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Xiandeng Hou - One of the best experts on this subject based on the ideXlab platform.

  • effect of variable ultraviolet wavelength and intensity on photochemical vapor generation of trace selenium detected by Atomic Fluorescence Spectrometry
    Microchemical Journal, 2018
    Co-Authors: Zhirong Zou, Xiandeng Hou, Yunfei Tian, Wen Zeng, Xiaoming Jiang
    Abstract:

    Abstract Selenium was taken as an example to investigate the effect of variable ultraviolet (UV) wavelength and intensity on its photochemical vapor generation (photo-CVG) process. A broadband laser-driven light source (LDLS) and a UV lamp were utilized as irradiation sources for the photo-CVG of trace selenium which was sensitively detected by Atomic Fluorescence Spectrometry (AFS). Five filters with bandpass at different wavelength (254 nm, 285 nm, 315 nm, 365 nm and 395 nm) were used to filtrate the light from the LDLS and the UV lamp. The signal change of Se(VI) by photo-CVG-AFS was monitored when a TiO2-coated quartz coil was irradiated by variable wavelength and intensity. The experimental results indicated: (1) the efficiency of Se(VI) photo-CVG varied with irradiation wavelength; (2) a synergistic effect existed for the photo-CVG, and the efficiency of the full spectrum was thus better or close to the sum of all wavelengths; and (3) the efficiency of Se(VI) photo-CVG was also affected by the UV intensity.

  • application of flow injection green chemical vapor generation Atomic Fluorescence Spectrometry to ultrasensitive mercury speciation analysis of water and biological samples
    Microchemical Journal, 2016
    Co-Authors: Ruoxi Zhang, Chengbin Zheng, Mengting Peng, Xiandeng Hou
    Abstract:

    Abstract A simple, non-chromatographic and green method based on flow injection UV photochemical or ultrasonic vapor generation Atomic Fluorescence Spectrometry (AFS) was developed for the determination and speciation analysis of mercury. Mercury cold vapor (Hg0) was generated by using only formic acid and UV or ultrasonic irradiation, and was subsequently detected by AFS. Both mercury (Hg2 +) and methyl mercury (MeHg) can be converted to Hg0 for the determination of total mercury with UV irradiation, while only Hg2 + can be reduced to Hg0 with ultrasonic irradiation, thus determining only Hg2 +. Then, the concentration of MeHg can be calculated by subtracting the Hg2 + concentration from the total mercury concentration. The optimal conditions for the best cold vapor generation efficiencies are discussed in detail, together with interference from transition metals. This new speciation analysis not only provides high sensitivity for the determination of mercury species but further eliminates the use of toxic reducing reagents and avoids potential destruction of analyte species that occur in chromatographic separation. Moreover, a simpler and less toxic Hg2 + standard series can be used for the calibration of both Hg2 + and MeHg. The limit of detection is 0.005 or 0.01 μg L− 1 for total mercury with the UV or inorganic mercury with the ultrasonic irradiation, respectively. This method was successfully applied to ultrasensitive mercury speciation analysis of water and biological samples.

  • ultrasensitive determination of inorganic arsenic by hydride generation Atomic Fluorescence Spectrometry using fe3o4 zif 8 nanoparticles for preconcentration
    Microchemical Journal, 2016
    Co-Authors: Zhirong Zou, Shanling Wang, Jia Jia, Zhou Long, Xiandeng Hou
    Abstract:

    Abstract In this work, magnetic Fe3O4@ZIF-8 core-shell nanoparticles (MNPs) were employed for effective adsorption of inorganic arsenic for preconcentration, with adsorption mechanism thoroughly discussed. The adsorbed inorganic arsenic was easily separated by a magnet along with the MNPs from the sample matrix, with possible matrix interference eliminated. The MNPs were then completely dissolved in hydrochloric acid prior to the determination of inorganic arsenic by hydride generation-Atomic Fluorescence Spectrometry. The Fe3O4@ZIF-8 MNPs were prepared with a facile step-by-step assembly method in aqueous solution at room temperature. Under the optimized conditions, the sensitivity for inorganic arsenic determination was significantly increased through preconcentration, with satisfactory analytical merits obtained.

  • application of preconcentration and separation techniques in Atomic Fluorescence Spectrometry
    Applied Spectroscopy Reviews, 2015
    Co-Authors: Dongyan Deng, Chengbin Zheng, Xiandeng Hou
    Abstract:

    AbstractWith 135 references, this review presents the recent application of various preconcentration and separation techniques in Atomic Fluorescence Spectrometry for the sensitive determination and speciation of various elements and their species. It focuses on sample pretreatment, separation, and enrichment-related techniques, including liquid–liquid extraction, solid-phase (micro)extraction, microwave/ultrasound-assisted extraction, pressurized liquid extraction, as well as chemical vapor generation. In this review, the historical development and overview of these preconcentration and separation methodologies are briefly discussed, together with a comprehensive collection of application of these methods in combination with Atomic Fluorescence Spectrometry for determination of ultratrace amounts of elements and their species in various sample matrices (liquids and solids).

  • dual mode chemical vapor generation for simultaneous determination of hydride forming and non hydride forming elements by Atomic Fluorescence Spectrometry
    Analyst, 2014
    Co-Authors: Yu Wang, Xiandeng Hou, Xiaoming Jiang, Chengbin Zheng
    Abstract:

    A dual-mode chemical vapor generation integrating hydride generation and photochemical vapor generation was developed for simultaneous multi-element analysis of hydride-forming and non-hydride-forming elements by Atomic Fluorescence Spectrometry. Four elements were selected as model elements of hydride-forming (As, Cd) and non-hydride-forming (Ni, Fe) elements to validate this proposed method. Standard or sample solutions were separately pumped to mix with tetrahydroborate, and concentrated formic acid and ammonia, and then directed to a hydride generator and a photochemical reactor to realize simultaneous hydride generation and photochemical vapor generation, respectively. Optimum conditions for dual-mode chemical vapor generation were carefully investigated. Under the optimized conditions, limits of detection of 0.05, 0.008, 0.8 and 0.1 μg L−1 were obtained for As, Cd, Fe and Ni, respectively. The precisions were 5.0, 5.5, 4.3 and 4.5% (n = 6, RSDs) for 2 μg L−1 of As, 1 μg L−1 of Cd, 50 μg L−1 of Fe and 10 μg L−1 of Ni, respectively. This method was validated for accuracy with three certified reference water samples and applied to the simultaneous determination of these elements in a tap water sample with spike recoveries in the range of 95–99%.

Guibin Jiang - One of the best experts on this subject based on the ideXlab platform.

  • evaluation of different extraction procedures for determination of organic mercury species in petroleum by high performance liquid chromatography coupled with cold vapor Atomic Fluorescence Spectrometry
    Talanta, 2013
    Co-Authors: Bin He, Zhenhua Wang, Thanh Wang, Guibin Jiang
    Abstract:

    An extraction procedure for extracting organic mercury species including methylmercury (MeHg) and ethylmercury (EtHg) from petroleum samples was developed. Three extraction methods (shaking, ultrasonic and microwave assisted extraction) using different extraction solvents (TMAH, KOH/CH3OH, HCI and acidic CuSO4/KBr) were investigated by comparing the extraction efficiency of the organic mercury species. Microwave assisted extraction at 60 W for 5 min using TMAH (tetramethylammonium hydroxide, 25%, m/v) provided the most satisfactory extraction efficiency for MeHg and EtHg in petroleum at 86.7% +/- 3.4% and 70.6% +/- 5.9%, respectively. Speciation analysis of mercury was done by on-line coupling of high performance liquid chromatography with cold vapor generation Atomic Fluorescence Spectrometry (HPLC-CV-AFS). The proposed method was successfully applied to analyze several crude oil and light oil samples. The concentrations of MeHg ranged from under detection limit to 0.515 ng g(-1), whereas EtHg was not detected in the samples. This method can be a very useful tool in evaluating the risk of mercury emissions from petroleum. (C) 2012 Elsevier B.V. All rights reserved.

  • application of gas chromatography Atomic Fluorescence Spectrometry hyphenated system for speciation of butyltin compounds in water samples
    Spectroscopy Letters, 2011
    Co-Authors: Guibin Jiang
    Abstract:

    ABSTRACT A laboratory-established capillary gas chromatography (GC)–Atomic Fluorescence Spectrometry (AFS) hyphenated system was applied to butyltin speciation in water samples. Monobutyltin (MBT), dibutyltin (DBT), and tributyltin (TBT) were extracted and preconcentrated with headspace solid-phase microextraction (SPME) technique after derivatization using KBH4, and then determined by GC-AFS directly. The experimental conditions—including the flow rates of carrier gas, argon and hydrogen–and the lamp current—were optimized in detail. Under the optimum conditions, the detection limits for MBT, DBT, and TBT, calculated as three times the baseline noise, were 10, 0.2, and 0.1 ng mL−1 Sn, respectively. Good linear relationships were obtained when the concentrations of MBT, DBT, and TBT increased to 3000, 100, and 200 ng mL−1 Sn. The relative standard deviations (RSDs) of five replicates were 5.2%, 7.4%, and 7.1% for MBT, DBT, and TBT, respectively. The recoveries of MBT, DBT, and TBT in three different types...

  • mercury speciation by a high performance liquid chromatography Atomic Fluorescence Spectrometry hyphenated system with photo induced chemical vapour generation reagent in the mobile phase
    Mikrochimica Acta, 2009
    Co-Authors: Yongguang Yin, Jingfu Liu, Jianbo Shi, Guibin Jiang
    Abstract:

    Speciation of mercury was accomplished by using a simple interface with photo-induced chemical vapour generation in a high performance liquid chromatography—Atomic Fluorescence Spectrometry (HPLC-AFS) hyphenated system. Acetic acid and 2-mercaptoethanol in the mobile phase were used as photochemical reagent. The operating parameters were optimized to give limits of detection of 0.53 µg L−1, 0.22 µg L−1, 0.18 µg L−1 and 0.25 µg L−1 for inorganic mercury, methylmercury, ethylmercury and phenylmercury, respectively. The method was validated with the certified reference material DORM-2 and applied to the analysis of seafood samples. The HPLC-AFS hyphenated system is simple, environmentally friendly, and represents an attractive alternative to the conventional peroxothiosulfate-borohydride method.

  • direct chemical vapour generation flame atomization as interface of high performance liquid chromatography Atomic Fluorescence Spectrometry for speciation of mercury without using post column digestion
    Journal of Analytical Atomic Spectrometry, 2009
    Co-Authors: Zhenhua Wang, Jinfeng Peng, Bin He, Guibin Jiang
    Abstract:

    A high performance liquid chromatography-direct chemical vapour generation-flame atomization-Atomic Fluorescence Spectrometry (HPLC-CVG-FA-AFS) system for speciation of methylmercury (MeHg+), inorganic mercury (Hg2+) and ethylmercury (EtHg+) without using post-column digestion is developed and characterized. In this novel system, organomercurial species separated by chromatography were transformed to their hydrides by KBH4, further atomized in the flame atomizer and detected by AFS. The conventionally used on-line UV or microwave digestion system was omitted, and no oxidation reagent was needed, which significantly simplified the instrumentation. Under the optimized conditions, the detection limits were 0.2, 0.4 and 0.4 µg L−1 (as Hg) for MeHg+, Hg2+, and EtHg+ (100 µL injection), which corresponds to absolute detection limits of 0.02, 0.04 and 0.04 ng (as Hg) for MeHg+, Hg2+, and EtHg+, respectively. The sensitivity of the developed method was comparable with the conventional high performance liquid chromatography-UV digestion-cold vapour generation-Atomic Fluorescence Spectrometry (HPLC-UV-CVG-AFS) system. Validation with biological certified reference materials showed that the proposed method is simple and accurate for mercury speciation.

  • selenium speciation by high performance anion exchange chromatography post column uv irradiation coupled with Atomic Fluorescence Spectrometry
    Journal of Chromatography A, 2006
    Co-Authors: Lina Liang, Yaqi Cai, Shifen Mou, Guibin Jiang, Ping Zhang, Meijuan Wen
    Abstract:

    A technique for the speciation of selenomethylcysteine (SeMeCys), selenocystine (SeCys), selenite [Se(IV)] and selenomethionine (SeMet) was established in this paper using high-performance anion-exchange chromatography coupled with Atomic Fluorescence Spectrometry (HPAEC-AFS). Analytes were separated on an AminoPac PA10 column and then digested by on-line ultraviolet (UV) irradiation, which destroyed organic compound structure. Hydride generation was used as an available sample introduction technique for Atomic Fluorescence detection. The detection limits of four compounds were 1-5 mu g/L (250 mu L injection, 10 times of the baseline noise). The relative standard deviations (RSDs), calculated from seven consecutive injections of 100 mu g/L standard mixtures, were from 2 to 4%. Selenious yeast tablet, which had been proposed as selenium supplement, and human urine collected from a volunteer were analyzed. Good spiked recoveries from 86 to 103% were obtained. (c) 2006 Elsevier B.V. All rights reserved.

Jixin Liu - One of the best experts on this subject based on the ideXlab platform.

  • ferric ion induced enhancement of ultraviolet vapour generation coupled with Atomic Fluorescence Spectrometry for the determination of ultratrace inorganic arsenic in surface water
    Analyst, 2016
    Co-Authors: Yuelong Wang, Jianhua Wang, Jixin Liu, Xuefei Mao, Lingling Lin, Deyuan Qin
    Abstract:

    A novel method of ultraviolet vapour generation (UVG) coupled with Atomic Fluorescence Spectrometry (AFS) was developed for the determination of ultratrace inorganic arsenic (iAs) in surface water. In this work, different ferric species were utilised for the first time as an enhancement reagent for the ultraviolet vapour generation of As(III), and their UVG efficiencies for volatile species of arsenic were investigated. 15 mg L−1 of ferric chloride provided the greatest enhancement of approximately 10-fold, using 20% acetic acid combined with 4% formic acid with 30 s ultraviolet irradiation at 200 mL min−1 Ar/H2 flow rate. Under the optimised conditions, the linear range was 1.0 μg L−1–100.0 μg L−1, and the spiked recoveries were 92%–98%. The limit of detection was 0.05 μg L−1 for iAs, and the relative standard deviation (RSD) value of the repeated measurements was 2.0% (n = 11). This method was successfully applied to the determination of ultratrace iAs in tap water, river water, and lake water samples using 0.2% H2SO4 (v:v) as the sample preserver. The obtained values for the water samples of certified reference materials (CRMs) including GSB-Z50004-200431, GBW08605 and GBW(E)080390 were all within the certified ranges.

  • assessment of homogeneity and minimum sample mass for cadmium analysis in powdered certified reference materials and real rice samples by solid sampling electrothermal vaporization Atomic Fluorescence Spectrometry
    Journal of Agricultural and Food Chemistry, 2013
    Co-Authors: Xuefei Mao, Li Feng, Jixin Liu, Yatao Huang, Lihua Zhang, Xiaoyan Tang, Jian Zhou, Yongzhong Qian, Min Wang
    Abstract:

    To optimize analytical quality controls of solid sampling electrothermal vaporization Atomic Fluorescence Spectrometry (SS-ETV-AFS), the homogeneity (HE) of rice samples and their minimum sample mass (M) for cadmium analysis were evaluated using three certified reference materials (CRMs) and real rice samples. The effects of different grinding degrees (particle sizes 1 mm) on HE and M of real rice samples were also investigated. The calculated M values of three CRMs by the Pauwels equation were 2.19, 19.76, and 3.79 mg. The well-ground real rice samples (particle size <0.25 mm) demonstrated good homogeneity, and the M values were 3.48–4.27 mg. On the basis of these results, the Cd concentrations measured by the proposed method were compared with the results by microwave digestion graphite furnace Atomic absorption Spectrometry with a 0.5 g sample mass. There was no significant difference between these two methods, which meant that SS-ETV-AFS could be used to accurately detect Cd ...

  • solid sampling graphite fibre felt electrothermal Atomic Fluorescence Spectrometry with tungsten coil Atomic trap for the determination of cadmium in food samples
    Journal of Analytical Atomic Spectrometry, 2010
    Co-Authors: Li Feng, Jixin Liu
    Abstract:

    A new solid sampling device and procedure for determination of trace cadmium in food samples by Atomic Fluorescence Spectrometry was developed, which made use of a graphite fibre felt (GFF) as the vaporizer and a tungsten-coil (TC) as the cadmium trap. The procedure was optimized by changing temperature and gas atmosphere at vaporizing, trapping and releasing steps respectively. Under optimized conditions, cadmium in solid sample was vaporized with the matrix by GFF at about 1600 °C, then separated from the matrix by trapping on the TC at room temperature; finally, cadmium was released from TC at 2000 °C and directly determined by a non-dispersion Atomic Fluorescence spectrometer (AFS) without extra atomization. The detection limit (DL) of this procedure was shown to be 30 ng L−1 (0.3 pg); the relative standard deviation (RSD) was less than 5% at 10 μg L−1 (100 pg); and no significant interference was found within a 10% error range. The recoveries for some certified reference materials and the spiked recoveries for some food samples were all satisfied. Furthermore, the mechanism of this procedure was interpreted.

  • a new hydride generation system applied in determination of arsenic species with ion chromatography hydride generation Atomic Fluorescence Spectrometry ic hg afs
    Talanta, 2007
    Co-Authors: Changjin Wei, Jixin Liu
    Abstract:

    A novel procedure was developed for the determination of arsenite (As(III)), arsenate (As(V)), monomethylarsonic (MMA) and dimethylarsinic acid (DMA) with ion chromatography-hydride generation-Atomic Fluorescence Spectrometry (IC-HG-AFS) by employing a new gas-liquid separator (GLS). The effective separation of the four arsenic species was achieved in about 12min. With a sample loading volume of 20mul, the measurable minimum for As(III), DMA, MMA and As(V) were 0.02, 0.045, 0.043 and 0.166ng, respectively, along with relative standard deviations of 1.1, 1.1, 1.7 and 2.2% at the 100mugl(-1) level (n=6) for As(III), DMA, MMA and As(V), respectively. The present procedure was applied for the speciation of arsenic in underground water and in urine samples, and the sum of the four arsenic species by IC-HG-AFS was in good agreement with the total value by HG-AFS.

Chengbin Zheng - One of the best experts on this subject based on the ideXlab platform.

  • application of flow injection green chemical vapor generation Atomic Fluorescence Spectrometry to ultrasensitive mercury speciation analysis of water and biological samples
    Microchemical Journal, 2016
    Co-Authors: Ruoxi Zhang, Chengbin Zheng, Mengting Peng, Xiandeng Hou
    Abstract:

    Abstract A simple, non-chromatographic and green method based on flow injection UV photochemical or ultrasonic vapor generation Atomic Fluorescence Spectrometry (AFS) was developed for the determination and speciation analysis of mercury. Mercury cold vapor (Hg0) was generated by using only formic acid and UV or ultrasonic irradiation, and was subsequently detected by AFS. Both mercury (Hg2 +) and methyl mercury (MeHg) can be converted to Hg0 for the determination of total mercury with UV irradiation, while only Hg2 + can be reduced to Hg0 with ultrasonic irradiation, thus determining only Hg2 +. Then, the concentration of MeHg can be calculated by subtracting the Hg2 + concentration from the total mercury concentration. The optimal conditions for the best cold vapor generation efficiencies are discussed in detail, together with interference from transition metals. This new speciation analysis not only provides high sensitivity for the determination of mercury species but further eliminates the use of toxic reducing reagents and avoids potential destruction of analyte species that occur in chromatographic separation. Moreover, a simpler and less toxic Hg2 + standard series can be used for the calibration of both Hg2 + and MeHg. The limit of detection is 0.005 or 0.01 μg L− 1 for total mercury with the UV or inorganic mercury with the ultrasonic irradiation, respectively. This method was successfully applied to ultrasensitive mercury speciation analysis of water and biological samples.

  • application of preconcentration and separation techniques in Atomic Fluorescence Spectrometry
    Applied Spectroscopy Reviews, 2015
    Co-Authors: Dongyan Deng, Chengbin Zheng, Xiandeng Hou
    Abstract:

    AbstractWith 135 references, this review presents the recent application of various preconcentration and separation techniques in Atomic Fluorescence Spectrometry for the sensitive determination and speciation of various elements and their species. It focuses on sample pretreatment, separation, and enrichment-related techniques, including liquid–liquid extraction, solid-phase (micro)extraction, microwave/ultrasound-assisted extraction, pressurized liquid extraction, as well as chemical vapor generation. In this review, the historical development and overview of these preconcentration and separation methodologies are briefly discussed, together with a comprehensive collection of application of these methods in combination with Atomic Fluorescence Spectrometry for determination of ultratrace amounts of elements and their species in various sample matrices (liquids and solids).

  • dual mode chemical vapor generation for simultaneous determination of hydride forming and non hydride forming elements by Atomic Fluorescence Spectrometry
    Analyst, 2014
    Co-Authors: Yu Wang, Xiandeng Hou, Xiaoming Jiang, Chengbin Zheng
    Abstract:

    A dual-mode chemical vapor generation integrating hydride generation and photochemical vapor generation was developed for simultaneous multi-element analysis of hydride-forming and non-hydride-forming elements by Atomic Fluorescence Spectrometry. Four elements were selected as model elements of hydride-forming (As, Cd) and non-hydride-forming (Ni, Fe) elements to validate this proposed method. Standard or sample solutions were separately pumped to mix with tetrahydroborate, and concentrated formic acid and ammonia, and then directed to a hydride generator and a photochemical reactor to realize simultaneous hydride generation and photochemical vapor generation, respectively. Optimum conditions for dual-mode chemical vapor generation were carefully investigated. Under the optimized conditions, limits of detection of 0.05, 0.008, 0.8 and 0.1 μg L−1 were obtained for As, Cd, Fe and Ni, respectively. The precisions were 5.0, 5.5, 4.3 and 4.5% (n = 6, RSDs) for 2 μg L−1 of As, 1 μg L−1 of Cd, 50 μg L−1 of Fe and 10 μg L−1 of Ni, respectively. This method was validated for accuracy with three certified reference water samples and applied to the simultaneous determination of these elements in a tap water sample with spike recoveries in the range of 95–99%.

  • improved hydride generation Atomic Fluorescence Spectrometry for determination of trace lead minimization of blank from potassium ferricyanide
    Analytical Methods, 2012
    Co-Authors: Ke Huang, Chengbin Zheng, Hui Xia, Ying Gao, Xiandeng Hou
    Abstract:

    A new efficient method was described for the purification of K3[Fe(CN)6] for the purpose of minimization of the blank in the determination of trace lead by hydride generation-Atomic Fluorescence Spectrometry using the HCl–K3[Fe(CN)6]–KBH4 system. The lead impurity in K3[Fe(CN)6] solution was removed by reacting with KBH4 to form PbH4, which was efficiently separated from the solution by a nitrogen gas flow. The purified K3[Fe(CN)6] was obtained via Cl2 oxidation and subsequent ethanol purification of its reduced compound. The optimum conditions for hydride generation of lead and purification of K3[Fe(CN)6] were carefully investigated. A limit of detection (LOD) of 0.05 μg L−1 was obtained, 100-fold better than that achieved with unpurified K3[Fe(CN)6]. The accuracy of the proposed method was validated by analyzing a Certified Reference hair sample (GBW07610) and two ore samples (GBW07106 and GBW07112) with satisfactory analytical results.

  • microwave enhanced cold vapor generation for speciation analysis of mercury by Atomic Fluorescence Spectrometry
    Talanta, 2012
    Co-Authors: Li Wu, Zhou Long, Qin Zhou, Chengbin Zheng
    Abstract:

    Abstract A new and simple cold vapor generation technique utilizing microwave irradiation coupled with Atomic Fluorescence Spectrometry is developed for the speciation analysis of mercury in biological and geological samples. In the presence of formic acid, inorganic mercury (Hg 2+ ) and total mercury (both Hg 2+ and methylmercury (MeHg)) can be converted to mercury cold vapor (Hg 0 ) by microwave irradiation without and with H 2 O 2 , respectively. The cold vapor was subsequently released from the liquid phase and rapidly transported to an Atomic Fluorescence spectrometer for the mercury detection. Optimum conditions for vapor generation as well as interferences from concomitant ions were carefully investigated. The conventionally required evaporation of the remnants of acid or oxidants was avoided because no significant interferences from these substances were observed, and thus analyte loss and potential contamination were minimized. A limit of detection of 0.005 ng mL −1 for total mercury or inorganic mercury was obtained. A precision of less than 3% (RSD) at 2 μg L −1 of mercury species was typical. The accuracy of the method was validated by determination of mercury in geological and biological certified reference materials. The speciation analysis of Hg 2+ and MeHg was achieved by controlling the conditions of microwave-enhanced cold vapor generation and validated via determination of Certified Reference Materials DORM-2, DORM-3 and a real river water sample.

Víctor Cerdà - One of the best experts on this subject based on the ideXlab platform.

  • Masking Agents Evaluation for Lead Determination by Flow Injection-Hydride Generation-Atomic Fluorescence Spectrometry Technique: Effect of KI, L-Cysteine, and 1,10-Phenanthroline.
    International journal of analytical chemistry, 2016
    Co-Authors: Blanca G. Beltrán, Luz O. Leal, Laura Ferrer, Víctor Cerdà
    Abstract:

    Hydride generation (HG) of lead technique presents interferences from foreign ions of complex matrix samples. In order to minimize these interferences, the effect of masking agents such as KI, L-cysteine, and 1,10-phenanthroline was studied in the absence and in the presence of selected interfering species (As, Cr, Cu, and Fe). Different modes of addition of masking agents were accomplished, that is, to either sample or KBH4 reducing solution. The lead determinations were performed using a flow injection analysis (FIA) system coupled to HG and Atomic Fluorescence Spectrometry (AFS). The linearity of calibration curves (1–10 μg Pb L−1) was not affected by the addition of the masking agents. The use of KI in the reducing solution diminished interferences from concentrations of As and Cu, while 1,10-phenanthroline showed a positive effect on the interference by As. Moreover, Cr and Cu appeared to be the most serious interfering ions for plumbane (PbH4), because they drastically reduced the analytical signal of lead. Fe did not present any interference under the employed experimental conditions, even at high levels. The accuracy was established through the analysis of certified reference material (i.e., BCR-610, groundwater) using KI as masking agent. The detection limit reached by FIA-HG-AFS proposed methodology was 0.03 μg Pb L−1.

  • Determination of lead in complex sample matrices by Atomic Fluorescence Spectrometry: optimisation of online hydride generation.
    International Journal of Environmental Analytical Chemistry, 2015
    Co-Authors: Blanca G. Beltrán, Luz O. Leal, Laura Ferrer, Víctor Cerdà
    Abstract:

    Lead hydride or plumbane (PbH4) generation was optimised by exploiting a simple flow-injection method coupled to Atomic Fluorescence Spectrometry (HG-AFS), and allowing ultra-trace lead determination. Plumbane was generated through two methods: (1) 5% (v/v) H2O2 was employed as oxidant with 1.5% (m/v) KBH4 as a reducing agent and 1.5% (v/v) HCl solution; (2) with 1.5% (m/v) K3[Fe(CN)6] as an oxidant/sensitiser, 1% (m/v) KBH4 as a reducing agent and 1.5% (v/v) HCl. Variables such as reagent concentrations, flow rates and sample and reagent volumes were tested and critically compared. The best results were obtained with potassium ferricyanide K3[Fe(CN)6], achieving a detection limit of 0.03 μg Pb L−1 and a relative standard deviation (RSD) of 1.1%. The selected method was validated by analysis of certified reference materials such as SRM-2976 (mussel tissue) and BCR-610 (groundwater), with good agreement with the certified values. The developed methodology was successfully applied to different environmental...

  • applicability of multisyringe chromatography coupled to cold vapor Atomic Fluorescence Spectrometry for mercury speciation analysis
    Analytica Chimica Acta, 2011
    Co-Authors: J L Guzmanmar, L Hinojosareyes, Antonio M Serra, Aracely Hernandezramirez, Víctor Cerdà
    Abstract:

    Abstract In this paper, a novel automatic approach for the speciation of inorganic mercury (Hg 2+ ), methylmercury (MeHg + ) and ethylmercury (EtHg + ) using multisyringe chromatography (MSC) coupled to cold-vapor Atomic Fluorescence Spectrometry (CV/AFS) was developed. For the first time, the separation of mercury species was accomplished on a RP C18 monolithic column using a multi-isocratic elution program. The elution protocol involved the use of 0.005% 2-mercapthoethanol in 240 mM ammonium acetate (pH 6)–acetonitrile (99:1, v/v), followed by 0.005% 2-mercapthoethanol in 240 mM ammonium acetate (pH 6)–acetonitrile (90:10, v/v). The eluted mercury species were then oxidized under post-column UV radiation and reduced using tin(II) chloride in an acidic medium. Subsequently, the generated mercury metal were separated from the reaction mixture and further atomized in the flame atomizer and detected by AFS. Under the optimized experimental conditions, the limits of detection (3 σ ) were found to be 0.03, 0.11 and 0.09 μg L −1 for MeHg + , Hg 2+ and EtHg + , respectively. The relative standard deviation (RSD, n  = 6) of the peak height for 3, 6 and 3 μg L −1 of MeHg + , Hg 2+ and EtHg + (as Hg) ranged from 2.4 to 4.0%. Compared with the conventional HPLC–CV/AFS hyphenated systems, the proposed MSC–CV/AFS system permitted a higher sampling frequency and low instrumental and operational costs. The developed method was validated by the determination of a certified reference material DORM-2 (dogfish muscle), and was further applied for the determination of mercury species environmental and biological samples.

  • hyphenating multisyringe flow injection lab on valve analysis with Atomic Fluorescence Spectrometry for on line bead injection preconcentration and determination of trace levels of hydride forming elements in environmental samples
    Analytical Chemistry, 2006
    Co-Authors: Xiangbao Long, Manuel Miro, Elo Harald Hansen, Jose Manuel Estela, Víctor Cerdà
    Abstract:

    In this work the third generation of flow injection analysis, that is, the so-called micro-lab-on-valve (μLOV) approach, is proposed for the first time for the separation, preconcentration, and monitoring of metalloids as hyphenated with Atomic Fluorescence Spectrometry (AFS). This was made feasible by interfacing the micromachined LOV-module with AFS by a multisyringe flowing stream network for on-line postcolumn derivatization of the eluate aimed at generation of hydride species. The potential of this new hyphenated technique for environmental assays was ascertained via determination of ultratrace level concentrations of total inorganic arsenic in freshwater. Employing quantitative preoxidation of As(III) to As(V) in the samples by means of permanganate, the method involves preconcentration of arsenate at pH 10 on a renewable anion exchanger, namely, Q-Sepharose, packed in a LOV microcolumn. The analyte species is afterward stripped out and concurrently prereduced by a 300 μL eluent plug containing 6 mo...

  • sequential injection analysis system for total inorganic arsenic determination by hydride generation Atomic Fluorescence Spectrometry
    Analytica Chimica Acta, 2000
    Co-Authors: N V Semenova, F Bauza M De Mirabo, R Forteza, Víctor Cerdà
    Abstract:

    Abstract A sequential injection analysis system is proposed for total inorganic arsenic determination by hydride generation-Atomic Fluorescence Spectrometry. The sample, a reducing sodium tetrahydroborate solution and a blank solution containing HCl, ascorbic acid and potassium iodide are sequentially aspirated and then dispensed into a gas–liquid separation cell. An Ar flow sweeps the arsine into the flame of an Atomic Fluorescence spectrometer. An auxiliary H 2 flow was necessary to support the flame. Linear calibration graphs were obtained for arsenic concentrations between 2.5 and 50 μg l −1 , the detection limit (3 σ b / S ) being 0.67 μg l −1 . The relative standard deviation of the method was 1.8% ( n =9) when 0.5 ml of a 20 μg l −1 As standard solution was aspirated. The sample throughput was 33 samples per hour. The proposed method has been validated by means of reference materials and the results obtained were in good agreement with the certified values.