A simple and sensitive method is presented for solid phase extraction (SPE) and preconcentration of trace quantities of beryllium using octadecyl silica gel modifed with aurin tricarboxylic acid (aluminon). Beryllium is then determined by flame atomic absorption spectroscopy. Parameters affecting SPE such as pH, sample solution and eluent flow rate, type, concentration and volume of eluent, interfering ions and breakthrough volume, were investigated. Under optimal conditions, the beryllium ions were retained on the sorbent at pH 6–6.7, while 3.0 mL of 0.05 mol L?1 HNO3 is sufficient to elute the ions. The limit of detection (LOD) based on 3σ was 0.8 µg L?1 for 250 mL sample solution and 5 mL 0.05 mol L?1 HNO3 as eluent. The LOD can reach 0.1 µg L?1 for 1 L sample solution and 3 mL of 0.05 mol L?1 HNO3. The accuracy and precision (RSD %) of the method is >90% and <10%, respectively. The method was applied to the determination of beryllium in aqueous samples. 相似文献
In the present study, the ?5-(4-dimethylaminobenzylidene)rhodanin-modified SBA-15? was applied as stable solid sorbent for the separation and preconcentration of trace amounts of cobalt ions in aqueous solution. SBA-15 was modified by ?5-(4-dimethylaminobenzylidene)rhodanin reagent. The sorption of Co2+ ions was done onto modified sorbent in the pH range of 6.8–7.9 and desorption occurred in 5.0 mL of 3.0 mol L?1 HNO3. The results exhibit a linear dynamic range from 0.01 to 6.0 mg L?1 for cobalt. Intra-day (repeatability) and inter-day (reproducibility) for 10 replicated determination of 0.06 mg L?1 of cobalt was ±1.82% and ?±1.97%?. Detection limit was 4.2 µg L?1 (3Sb, n = 5) and preconcentration factor was 80. The effects of the experimental parameters, including the sample pH, flow rates of sample and eluent solution, eluent type and interference ions were studied for the preconcentration of Co2+. The proposed method was applied for the determination of cobalt in standard samples, water samples and agricultural products. 相似文献
An anion‐exchange chromatography method combined solid phase extraction (SPE) was developed for the simultaneous analysis of glycolate acid (GL), monochloroacetic acid (MCA) and dichloroacetic acid (DCA) in synthetical betaine products. The analytes and unknown anionic impurities were well separated on a Metrosep A supp5 anion‐exchange column (150 mm×4 mm) with 2.0 mmol/L Na2CO3+2.0 mmol/L NaHCO3 solution as eluent. Suppressed conductivity detection was used. A strong cation exchange (SCX) solid phase extraction (SPE) cartridge was used to reduce the concentration of matrix betaine and a Cleanert IC‐Ag pretreatment cartridge was used to remove high Cl? concentration. The detection limits of GL, MCA and DCA were 0.09, 0.017 and 0.05 µg/L, respectively. The relative standard deviations (RSDs) of the retention times and peak areas were less than 0.09% and 0.49%, respectively. The recoveries of the three analytes were between 90.6% and 100.8%. The analytical results showed that GL and DCA were present in high concentration and no MCA was found when the proposed ion chromatography method was applied to three synthetical betaine samples. The proposed method is simple, sensitive and timesaving, and is also suitable for routine analysis in quality control of synthetical betaine products. 相似文献
In the present study, multiwalled carbon nanotubes (MWCNTs) as solid phase extraction sorbent were developed for preconcentration of arsenic(V) species prior to graphite furnace atomic absorption spectrometry (GFAAS) determination. Arsenic(V) was selectively sorbed on the packed column with MWCNTs within a pH 9.5 in the presence of 2-(5-bromo-2-pyridylazo)-5-diethyl amino phenol (5-Br-PADAP). The adsorbed species was then desorbed with 1 mL of 2.0 M HNO3. Experimental parameters including pH, sample volume and flow rate, type, volume and concentration of eluent that influence the recovery of the arsenic(V) species were optimised. Under the optimised conditions, the calibration curve was linear in the range of 0.2–10.0 µg L?1 with detection limit of 0.016 µg L?1. The relative standard deviations (RSD) for seven replicate determinations at 1.0 µg L?1 level of arsenic was 6.69%. The proposed method was successfully applied to the determination of arsenic in water samples and certified reference material (NIST RSM 1643e). 相似文献
We report on the synthesis of Fe3O4-functionalized metal-organic framework (m-MOF) composite from Zn(II) and 2-aminoterephthalic acid by a hydrothermal reaction. The magnetic composite is iso-reticular and was characterized by FTIR, X-ray diffraction, SEM, magnetization, and TGA. The m-MOF was then applied as a sorbent for the solid-phase extraction of trace levels of copper ions with subsequent quantification by electrothermal AAS. The amount of sorbent applied, the pH of the sample solution, extraction time, eluent concentration and volume, and desorption time were optimized. Under the optimum conditions, the enrichment factor is 50, and the sorption capacity of the material is 2.4 mg g?1. The calibration plot is linear over the 0.1 to 10 μg L?1 Cu(II) concentration range, the relative standard deviation is 0.4 % at a level of 0.1 μg L?1 (for n?=?10), and the detection limit is as low as 73 ng L?1. We consider this magnetic MOF composite to be a promising and highly efficient material for the preconcentration of metal ions.
Figure
Magnetic metal-organic frameworks was synthesized and used as a new sorbent for lead adsorption with detection by electrothermal atomic absorption spectrometry. 相似文献
In this research, nickel ferrite (NiFe2O4) magnetic nanoparticles were synthesised by a simple method and applied as sorbent for magnetic solid-phase extraction of trace amounts of Au(III) from water samples. Detection in this technique was performed by flame atomic absorption spectrometry. The effects of sample pH, amount of sorbent, extraction time, desorption solvent and its volume on the extraction process were optimised. The effects of interfering ions on the recovery of the analyte were also evaluated in model solutions. The best results were obtained at pH 6.5 with 5 mL of eluent solution (0.1 mol L?1 sodium thiosulphate) and an extraction time of 30 min. Under optimal conditions, the sorption capacity was 34.6 mg g?1. Also, enhancement factor (for 100 mL of sample solution) was found to be 19.3. The calibration graph was linear in the range of 4.4–800.0 µg L?1 gold concentration and the limit of detection was 1.32 µg L?1. The relative standard deviation of the method (for n = 8) was 1.57%. The method was successfully applied to the extraction of Au(III) from water samples. 相似文献
Silica gel surface was chemically functionalized by reaction the silanol from the silica surface with 3-chloropropyltrimethoxysilane followed by reaction with Sulfasalazine. This new sorbent has been used for the preconcentration of low levels of U(VI) ions from an aqueous phase. Parameters involved in extraction efficiency such as pH, weight of the sorbent, volume of sample and eluent were optimized in batch and column methods prior to determination by spectrophotometry using arsenazo(III) reagent. The results showed that U(VI) ions can be sorbed at pH range of 5.0–6.0 in a minicolumn and quantitative recovery of U(VI) (>98.0?±?1.6%) was achieved by stripping with 2.5 mL of 0.1 mol L?1 HCl. The sorption capacity of the functionalized silica gel was 1.15 mmol g?1 of U(VI). A linear calibration graph was obtained over the concentration range of 0.02–27.0 μg mL?1 with a limit of detection of 1 μg L?1 in treatment with 1000 mL of the U(VI) solution in which the preconcentration factor was as high as 400. The method was employed to the preconcentration of U(VI) ions from spiked ground water and synthetic sea water samples. 相似文献
In this study, a new Cr(III)-imprinted polymer (Cr(III)-IIP) is prepared from CrCl3·6H2O, methacrylic acid functional monomer, ethyleneglycoldimethacrylate cross-linking agent, 2,2?-azobisisobutyronitrile radical initiator and 2,2-(azanediylbis (ethane-2,1-diyl))bis(isoindoline-1,3-dione) ligand. To obtain the maximum adsorption capacity, the optimum condition was studied through pH, type and concentration of eluent, IIP weight, sample volume as well as the adsorption and desorption times. The Cr(III) ion content was determined via flame atomic absorption spectrometer. In optimum conditions, the adsorption capacity of the IIP for Cr(III) was obtained to be 74.65 mg g?1, using 50 mg of IIP and the initial pH solution of 3.0. Both the adsorption and desorption times for quantitative analyses of Cr(III) ions were 15 and 5 min; respectively. After elution of the adsorbed ions by 3 mL of 4 mol L?1 HNO3 aqueous solution, the established IIP-based SPE procedure provides a reasonable pre-concentration factor of 100. The IIP-based pre-concentration method provides a low detection limit of 1.7 µg L?1 with good repeatability (RSD?=?3.22%). Reusability studies confirmed that synthesis IIP is reusable and recoverable up to six cycles. According to the selectivity experiments, it was concluded that the prepared sorbent possesses more affinity toward Cr(III) ions than other ions such as Al3+, Pb2+, Cu2+, Mn2+, Fe2+, Zn2+, and Ni2+ ions. To evaluate the potential applicability of the proposed separation method, the pre-concentration and determination of trace amounts of Cr(III) were performed successfully in food samples with complex matrices, a bestial sample (i.e. cow liver) and an herbal product (i.e., broccoli) as real samples. 相似文献
A new column loaded with modified silica gel-chitosan is proposed as a preconcentration system for adsorption of trace cadmium (II) and copper (II). The optimization steps were performed under dynamic conditions, involving pH, sample flow rate, eluent selection, concentration, volume, and flow rate. Trace Cd(II) and Cu(II) were quantitatively adsorbed by the modified silica gel-chitosan. The metal ions adsorbed on the separation column were eluted with 0.1 M HNO3 and determined by flame atomic absorption spectrometry. Under the optimum conditions, this method allowed the determination of cadmium and copper with limits of detection (LOD) of 20 ng L?1 and 38 ng L?1, respectively. The relative standard deviation values (RSDs) for 1.0 mg L?1 of cadmium and 1.0 mg L?1 of copper were 2.62% and 2.85%, respectively. 相似文献
The authors describe a 3-component nanoparticle system composed of a silica-coated magnetite (Fe3O4) core and a layered double (Cu-Cr) hydroxide nanoplatelet shell. The sorbent has a high anion exchange capacity for extraction anionic species. A simple online system, referred to as "on-line packed magnetic-in-tube solid phase microextraction" was designed. The nanoparticles were placed in a stainless steel cartridge via dry packing. The cartridge was then applied to the preconcentration acidic drugs including naproxen and indomethacin from urine and plasma. Extraction and desorption times, pH values of the sample solution and flow rates of sample solution and eluent were optimized. Analytes were then quantified by HPLC with UV detection. Under optimal conditions, the limits of detection range from 70 to 800 ng L?1, with linear responses from 0.1–500 μg L?1 (water samples), 0.6–500 μg L?1 (spiked urine), and 0.9–500 μg L?1 (spiked plasma). The inter- and intra-assay precisions (RSDs, for n?=?5) are in the range of 2.2–5.4%, 2.8–4.9%, and 2.0–5.2% at concentration levels of 5, 25 and 50 μg L?1, respectively. The method was applied to the analysis of the drugs in spiked human urine and plasma, and good results were achieved.
Graphical abstract Fe3O4@SiO2@CuCr-LDH magnetic nanoparticles were synthesized and packed in to a stainless steel column. The column was applied to solid phase microextraction of acidic drugs from biological samples.
A rapid and simple on-line method is described for the determination of Au(III) in various samples. The method is based on the sorption of gold(III) on Lewatit MonoPlus TP207 chelating resin including the iminodiacetate group, which is used as sorbent material and packed in a minicolumn. The chemical variables such as the pH of the sample solution, eluent type, interfering ions and concentrations of reagents, and instrumental variables such as sample loading volume, reagents flow rates, and tubing length, which affect the efficiency of the method were studied and optimised. Au(III) was sorbed on the chelating resin, from which it could be eluted with 3 mol L?1 HCl, and then introduced directly to the nebuliser-burner system of FAAS. The limit of detection of the method was 0.2 µg L?1 while the relative standard deviation was <4.0% for 20 µg L?1 Au(III) concentration. The preconcentration factor was found to be 106 while the optimised sample volume was 15.3 mL. The accuracy of the method was verified by analysing the certified reference material. The developed method was applied successfully for the determination of gold in different samples with satisfactory results. 相似文献
An amine-functionalized metal–organic framework based on aluminum (NH2-MIL-53(Al)) was synthesized and employed as a sorbent for the extraction of phenolic pollutants. A new designed sorbent-injection vortex-assisted dispersive microsolid-phase extraction was proposed in which the sorbent suspension was simply injected into the sample solution. Herein the experimental parameters that affected the extraction efficiency for the target analytes were optimized, including volume of sorbent suspension, vortex agitation time, eluent type and its volume, and sample volume. Good linearity was obtained in the concentration range of 0.1–10.0 mg L?1 with the correlation coefficients in the range of 0.9970–0.9981. The LODs and LOQs were in the ranges of 0.030–0.055 and 0.090–0.150 mg L?1, respectively. The results of the intra- and inter-day experiments showed good precision of peak area with the relative standard deviation (RSD) values of better than 5.82 and 7.85%, respectively. The developed method has been successfully applied to determine phenolic residues in water samples. The satisfactory recoveries were obtained in the range of 83.0–122.4% with the RSDs of less than 12.9%. In addition, molecular docking was performed to predict the adsorption ability of NH2-MIL-53(Al) sorbent toward the target analytes. The computational results were in good agreement with data obtained experimentally. 相似文献
An investigation was carried out into the fast determination of five homologue imidazolium cations in ionic liquids by ion chromatography using a cation-exchange column and direct conductivity detection. Ethylenediamine, complex organic acid (citric acid, oxalic acid and tartaric acid) and organic modifiers (acetonitrile) were used as mobile phase. The influences of the eluent types, eluent concentration, eluent pH and column temperature on separation of the cations were discussed. Simultaneous separation and determination of the five homologue imidazolium cations in ionic liquids were achieved under an optimum condition. The optimized mobile phase was consisted of 0.25 mmol L?1 ethylenediamine + 0.5 mmol L?1 citric acid + 3% acetonitrile (v/v) (pH 4.1), set at a flow rate of 1.0 mL min?1. The column temperature was 40 °C and detection limits were obtained in the range of 1.1–45.6 mg L?1. The relative standard deviations of the chromatographic peak areas for the cations were <3.0% (n = 5). This method was successfully applied to separate imidazolium cations in ionic liquids produced by organic synthesis. The recoveries of spiked components were 92.5–101.9%. 相似文献
A method for analysis of short-chain chlorinated paraffins (SCCPs) in water based on solid-phase extraction (SPE) was established using electron capture negative chemical ionization mass spectrometry (GC-ENCI-MS). The SPE parameters, including the sorbent, eluent and elution volume were optimized. The Agilent Bond Elut-C18 was precleaned with 3 mL of hexane and 3 mL of methanol, and subsequently conditioned with 3 mL H2O prior to use. After the water samples were enriched by the cartridge, the sample was washed with 3 mL of 10% (V/V) methanol and eluted with 3 mL of hexane-dichloromethane (1:1, V/V) solution. The results indicated that the limits of detection (LOD) for SCCPs were 18 ng L?1, while the corresponding limits of quantitation (LOQ) were 60 ng L?1. The spiked recovery range was 90%–135%, with a relative standard deviation of less than 10%. Finally, 20 surficial water samples around Beijing were collected and SCCPs contents were analyzed using the proposed method. The SCCPs concentrations ranged from less than LOD to 682 ng L?1 with a mean concentration of 216 ng L?1. 相似文献
Extraction, pre-concentration and determination of trace amounts of mercury ions from water samples were investigated by magnetic solid phase extraction (MSPE) method using Fe3O4 nanoparticles decorated with polythionine as an adsorbent. A simple chemical synthesis by catalytic reaction of thionine in the presence of FeCl3 and hydrogen peroxide was used for preparation of the magnetic sorbent. Scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, vibrating sample magnetometer analysis and Fourier transform infrared spectroscopy were used to characterise the adsorbent. Mercury ions were determined by cold vapour atomic absorption spectrometry. The parameters for MSPE procedure, such as pH of the extraction solution, adsorption time, weight adsorbent, elution conditions (type, concentration and volume of the eluent), volume of the sample solution and effects of coexisting ions were investigated. The obtained optimal conditions were: sample pH of 4; sorbent amount of 4 mg; sorption time of 20 min; elution solvent of HNO3 (0.3 mol L?1)/thiourea (2% w/v) with volume of 2 mL, and breakthrough volume of 400 mL. A good linearity in the concentration range of 0.025–40 µg L?1 (R2 > 0.999) with the pre-concentration factor of 198 was obtained. The limits of detection and quantification were achieved as 0.008 and 0.025 µg L?1, respectively. Furthermore, sea and river water samples were analysed and good recoveries (97.1–99.6%) were obtained. 相似文献
A new functionalized nanometer mesoporous silica (MCM-41) using 2,4-dihydroxybenzaldehyde (4-OHsal) was applied as an effective sorbent for solid phase extraction (SPE) of beryllium ions from aqueous solution followed by inductively coupled plasma optical emission spectrometric detection (ICP OES). The influences of some analytical parameters on the quantitative recoveries of the analyte ion were investigated in batch method. In order to perform the batch mode of SPE, known amount of sorbent was added to a test tube containing sample solution buffered at pH 7.2. After manual shaking and centrifugation the aqueous phase was decanted and beryllium was desorbed by adding 1.0 mL of 1.0 mol L?1 HNO3 to the sedimented sorbent. The sorbent was separated by centrifugation and the concentration of beryllium in the supernatant was determined by ICP OES. The maximum sorption capacity of the modified MCM-41 was found to be 34 mg g?1. The sorbent exhibited good stability, reusability and fast rate of equilibrium for sorption/desorption of beryllium ions. The present method was used for preconcentration and determination of beryllium for water samples. Under optimal conditions, the limit of detection (LOD) obtained was 0.3 ng L?1. The accuracy of the procedure was evaluated by analysis of the certified reference material (NIST 1640). 相似文献
In this work functionalised mesoporous silica spheres have been utilised for the simultaneous preconcentration of nickel and cobalt. The silica spheres (SiSPs) prepared by the sol-gel method were functionalised with sodium diethyldithiocarbamate (DDTC-SiSPs). They were characterised by SEM, TEM, XRD, FTIR, CHN and nitrogen adsorption. The adsorption efficiency of DDTC-SiSPs was examined by batch equilibrium technique. The DDTC-SiSPs showed 100% adsorption for Ni (II) and Co (II). The effect of changing variables such as pH, shaking time, sample volume, preconcentration factor, eluent type and volume were investigated so as to obtain maximum recovery with high selectivity over interfering ions. The maximum adsorption capacity was found to be 15.15 mg g?1 and 11.80 mg g?1 for Ni (II) and Co (II) respectively using DDTC-SiSPs. 100% recovery was achieved with 5 mL of 2 M HNO3. The maximum preconcentration factor was 400 and the 3σ limits of detection were 0.201 µg L?1 and 0.198 µg L?1 for Ni (II) and Co (II) respectively. Thermodynamic studies showed that adsorption of Ni (II) and Co (II) on DDTC-SiSPs is exothermic with enthalpy changes of –0.514 KJ mol?1 and –0.854 KJ mol?1 for Ni (II) and Co (II) respectively. The method was applied to the preconcentration and determination of Ni (II) and Co (II) from tap, river and sea water. 相似文献
A surface molecular imprinting technology was developed to adsorb Ce(III) ions that showed much higher adsorption affinity and selectivity for than for other metal ions. The batch adsorption process was studied with respect to effects of pH value, residence time, temperature, and initial concentration of Ce(III) ion. The maximum adsorption capacity is 43 mg g?1 at an initial Ce(III) concentration of 300 mg L?1 and at a sorbent dosage of 1.0 g L?1. A Langmuir isotherm fits the experimental data. The imprinted sorbent exhibits a much higher separation and selectivity for the target imprinted ion than the non-imprinted polymer. Cerium ion can be desorbed with 1M hydrochloric acid solution which is also proven by scanning electron microoscopy and X-ray diffraction experiments. The limit of detection is 37 ng mL?1. The sorbent has been applied to the determination of trace cerium in different environmental samples with satisfactory results. 相似文献
The present work reports the effectiveness of a 2D imprinting method based on a surface imprinting technique for the development of a selective and sensitive flow sorbent preconcentration system for Co2+ ion determination. Cobalt ions were determined by UV-vis spectrophotometry exploiting the complexation with 1-(2-piridylazo)-2-naphtol (PAN). Based on a coefficient of relative selectivity (k'), the ion-imprinted amino-functionalized silica gel sorbent (ISG), compared with modified but non-imprinted sorbent (MSG) and silica gel (SG), showed a very high selectivity. A limit of detection of 0.51 µg L?1 and precision (n = 10) as a relative standard deviation of 2.63 and 1.50% for Co2+ concentration of 10.0 and 90.0 µg L?1, respectively, were achieved. A comparison of the proposed method with other previously published methods shows advantages in terms of sample consumption, sample throughput, and limit of detection. The application of the present method was successfully performed for the direct determination of Co2+ content in urine and environmental water samples without any interference and without sample preparation, with satisfactory results. 相似文献
The development of a solid-phase extraction (SPE) procedure for the pre-concentration of trace amounts of Pb2+ ion on 2-furan-2-yl-1-furan-2-ylmethyl-1H-benzoimidazole loaded on activated carbon modified with silver nanoparticles (L-AC-Ag-NP) was presented. The metal ion retained on the sorbent was quantitatively determined via complexation with the ligand. The complexed metal ion was efficiently eluted using 10 mL of 4 mol L?1 sulphuric acid in 10 w/v% acetone. The influences of the analytical parameters, including pH, amounts of the ligand and the solid phase, eluent conditions and sample volume, on the recoveries of the metal ion were optimised. Using the optimised parameters, the linear response of the SPE method for Pb2+ ion were in the ranges of 0.2–160 µg L?1, and the detection limit for Pb2+ ion was 0.034 µg L?1. The proposed method exhibits a pre-concentration factor (PF) of 80 and an enhancement factor of 30 for Pb2+ ion. The presented results demonstrate the successful application of the proposed method for the determination of Pb2+ ion in some real samples with high recoveries (>93%) and reasonable relative standard deviation (RSD < 2%). 相似文献