.09 microg l(-1) for Me3SbCl2 and 0.04 microg l(-1) for Sb(III) as well as repeatability and reproducibility better than 5% R.S.D. (n = 10) and 9% R.S.D. (n = 30) (for 1 and 5 microg l(-1) of Sb(V) and Sb(III) and 5 and 10 microg l(-1) of Me3SbCl2) were obtained. Accuracy and recovery studies were carried out by analysing one river freshwater sample and two water certified reference materials. The proposed methodology can be considered reliable and straightforward for antimony speciation in fresh water samples.     

Controlled synthesis, characterization, and catalytic properties of Mn(2)O(3) and Mn(3)O(4) nanoparticles supported on mesoporous silica SBA-15

A method established in the present study has proven to be effective in the synthesis of Mn(2)O(3) nanocrystals by the thermolysis of manganese(III) acetyl acetonate ([CH(3)COCH=C(O)CH(3)](3)-Mn) and Mn(3)O(4) nanocrystals by the thermolysis of manganese(II) acetyl acetonate ([CH(3)COCH=C(O)-CH(3)](2)Mn) on a mesoporous silica, SBA-15. In particular, Mn(2)O(3) nanocrystals are the first to be reported to be synthesized on SBA-15. The structure, texture, and electronic properties of nanocomposites were studied using various characterization techniques such as N2 physisorption, X-ray diffraction (XRD), laser Raman spectroscopy (LRS), temperature-programmed reduction (TPR), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). The results of powder XRD at low angles show that the framework of SBA-15 remains unaffected after generation of the manganese oxide (MnO(x)) nanoparticles, whereas the pore volume and the surface area of SBA-15 dramatically decreased as indicated by N2 adsorption-desorption. TEM images reveal that the pores of SBA-15 are progressively blocked with MnO(x) nanoparticles. The formation of the hausmannite Mn(3)O(4) and bixbyite Mn(2)O(3) structures was clearly confirmed by XRD. The surface structures of MnO(x) were also determined by LRS, XPS, and TPR. The crystalline phases of MnO(x) were identified by LRS with corresponding out-of-plane bending and symmetric stretching vibrations of bridging oxygen species (M-O-M) of both MnO(x) nanoparticles and bulk MnO(x). We also observed the terminal Mn=O bonds corresponding to vibrations at 940 and 974 cm-1 for Mn(3)O(4)/SBA-15 and Mn(2)O(3)/SBA-15, respectively. These results show that the MnO(x) species to be highly dispersed inside the channels of SBA-15. The nanostructure of the particles was further identified by the TPR profiles. Furthermore, the chemical states of the surface manganese (Mn) determined by XPS agreed well with the findings of LRS and XRD. These results suggest that the method developed in the present study resulted in the production of MnO(x) nanoparticles on mesoporous silica SBA-15 by controlling the crystalline phases precisely. The thus-prepared nanocomposites of MnO(x) showed significant catalytic activity toward CO oxidation below 523 K. In particular, the MnO(x) prepared from manganese acetyl acetonate showed a higher catalytic reactivity than that prepared from Mn(NO(3))2.     

Development of an analytical method for antimony speciation in vegetables by HPLC-hydride generation-atomic fluorescence spectrometry

A new method for antimony speciation in terrestrial edible vegetables (spinach, onions, and carrots) was developed using HPLC with hydride generation-atomic fluorescence spectrometry. Mechanical agitation and ultrasound were tested as extraction techniques. Different extraction reagents were evaluated and optimal conditions were determined using experimental design methodology, where EDTA (10 mmol/L, pH 2.5) was selected because this chelate solution produced the highest extraction yield and exhibited the best compatibility with the mobile phase. The results demonstrated that EDTA prevents oxidation of Sb(III) to Sb(V) and maintains the stability of antimony species during the entire analytical process. The LOD and precision (RSD values obtained) for Sb(V), Sb(III), and trimethyl Sb(V) were 0.08, 0.07, and 0.9 microg/L and 5.0, 5.2, and 4.7%, respectively, for a 100 microL sample volume. The application of this method to real samples allowed extraction of 50% of total antimony content from spinach, while antimony extracted from carrots and onion samples ranged between 50 and 60 and 54 and 70%, respectively. Only Sb(V) was detected in three roots (onion and spinach) that represented 60-70% of the total antimony in the extracts.     

New layered manganese oxide halides

The first layered manganese(III) oxide chlorides, Sr2MnO3Cl and Sr4Mn3O8-yCl2, have been synthesised; Sr2MnO3Cl adopts a K2NiF4 type structure with sheets of MnO5 square based pyramids linked through oxygen and separated by SrCl layers; it is the end member of a new family of Ruddlesden-Popper type manganese oxide halides which includes the three-layer member Sr4Mn3O8-yCl2 also reported herein.     

Structure analysis of exfoliated unilamellar crystallites of manganese oxide nanosheets

Structure analysis of unilamellar manganese oxide nanosheets obtained via exfoliation of layered manganese oxides was carried out utilizing synchrotron radiation (SR) X-ray in-plane diffraction and polarization-dependent total reflection fluorescence X-ray absorption fine structure (PTRF-XAFS) analyses. A combination of SR excitation and the total reflection of incoming X-rays provides signals strong enough for both analyses even from a monolayer of the MnO(2) nanosheets having a concentration of 0.7 microg cm(-2). In addition, the mean oxidation state of constituent manganese ions in the MnO(2) sheets was estimated on the basis of XANES spectra, and bond valence sum calculations with the bond length obtained from the present EXAFS analyses. The obtained structural data revealed that the two-dimensional lattice of the MnO(2) sheets underwent a slight elongation upon delamination. These changes correspond to approximately 1% expansion of sheet area and 1-2% expansion of thickness, which can be understood by reduction of the mean oxidation number of manganese ions in the sheet through the exfoliation process.     

A Coulometric Analysis Method and an Ion-exclusion Chromatographic Method for the Determination of Antimony(V) in Large Excess of Antimony(III)

A coulometric analysis method and an ion-exclusion chromatographic method were developed for the determination of antimony(V) in a large excess of antimony(III). Antimony(V) reacted with potassium iodide in a high concentration hydrochloric acid; the liberated iodine was determined by the standard-addition method using coulometrically generated iodine. Using a Dionex ICE-AS1 ion-exclusion column, antimony(V) was eluted with 40 mmol/L sulfuric acid; on the other hand, antimony(III) was strongly retained on the column. The content, expressed as the amount ratio of antimony(V) to antimony(III), was 0.035% in a 10 g/kg antimony(III) solution prepared from an antimony(III) oxide reagent by the coulometric analysis method and 0.036% in a 1 g/kg antimony(III) solution prepared from the same antimony(III) oxide by the ion-exclusion chromatographic method. The results of both methods were in good agreement with each other. The detection limit of antimony(V) in antimony(III) oxide by the former method was 0.004% of antimony(III), and that by the latter method was 0.002% of antimony(III).     

Detailed studies of a high-capacity electrode material for rechargeable batteries, Li2MnO3-LiCo(1/3)Ni(1/3)Mn(1/3)O2

Lithium-excess manganese layered oxides, which are commonly described by the chemical formula zLi(2)MnO(3)-(1-z)LiMeO(2) (Me = Co, Ni, Mn, etc.), are of great importance as positive electrode materials for rechargeable lithium batteries. In this Article, Li(x)Co(0.13)Ni(0.13)Mn(0.54)O(2-δ) samples are prepared from Li(1.2)Ni(0.13)Co(0.13)Mn(0.54)O(2) (or 0.5Li(2)MnO(3)-0.5LiCo(1/3)Ni(1/3)Mn(1/3)O(2)) by an electrochemical oxidation/reduction process in an electrochemical cell to study a reaction mechanism in detail before and after charging across a voltage plateau at 4.5 V vs Li/Li(+). Changes of the bulk and surface structures are examined by synchrotron X-ray diffraction (SXRD), X-ray absorption spectroscopy (XAS), X-ray photoelectron spectroscopy (XPS), and time-of-flight secondary ion mass spectroscopy (SIMS). SXRD data show that simultaneous oxygen and lithium removal at the voltage plateau upon initial charge causes the structural rearrangement, including a cation migration process from metal to lithium layers, which is also supported by XAS. This is consistent with the mechanism proposed in the literature related to the Li-excess manganese layered oxides. Oxygen removal associated with the initial charge on the high voltage plateau causes oxygen molecule generation in the electrochemical cells. The oxygen molecules in the cell are electrochemically reduced in the subsequent discharge below 3.0 V, leading to the extra capacity. Surface analysis confirms the formation of the oxygen containing species, such as lithium carbonate, which accumulates on the electrode surface. The oxygen containing species are electrochemically decomposed upon second charge above 4.0 V. The results suggest that, in addition to the conventional transition metal redox reactions, at least some of the reversible capacity for the Li-excess manganese layered oxides originates from the electrochemical redox reaction of the oxygen molecules at the electrode surface.     

MnOx／TiO2催化剂的表面状态与氧化活性

研究了不同负载量的MnO_2/TiO_2系列催化剂的表面状态及CO氧化活性。结果表明,当MnO_2负载量低于5.7wt％时,MnO_2呈Mn_2O_3相;高于5.7wt％时,MnO_2则为Mn_2O_3+MnO_2混合相。Mn_2O_3由分散态到聚集态的分散阀值为0.028g Mn_2O_3/100mm~2 TiO_2。催化剂氧化活性与其表面状态密切相关。当Mn~(3+)、Mn~(4+)共存时,有利于提高氧化活性。     

Heat-treated Saccharomyces cerevisiae for antimony speciation and antimony(III) preconcentration in water samples

An analytical method was developed for antimony speciation and antimony(III) preconcentration in water samples. The method is based on the selective retention of Sb(III) by modified Saccharomyces cerevisiae in the presence of Sb(V). Heat, caustic and solvent pretreatments of the biomass were investigated to improve the kinetics and thermodynamics of Sb(III) uptake process at room temperature. Heating for 30 min at 80 degrees C was defined as the optimal treatment. Antimony accumulation by the cells was independent of pH (5-10) and ionic strength (0.01-0.1 mol L(-1)). 140 mg of yeast and 2h of contact were necessary to ensure quantitative sequestration of Sb(III) up to 750 microg L(-1). In these conditions, Sb(V) was not retained. Sb(V) was quantified in sorption supernatant by inductively coupled plasma mass spectrometry (ICP-MS) or inductively coupled plasma optical emission spectrometry (ICP-OES). Sb(III) was determined after elution with 40 mmol L(-1) thioglycolic acid at pH 10. A preconcentration factor close to nine was achieved for Sb(III) when 100mL of sample was processed. After preconcentration, the detection limits for Sb(III) and Sb(V) were 2 and 5 ng L(-1), respectively, using ICP-MS, 7 and 0.9 microg L(-1) using ICP-OES. The proposed method was successfully applied to the determination of Sb(III) and Sb(V) in spiked river and mineral water samples. The relative standard deviations (n=3) were in the 2-5% range at the tenth microg L(-1) level and less than 10% at the lowest Sb(III) and Sb(V) tested concentration (0.1 microg L(-1)). Corrected recoveries were in all cases close to 100%.