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1.
Jiaheng He Hu Song Yuan Jian Lin Jiang Wenbin Zhong Xinliang Li Zongping Ma Guoping Liu 《Journal of Radioanalytical and Nuclear Chemistry》2011,290(2):469-473
The adsorption of 125I on palladium coated silver wires was studied in this paper. The experimental conditions, e.g., reaction volume, carrier
concentration, reaction time, reaction temperature, pH of the reaction mixture, were systematically optimized to obtain quantitative
adsorption of 125I on palladium coated silver wires. The experiments were performed using potassium iodide 8–9 μg as carrier in a reaction
volume of 100 μL incubated in ~50 °C water bath for ~1 h, and the pH of the reaction system was controlled at 2–2.5. The distribution
of activity on palladium coated silver wire was uniform, and the source cores can be easily sealed by laser welding into titanium
capsules. 相似文献
2.
Wu S Zhang L Yang K Liang Z Zhang L Zhang Y 《Analytical and bioanalytical chemistry》2012,402(2):703-710
Initially, a poly (glycidyl methacrylate-co-acrylamide-co-methylenebisacrylamide) monolith was prepared in the 100 μm i.d.
capillary, and then was grafted with polyethylenimine (Mw, ∼25,000) for adsorbing Cu2+, followed by chelating trypsin. As a result, efficient digestion for BSA (100 ng/μL) was completed within 50 s via such immobilized
enzyme reactor (IMER); yielding 47% sequence coverage by matrix-assisted laser desorption/ionization-time of flight mass spectrometry
(MALDI-TOF MS) analysis. Compared with the conventional method for preparing the metal-ion chelated IMER, the regeneration
of such IMER can be achieved facilely by the respective 30 min desorption and re-adsorption of trypsin, and 51% sequence coverage
was obtained for 50 s BSA digestion after regeneration. BSA down to femtomole was also efficiently digested by the prepared
regenerable IMER. Meanwhile, after the consecutive digestion of myoglobin and BSA, there was not any mutual interference for
both during MALDI-TOF MS identification, indicating the low nonspecific adsorption of such regenerable IMER. To test the applicability
of regenerable IMER for complex sample profiling, proteins (150 ng) extracted from Escherichia coli were digested within 80 s by the regenerable IMER and further analyzed by nanoreversed phase liquid chromatography–electrospray
ionization–mass spectrometry successfully, showing its practicability for the high throughput analysis of complex samples. 相似文献
3.
Preparation and characterization of a molecularly imprinted polymer by grafting on silica supports: a selective sorbent for patulin toxin 总被引:1,自引:0,他引:1
A new molecularly imprinted polymer (MIP) has been prepared on silica beads using the radical “grafting from” polymerization
method for selective extraction of minor contaminant mycotoxin of patulin (PTL). After the introduction of amino groups onto
the silica surface with 3-aminopropyltriethoxysilane, azo initiator onto the silica surface was achieved by the reaction of
surface amino groups with 4,4′-azobis(4-cyanopentanoic acid). The scale-up synthesis of MIP was then carried out in the presence
of 6-hydroxynicotinic acid as template substitute, functional, and cross-linking monomers. The prepared sorbent was characterized
using FT-IR spectroscopy, scanning electron microscopy, elemental analysis, and the adsorption–desorption selectivity, and
the capacity characteristic of the polymer was investigated by a conventional batch adsorption test and Scatchard plot analysis.
The results indicated that coated polymers had specific adsorption to PTL as compared with its co-occurring 5-hydroxymethyl-2-furaldehyde
(hydroxymethylfurfural (HMF)), at the same bulk concentration for solution of PTL and HMF, the maximum absorbance in the solid-phase
extraction (SPE) method to PTL were 93.97% or 0.654 μg/mg while to HMF they were 76.89% or 0.496 μg/mg. Scatchard analysis
revealed that two classes of binding sites were formed in PTL-MIP with dissociation constants of 3.2 × 10−2 and 5.0 × 10−3 mg/mL and the affinity binding sites of 8.029 and 1.364 mg/g, respectively. The recoveries of PTL were more than 90% for
the developed MISPE and around 75% for the traditional liquid–liquid extraction in spiked apple juice samples. It was concluded
that the method is suitable for the scale-up synthesis of PTL-MIP grafted on silica, and the polymer can be effectively applied
as SPE coupled with high-performance liquid chromatography (HPLC) for the determination of PTL in apple juice or other related
products. 相似文献
4.
Fluoridized iron phosphate (F-FePO) is prepared via a hydrothermal protocol and characterized by means of 57Fe M?ssbauer spectra, Fourier transform infrared, and surface charge analysis. For the first time, F-FePO is used as an adsorbent
for the adsorption of proteins, which exhibits favorable selectivity toward cytochrome c (cyt-c) in the presence of acidic
and neutral proteins under controlled experimental conditions. At pH 10.5, an adsorption efficiency of 100% is achieved for
60 mg L−1 cyt-c in 1.0 mL of sample solution using 6.0 mg F-FePO. The adsorption behavior is consistent with the Langmuir adsorption
model, corresponding to a theoretical adsorption capacity of 37.59 μg mg−1. The retained cyt-c on F-FePO could be readily collected by 0.1 mol L−1 Na2CO3–NaHCO3 buffer (pH 10.5), deriving a recovery of 100%. Circular dichroism spectra indicate no conformational change for cyt-c after
the adsorption and desorption processes, demonstrating the favorable biocompatibility of the fluoridized iron phosphate. F-FePO
is employed for the selective isolation of cyt-c from a spiked human whole blood, achieving satisfactory results by assay
with SDS-polyacrylamide gel electrophoresis and native polyacrylamide gel electrophoresis. 相似文献
5.
Herman K Szabó L Leopold LF Chiş V Leopold N 《Analytical and bioanalytical chemistry》2011,400(3):815-820
A new, simple, and effective approach for multianalyte sequential surface-enhanced Raman scattering (SERS) detection in a
flow cell is reported. The silver substrate was prepared in situ by laser-induced photochemical synthesis. By focusing the
laser on the 320 μm inner diameter glass capillary at 0.5 ml/min continuous flow of 1 mM silver nitrate and 10 mM sodium citrate
mixture, a SERS active silver spot on the inner wall of the glass capillary was prepared in a few seconds. The test analytes,
dacarbazine, 4-(2-pyridylazo)resorcinol (PAR) complex with Cu(II), and amoxicillin, were sequentially injected into the flow
cell. Each analyte was adsorbed to the silver surface, enabling the recording of high intensity SERS spectra even at 2 s integration
times, followed by desorption from the silver surface and being washed away from the capillary. Before and after each analyte
passed the detection window, citrate background spectra were recorded, and thus, no “memory effects” perturbed the SERS detection.
A good reproducibility of the SERS spectra obtained under flow conditions was observed. The laser-induced photochemically
synthesized silver substrate enables high Raman enhancement, is characterized by fast preparation with a high success rate,
and represents a valuable alternative for silver colloids as SERS substrate in flow approaches. 相似文献
6.
Kolarov F Niedergall K Bach M Tovar GE Gauglitz G 《Analytical and bioanalytical chemistry》2012,402(10):3245-3252
Molecularly imprinted nanospheres obtained by miniemulsion polymerization have been applied as the sensitive layer for label-free
direct optical sensing of small molecules. Using these particles as the sensitive layer allowed for improving response times
in comparison to sensors using MIP layers. As a model compound, well-characterized nanospheres imprinted against l-Boc-phenylalanine anilide (l-BFA) were chosen. For immobilization, a simple concept based on electrostatic adsorption was used, showing its applicability
to different types of surfaces, leading to a good surface coverage. The sensor showed short response times, good selectivity,
and high reversibility with a limit of detection down to 60 μM and a limit of quantitation of 94 μM. Furthermore, reproducibility,
selectivity, and long-term stability of the sensitive layers were tested. The best results were achieved with an adsorption
on aminopropylsilane layers, showing a chip-to-chip reproducibility of 22%. Furthermore, the sensors showed no loss in signal
after a storage time of 1 year. 相似文献
7.
Junping Dong Yanyan Hu Shenmin Zhu Jiaqiang Xu Yinjuan Xu 《Analytical and bioanalytical chemistry》2010,396(5):1755-1762
An ordered mesoporous carbon material functionalized with carboxylic acid groups was synthesized. It was characterized by
powder X-ray diffraction, transmission electron microscopy, Fourier transform IR spectroscopy and N2 adsorption/desorption. Furthermore, this material was used to modify an electrode surface combined with a hydrophobic ionic
liquid. The functionalized ordered mesoporous carbon/ionic liquid gel modified electrode shows excellent electrocatalytic
performances for the oxidation of dopamine, uric acid and ascorbic acid. The presence of the ionic liquid promotes the electron
transfer. Linear responses for dopamine and uric acid were obtained in the ranges of 0.1 to 500 μM and from 0.1 to 100 μM
with detection limits of 4.1 and 2.5 nM (signal-to-noise ratio of 3), respectively, under optimum conditions. A quick and
sensitive biosensor based on functionalized ordered mesoporous carbon and an ionic liquid has been developed for the first
time for the detection of dopamine and uric acid in the presence of a large amount of ascorbic acid. 相似文献
8.
L. A. Onuchak I. A. Platonov P. V. Smirnov A. V. Didenko 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2008,82(4):643-646
Adsorption and chromatographic properties of a porous-layer open-tubular (PLOT) capillary column with aerosil were studied.
The retention factors k of n-alkanes, not condensed arenes, and alcohols were determined over the temperature range 120–180°C, and the heats of their
adsorption were calculated. The Rohrschneider constants (100°C) and the contributions of specific interactions to the adsorption
heats were determined. It was shown that the PLOT/SiO2 column was similar in chromatographic properties to wall coated open tubular columns with polysiloxane stationary phases
but superior to them as concerns thermal stability and service life.
Original Russian Text ? L.A. Onuchak, I.A. Platonov, P.V. Smirnov, A.V. Didenko, 2008, published in Zhurnal Fizicheskoi Khimii,
2008, Vol. 82, No. 4, pp. 745–748. 相似文献
9.
A method was developed for sampling and selective quantitative determination of typical volatile organic compounds (VOCs)
in ambient urban air. A mobile and self-contained dual-channel air sampling tool based on solid phase adsorption was constructed.
A simple calibration procedure circumventing the adsorption/desorption process was designed. The method was validated for
seven “key-analytes”: n-hexane, 3-methyl-2-pentene, benzene, tetrachloroethene, styrene, 1,2,4-trimethylbenzene and acetophenone.
The complete air sampling equipment is easily accommodated in a business suitcase. The lower limits of the practical working
ranges are between 0.1 μg m–3 (tetrachloroethene) and 1.2 μg m–3 (benzene). Air samples were collected at a location in Salzburg with heavy motor vehicle traffic and measured in order to
prove a satisfactory method performance under practical monitoring conditions.
Received: 4 January 1998 / Revised: 14 September 1998 / Accepted: 21 October 相似文献
10.
Baldini F Carloni A Giannetti A Porro G Trono C 《Analytical and bioanalytical chemistry》2008,391(5):1837-1844
A novel fluorescence-based optical platform for the interrogation of an optical biochip was designed and developed. The optical
biochip was made of poly(methyl methacrylate) (PMMA) formed by two pieces of PMMA appropriately shaped in order to obtain
four microchannels that are 500-μm wide and 400-μm high. The lower part includes the microchannels and the inlet and outlet
for the fluidics, while the sensing biolayer was immobilized on the upper part. The optical signal comprised the fluorescence
emitted by the biolayer, which was anisotropically coupled to the PMMA cover and suitably guided by the PMMA chip. The potentiality
of the optical chip as a biosensor was investigated by means of a direct IgG/anti-IgG interaction carried out inside the flow
channels. The mouse-IgG was covalently immobilized on the internal wall of the PMMA cover, and the Cy5-labelled anti-mouse
IgG was used for the specific interaction. Several chemical treatments of the PMMA surface were investigated, poly(L-lactic acid), Eudragit L100 and NaOH, in order to obtain the most effective distribution of carboxylic groups useful for
the covalent immobilisation of the mouse-IgG. The treatment with Eudragit L100 was found to be the most successful. Limits
of detection and quantification of 0.05 μg mL−1 and 0.2 μg mL−1, respectively, were obtained with the configuration described. 相似文献
11.
Jingjing Yu Jiaxing Tu Faqiong Zhao Baizhao Zeng 《Journal of Solid State Electrochemistry》2010,14(9):1595-1600
A magnetic mesoporous carbon material (i.e., mesoporous iron oxide/C, mesoFe/C) is synthesized for protein immobilization,
using glucose oxidase (GOx) as model. Transmission electron microscopy images show that mesoFe/C has highly ordered porous
structure with uniform pore size, and iron oxide nanoparticles are dispersed along the wall of carbon. After adsorption of
GOx, the GOx-mesoFe/C composite is separated with magnet. The immobilized GOx remains its natural structure according to the
reflection–absorption infrared spectra. When the GOx-mesoFe/C composite is coated on a Pt electrode surface, the GOx gives
a couple of quasireversible voltammetric peaks at −0.5 V (vs. saturated calomel electrode) due to the redox of FAD/FADH2. The electron-transfer rate constant (k
s) is ca. 0.49 s−1. The modified electrode presents remarkably amperometric response to glucose at 0.6 V. The response time (t
95%) is less than 6 s; the response current is linear to glucose concentration in the range of 0.2–10 mM with a sensitivity of
27 μA mM−1 cm−2. The detection limit is 0.08 mM (S/N = 3). The apparent Michaelis–Menten constant (K
mapp) of the enzyme reaction is ca. 6.6 mM, indicating that the GOx immobilized with mesoFe/C has high affinity to the substrate. 相似文献
12.
Sandra Biedermann Patrik Tschudin Koni Grob 《Analytical and bioanalytical chemistry》2010,398(1):571-576
Of 13 thermal printing papers analyzed, 11 contained 8–17 g/kg bisphenol A (BPA). When taking hold of a receipt consisting
of thermal printing paper for 5 s, roughly 1 μg BPA (0.2–6 μg) was transferred to the forefinger and the middle finger if
the skin was rather dry and about ten times more if these fingers were wet or very greasy. This amount transferred to dry
skin was neither significantly increased when taking hold of the paper at up to 10 sites, nor reduced when BPA-free paper
was contacted afterwards. After 60–90 min, BPA applied to the skin as a solution in ethanol was only partially or no longer
at all extractable with ethanol, whereas BPA transferred to the skin by holding thermal printer paper remained largely extractable
after 2 h. This suggests that penetration of the skin depends on the conditions. Extractability experiments did not enable
us to conclude whether BPA passes through the skin, but indicated that it can enter the skin to such a depth that it can no
longer be washed off. If this BPA ends up in the human metabolism, exposure of a person repeatedly touching thermal printer
paper for 10 h/day, such as at a cash register, could reach 71 μg/day, which is 42 times less than the present tolerable daily
intake (TDI). However, if more than just the finger pads contact the BPA-containing paper or a hand cream enhances permeability
of the skin, this margin might be smaller. 相似文献
13.
Summary Reproducibility of the Kovats retention indices of alkylbenzenes was studied on conventional “PONA” fused-silica capillary
columns coated with crosslinked dimethyl silicone phase, with a film thickness of 0.5 μm. The data were compared with those
obtained on conventional OV-101 columns. The tested PONA columns showed reproducible chromatographic properties, capacity
ratios and high efficiencies. Having a standard deviation of s=0.03 i.u. of the retention indices on a single column, the
column-to-columns differences were found to be up to 0.3 i.u. Higher indices were determined for crosslinked columns, the
difference being in most cases about one i.u. 相似文献
14.
Hui-Ling Cheng Shyh-Shin Chiou Yu-Mei Liao Chi-Yu Lu Yen-Ling Chen Shou-Mei Wu 《Analytical and bioanalytical chemistry》2010,398(5):2183-2190
We establish a triple-stacking capillary electrophoresis (CE) separation method to monitor methotrexate (MTX) and its eight
metabolites in cerebrospinal fluid (CSF). Three stacking methods with different mechanisms were combined and incorporated
into CE separation. Complete stacking and sharp peaks were achieved. Firstly, the optimized buffer (60 mM phosphate containing
15% THF and 100 mM SDS) was filled into the capillary, which was followed by the higher conductivity buffer (100 mM phosphate,
2 psi for 45 s). The analytes extracted from CSF were injected at 2 psi for 99.9 s, which provided long sample zones and pH
junction for focusing. Finally, the stacking step was performed by sweeping, and separation was achieved by micellar electrokinetic
chromatography. The results of the linear regression equations indicated high linearity (r ≥ 0.9981) over the range of 0.5–7 μM. In intra- and inter-batch results, all data of RSD and RE were below 11%, indicating
good precision and accuracy of this method. The LODs (S/N = 3) were 0.1 μM for MTX, 7-hydroxymethotrexate (7-OHMTX) and MTX-polyglutamates (MTX-(Glu)
n, n = 2–5), 0.2 μM for MTX-(Glu)6, and 0.3 μM for 2,4-diamino-N
10-methylpteroic acid (DAMPA) and MTX-(Glu)7. Our method was implemented for analysis of MTX and its metabolites in the CSF, and could be used for evaluation of its curative
effects of acute lymphoblastic leukemia patients. The data were also confirmed by matrix-assisted laser desorption ionization
time-of-flight mass spectrometry. The results showed good coincidence. 相似文献
15.
The worldwide contamination of winery by-products by mycotoxins may present a serious hazard to human and animal health. Mycotoxins
are secondary metabolites of fungi with possible adverse effects on humans, animals, and crops that result in illnesses and
economic losses. Mycotoxins are under continuous survey in Europe, but the regulatory aspects still need to be set up for
winery by-products, which may be used in animal feed. The aim of this study was to implement a simple but reliable analytical
methodology for ochratoxin A (OTA) quantification in grape pomaces in order to perform a survey of samples from the Douro
Demarcated Region, Portugal. The method involved a unique preparation step, solvent extraction, followed by high-performance
liquid chromatography (HPLC) with fluorescence (FL) detection. A comparative study was performed with two extraction solvents
(ethyl acetate and methanol) as well as using extraction on an immunoaffinity column. The linearity range for OTA analysis
was 0.05–23.5 μg L−1 with a detection limit of 0.05 μg L−1 and a precision (expressed by the coefficient of variation under repeatability conditions) of 0.4–14.7%. The percentage of
recovery was on average 23.5 ± 3.6% (extraction with ethyl acetate) or 70.1 ± 2.5% (extraction with 70% methanol). Accounting
for the recovery factor and the chromatographic detection limit, as well as the preconcentration factor, the limit of detection
in grape pomaces is 0.04 μg kg−1 (ethyl acetate extraction) and 0.33 μg kg−1 (methanol extraction). Samples from 12 out of 13 sites in the Douro Demarcated Region showed OTA presence with concentrations
not exceeding 0.4 μg kg−1. Both developed methods for evaluation of OTA in grape pomace are simple but efficient.
Figure Extraction of ochratoxin A (OTA) from grape pomaces allows simple but efficient quantification of OTA in winery by-products
by HPLC-FL 相似文献
16.
Saliva contains various proteins, particularly abundant are phosphoproteins, that may be related to disease occurrences and
that play significant roles in a biological system. Thus, medical diagnostics will benefit tremendously if disease-related
protein biomarkers are discovered from saliva. In this paper, we propose and demonstrate an approach using functional zinc
oxide coated iron oxide magnetic nanoparticles (Fe3O4@ZnO MNPs) as affinity probes to selectively enrich phosphoproteins from complex saliva samples and as microwave absorbers
to assist the enrichment and subsequent tryptic digestion of trapped proteins under microwave heating. The target species
trapped by MNPs were characterized by matrix-assisted laser desorption/ionization mass spectrometry (MALDI MS) combined with
protein database search. Entire analysis time was shortened to less than 20 min. The detection limit of this approach for
a monophosphopeptide was as low as 250 pM (10 μL). 相似文献
17.
Ana Fortuna Joana Sousa Gilberto Alves Amílcar Falcão Patrício Soares-da-Silva 《Analytical and bioanalytical chemistry》2010,397(4):1605-1615
For the first time, a simple, selective and accurate high-performance liquid chromatography method with ultraviolet detection
was developed and validated to quantify simultaneously three structurally related antiepileptic drugs; carbamazepine, oxcarbazepine,
and the recently launched eslicarbazepine acetate and their main metabolites, carbamazepine-10,11-epoxide, 10,11-trans-dihydroxy-10,11-dihydro-carbamazepine, and licarbazepine. The method involves a solid-phase extraction and a reverse-phase
C18 column with 5 cm length. The mobile phase consisting of water, methanol, and acetonitrile in the ratio 64:30:6 was selected
as the best one and pumped at 1 mL/min at 40 °C. The use of this recent column and an aqueous mobile phase instead of buffers
gives several advantages over the method herein developed; namely the fact that the chromatographic analysis takes only 9 min.
The method was validated according to the guidelines of the Food and Drug Administration, showing to be accurate (bias within
±12%), precise (coefficient variation <9%), selective and linear (r
2 > 0.997) over the concentration range of 0.05–30 μg/mL for carbamazepine; 0.05–20 μg/mL for oxcarbazepine; 0.15–4 μg/mL for
eslicarbazepine acetate; 0.1–30 μg/mL for carbamazepine-10,11-epoxide; 0.1–10 μg/mL for 10,11-trans-dihydroxy-10,11-dihydro-carbamazepine, and 0.1–60 μg/mL for licarbazepine. It was also shown that this method can adequately
be used for the therapeutic drug monitoring of the considered antiepileptic drugs, carbamazepine, oxcarbazepine, eslicarazepine
acetate, and their metabolites. 相似文献
18.
Debasish Das M. K. Sureshkumar K. Radhakrishnan J. Nuwar C. G. S. Pillai 《Journal of Radioanalytical and Nuclear Chemistry》2011,289(1):275-285
Chitosan tripolyphosphate (CTPP) beads were prepared at two different cross-linking densities and adsorption of Cr(III) onto
it were studied as a function of different operational parameters such as solution pH, equilibration time and initial Cr(III)
ion concentration. Higher cross-linked beads were found to have more adsorption capacity at all the experimental pH employed
(pH = 3–5), whereas adsorption capacity is found to increase with increase in pH. Adsorption data were analyzed using Langmuir
and Freundlich isotherm models. Langmuir model is found be more suitable to explain the experimental results with a monolayer
adsorption capacity of 469.5 mg/g. Among the kinetic models used, pseudo-second order kinetic model could best describe the
adsorption process. Competition experiments done in presence of Na(I), Mg(II), Ca(II), Al(III) and Fe(III) revealed that,
except in the case of Al(III), adsorption of Cr(III) is not significantly affected by the presence of foreign cations. NaCl
is found to be a suitable leaching agent for the desorption of adsorbed Cr(III) from CTPP beads. FTIR spectroscopic investigations
confirmed that phosphate groups are the principal binding site responsible for the sorption of Cr(III) onto CTPP beads. 相似文献
19.
Suling Yang Gang Li Ran Yang Miaomiao Xia Lingbo Qu 《Journal of Solid State Electrochemistry》2011,15(9):1909-1918
An electrochemically functional nanocomposite through the adsorption of methylene blue onto the multi-walled nanotubes (MB-MWNTs)
was prepared, and a sensitive voltammetric sensor was fabricated. The modified electrode showed excellent electrocatalytic
activity toward dopamine (DA) and uric acid (UA) in 0.1 M phosphate solution medium (pH 3.0). Compared to the bare electrode,
the MB-MWNTs film-modified electrode not only remarkably enhanced the anodic peak currents of DA and UA, i.e., shifted the
anodic peak potential of DA negatively, but also avoided the overlapping of the anodic peaks of DA and UA. The interference
of ascorbic acid (AA) was eliminated. Under the optimized conditions, the peak separation between AA and DA and between DA
and UA was 219 and 174 mV, respectively. In the presence of 1.0 mM AA and 10.0 μM UA, the anodic peak current was linear to
the concentration of DA in the range of 0.4–10.0 μM with a detection limit of 0.2 μM DA. The anodic peak current of UA was
linear to the concentration in the range of 2.0–20.0 and 20.0–200.0 μM with a lowest detection limit of 1.0 μM in the presence
of 1.0 mM AA and 1.0 μM DA. 相似文献
20.
Ivan Carabante Mattias Grahn Allan Holmgren Jurate Kumpiene Jonas Hedlund 《Colloids and surfaces. A, Physicochemical and engineering aspects》2009,346(1-3):106-113
Stabilization of arsenic contaminated soils by iron oxides has been proposed as a remediation technique to prevent leaching of arsenate into the environment. Fundamental studies are needed to establish under which conditions the complexes formed are stable. In the present work, a powerful technique, viz. ATR-FTIR spectroscopy, is adapted to the studies of adsorption of arsenate species on iron oxides. This technique facilitates acquisition of both quantitative and qualitative in situ adsorption data.In the present work, about 800 nm thick films of 6-lineferrihydrite were deposited on ZnSe ATR crystals. Arsenate adsorption on the ferrihydrite film was studied at pD values ranging from 4 to 12 and at an arsenate concentration of 0.03 mM in D2O solution. The amount of adsorbed arsenate decreased with increasing pD as a result of the more negatively charged iron oxide surface at higher pD values. The adsorption and desorption kinetics were also studied. Arsenate showed a higher adsorption rate within the first 70 min and a much lower adsorption rate from 70 to 300 min. The low adsorption rate at longer reaction times was partly due to a low desorption rate of already adsorbed carbonate species adsorbed at the surface. The desorption of carbonate species was evidenced by the appearance of negative absorption bands. The desorption of adsorbed arsenate complexes was examined by flushing with D2O at pD 4 and 8.5 and it was found that the complexes were very stable at pD 4 suggesting formation of mostly inner-sphere complexes whereas a fraction of the complexes at pD 8.5 were less stable than at pD 4, possibly due to the formation of outer-sphere complexes.In summary, the ATR technique was shown to provide in situ information about the adsorption rate, desorption rate and the speciation of the complexes formed within a single experiment, which is very difficult to obtain using other techniques. 相似文献