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1.
Frank LA Borisova VV Markova SV Malikova NP Stepanyuk GA Vysotski ES 《Analytical and bioanalytical chemistry》2008,391(8):2891-2896
Two kinds of Ca2+-regulated photoprotein obelin with altered color of bioluminescence were obtained by active-center amino acid substitution.
The mutant W92F-H22E emits violet light (λmax = 390 nm) and the mutant Y139F emits greenish light (λ
max = 498 nm), with small spectral overlap, both display high activity and stability and thus may be used as reporters. For demonstration,
the mutants were applied in dual-color simultaneous immunoassay of two gonadotropic hormones—follicle-stimulating hormone
and luteinizing hormone. Bioluminescence of the reporters was simultaneously triggered by single injection of Ca2+ solution, divided using band-pass optical filters and measured with a two-channel photometer. The sensitivity of simultaneous
bioluminescence assay was close to that of a separate radioimmunoassay.
Figure Two kinds of Ca2+-regulated photoprotein obelin with altered color of bioluminescence were obtained and applied in dual-color simultaneous
immunoassay of two gonadotropic hormones. 相似文献
2.
Enzyme-linked immunosorbent assay (ELISA), horseradish peroxidase (HRP)-catalyzed fluorescent reaction, and oxalate chemiluminescence
imaging analysis have been combined to develop a sensitive, simple, and rapid method for analysis of interferon alpha (α-IFN)
in human serum samples. A typical “sandwich type” immunoassay was used. Reaction of o-phenylenediamine (OPD) with hydrogen peroxide (H2O2), catalyzed by HRP, produced 2,3-diaminophenazine (PDA), which was detected by chemiluminescence imaging analysis with the
bis(2,4,6-trichlorophenyl)oxalate (TCPO)–H2O2–glyoxaline–PDA chemiluminescent system. The TCPO chemiluminescent imaging system is more sensitive and the chemiluminescence
quantum yield is at least five times higher than for the luminol–H2O2–HRP–PIP (p-iodophenol) chemiluminescent imaging system. The results showed there was a very good linear correlation between response
and amount of α-IFN in the range 1.3–156.0 pg mL−1 (R = 0.9991) and the detection limit was 0.8 pg mL−1 (S/N=3). The relative standard deviation (n = 9) was 4.7%. The proposed method has been used for successful analysis of the amount of α-IFN in human serum. The results
obtained compared well with those obtained by conventional colorimetric ELISA and luminol chemiluminescent ELISA.
Figure Procedures of the proposed method 相似文献
3.
The damped glycolytic oscillation phenomenon occurring in starved cells of the yeast Saccharomyces cerevisiae (NBRC 0565) was characterization for application to a toxicity bioassay. S. cerevisiae was grown under semi-anaerobic conditions. The transient oscillations were observed photometrically as the time course of
the fluorescent intensity of reduced pyridine nucleotide resulting from instantaneous addition of glucose to a cell suspension.
In this study, simple and reproducible conditions inducing damped oscillations were obtained by modifying a literature method.
For estimation of the wave shapes of the damped oscillations we used six indexes. To investigate the total reproducibility
as the averaged relative standard deviation (RSDav) for the six indexes obtained from the wave shapes, the damped oscillations were induced under the optimum conditions and
the RSDav values were calculated as 14% in a buffer cell suspension (n = 62) and 22% in a water cell suspension (n = 78). Finally, the effects of glucose concentration on the six indexes were examined, and all the indexes changed when the
glucose concentration was changed. Excellent correlations were obtained between the index of oscillation-state time and the
concentration of glucose in a buffer cell suspension (r = 0.9985, 0.5–250 mmol L−1, 10 points) and in a water cell suspension (r = 0.9989, 2.5 μmol L−1–250 mmol L−1, 12 points), respectively.
Figure Characterization of damped glycolytic oscillation, (a) typical shape, and (b) its estimation
Electronic supplementary material The online version of this article (doi:)contains supplementary material, which is available to authorized users. 相似文献
4.
Limbut W Hedström M Thavarungkul P Kanatharana P Mattiasson B 《Analytical and bioanalytical chemistry》2007,389(2):517-525
A capacitive biosensor for the detection of bacterial endotoxin has been developed. Endotoxin-neutralizing protein derived
from American horseshoe crab was immobilized to a self-assembled thiol layer on a biosensor transducer (Au). Upon injection
of a sample containing endotoxin, a decrease in the observed capacitive signal was registered. Endotoxin could be determined
under optimum conditions with a detection limit of 1.0 × 10−13 M and linearity ranging from 1.0 × 10−13 to 1.0 × 10−10 M. Good agreement was achieved when applying endotoxin preparations purified from an Escherichia coli cultivation to the capacitive biosensor system, utilizing the conventional method for quantitative endotoxin determination,
the Limulus amebocyte lysate test as a reference. The capacitive biosensor method was statistically tested with the Wilcoxon signed rank test, which proved
the system is acceptable for the quantitative analysis of bacterial endotoxin (P < 0.05).
Figure The flow-injection capacitive biosensor system and the capacitive properties of the transducer surface, where CSAM is the capacitance change of the self-assembled thiol monolayer, CP is the capacitance change of the protein layer, Ca is the capacitance change of the analyte layer and CTotal is the total capacitance change measured at the working electrode/solution interface (modified from Limbut et al., 2006.
Biosens Bioelectron 22: 233-240) 相似文献
5.
The application of near-infrared (NIR) dyes (λ
em > 750 nm) to the analysis of biological samples shows much promise, because the long emission wavelengths of such dyes allow
interferences from biomolecule matrices to be minimized. In this paper, a novel NIR dye, 5,5′-dicarboxy-1,1′-disulfobutyl-3,3,3′,3′-tetramethylindotricarbocyanine
(DCDSTCY) has been developed for the spectrophotometric determination of total protein in serum. Under acidic conditions,
the binding of DCDSTCY to proteins caused a new peak at 878 nm, the height of which was proportional to the concentration
of protein. The linear range of the method was found to be 0.04–0.5 μg mL−1 for bovine serum albumin (BSA) and human serum albumin (HSA), and detection limits of 5 ng mL−1 were obtained for these substances. The maximum binding number of BSA with DCDSTCY was measured to be 133. The method proposed
here has been applied to the quantitation of total protein in serum, and recoveries of 96.6–104% were achieved.
Figure Near-infrared probe for protein determination 相似文献
6.
Radix Scrophulariae (Xuanshen) is one of the famous Chinese herbal medicines widely used to treat rheumatism, tussis, pharyngalgia, arthritis,
constipation, and conjunctival congestion. Harpagoside and cinnamic acid are the main bioactive components of Xuanshen. The
purpose of this study was to develop an HPLC–UV method for simultaneous determination of harpagoside and cinnamic acid in
rat plasma and investigate pharmacokinetic parameters of harpagoside and cinnamic acid after oral administration of Xuanshen
extract (760 mg kg−1). After addition of syringin as internal standard, the analytes were isolated from plasma by liquid–liquid extraction. Separation
was achieved on a Kromasil C18 column, and detection was by UV absorption at 272 nm. The described assay was validated in terms of linearity, accuracy,
precision, recovery, and limit of quantification according to the FDA validation guidelines. Calibration curves for both analytes
were linear with the coefficient of variation (r) for both was greater than 0.999. Accuracy for harpagoside and cinnamic acid ranged from 100.7–103.5% and 96.9–102.9%, respectively,
and precision for both analytes were less than 8.5%. The main pharmacokinetic parameters found for harpagoside and cinnamic
acid after oral infusion of Xuanshen extract were as follows: C
max 1488.7 ± 205.9 and 556.8 ± 94.2 ng mL−1, T
max 2.09 ± 0.31 and (1.48 ± 0.14 h, AUC0–24 10336.4 ± 1426.8 and 3653.1 ± 456.4 ng h mL−1, 11276.8 ± 1321.4 and 3704.5 ± 398.8 ng h mL−1, and t
1/2 4.9 ± 1.3 and 2.5 ± 0.9 h, respectively. These results indicated that the proposed method is simple, selective, and feasible
for pharmacokinetic study of Radix Scrophulariae extract in rats.
Figure Radix Scrophulariae 相似文献
7.
Garrigosa AM Ariño C Díaz-Cruz JM Esteban M 《Analytical and bioanalytical chemistry》2008,391(6):2209-2218
A comparison of a differential pulse polarographic with a phase sensitive alternating current polarographic study of the Cd-Cys-Gly
and Cd-PC2 systems [PC2 being a phytochelatin of general structure (γ-Glu-Cys)
n
-Gly, with n = 2] has been performed. The chemometric multivariate curve resolution method with alternating least squares was applied
in the experimental data analysis. The results obtained by both polarographic techniques have made it possible to find out
the formation sequences of the complexes and their final stoichiometries. The alternating current polarograms compared with
the differential pulse ones show some differences (a new signal and an important shift of peak potentials), which anyway are
consistent with some of the conclusions obtained by differential pulse polarography. This fact implies that although the alternating
current polarography results need some corrections before data treatment, they provide extra information that complements
the conclusions achieved by differential pulse polarography.
Figure Voltammograms at ACP(−10°), ACP(−65°) and corrected ACP during the titration of a 10−5 mol L−1 Cd(II) solution with PC2 at pH 8.5 in 0.05 L−1 Tris. 相似文献
8.
Cho SK Shim SH Park KR Choi SH Lee S 《Analytical and bioanalytical chemistry》2006,386(7-8):2027-2033
Three hundred and thirty two bacterial colonies were isolated from soil contaminated by an oil spill. All the bacteria were
cultured in a liquid medium individually, and the surface tensions of the media were compared. The bacterium whose culture
medium had the lowest surface tension was identified as Pseudomonas sp. G11. A biosurfactant was produced by cultivation of the Pseudomonas sp. G11 in the LB media. For extraction of the biosurfactant, two solvent systems were used (n-hexane and a 2:1 (v/v) mixture of chloroform/MeOH), and the results were compared. Various experimental conditions (solvent
composition, flow rate, etc.) were tested to optimize the analysis of the biosurfactant by asymmetrical flow field-flow fractionation
(AsFlFFF). The biosurfactant was successfully separated from the culture medium by AsFlFFF when pure water was used as the
carrier. From the retention data, the hydrodynamic diameter (d
H) and molecular weight (M) of the biosurfactant were determined by AsFlFFF. The molecular weight was determined by using pullulans as the calibration
standards. The d
H and M were 49 nm and 2.3 × 105 Da when extracted with n-hexane, and 39 nm and 1.13 × 105 Da when extracted with the 2:1 mixture of chloroform/MeOH, respectively.
Figure Separation of biosurfactant from its culture medium by flow FFF 相似文献
9.
A novel electrochemical sensor for methyl parathion based on silicate– cetyltrimethylammonium bromide nanocomposite film has
been fabricated by electro-assisted deposition onto glassy carbon electrode in one-step via an electrochemical modulation
of pH at the electrode/solution interface to promote controlled gelification of tetraethylorthosilicate sol, and was characterized
with scanning electron microscopy, X-ray diffraction, and electrochemical impedance spectroscopy. The electrochemical sensing
of methyl parathion on the film-modified electrode was investigated applying cyclic voltammetry and square wave voltammetry.
Compared to the unmodified electrode, the shapes of the redox peaks were improved and the peak currents significantly increased.
Experimental parameters such as deposition time, pH value, and accumulation conditions have been optimized. A linear relationship
between the peak current and methyl parathion concentration was obtained in the range from 1.0 × 10−7 to 1.0 × 10−4 mol L−1 with a detection limit of 1.04 × 10 −8 mol L−1 (S/N = 3) after accumulation at 0 V for 120 s. The film electrode shows great promise for determination of methyl parathion in
real samples.
相似文献
10.
The use of olaquindox (OLA) as an additive in animal feedstuffs has been prohibited in the European Union and many other countries.
In this study, a highly sensitive and specific indirect competitive enzyme-linked immunosorbent assay (ELISA) for determination
of OLA in animal feed samples was developed. OLA was activated by N′N-carbonyldiimidazole and coupled with bovine serum albumin (BSA) and ovalbumin (OVA). It was found that the sensitivity and
specificity of the two antisera were very similar, with the IC50 values of 16 ng mL−1 and 19 ng mL−1, respectively. Cross-reactivity was less than 35% for four structurally related compounds and no recognition of five other
antibiotics was observed. The better antiserum I was selected for further experiments, for example testing stability, solvent
effect, accuracy, and precision. The IC50 value for eight standard curves was in the range 12–18 ng mL−1 and the LOD at a signal-to-noise ratio of 3 (S/N = 3) was 0.31 ± 0.11 ng mL−1. The ELISA tolerated 5% methanol without significant influence on IC50 value. The recoveries of spiked OLA in five different animal feed types including auxin, pig complex feed, fish complex feed,
broiler concentrated feed, and pig premix feed were in the range 88.3–119.0% and the intra-assay relative standard deviation
(RSD) was within 4.7–33.5% (n = 3). The ELISA for unspiked feed samples was confirmed by high-performance liquid chromatography (HPLC), with a high correlation
coefficient of 0.9862 (n = 5). The proposed ELISA could be a feasible quantitative/screening method for OLA analysis in feed samples with the properties
of high sensitivity, specificity, simplicity of sample pretreatment, high sample throughput, and low expense.
Figure Polyclonal antibody based ELISA for detection of olaquindox 相似文献
11.
We have developed a circular-dichroism thermal lens microscope for UV wavelengths (UV-CD-TLM), for the first time, to realize
sensitive chiral analysis on a microchip. Quasi-continuous-wave phase modulation of a pulsed UV laser was used to generate
left-circularly polarized light and right-circularly polarized light and to detect the generated TL signal amplitude and phase
with a lock-in amplifier. The amplitude and phase were used to determine the concentration and chirality, respectively, of
a sample. The basic principle of UV-CD-TLM for chiral analysis on a microchip was verified by measuring aqueous solutions
of optically active camphorsulfonic acids (CSA). Lower limits of detection (LOD) were calculated at S/N = 2 and were 8.7 × 10−4 mol L−1 (ΔA = 5.2 × 10−6 Abs.) for (+)-CSA and 8.4 × 10−4 mol L−1 (ΔA = 5.0 × 10−6 Abs.) for (−)-CSA. In terms of number of molecules, LODs for UV-CD-TLM were calculated to be 8.7 fmol and 8.4 fmol, respectively.
This is at least three orders of magnitude lower than previously obtained. The applicability of UV-CD-TLM for chiral analysis
on a microchip was verified.
Figure Sensitive chiral analysis by thermal lens microscope (TLM) 相似文献
12.
Stratis-Cullum DN Griffin GD Mobley J Vo-Dinh T 《Analytical and bioanalytical chemistry》2008,391(5):1655-1660
This paper reports the first intensified biochip system for chemiluminescence detection and the feasibility of using this
system for the analysis of biological warfare agents is demonstrated. An enzyme-linked immunosorbent assay targeting Bacillus globigii spores, a surrogate species for Bacillus anthracis, using a chemiluminescent alkaline phosphatase substrate is combined with a compact intensified biochip detection system.
The enzymatic amplification was found to be an attractive method for detection of low spore concentrations when combined with
the intensified biochip device. This system was capable of detecting approximately 1 × 105
Bacillus globigii spores. Moreover, the chemiluminescence method, combined with the self-contained biochip design, allows for a simple, compact
system that does not require laser excitation and is readily adaptable to field use.
Figure Schematic diagram of the miniature biochip detection system 相似文献
13.
A novel fluorescence quenching method for the determination of cationic surfactants (CS), specifically cetyltrimethylammonium
bromide (CTAB), dodecyltrimethylammonium bromide (DTAB), and cetylpyridinium chloride (CPC), has been developed using water-soluble
luminescent CdTe quantum dots (QDs) modified with thioglycolic acid (TGA). The possible interference from heavy and transition
metals (HTM) has been efficiently eliminated through simple sample treatment with mercapto cotton made in-house. Under optimum
conditions, the extent of fluorescence quenching of CdTe QDs is linearly proportional to the concentration of CS from 2.0 × 10−7 to 7.0 × 10−6 mol L−1 with a detection limit of 5.0 × 10−8 mol L−1. The relative standard deviation for 1.0 × 10−6 mol L−1 CTAB is 2.5% (n = 6). The proposed method exhibits high sensitivity and selectivity and furthermore avoided the use of toxic organic solvents
and tedious solvent extraction procedures. It has been applied to the determination of trace CS in natural river water and
commodity samples with satisfactory results.
Potential interference from heavy and transition metals is eliminated during photoluminescence detection of CS through simple
sample pre-treatment with mercapto cotton 相似文献
14.
Lee KC Cheuk MW Chan W Lee AW Zhao ZZ Jiang ZH Cai Z 《Analytical and bioanalytical chemistry》2006,386(7-8):2225-2232
A reversed-phase HPLC method has been developed for determination of twelve intact glucosinolates—glucoiberin, glucocheirolin,
progoitrin, sinigrin, epiprogoitrin, glucoraphenin, sinalbin, gluconapin, glucosibarin, glucotropaeolin, glucoerucin, and
gluconasturtiin—in ten traditional Chinese plants. The samples were extracted with methanol and the extracts were cleaned
on an activated Florisil column. A mobile phase gradient prepared from methanol and 30 mmol L−1 ammonium acetate at pH 5.0 enabled baseline separation of the glucosinolates. Glucosinolate detection was confirmed by quadrupole
time-of-flight tandem mass spectrometric analysis in negative-ionization mode. Detection limits ranged from 0.06 to 0.36 μg
g−1 when 5 g of dried plant was analyzed. Recoveries of the glucosinolates were better than 85% and precision (relative standard
derivation, n = 3) ranged from 5.3 to 14.6%. Analysis of the glucosinolates provided scientific evidence enabling differentiation of three
pairs of easily confused plants.
Figure Glucosinolates Analysis for the Differentiation of Easily-Confusing Herbs 相似文献
15.
A cobalt hexacyanoferrate (CoHCF)-modified graphite paraffin wax composite electrode was prepared by a new approach. An amine-functionalised
graphite powder was used for the fabrication of the electrode. A functionalised graphite paraffin wax composite electrode
was prepared and the surface of the electrode was modified with a thin film of CoHCF. Various parameters that influence the
electrochemical behaviour of the modified electrode were studied by varying the background electrolytes, scan rates and pH.
The modified electrode showed good electrocatalytic activity towards the oxidation of butylated hydroxyanisole (BHA) under
optimal conditions and showed a linear response over the range from 7.9 × 10−7 to 1.9 × 10−4 M of BHA with a correlation coefficient of 0.9988. The limit of detection was 1.9 × 10−7 M. Electrocatalytic oxidation of BHA was effective at the modified electrode at a significantly reduced potential and at
a broader pH range. The utility of the modified electrode as an amperometric sensor for the determination of BHA in flow systems
was evaluated by carrying out hydrodynamic and chronoamperometric experiments. The modified electrode showed very good stability
and a longer shelf life. The modified electrode was applied for the determination of BHA in spiked samples of chewing gum
and edible sunflower oil. The advantage of this method is the ease of electrode fabrication, good stability, longer shelf
life, low cost and its diverse application for BHA determination.
Figure Cyclic Voltammogram of () CoHCF modified electrode, () in presence of 1.9 x 10−5 M of BHA and () bare electrode, () in the presence of 1.9 x 10−5 M of BHA in 1.0 M NaCl, pH 7.0 相似文献
16.
de Jesus Rodrigues Santos W Lima PR Tarley CR Kubota LT 《Analytical and bioanalytical chemistry》2007,389(6):1919-1929
Despite the increasing number of applications of molecularly imprinted polymers (MIP) in analytical chemistry, the synthesis
of polymers with hemin introduced as the catalytic center to mimic the active site of peroxidase remains as a challenge. In
the current work, a new type of molecularly imprinted polymer (MIP) was synthesized with 4-aminophenol (4-APh) as the template
and two monomers: hemin, which acts as the catalytic center, and methacrylic acid (MAA), which is used to build the active
sites. This work shows that MIP successfully mimics peroxidase. For this purpose, a flow injection analysis system coupled
to an amperometric detector was investigated through multivariate analysis. The determination of 4-APh was not affected by
the equimolar presence of structurally similar phenol compounds, including catechol, 4-chloro-3-methylphenol, 2-aminophenol,
guaiachol, chloroguaiachol and 2-cresol, thus highlighting the good performance of the imprinted polymer. Under the optimized
experimental conditions, an analytical curve covering a wide linear response range from 0.8 up to 500 μmol L−1 (r > 0.999) was obtained, and the method gave satisfactory precisions (n = 8), as evaluated via the relative standard deviation (RSD), of 4.1 and 3.2% for solutions of 4-APh of 50 and 500 μmol L−1, respectively. Recoveries of 96–111% from water samples (tap water and river water) spiked with 4-APh were achieved, thus
illustrating the accuracy of the proposed system.
Figure Schematic presentation of the synthesis of the MIP 相似文献
17.
The electrochemical behavior of paracetamol in 0.1 M acetate buffer solution (pH 4.6) was investigated at a traditional carbon
paste electrode (TCPE) and a carbon ionic liquid electrode (CILE) fabricated by replacing nonconductive organic binders with
a conductive hydrophobic room temperature ionic liquid, 1-butyl-3-methylimidazolium hexafluorophosphate (BmimPF6). The results showed that the CILE exhibited better reversibility for the electrochemical redox of paracetamol. The oxidation
potential of paracetamol at the CILE is +0.462 V, which is approximately 232 mV lower than that at the TCPE; the oxidation
peak current response is nine times higher than that at the TCPE. The differential pulse voltammetric determination of paracetamol
at the CILE was established based on this behavior. After optimizing several important parameters controlling the performance
of paracetamol at the CILE, the oxidation peak current versus paracetamol concentration at the CILE showed linearity in the
range from 1.0 μM to 2.0 mM (R
2
= 0.9992) with a detection limit of 0.3 μM (S/N = 3). The method has been applied to the determination of paracetamol in
tablets and urine samples and the average recovery of paracetamol was 98.5% and 99.3%, respectively. The proposed CILE showed
good sensitivity and reproducible response without influence of interferents commonly existing in pharmaceutical and urine
samples.
Figure CV curves of paracetamol illustrate the enhanced electrochemical behavior of paracetamol at the CILE (b), which forms the basis for the differential pulse voltammetric determination of paracetamol 相似文献
18.
A new spectrofluorimetric method was developed for the determination of trace amounts of lecithin using the ciprofloxacin (CIP)–terbium (Tb3+) ion complex as a fluorescent probe. In a buffer solution at pH=5.60, lecithin can remarkably reduce the fluorescence intensity of the CIP–Tb3+ complex at λ=545 nm. The reduced fluorescence intensity of the Tb3+ ion is proportional to the concentration of lecithin. Optimum conditions for the determination of lecithin were also investigated. The linear range and detection limit for the determination of lecithin were 1.0×10−6–3.0×10−5 mol L−1 and 3.44×10−7 mol L−1, respectively. This method is simple, practical, and relatively free of interference from coexisting substances. Furthermore, it has been successfully applied to assess lecithin in serum samples.
相似文献
19.
Amatatongchai M Hofmann O Nacapricha D Chailapakul O deMello AJ 《Analytical and bioanalytical chemistry》2007,387(1):277-285
A microfluidic system incorporating chemiluminescence detection is reported as a new tool for measuring antioxidant capacity.
The detection is based on a peroxyoxalate chemiluminescence (PO-CL) assay with 9,10-bis-(phenylethynyl)anthracene (BPEA) as
the fluorescent probe and hydrogen peroxide as the oxidant. Antioxidant plugs injected into the hydrogen peroxide stream result
in inhibition of the CL emission which can be quantified and correlated with antioxidant capacity. The PO-CL assay is performed
in 800-μm-wide and 800-μm-deep microchannels on a poly(dimethylsiloxane) (PDMS) microchip. Controlled injection of the antioxidant
plugs is performed through an injection valve. Of the plant-food based antioxidants tested, β-carotene was found to be the
most efficient hydrogen peroxide scavenger (SA
HP of 3.27 × 10−3 μmol−1 L), followed by α-tocopherol (SA
HP of 2.36 × 10−3 μmol−1 L) and quercetin (SA
HP of 0.31 × 10−3 μmol−1 L). Although the method is inherently simple and rapid, excellent analytical performance is afforded in terms of sensitivity,
dynamic range, and precision, with RSD values typically below 1.5%. We expect our microfluidic devices to be used for in-the-field
antioxidant capacity screening of plant-sourced food and pharmaceutical supplements.
Figure Assembled PDMS microchip sandwiched between two glass plates with the top plate containing capillary reservoirs 相似文献
20.
Small-volume fiber-optic evanescent-wave absorption sensor for nitrite determination 总被引:1,自引:0,他引:1
Yan Xiong Dao-qian Zhu Chun-feng Duan Jian-wei Wang Ya-feng Guan 《Analytical and bioanalytical chemistry》2010,396(2):943-948
A novel small-volume fiber-optic evanescent-wave absorption sensor based on the Griess–Ilosvay reaction has been developed
and evaluated for nitrite determination. The sensor was constructed by inserting a decladded optical fiber into a transparent
capillary to form an annular column microchannel. The Evanescent wave (EW) field produced on the optical fiber core surface
penetrated into the surrounding medium and interacted with the azo dye, which was generated by the reaction of nitrite and
nitrite-sensitive reagents. The detector was designed to be parallel to the axis of the optical fiber. The defined absorbance
was linear with the concentration of nitrite in the range from 0.05 to 10 mg L−1, and the detection limit was 0.02 mg L−1 (3σ) with the relative standard deviation (RSD) of 2.6% (n = 8). The present sensor was successfully used to determine nitrite in real samples of mineral water, tap water, rain water,
and seawater. The results were consistent with the data obtained by standard spectrophotometric method, showing potential
of the proposed sensor for practical application.
相似文献