Abstract:Comparison of Three Sequential Extraction Methods for the Determination of Iron, Manganese, and Thallium in Asphaltite Samples

Abstract:As one of the most hazardous elements in the environment, mercury poses a threat to humans, plants, and animals. Determination of mercury in water is crucial for environmen_x0002_tal management and toxicological research. In this study, a new method was developed for the determination of ultratrace mercury in tap and lake water based on on-line solid phase extraction (SPE) and ultraviolet vapor generation (UVG), coupled with inductively coupled plasma mass spectrometry (ICP-MS). A SPE column (C18 reverse-phase column) was used to enrich the samples and to eliminate potential interferences from matrix and reagent impurities. Formic acid of 10% (v/v) was used to reduce the mercury ions in water into mercury vapor. Good linearity (R2=0.995) was obtained ranging from 1-1000 ng L-1 Hg2+, with a limit of detection of 0.5 ng L-1 and an RSD of less than 5%. The developed method was validated by spike and recovery experiments and analysis of a certified reference material GBW 10050Prawn. The results show that the SPE-UVG-ICP-MS method is sensitive, fast, precise, and cost-effective for mercury analysis, especially for natural water samples.

Abstract:A spectroanalytical method for remediation of chromium species from contaminated water samples based on flow injection hyphenated to a flame atomic absorption spectrometer is proposed. Iminodiacetic acid (IDA) was used as the chelating agent, and the chromium–IDA complex was preconcentrated on the minicolumn filled with polytetrafluoroethylene (PTFE) beads. The chemical and flow variables were optimized. The effect of commonly occurring matrix ions on the recovery of the chromium species was also studied. For a preconcentration time of 120 s, preconcentration factors and detection limits achieved for Cr(III)/Cr(VI) were 68/59, 0.11/0.13 μg L-1, respectively. The relative standard deviation for 5 replicates of measurements for 100 μg L-1 level was 1.2/1.4% for Cr(III)/Cr(VI), respectively. Real water samples collected from industrial sites and the Yamuna river were analyzed and spike recovery tests were performed. The method validation was done by analyzing the chromium concentration in NIST SRM 1640a Trace Elements in Natural Water.

Abstract:The determination of lanthanides in six soil and six sediment reference materials was investigated by inductively cou- pled plasma mass spectrometry (ICPMS) using fusion and acid digestion. In the present study, the samples were fused with lithium metaborate (LiBO2) and lithium tetraborate (Li2B4O7). In the case of acid decomposition, the samples were digested with a mixture of hydrofluoric acid (HF) and perchloric acid (HClO4). For both cases, 1:1 HNO3 was used for extraction of the decomposed samples. The internal standard (10 ppb indium) was used to take care of the signal drift of the instrument. The measurement was done using a 1 ppb matrix- matched calibration standard prepared from lanthanide salts. The effect of different combina- tions of fusion flux was investi- gated. A detailed study was also made taking a different isotopic mass for measurement of the lan- thanides. Both dissolution techniques were evaluated. Uniform and good recovery of the lanthanides was observed using a fusion mix- ture containing 35% lithium tetraborate and 65% lithium metaborate. The accuracy of the methodology was excellent. Extraction of the lanthanides from the soil and sediment sam- ples by acid digestion method varied from 80–105%. Precision and accuracy in case of the fusion method was very good. The limit of quantitation (10σ) for the determination of the lan- thanides in soil and sediment samples was in the ppb range.

Abstract:A simple method based on the dynamic reaction cell (DRC) technology to eliminate the spectral interference in the simultaneous determination of trace cadmium and silver in soil samples by ICP-MS was established. Under the optimized O2 flow rate (2.7 mL min-1) and the DRC rejection parameter RPq (0.8 for Ag, 0.7 for Cd), the interference caused by Zr, Nb, and Mo (such as 95Mo16O+, 94Mo16OH+, 94Zr16OH+ on 111Cd+ and 93Nb16O+, 92Zr16OH+ on 109Ag+) could be effectively eliminated, and the background signal was reduced up to 100-fold at m/z 109 and 111. The limit of quantitation (LOQ, 10σ) for 109Ag+ and 111Cd+ was 0.1 and 0.2 ng g-1, respectively. The proposed method was applied to the direct determination of Ag and Cd in soil standard reference materials, and the results were in good agreement with the certified values.

Abstract:A method for total As and Cr determination in seawater sam- ples has been developed. As and Cr were measured using the seaFAST2 automated sample introduction system coupled to an ICP-MS. The sampling system allows on-line sample dilution (10 times) before introduction into the ICP-MS. Calibration was performed using the standard addition method, working in the concen- tration range of 0 to 50 μg L-1 for As and 0 to 25 μg L-1 for Cr. The method shows good sensitivity resulting in LODs and LOQs of 0.3 and 0.9 μg L-1, respectively, for As and of 0.03 and 0.09, respectively, for Cr determina- tion. The method was precise (RSD <2%) and accurate. This method was applied to the determination of As and Cr in different seawater samples from the Galician coast of Spain. The concentrations found ranged from 0.3 to 3.1 μg L-1 for As and from 0.03 to 0.1 μg L-1 for Cr.

Abstract:Water supply from boreholes is today used by people from rural areas of Turkey more com- monly due to the reduction of available surface water. For this reason, the concentrations of Al, As, B, Be, Ca, Cd, Co, Cr, Fe, Hg, K, Mg, Mn, Mo, Na, Ni, Pb, Se, Sn, and Zn in borehole waters of the Diyarbak?r province (SE Ana- tolia) were determined in this study. Thirty borehole waters were sampled from different towns and villages. The samples were analyzed by inductively coupled plasma optical emission spectrometry (ICP–OES). The results of the analyses were com- pared with guidelines as set by Turkey, the WHO, and the EU. From the results it could be con- cluded that the ICP-OES method can be considered useful for the routine determination of trace elements in waters and similar matrices. For quality control pur- poses, the certified reference material TMDW-B Drinking Water was employed for valida- tion. The recovery values were in the range of 93–101%. The Al, As, B, Be, Cd, Co, Cr, Hg, Mn, Mo, Ni, Pb, and Sn concentrations in the samples were found lower than the recommended LOD. The concentrations found were in the range of 12.71–111.4 mg/L for Na, 0.76–3.07 mg/L for K, 9.62–115.5 mg/L for Ca, 2.69–41.85 mg/L for Mg, 10 μg/L.

Abstract:In this study, toxic heavy metal contamination in dust sam- ples obtained from different streets in Denizli, Turkey, was monitored. The areas selected include heavy, moderate, and normal traffic flow, building con- struction sites and other indus- trial activities near roads, car parks, school gardens, health cen- ters, and hospitals. The metals were determined by flame atomic absorption spectrometry. The concentration ranges were Cu at 20.4–147.4 μg g-1, Cr at 9.9–75.0 μg g-1, Ni at 22.8–86.2 μg g-1, Pb at 14.4–145.3 μg g-1, and Mn at 52.3–158.3 μg g-1. The Cd content for all dust samples was below 0.1 μg g-1. According to the geoaccumulation index (Igeo) clas- sification, Cr and Mn were pre- sent at the lower level (0

Abstract:Investigation of the iodine species is important to better understand the sources and mobilization processes of high- iodine groundwater. A fast and sensitive method for the deter- mination of iodate (IO3–) and iodide (I–) in groundwater using an improved ion chromatogra- phy method coupled with induc- tively coupled plasma mass spectrometry (IC-ICP-MS) is described. To shorten the sepa- ration time of iodine species, a short anion-exchange column, Dionex AG-19, was examined as the analytical column. Isocratic elution using 30 mM KOH facili- tated the chromatographic sepa- ration of IO3– and I– within one minute, reducing the time in comparison to previous IC-ICP- MS methods with conventional long IC columns (i.e., Hamilton X-100 or Dionex AS-16) by 90%. Moreover, the low analytical sensitivity of iodine, due to its high ionization potential (10.08 eV), was improved five-fold by addition of small amounts of CH4 to the Ar plasma. The detection limit was 0.005 μg L–1 for IO3– and 0.006 μg L–1 for I–, while the relative standard deviation for five injections of 0.2 μg L–1 I– or IO3– was 1.2–3.3%. The analyti- cal results for three water stan- dard reference materials were in agreement with the certified values. The proposed method was successfully applied to the determination of I– and IO3– in seven shallow groundwater sam- ples collected from the Datong Basin, Northern China. The dis- tributions of the iodine species, differing from mountain front plains to flat alluvial plain regions, indicate that the mobi- lization process of iodine is asso- ciated with complex redox conditions.

Abstract:A solid phase preconcentra- tion method has been developed using hydroxyl multi-wall carbon nanotubes (MWNTs) as the absorbent. The method was opti- mized for the determination of rare earth elements (REEs) in deep groundwater samples by inductively coupled plasma mass spectrometry (ICP-MS). The effects of the experimental para- meters, including pH, eluent con- centration and volume, flow rates of sample and eluent solutions, and the sample volume on the recoveries of the analytes were examined in detail. Under opti- mum conditions, REEs can be quantitatively retained by MWNTs when the pH exceeds 3.0 and are then eluted com- pletely with 1% HNO3. The detection limits of this method ranged from 0.31 ng L-1 to 1.2 ng L-1 and the relative standard devi- ations (RSDs) were less than 5%. The method was validated using a certified reference material and was applied for the determina- tion of REEs in deep groundwater samples with satisfactory results.