Preconcentration of trace elements from natural water with palladium precipitation

Palladium salts can be used as a coprecipitation carrier for the preconcentration of trace elements from natural water prior to their measurement by atomic spectrometry (AAS). The palladium is subsequently reduced by the introduction of hydrogen gas into the sample solution. The procedure is applied to the determination of Cu, Pb and Cd in seawater (enrichment factor 50) and synthetic water samples. Operating conditions have been optimized for the analysis of real samples. With the technique established an enrichment factor (500 fold) is feasible in synthetic samples. The recoveries of Cu, Cd and Pb from seawater are 95, 103 and 100%, respectively. This simple and rapid method can be applied in a wide pH-range and with complex matrices.     

Thioacetamide chemically immobilized on silica gel as a solid phase extractant for the extraction and preconcentration of copper(II), lead(II), and cadmium(II)

Thioacetamide immobilized on silica gel was prepared via the Mannich reaction. The extraction and enrichment of copper(II), lead(II), and cadmium(II) ions from aqueous solutions has been investigated. Conditions for effective extraction are optimized with respect to different experimental parameters in both batch and column processes prior to their determination by flame atomic absorption spectrometry (FAAS). The optimum pH ranges for quantitative adsorption are 4.0-8.0, 2.0-7.0, and 5.0-10.0 for Pb(II), Cu(II), and Cd(II), respectively. Pb(II) and Cd(II) can be desorbed with 3 mol/L and 0.1 mol/L HCl/HNO3, and Cu(II) can be desorbed with 2.5% thiourea. The adsorption capacity of the matrix has been found to be 19.76, 16.35, and 12.50 mg/g for Pb(II), Cu(II), and Cd(II), respectively, with the preconcentration factor of approximately equal to 300 for Pb(II) and approximately equal to 200 for Cu(II) and Cd(II). Analytical utility is illustrated in real aqueous samples generated from distilled water, tap water, and river water samples.     

On-line preconcentration method for the determination of trace metals in water samples using a fully automated pretreatment system coupled with ICP-AES.

An automated on-line sample-preparation method using a computer-controlled pretreatment system (Auto-Pret AES system) coupled with ICP-AES was developed. In this work, an iminodiacetate chelating resin, packed in a mini-column and installed in the system was employed for the collection/concentration of 13 trace metals, including such toxic metals as Be, Cd, Cr, Cu and Pb. The limits of detection of the proposed method for trace metals were in the range of 0.001 (Be) -0.18 (Pb) ng mL-1. The enrichment factors for metal ions were about 19 times, when 5 mL of samples were used. The sample throughput was 11 h-1. The accuracy and the precision of the method were evaluated using river-water reference materials, SLRS-4 from NRCC, JSAC 0301-1 and JSAC 0302 from the Japan Society for Analytical Chemistry. The proposed method can be favorably applied to the collection/concentration of trace metals in natural water samples.     

Solid phase extraction of lead (II), copper (II), cadmium (II) and nickel (II) using gallic acid-modified silica gel prior to determination by flame atomic absorption spectrometry

The immobilization of gallic acid on the surface of amino group-containing silica gel phases for the formation of a newly chelating matrix (GASG) is described. The newly synthesized extractant, characterized by the diffuse reflectance infrared Fourier transformation spectroscopy and elemental analysis, was used to preconcentrate Pb(II), Cu(II), Cd(II) and Ni(II). The pH ranges for quantitative sorption and the concentrations of HCl for eluting Pb(II), Cd(II), Cu(II) and Ni(II) were opimized, respectively. The sorption capacity of the matrix has been found to be 12.63, 6.09, 15.38, 4.62mg/g for Pb(II), Cd(II), Cu(II) and Ni(II), respectively, with the preconcentration factor of approximately 200 ( approximately 100 for Cd(II)). The effects of flow rates, the eluants, the electrolytes and cations on the metal ions extraction, as well as the chelating matrix stability and reusability, were also studied. The extraction behavior of the matrix was conformed with Langmuir's equation. The present preconcentration and determination method was successfully applied to the analysis of synthetic metal mixture solution and river water samples. The 3sigma detection limit and 10sigma quantification limit for Pb(II), Cu(II), Cd(II) and Ni(II) were found to be 0.58, 0.86, 0.65, 0.92microg/L and 1.08, 1.23, 0.87, 1.26microg/L, respectively.     

微晶蒽分离富集测定痕量铜(II)

建立了一种利用微晶蒽吸附分离富集环境水样中痕量Cu(Ⅱ)的新方法。 研究表明,pH=3.0时, Cu(Ⅱ)与1-(2-吡啶偶氮)-2-萘酚形成红棕色螯合物被微晶蒽定量吸附,而Pb(Ⅱ)、Mn(Ⅱ)、Co(Ⅱ)、Ni(Ⅱ)、Cd(Ⅱ)、Zn(Ⅱ)、Fe(Ⅲ)和Al(Ⅲ)等完全留在溶液中,从而实现Cu(Ⅱ)与它们的分离。 该方法可直接用于1 L水样中痕量Cu(Ⅱ)的分离与富集,富集倍数达200倍,回收率91.0%~104.0%, 最低检出限为0.026 μg/L;应用于不同水样中Cu(Ⅱ)的测定,结果令人满意。     

On-line Preconcentration and Determination of Trace Metals in Water Samples by Flow Injection Combined with Flame Atomic Absorption Spectrometry via Calix[4]arene Carboxylic Acid Packed Micro-column

An adsorbent calix[4]arene carboxylic acid was employed as the adsorption material for on-line flow injection( FI) micro-column preconcentration coupled with flame atomic absorption spectrometry(FAAS) determination of trace heavy metals(Cu, Pb, Co, Ni and Cd). Parameters such as the pH, loading time and flow rate of sample, and the concentration, volume and flow rate of eluent were optimized. The enrichment factors are 50.0, 56.5, 11.6, 12.1 and 19.1 for Cu, Pb, Co, Ni, and Cd, respectively, and a sample throughput of 20 h^-1 was obtained. The limits of detection for Cu, Pb, Co, Ni, and Cd were in a range of 1.56―3.91 μg/L, and the relative standard deviations(RSDs) were less than 2.76%(n=7). Furthermore, the proposed method was successfully applied to the determination of Cu, Pb, Co, Ni, and Cd in certified reference materials and various water samples.     

Simultaneous Determination of Cadmium,Lead, Copper,and Thallium in Highly Saline Samples by Anodic Stripping Voltammetry (ASV) Using Mercury‐Film and Bismuth‐Film Electrodes

This paper describes a comparative study of the simultaneous determination of Cd(II), Pb(II), Tl(I), and Cu(II) in highly saline samples (seawater, hydrothermal fluids, and dialysis concentrates) by ASV using the mercury‐film electrode (MFE) and the bismuth‐film electrode (BiFE) as working electrodes. The features of MFE and BiFE as working electrodes for the single‐run ASV determinations are shown and their performances are compared with that of HMDE under similar conditions. It was observed that the stripping peak of Tl(I) was well separated from Cd(II) and Pb(II) peaks in all the studied saline samples when MFE was used. Because of the severe overlapping of Bi(III) and Cu(II) stripping peaks in the ASV using BiFE, as well as the overlapping of Pb(II) and Tl(I) stripping peaks in the ASV using HMDE, the simultaneous determination of these metals was not possible in highly saline medium using these both working electrodes. The detection limits calculated for the metals using MFE and BiFE (deposition time of 60 s) were between 0.043 and 0.070 μg L^?1 for Cd(II), between 0.060 and 0.10 μg L^?1 for Pb(II) and between 0.70 and 8.12 μg L^?1 for Tl(I) in the saline samples studied. The detection limits calculated for Cu(II) using the MFE were 0.15 and 0.50 μg L^?1 in seawater/hydrothermal fluid and dialysis concentrate samples, respectively. The methods were applied to the simultaneous determination of Cd(II), Pb(II), Tl(I), and Cu(II) in samples of seawater, hydrothermal fluids and dialysis concentrates.     

Investigations of trace elements in high salinity waters by ICP-MS

A separation and enrichment procedure for the analysis of trace elements (Cd, Co, Cu, Fe, Mn, Ni, Pb, Tl, U, Zn) in seawater or brines from ore dumps by ICP-MS was established based on the complexation with sodium diethyldithiocarbamate-trihydrate (Na-DDTC) and separation on a phenyl column. The method was tested with seawater samples from the hydrothermal system of Axial Seamount, Juan de Fuca Ridge. The analytical results demonstrated the influence of hydrothermal activity on the concentration of Fe and Mn. Received: 2 December 1998 / Revised: 25 February 1999 / Accepted: 1 March 1999     

Determination of some trace metals in waters by flame atomic absorption spectrometry after preconcentration on Amberlite XAD-16 resin with sodium tetraborate

A method was described for the determination of the elements Cr, Mn, Fe, Co, Ni, Cu, Cd, Pb, and Bi in waters by flame atomic absorption spectrometry (FAAS) after separation and preconcentration on Amberlite XAD-16 resin with sodium tetraborate using a chromatographic column. Parameters influencing the analytical performance, including pH and the volume of sample, amount of analyte and interfering effect of co-existing ions, were studied in detail. The recovery values were quantitative (> or = 95%), and the relative standard deviation (RSD) and detection limit (DL) varied in the range of 1.1-2.4% (n=10) and 0.002-0.177 microg m(-1) (3s, n=20), respectively. After being optimized, the proposed method was applied to the drinking water, waste water and artificial sea water samples. Recovery values of the elements investigated, were quantitative for tap water and synthetic sea water, except for Mn, Co and Ni (including also Cd for synthetic sea water). Recovery values of Cd, Pb, Cu and Co were found to be 95, 102, < or = 87, and < or = 83%, respectively, for the waste water samples.     

Investigations of trace elements in high salinity waters by ICP-MS

A separation and enrichment procedure for the analysis of trace elements (Cd, Co, Cu, Fe, Mn, Ni, Pb, Tl, U, Zn) in seawater or brines from ore dumps by ICP-MS was established based on the complexation with sodium diethyldithiocarbamate-trihydrate (Na-DDTC) and separation on a phenyl column. The method was tested with seawater samples from the hydrothermal system of Axial Seamount, Juan de Fuca Ridge. The analytical results demonstrated the influence of hydrothermal activity on the concentration of Fe and Mn. Received: 2 December 1998 / Revised: 25 February 1999 / Accepted: 1 March 1999     

Simultaneous on-line preconcentration and determination of trace metals in environmental samples by flow injection combined with inductively coupled plasma mass spectrometry using a nanometer-sized alumina packed micro-column

A flow injection (FI) on-line preconcentration procedure by using a nanometer-sized alumina packed micro-column coupled to inductively coupled plasma mass spectrometry (ICP-MS) was described for simultaneous determination of trace metals (V, Cr, Mn, Co, Ni, Cu, Zn, Cd and Pb) in the environmental samples. The effects of pH value, sample flow rate, preconcentration time, and interfering ions on the preconcentration of analytes have been investigated. Under the optimized operating conditions, the adsorption capacity of the nanometer-sized alumina for V, Cr, Mn, Co, Ni, Cu, Zn, Cd and Pb were found to be 11.7, 13.6, 15.7, 9.5, 12.2, 13.3, 17.1, 17.7 and 17.5 mg g⁻¹, respectively. With 60 s preconcentration time and 60 s elution time, an enrichment factor of 5 and the sampling frequency of 15 h⁻¹ were obtained. The proposed method has been applied to the determination of trace metals in environmental certified reference materials and natural water samples with satisfactory results.     

Preconcentration and determination of trace metals in seawater using a thiol cotton fiber minicolumn coupled with inductively coupled plasma mass spectrometry.

A rapid separation and preconcentration method was developed for the determination of trace metals Cu, Zn, Cd, and Pb in seawater using a minicolumn packed with thiol cotton fiber (TCF) coupled with inductively coupled plasma mass spectrometry (ICP-MS). Preconcentration parameters, such as seawater sample volume and flow rate and eluent hydrochloric acid concentration, volume and flow rate, were optimized. Under the optimized conditions, trace metals Cu, Zn, Cd, and Pb in seawater can be determined with no interference from saline matrices. When a sample volume of 1500 ml and a sample flow rate of 15 ml min(-1) were used, the preconcentration factor of 1500 and RSD value of <7% at ng ml(-1) were achieved. The accuracy of the recommended method was verified by the analysis of certified reference materials.     

The determination of trace metals in estuarine and coastal waters using a voltammetric in situ profiling system

This work presents the optimisation, validation and field deployment of a voltammetric in situ profiling (VIP) system for the simultaneous determinations of dynamic Cd(II), Cu(II) and Pb(II) in estuarine and coastal waters. Systematic studies in NaNO3 (as a supporting electrolyte) and seawater, indicated that variations in ionic strength, pH and dissolved oxygen did not affect the response of the instrument, whereas an Arrhenius type temperature response was observed. The VIP instrument allows the determination of 2-3 samples h(-1), and has a detection limit (defined as 3sigma) in seawater for Cd(II): 23 pM, Cu(II): 1.13 nM, and Pb(II): 23 pM. The VIP system accurately measured the total dissolved concentrations of Cd(II), Cu(II) and Pb(II) in two certified reference materials; SLRS-3, a river water, and SLEW-2, an estuarine water. Field evaluation of the instrumentation and analytical methods was achieved through a series of surveys in the Plym Estuary (Devon, UK), from which environmental data are presented.     

Solid Phase Extraction of Trace Metals in Seawater Using Morpholine Dithiocarbamate‐Loaded Amberlite XAD‐4 and Determination by ICP‐AES

Abstract

Application of morpholine dithiocarbamate (MDTC) coated Amberlite XAD‐4, for preconcentration of Cu(II), Cd(II), Zn(II), Pb(II), Ni(II) and Mn(II) by solid phase extraction and determination by inductively coupled plasma (ICP) atomic emission spectrometry (AES) was studied. The optimum pH values for quantitative sorption of Cu(II), Cd(II), Zn(II), Pb(II), Ni(II), and Mn(II) were 6.5–8.0, 7.0–8.5, 6.0–8.5, 6.5–8.5, 7.5–9.0, and 8.0–8.5, respectively. The metals were desorbed with 2 mol L^?1. The t_1/2 values for sorption of metal ions were 2.6, 2.9, 2.5, 2.6, 3.0, and 3.8 min respectively for Cu(II), Cd(II), Zn(II), Pb(II), Ni(II) and Mn(II). The effect of diverse ions on the determination of the previously named metals was studied. Simultaneous enrichment of the six metals was accomplished, and the method was applied for use in the determination of trace metal ions in seawater samples.     

用1-亚硝基-2-萘酚修饰的微晶蒽分离富集与测定环境水中钴

建立了微晶蒽分离富集环境水样中痕量Co(II)的方法。在pH3.0条件下,1-亚硝基-2-萘酚与Co(II)形成红棕色螯合物被微晶蒽定量吸附,能使Co(II)与Pb(II)、Ni(II)、Mn(II)、Cu(II)、Cd(II)、Zn(II)、Fe(III)、Cr(III)、Al(III)等常见离子分离。本法富集倍数达100倍,检出限为0.14μg/L,回收率97.5%～105%,已应用于不同水样中Co(II)的测定。     

六极杆碰撞反应池–ICP–MS法测定海水中痕量金属元素

建立了直接稀释法测定海水中痕量金属元素Cr,Cu,Zn,Cd,Pb的方法。样品经稀释10倍后,使用基体匹配及内标校正,采用六极杆碰撞反应池–电感耦合等离子体质谱仪直接测定稀释后海水样品中的5种元素Cr,Cu,Zn,Cd,Pb。各元素在0.0~100μg/L范围内均呈现良好的线性关系,线性相关系数(r~2)均大于0.999 0,方法检出限为0.004~0.209μg/L。测定结果的相对标准偏差为2.4%~4.4%(n=6),加标回收率为92%~113%。该方法简单快捷,适用于近岸海水中痕量元素Cr,Cu,Zn,Cd,Pb的分析。     

Assessing spatial distribution,sources, and potential ecological risk of heavy metals in surface sediments of the Nansi Lake,Eastern China

The study is conducted to investigate the spatial distribution, sources and ecological risk of seven heavy metals in surface sediments of Nansi Lake, Eastern China. A total of 29 samples were collected in surface sediments of Nansi Lake, and were analyzed for three nutrients (TN, TOC and TP), two major metals (Al and Fe), as well as seven trace metals (As, Cd, Cr, Cu, Hg, Pb and Zn). The mean concentrations of As, Cd, Cr, Cu, Hg, Pb, Zn, Fe and Al were 14.41, 0.22, 71.10, 30.1, 0.048, 29.14, 90.2, 30,816 and 70,653 mg kg^?1, respectively, and the mean contents of these metals were higher than the background values with the exception of Cu and Fe. The spatial distribution indicated that the contents of all seven heavy metals were characterized by relatively higher contents in the upper lake than the lower lake. The hotspots with high values of As, Cd and Hg were associated with the river mouths, and the hotspots of Pb were mainly located around the dam in the central part, while no significant associations were displayed between spatial distribution of Cr, Cu, Zn and the river mouths. The mean enrichment factor (EF) values of As, Cd, Hg and Pb were 2.03, 2.93, 3.21 and 2.18, respectively, showing their moderate enrichment, while Cr, Cu and Zn with mean EF values of 1.19, 0.89 and 1.01 were deficiency to minimal enrichment. Multivariate and geostatistical analyses suggested that PC1 controlled by Cr, Cu and Zn was a lithogenic component, and come from parent rocks leaching. PC2 including Cd and partially Hg represented the factor from industrial wastewater discharge. PC3 showed elevated loadings of As and partially Cd, and could be attributed to the agricultural practices. While PC4 including Pb and partially Hg, was dominated by coal combustion. The results of potential ecological risk suggested that sediment environment of Nansi Lake suffered from high ecological risk.     

Trace metal detection in Šibenik Bay, Croatia: Cadmium, lead and copper with anodic stripping voltammetry and manganese via sonoelectrochemistry. A case study

The vertical profiles of the concentration of reactive Mn and total concentrations of Cd, Pb, and Cu ions in the water column of the ?ibenik Bay (Krka river estuary) were determined. The measured ranges of concentrations are: 60–1300 ng l^?1 for Mn, 5–13 ng l^?1 for Cd, 70–230 ng l^?1 for Pb, and 375–840 ng l^?1 for Cu. These values are comparable with the concentrations found in the unpolluted estuaries. The Krka river estuary is highly stratified, with the measured salinity gradient of 20% within a half meter of the freshwater-seawater interface (FSI). The main changes in the vertical profiles of the measured parameters occur in the FSI: the temperature increases for 1 °C and the pH decreases for 0.1 unit, whereas the metal concentrations show different behaviour. Generally, Mn, Pb, and Cd ions show the increase of concentrations in the FSI, while copper concentration profile indicates anthropogenic pollution in the brackish layer caused by agriculture activities and by the paint with copper basis used as an antifoulant biocide for the ships. UV-digested samples show an increase in manganese concentrations for at least 3.5 times comparing to non UV-digested. This suggests that in natural water manganese exists mainly in the form of inert complexes and as associated to particulate matter (about 70–80%). UV irradiation has no influence on the concentration of cadmium, while for lead an increase of 50% in the seawater layer is observed. The twofold increase of the copper concentration in the upper freshwater layer and at least the fourfold one in the seawater layer were measured in the UV-digested samples. These results show that copper is strongly bound to inert complexes, and that UV-digestion is necessary step in determination of the total metal concentrations in natural water samples. No significant increase of the metal concentrations in the deeper seawater layer was observed, indicating the absence of the processes of remobilization or dissolution of metals from the sediment. Presented results confirm that the new method for the determination of manganese by CSV on boron-doped diamond electrode with ultrasound enhanced accumulation can be successfully applied to natural waters.     

Determination of trace elements in seawater by electrothermal atomic absorption spectrometry with and without a preconcentration step

The determination of the trace metals Cd, Pb and Cu in seawater by electrothermal atomic absorption spectrometry (ETA-AAS) has been investigated. A combination of the platform with mixed palladium nitrate-magnesium nitrate as matrix modifier and Zeeman background correction allows Cd an Pb to be determined by aqueous standard calibration in appropriately diluted seawater samples. Copper can be determined in undiluted seawater samples without chemical modification using a standard additions method. Detection limits (3) of 2.97,5.27 and 1.1 gl^–1 are obtained for Cd, Pb and Cu respectively. A Kelex-100 impregnated silica C18 material (Kelex 100-C18) has been tried and has proved to be effective as a column packing for extraction/preconcentration of these metals from seawater. Using the column extraction method, the sensitivity of the graphite furnace technique is enhanced 50-fold using a 10 l injection volume. Thus, the determination of the studied three metals in seawater at the ng.l^–1 level could be achieved.     

Multielemental speciation of trace elements in estuarine waters with automated on-site UV photolysis and resin chelation coupled to inductively coupled plasma mass spectrometry

An integrated approach for the accurate determination of total, labile and organically bound dissolved trace metal concentration in the field is presented. Two independent automated platforms consisting of an ultraviolet (UV) on-line unit and a chelation/preconcentration/matrix elimination module were specifically developed to process samples on-site to avoid sample storage prior to inductively coupled plasma mass spectrometry (ICP-MS) analysis. The speciation scheme allowed simultaneous discrimination between labile and organic stable dissolved species of seven trace elements including Cd, Cu, Mn, Ni, Pb, U and Zn, using only 5 ml of sample with detection limits ranging between 0.6 ng l⁻¹ for Cd and 33 ng l⁻¹ for Ni. The influence of UV photolysis on organic matter and its associated metal complexes was investigated by fluorescence spectroscopy and validated against natural samples spiked with humic substances standards. The chelation/preconcentration/matrix elimination procedure was validated against an artificial seawater spiked sample and two certified reference materials (SLRS-4 and CASS-4) to ensure homogenous performance across freshwater, estuarine and seawater samples. The speciation scheme was applied to two natural freshwater and seawater samples collected in the Adour Estuary (Southwestern, France) and processed in the field. The results indicated that the organic complexation levels were high and unchanged for Cu in both samples, whereas different signatures were observed for Cd, Mn, Ni, Pb, U and Zn, suggesting organic ligands of different origin and/or their transformation/alteration along estuarine water mixing.