A new issue of this journal has just
been published. To see abstracts of the papers it contains (with links through
to the full papers) click here:
Selected
papers from the latest issue:
Dual-color upconversion fluorescence and aptamer-functionalized magnetic nanoparticles-based bioassay for the simultaneous detection of Salmonella Typhimurium and Staphylococcus aureus
26 March 2012,
09:47:20
Publication year:
2012
Source:Analytica Chimica Acta, Volume 723
Nuo Duan, Shijia Wu, Changqing Zhu, Xiaoyuan Ma, Zhouping Wang, Ye Yu, Yuan Jiang
A sensitive luminescent bioassay for the simultaneous detection of Salmonella Typhimurium and Staphylococcus aureus was developed using aptamer-conjugated magnetic nanoparticles (MNPs) for both recognition and concentration elements and using upconversion nanoparticles (UCNPs) as highly sensitive dual-color labels. The bioassay system was fabricated by immobilizing aptamer 1 and aptamer 2 onto the surface of MNPs, which were employed to capture and concentrate S. Typhimurium and S. aureus. NaY0.78F4:Yb0.2,Tm0.02 UCNPs modified aptamer 1 and NaY0.28F4:Yb0.70,Er0.02 UCNPs modified aptamer 2 further were bond onto the captured bacteria surface to form sandwich-type complexes. Under optimal conditions, the correlation between the concentration of S. Typhimurium and the luminescent signal was found to be linear within the range of 101–105 cfumL−1 (R 2 =0.9964), and the signal was in the range of 101–105 cfumL−1 (R 2 =0.9936) for S. aureus. The limits of detection of the developed method were found to be 5 and 8cfumL−1 for S. Typhimurium and S. aureus, respectively. The ability of the bioassay to detect S. Typhimurium and S. aureus in real water samples was also investigated, and the results were compared to the experimental results from the plate-counting methods. Improved by the magnetic separation and concentration effect of MNPs, the high sensitivity of UCNPs, and the different emission lines of Yb/Er- and Yb/Tm-doped NaYF4 UCNPs excited by a 980nm laser, the present method performs with both high sensitivity and selectivity for the two different types of bacteria.
Source:Analytica Chimica Acta, Volume 723
Nuo Duan, Shijia Wu, Changqing Zhu, Xiaoyuan Ma, Zhouping Wang, Ye Yu, Yuan Jiang
A sensitive luminescent bioassay for the simultaneous detection of Salmonella Typhimurium and Staphylococcus aureus was developed using aptamer-conjugated magnetic nanoparticles (MNPs) for both recognition and concentration elements and using upconversion nanoparticles (UCNPs) as highly sensitive dual-color labels. The bioassay system was fabricated by immobilizing aptamer 1 and aptamer 2 onto the surface of MNPs, which were employed to capture and concentrate S. Typhimurium and S. aureus. NaY0.78F4:Yb0.2,Tm0.02 UCNPs modified aptamer 1 and NaY0.28F4:Yb0.70,Er0.02 UCNPs modified aptamer 2 further were bond onto the captured bacteria surface to form sandwich-type complexes. Under optimal conditions, the correlation between the concentration of S. Typhimurium and the luminescent signal was found to be linear within the range of 101–105 cfumL−1 (R 2 =0.9964), and the signal was in the range of 101–105 cfumL−1 (R 2 =0.9936) for S. aureus. The limits of detection of the developed method were found to be 5 and 8cfumL−1 for S. Typhimurium and S. aureus, respectively. The ability of the bioassay to detect S. Typhimurium and S. aureus in real water samples was also investigated, and the results were compared to the experimental results from the plate-counting methods. Improved by the magnetic separation and concentration effect of MNPs, the high sensitivity of UCNPs, and the different emission lines of Yb/Er- and Yb/Tm-doped NaYF4 UCNPs excited by a 980nm laser, the present method performs with both high sensitivity and selectivity for the two different types of bacteria.
Graphical Abstract
Graphical abstract Highlights
Fabrication process of biofunctionalized nanoparticles and principle of the performed bioassay. First, aptamer 1 and aptamer 2 were immobilized onto the surface of MNPs and the surface of NaY0.78F4:Yb0.2, Tm0.02 UCNPs, and NaY0.28F4:Yb0.70, Er0.02 UCNPs. Next, S. Typhimurium and S. aureus were added and, due to the highly affinity of aptamer to corresponding bacteria, the aptamer 1-MNPs-S. Typhimurium complex bind NaY0.78F4:Yb0.2, Tm0.02 UCNPs modified aptamer 1, and the aptamer 2-MNPs-S. aureus bind NaY0.28F4:Yb0.70, Er0.02 UCNPs modified aptamer 2. Finally, the luminescent signal was effectively amplified with the help of a magnetic field. ► Simultaneous detection of two kind of bacteria. ► Bacteria-specific aptamer recognition. ► Dual-color upconversion luminescent nanoparticles labeling. ► Aptamer conjugated-magnetic nanoparticles-based separation and concentration.Semi-automated alignment and quantification of peaks using parallel factor analysis for comprehensive two-dimensional liquid chromatography–diode array detector data sets
26 March 2012,
09:47:20
Publication year:
2012
Source:Analytica Chimica Acta, Volume 723
Robert C. Allen, Sarah C. Rutan
Parallel factor analysis was used to quantify the relative concentrations of peaks within four-way comprehensive two dimensional liquid chromatography–diode array detector data sets. Since parallel factor analysis requires that the retention times of peaks between each injection are reproducible, a semi-automated alignment method was developed that utilizes the spectra of the compounds to independently align the peaks without the need for a reference injection. Peak alignment is achieved by shifting the optimized chromatographic component profiles from a three-way parallel factor analysis model applied to each injection. To ensure accurate shifting, components are matched up based on their spectral signature and the position of the peak in both chromatographic dimensions. The degree of shift, for each peak, is determined by calculating the distance between the median data point of the respective dimension (in either the second or first chromatographic dimension) and the maximum data point of the peak furthest from the median. All peaks that were matched to this peak are then aligned to this common retention data point. Target analyte recoveries for four simulated data sets were within 2% of 100% recovery in all cases. Two different experimental data sets were also evaluated. Precision of quantification of two spectrally similar and partially coeluting peaks present in urine was as good as or better than 4%. Good results were also obtained for a challenging analysis of phenytoin in waste water effluent, where the results of the semi-automated alignment method agreed with the reference LC–LC MS/MS method within the precision of the methods.
Source:Analytica Chimica Acta, Volume 723
Robert C. Allen, Sarah C. Rutan
Parallel factor analysis was used to quantify the relative concentrations of peaks within four-way comprehensive two dimensional liquid chromatography–diode array detector data sets. Since parallel factor analysis requires that the retention times of peaks between each injection are reproducible, a semi-automated alignment method was developed that utilizes the spectra of the compounds to independently align the peaks without the need for a reference injection. Peak alignment is achieved by shifting the optimized chromatographic component profiles from a three-way parallel factor analysis model applied to each injection. To ensure accurate shifting, components are matched up based on their spectral signature and the position of the peak in both chromatographic dimensions. The degree of shift, for each peak, is determined by calculating the distance between the median data point of the respective dimension (in either the second or first chromatographic dimension) and the maximum data point of the peak furthest from the median. All peaks that were matched to this peak are then aligned to this common retention data point. Target analyte recoveries for four simulated data sets were within 2% of 100% recovery in all cases. Two different experimental data sets were also evaluated. Precision of quantification of two spectrally similar and partially coeluting peaks present in urine was as good as or better than 4%. Good results were also obtained for a challenging analysis of phenytoin in waste water effluent, where the results of the semi-automated alignment method agreed with the reference LC–LC MS/MS method within the precision of the methods.
Graphical Abstract
Graphical abstract Highlights
Three replicate injections of a localized region of a LC×LC–DAD data set. ► We describe a spectrally based alignment method for LC×LC–DAD data. ► Alignment between injections is not dependent on selection of a reference injection. ► The alignment process allows for non-linear peak shifting between injections. ► Simulated data sets aligned by this method produced % recoveries close to 100%. ► The method was able to align and quantify experimental data with overlapping peaks.Tucker core consistency for validation of restricted Tucker3 models
26 March 2012,
09:47:20
Publication year:
2012
Source:Analytica Chimica Acta, Volume 723
Mohsen Kompany-Zareh, Yousef Akhlaghi, Rasmus Bro
In Tucker3 analysis of three-way data array obtained from a chemical or biological system, it is sometimes possible to use a priori knowledge about the system to specify what is called a restricted Tucker3 model. Often, the restricted Tucker3 model is characterized by having some elements of the core forced to zero. As a simple example, an F-component PARAFAC model can be seen as a restricted (F, F, F) Tucker3 model in which only superdiagonal elements of the core are allowed to be nonzero. The core consistency diagnostic was previously introduced by Bro and Kiers for determining the proper number of components in PARAFAC analysis. In the current study, this diagnostic is extended to other restricted Tucker3 models to validate the appropriateness of the applied constraints. The new diagnostic is named Tucker core consistency (TuckCorCon). When the dimensionality and the pattern of the restricted core is valid, the simple core of restricted Tucker3 model and a corresponding unrestricted core will be similar and in this case the TuckCorCon will be close to maximum (100%). A simulated chemical equilibrium data set and two experimental data sets were used to evaluate the applicability of the TuckCorCon to decide about the appropriateness of dimensionality and pattern of the core nonzero elements in the restricted Tucker3 models.
Source:Analytica Chimica Acta, Volume 723
Mohsen Kompany-Zareh, Yousef Akhlaghi, Rasmus Bro
In Tucker3 analysis of three-way data array obtained from a chemical or biological system, it is sometimes possible to use a priori knowledge about the system to specify what is called a restricted Tucker3 model. Often, the restricted Tucker3 model is characterized by having some elements of the core forced to zero. As a simple example, an F-component PARAFAC model can be seen as a restricted (F, F, F) Tucker3 model in which only superdiagonal elements of the core are allowed to be nonzero. The core consistency diagnostic was previously introduced by Bro and Kiers for determining the proper number of components in PARAFAC analysis. In the current study, this diagnostic is extended to other restricted Tucker3 models to validate the appropriateness of the applied constraints. The new diagnostic is named Tucker core consistency (TuckCorCon). When the dimensionality and the pattern of the restricted core is valid, the simple core of restricted Tucker3 model and a corresponding unrestricted core will be similar and in this case the TuckCorCon will be close to maximum (100%). A simulated chemical equilibrium data set and two experimental data sets were used to evaluate the applicability of the TuckCorCon to decide about the appropriateness of dimensionality and pattern of the core nonzero elements in the restricted Tucker3 models.
Graphical Abstract
Graphical abstract Highlights
. ► Tucker core consistency (TuckCorCon) parameter is presented for the first time. ► TuckCorCon can be used to evaluate the Tucker3 models with simplified cores. ► TuckCorCon is close to 100 for a good simple core and it is low for a bad one. ► TuckCorCon was tested and approved using simulated and experimental data sets. ► The TuckCorCon parameter helps to decide about the proper size of the core.Electrochemical detection of a powerful estrogenic endocrine disruptor: Ethinylestradiol in water samples through bioseparation procedure
26 March 2012,
09:47:20
Publication year:
2012
Source:Analytica Chimica Acta, Volume 723
Noelia A. Martínez, Sirley V. Pereira, Franco A. Bertolino, Rudolf J. Schneider, Germán A. Messina, Julio Raba
The synthetic estrogen ethinylestradiol (EE2) is an active component of oral contraceptives (OCs), considered as an endocrine disrupting compound (EDC). It is excreted from humans and released via sewage treatment plant effluents into aquatic environments. EDCs are any environmental pollutant chemical that, once incorporated into an organism, affects the hormonal balance of various species including humans. Its presence in the environment is becoming of great importance in water quality. This paper describes the development of an accurate, sensitive and selective method for capture, preconcentration and determination of EE2 present in water samples using: magnetic particles (MPs) as bioaffinity support for the capture and preconcentration of EE2 and a glassy carbon electrode modified with multi-walled carbon nanotubes (MWCNTs/GCE) as detection system. The capture procedure was based on the principle of immunoaffinity, the EE2 being extracted from the sample using the anti-EE2 antibodies (anti-EE2 Ab) which were previously immobilized on MPs. Subsequently the analyte desorption was done employing a sulfuric acid solution and the determination of the EE2 in the pre-concentrated solution was carried out by square wave voltammetry (SWV). This method can be used to determine EE2 in the range of 0.035–70ngL−1 with a detection limit (LOD) of 0.01ngL−1 and R.S.D.<4.20%. The proposed method has been successfully applied to the determination of EE2 in water samples and it has promising analytical applications for the direct determination of EE2 at trace levels.
Source:Analytica Chimica Acta, Volume 723
Noelia A. Martínez, Sirley V. Pereira, Franco A. Bertolino, Rudolf J. Schneider, Germán A. Messina, Julio Raba
The synthetic estrogen ethinylestradiol (EE2) is an active component of oral contraceptives (OCs), considered as an endocrine disrupting compound (EDC). It is excreted from humans and released via sewage treatment plant effluents into aquatic environments. EDCs are any environmental pollutant chemical that, once incorporated into an organism, affects the hormonal balance of various species including humans. Its presence in the environment is becoming of great importance in water quality. This paper describes the development of an accurate, sensitive and selective method for capture, preconcentration and determination of EE2 present in water samples using: magnetic particles (MPs) as bioaffinity support for the capture and preconcentration of EE2 and a glassy carbon electrode modified with multi-walled carbon nanotubes (MWCNTs/GCE) as detection system. The capture procedure was based on the principle of immunoaffinity, the EE2 being extracted from the sample using the anti-EE2 antibodies (anti-EE2 Ab) which were previously immobilized on MPs. Subsequently the analyte desorption was done employing a sulfuric acid solution and the determination of the EE2 in the pre-concentrated solution was carried out by square wave voltammetry (SWV). This method can be used to determine EE2 in the range of 0.035–70ngL−1 with a detection limit (LOD) of 0.01ngL−1 and R.S.D.<4.20%. The proposed method has been successfully applied to the determination of EE2 in water samples and it has promising analytical applications for the direct determination of EE2 at trace levels.
Graphical Abstract
Graphical abstract Highlights
► We developed an electrochemical method for the determination of ethinylestradiol in water samples. ► Modified magnetic particles were employed for the bioseparation and preconcentration procedures. ► The use of magnetic particles offers high selectivity due to antigen–antibody binding specificity. ► The detection was carried out by using a glassy carbon electrode modified with carbon nanotubes.Electrochemical sensor for naphthols based on gold nanoparticles/hollow nitrogen-doped carbon microsphere hybrids functionalized with SH-β-cyclodextrin
26 March 2012,
09:47:20
Publication year:
2012
Source:Analytica Chimica Acta, Volume 723
Gangbing Zhu, Pengbo Gai, Yan Yang, Xiaohua Zhang, Jinhua Chen
Due to awfully harmful to the environment and human health, the qualitative and quantitative determinations of naphthols [1-naphthol (1-NAP) and 2-naphthol (2-NAP)] are of great significance and receive great attention. In this paper, gold nanoparticles (AuNPs)/hollow nitrogen-doped carbon microspheres (HNCMS) hybrids (AuNPs/HNCMS) were prepared and functionalized with thiolated-β-cyclodextrin (HS-β-CD) for the first time, and then applied successfully in sensitive and simultaneous electrochemical detection of naphthols. The results show that the oxidation peak currents of naphthols obtained on the HS-β-CD/AuNPs/HNCMS modified glassy carbon (GC) electrode are much higher than that on the AuNPs/HNCMS/GC, HNCMS/GC and bare GC electrodes. Additionally, compared with other electrochemical sensors developed previously, the proposed electrode results in improved detection limits of about four times for 1-NAP (1.0nM) and two orders of magnitude for 2-NAP (1.2nM). The linear response ranges of both 1-NAP and 2-NAP are 2–150nM.
Source:Analytica Chimica Acta, Volume 723
Gangbing Zhu, Pengbo Gai, Yan Yang, Xiaohua Zhang, Jinhua Chen
Due to awfully harmful to the environment and human health, the qualitative and quantitative determinations of naphthols [1-naphthol (1-NAP) and 2-naphthol (2-NAP)] are of great significance and receive great attention. In this paper, gold nanoparticles (AuNPs)/hollow nitrogen-doped carbon microspheres (HNCMS) hybrids (AuNPs/HNCMS) were prepared and functionalized with thiolated-β-cyclodextrin (HS-β-CD) for the first time, and then applied successfully in sensitive and simultaneous electrochemical detection of naphthols. The results show that the oxidation peak currents of naphthols obtained on the HS-β-CD/AuNPs/HNCMS modified glassy carbon (GC) electrode are much higher than that on the AuNPs/HNCMS/GC, HNCMS/GC and bare GC electrodes. Additionally, compared with other electrochemical sensors developed previously, the proposed electrode results in improved detection limits of about four times for 1-NAP (1.0nM) and two orders of magnitude for 2-NAP (1.2nM). The linear response ranges of both 1-NAP and 2-NAP are 2–150nM.
Graphical Abstract
Graphical abstract Highlights
► HS-β-CD/AuNPs/hollow nitrogen-doped carbon microspheres hybrids were synthesized. ► A new electrochemical sensor for naphthols was developed based on the prepared hybrids. ► The sensor shows good analytical performance for simultaneous detection of naphthols.Nonenzymatic glucose sensor based on CuO microfibers composed of CuO nanoparticles
26 March 2012,
09:47:20
Publication year:
2012
Source:Analytica Chimica Acta, Volume 723
Fei Cao, Jian Gong
Fluorine tin oxide (FTO) electrode modified by copper oxide microfibers (CuO-MFs) composed of numerous interconnected CuO nanoparticles (CuO-NPs) for nonenzymatic glucose sensor was prepared by electrospinning precursor containing high percentage content of copper nitrate with subsequent calcination. The results of scanning electron microscope (SEM) showed the size of CuO particles composing CuO-MFs depended on the percentage content of copper nitrate in precursor solution. With increasing the percentage content of copper nitrate, the interconnected CuO-NPs would gradually replace the large-size CuO particles to accumulate the CuO-MFs, which have the potential to provide larger surface area and more reaction sites for electrocatalytic activity toward glucose. As a glucose sensor, the CuO-MFs modified FTO electrode prepared by 40wt.% of copper nitrate exhibited a high sensitivity of 2321μAmM−1 cm−2 with a low detection limit of 2.2nM (signal/noise ratio (S/N)=3). Additionally, the application of the CuO-MFs modified FTO electrode as a glucose sensor for biological samples was demonstrated with satisfactory results.
Source:Analytica Chimica Acta, Volume 723
Fei Cao, Jian Gong
Fluorine tin oxide (FTO) electrode modified by copper oxide microfibers (CuO-MFs) composed of numerous interconnected CuO nanoparticles (CuO-NPs) for nonenzymatic glucose sensor was prepared by electrospinning precursor containing high percentage content of copper nitrate with subsequent calcination. The results of scanning electron microscope (SEM) showed the size of CuO particles composing CuO-MFs depended on the percentage content of copper nitrate in precursor solution. With increasing the percentage content of copper nitrate, the interconnected CuO-NPs would gradually replace the large-size CuO particles to accumulate the CuO-MFs, which have the potential to provide larger surface area and more reaction sites for electrocatalytic activity toward glucose. As a glucose sensor, the CuO-MFs modified FTO electrode prepared by 40wt.% of copper nitrate exhibited a high sensitivity of 2321μAmM−1 cm−2 with a low detection limit of 2.2nM (signal/noise ratio (S/N)=3). Additionally, the application of the CuO-MFs modified FTO electrode as a glucose sensor for biological samples was demonstrated with satisfactory results.
Graphical Abstract
Graphical abstract Highlights
► Electrospinning CuO microfibers onto electrodes as glucose sensors were studied. ► The CuO microfibers were composed of CuO particles. ► Size of CuO particles relies on percentage content of copper nitrate in precursor. ► Performance of the sensor depends on size of CuO particles.Bovine serum albumin recognition via thermosensitive molecular imprinted macroporous hydrogels prepared at two different temperatures
26 March 2012,
09:47:20
Publication year:
2012
Source:Analytica Chimica Acta, Volume 723
Dan Ran, Yuzhi Wang, Xiaopin Jia, Chan Nie
A novel temperature-sensitive molecular imprinted hydrogel composed of 2-acrylamido-2-methyl-propanosulfonic acid (AMPS), N-isopropylacrylamide (NIPAm) and acrylamide (AAm) has been prepared by free-radical cross-linking copolymerization in aqueous solution under two different temperatures (25°C and −20°C). Bovine serum albumin (BSA, pI 4.9, MW 66.0kDa) is used as the template protein. The influence of the external temperature stimuli on the affinity of the hydrogels was investigated, and the optimal binding conditions were tested. The adsorption capacity (Q max) and association constant (K) for the specific interaction between the hydrogel and the template protein were determined by Langmuir isotherm plots. Several types of reference protein, which are different in molecular weights and isoelectric points were chosen to investigate the selectivity of the hydrogels. It was shown that the shape memory and the charge effect were the major factors for the recognition. This imprinted hydrogel was used to specifically adsorb the BSA from the protein mixture and real sample, which demonstrated its potential selectivity.
Source:Analytica Chimica Acta, Volume 723
Dan Ran, Yuzhi Wang, Xiaopin Jia, Chan Nie
A novel temperature-sensitive molecular imprinted hydrogel composed of 2-acrylamido-2-methyl-propanosulfonic acid (AMPS), N-isopropylacrylamide (NIPAm) and acrylamide (AAm) has been prepared by free-radical cross-linking copolymerization in aqueous solution under two different temperatures (25°C and −20°C). Bovine serum albumin (BSA, pI 4.9, MW 66.0kDa) is used as the template protein. The influence of the external temperature stimuli on the affinity of the hydrogels was investigated, and the optimal binding conditions were tested. The adsorption capacity (Q max) and association constant (K) for the specific interaction between the hydrogel and the template protein were determined by Langmuir isotherm plots. Several types of reference protein, which are different in molecular weights and isoelectric points were chosen to investigate the selectivity of the hydrogels. It was shown that the shape memory and the charge effect were the major factors for the recognition. This imprinted hydrogel was used to specifically adsorb the BSA from the protein mixture and real sample, which demonstrated its potential selectivity.
Graphical Abstract
Graphical abstract Highlights
► The preparation of thermo-sensitive molecular imprinted hydrogel (MIH) for the template BSA. ► Choosing 2-acrylamido-2-methyl-propanosulfonic acid (AMPS), N-isopropylacrylamide (NIPAm) and acrylamide (AAm) as the monomers. ► Temperature, functional monomer and cross-linking degree were optimized respectively. ► The MIH were characterized by FT-IR and SEM, and investigated by different adsorption experiments. ► The selectivity of the MIH was verified by direct adsorption of single reference protein, protein mixture and real sample.Cadmium (II) imprinted 3-mercaptopropyltrimethoxysilane coated stir bar for selective extraction of trace cadmium from environmental water samples followed by inductively coupled plasma mass spectrometry detection
26 March 2012,
09:47:20
Publication year:
2012
Source:Analytica Chimica Acta, Volume 723
Nan Zhang, Bin Hu
Cd(II) imprinted 3-mercaptopropyltrimethoxysilane (MPTS)-silica coated stir bar was prepared by sol–gel technique combining with a double-imprinting concept for the first time and was employed for stir bar sorptive extraction (SBSE) of trace Cd(II) from water samples followed by inductively coupled plasma mass spectrometry (ICP-MS) detection. A tetramethoxysilane (TMOS) coating was first in situ created on the glass bar surface. Afterward, a sol solution containing MPTS as the functional precursor, ethanol as the solvent and both Cd(II) and surfactant micelles (cetyltrimethylammonium bromide, CTAB) as the template was again coated on the TMOS bar. The structures of the stir bar coating were characterized by FT-IR spectroscopy. Round-bottom vial was used for the extraction of Cd(II) by SBSE to avoid abrasion of stir bar coatings. The factors affecting the extraction of Cd(II) by SBSE such as pH, stirring rate and time, sample/elution volume and interfering ions have been investigated in detail, and the optimized experimental parameters were obtained. Under the optimized conditions, the adsorption capacities of non-imprinted and imprinted coating stir bars were found to be 0.5μg and 0.8μgbar−1. The detection limit (3σ) based on three times standard deviations of the method blanks by 7 replicates was 4.40ngL−1 and the relative standard deviation (RSD) was 3.38% (c =1μgL−1, n =7). The proposed method was successfully applied for the analysis of trace Cd(II) in rain water, East Lake and Yangtze River water. To validate the proposed method, certified reference material of GSBZ 50009-88 environmental water was analyzed and the determined value is in a good agreement with the certified value. The developed method is rapid, selective, sensitive and applicable for the analysis of trace Cd(II) in environmental water samples.
Source:Analytica Chimica Acta, Volume 723
Nan Zhang, Bin Hu
Cd(II) imprinted 3-mercaptopropyltrimethoxysilane (MPTS)-silica coated stir bar was prepared by sol–gel technique combining with a double-imprinting concept for the first time and was employed for stir bar sorptive extraction (SBSE) of trace Cd(II) from water samples followed by inductively coupled plasma mass spectrometry (ICP-MS) detection. A tetramethoxysilane (TMOS) coating was first in situ created on the glass bar surface. Afterward, a sol solution containing MPTS as the functional precursor, ethanol as the solvent and both Cd(II) and surfactant micelles (cetyltrimethylammonium bromide, CTAB) as the template was again coated on the TMOS bar. The structures of the stir bar coating were characterized by FT-IR spectroscopy. Round-bottom vial was used for the extraction of Cd(II) by SBSE to avoid abrasion of stir bar coatings. The factors affecting the extraction of Cd(II) by SBSE such as pH, stirring rate and time, sample/elution volume and interfering ions have been investigated in detail, and the optimized experimental parameters were obtained. Under the optimized conditions, the adsorption capacities of non-imprinted and imprinted coating stir bars were found to be 0.5μg and 0.8μgbar−1. The detection limit (3σ) based on three times standard deviations of the method blanks by 7 replicates was 4.40ngL−1 and the relative standard deviation (RSD) was 3.38% (c =1μgL−1, n =7). The proposed method was successfully applied for the analysis of trace Cd(II) in rain water, East Lake and Yangtze River water. To validate the proposed method, certified reference material of GSBZ 50009-88 environmental water was analyzed and the determined value is in a good agreement with the certified value. The developed method is rapid, selective, sensitive and applicable for the analysis of trace Cd(II) in environmental water samples.
Graphical Abstract
No comments:
Post a Comment