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1.
Gerda Redl Fatima T. Husain Ines E. Bretbacher Albert Nemes Margit Cichna-Markl 《Analytical and bioanalytical chemistry》2010,398(4):1735-1745
This paper presents a sandwich enzyme-linked immunosorbent assay (ELISA) that allows the determination of traces of sesame
in food. Chicken anti-sesame antibodies, used as coating antibodies, and rabbit anti-sesame antibodies, used as secondary
antibodies, were prepared by immunization with a protein extract of white, peeled sesame. The ELISA did not show any cross-reactivity
with 19 food ingredients commonly found in sesame-containing foodstuffs such as seeds, nuts, and cereals. In whole grain bread,
crisp toast, and snacks, the limit of detection (S/N = 3) was 0.5, 0.5, and 0.3 μg sesame protein/g, and the limit of quantification (S/N = 10) was 0.6, 0.8, and 1.4 μg sesame protein/g, respectively. The analysis of blank food matrices (whole grain bread, white
bread, crisp toast, and snacks) spiked with sesame protein at four spike levels generally resulted in mean recoveries from
72% to 145%. In the case of spiking blank food matrices with sesame seeds, the ELISA proved to be more accurate for whole
wheat cookies than for whole wheat bread. 相似文献
2.
Steve L. Taylor Julie A. Nordlee Lynn M. Niemann Debra M. Lambrecht 《Analytical and bioanalytical chemistry》2009,395(1):83-92
The enzyme-linked immunosorbent assay (ELISA) offers many advantages for the detection of potentially hazardous allergenic
food residues that might become adventitious components of other foods during the course of food production and processing.
ELISAs detect proteins, and food allergens are proteins. ELISAs are sufficiently sensitive and specific for detection of food
allergen residues. ELISAs can also be produced in formats that are compatible with the industrial food processing environment.
However, ELISAs also have disadvantages that should be carefully evaluated and widely recognized. Various food-processing
operations can have profound effects on the detectability of allergenic food residues. ELISAs detect intact proteins but protein
hydrolysates evade detection in some ELISA formats. The residual proteins present in some ingredients derived from commonly
allergenic sources may also not be easily detected with ELISAs because of the nature of the protein residues remaining, e.g.
lipophilic. Processing operations can dramatically lower the solubility of proteins. In some food formulations, heat processing,
in particular, induces chemical modifications that can affect antibody binding to epitopes in the ELISA. The use of naturally
incurred standards where allergenic food residues are incorporated into various representative food matrices and then processed
in a manner similar to “real-world” food processing can reveal some of the limitations of allergen ELISAs. Methods for the
preparation of naturally incurred standards in chocolate, cookie, muffin, ice cream, pasta, frankfurter, and cream of potato
soup are provided as examples. 相似文献
3.
B. Miksa S. Slomkowski M. M. Chehimi M. Delamar J.-P. Majoral A.-M. Caminade 《Colloid and polymer science》1999,277(1):58-65
Quartz plates were modified by consecutive immobilization of γ-aminopropyltriethoxysilane (APTS), phosphorus containing dendrimers
with aldehyde groups (generation 5 – G5), Starburst PAMAM dendrimers generation 4 (G4-PAMAM), and poly(styrene/acrolein/divinylbenzene)
microspheres [P(SAD)]. In this way surfaces with heterogeneity on molecular, macromolecular, and microscopic levels, and which
were equipped with functional amino or aldehyde groups were obtained. Surface layers were characterized by X-ray photoelectron
spectroscopy (XPS) and by contact-angle measurements. Analysis of XPS spectra revealed that the thickness of the layer of
G5 on the SiO2-APTS substrate was 3.7 nm, i.e., the thickness was typical for macromolecular dimensions. The average thickness of the layer
of PAMAM dendrimers on SiO2-APTS-G5 was found to be 0.35 and 0.29 nm, depending on whether calculations were based on attenuation of the intensity of
the Si2p or the P2p signal respectively. This thickness was unreasonably low for a monolayer of PAMAM dendrimers and indicated that the surface
of the SiO2-APTS-G5 substrate was incompletely covered with these macromolecules. The XPS method was also used for the determination
of the degree of coverage of the surface of a SiO2-APTS-G5-PAMAM plate with P(SAD) microspheres. The degree of coverage was found to be 0.60 and approaches the maximum theoretically
possible value (0.62) for microspheres attached chaotically and irreversibly to the surface in an arrangement one microsphere
thick. Subsequent coverage of the SiO2-APTS-G5-PAMAM-P(SAD) substrate with PAMAM dendrimers resulted in the formation of a PAMAM adlayer 3.2 nm thick, close to
the molecular dimensions of these dendrimers. Contact-angle measurements revealed considerable differences in the hydrophobicity
of the surfaces of the quartz plates, depending on their modification. Hydrophobicity increased in the order SiO2 < SiO2-APTS-G5-PAMAM < SiO2-APTS ≤ SiO2-APTS-G5 < SiO2-APTS-G5-PAMAM-P(SAD).
Received: 17 March 1998 Accepted: 14 September 1998 相似文献
4.
Careri M Elviri L Lagos JB Mangia A Speroni F Terenghi M 《Journal of chromatography. A》2008,1206(2):89-94
Complex matrices commonly affect the sensitivity and selectivity of liquid chromatography-mass spectrometry (LC-MS) analysis. Thus, selective sample enrichment strategies are useful particularly to analyze organic biomarkers present in low abundance in samples. A selective immunomagnetic extraction procedure to isolate trace peanut allergen protein Ara h3/4 from breakfast cereals combined with microwave-assisted tryptic digestion and liquid chromatography-electrospray ion-trap tandem mass spectrometry (LC-ESI-IT-MS/MS) measurement was developed. Using protein A-coated magnetic bead (MB) support, anti-Ara h3/4 monoclonal antibodies (Abs) were used as selective capture molecules. The results obtained by LC-ESI-IT-MS/MS in terms of limit of detection (3mg peanuts/kg matrix) and a significantly reduced matrix effect demonstrated that the Ab-coated magnetic bead was very effective to selectively trap Ara h3/4 protein in breakfast cereals. The magnetic bead-based sample treatment followed by LC-IT-MS/MS method here developed can be proposed as very rapid and powerful confirmatory analytical method to verify the reliability of enzyme-linked immunosorbent assay (ELISA) screening methods, since the magnetic bead-LC-IT-MS/MS method combines good sensitivity to the identification capabilities of mass spectrometry. 相似文献
5.
Yang Song Yu Ge Yan Zhang Bing Liu Yang Lu Tingting Dong Shuo Wang 《Analytical and bioanalytical chemistry》2009,393(8):2001-2008
In this study, a panel of haptens was synthesized for immunoconjugate preparation, and several haptens for heterologous tracer
conjugates were also prepared. A highly sensitive polyclonal antibody against the organophosphorus insecticide phosmet was
obtained and competitive direct enzyme-linked immunosorbent assays (cd-ELISA) for this pesticide were developed. In the cd-ELISA,
the limit of detection (IC15) was 0.6 μg kg−1 and the sensitivity (IC50) was 20 μg kg−1. The suitability of the ELISA for pesticide quantification in peach, apple, orange juice, and apple juice was also studied.
Good accuracy and precision were obtained with mean recoveries between 78% and 102.3% and mean coefficients of variation below
13.63%. Validation of the ELISA was conducted by high-performance liquid chromatography. The correlation between the data
obtained using the microwell assay and the high-performance liquid chromatography was good (R
2 = 0.9849). The developed immunoassay methods were suitable for the rapid quantitative or qualitative determination of phosmet
in food samples. 相似文献
6.
Commercialized rapid immunoanalytical tests for determination of allergenic food proteins: an overview 总被引:1,自引:0,他引:1
Patricia Schubert-Ullrich Judith Rudolf Parisa Ansari Brigitte Galler Manuela Führer Alexandra Molinelli Sabine Baumgartner 《Analytical and bioanalytical chemistry》2009,395(1):69-81
Food allergies have become an important health issue especially in industrialized countries. Undeclared allergenic ingredients
or the presence of “hidden” allergens because of contamination during the food production process pose great health risks
to sensitised individuals. The EU directive for food labelling lists allergenic foods that have to be declared on food products
by the manufacturers. The list includes gluten-containing cereals, crustaceans, eggs, fish, peanuts, soybeans, milk, various
nuts (e.g. almond, hazelnut, and walnut, etc.), celery, mustard, sesame seeds, lupin, and molluscs. Reliable methods for detection
and quantification of food allergens are needed that can be applied in a fast and easy-to-use manner, are portable, and need
only limited technical equipment. This review focuses on the latest developments in food allergen analysis with special emphasis
on fast immunoanalytical methods such as rapid enzyme-linked immunosorbent assays (ELISA), lateral-flow immunochromatographic
assays (LFA) and dipstick tests. Emerging technologies such as immunochemical microarrays and biosensors are also discussed
and their application to food allergen analysis is reviewed. Finally, a comprehensive overview of rapid immunochemical test
kits that are currently available commercially is given in tabular form. 相似文献
7.
Careri M Elviri L Maffini M Mangia A Mucchino C Terenghi M 《Rapid communications in mass spectrometry : RCM》2008,22(6):807-811
A comparison of two methods for the identification and determination of peanut allergens based on europium (Eu)-tagged inductively coupled plasma mass spectrometry (ICP-MS) immunoassay and on liquid chromatography/electrospray ionization tandem mass spectrometry (LC/ESI-MS/MS) with a triple quadrupole mass analyzer was carried out on a complex food matrix like a chocolate rice crispy-based snack. The LC/MS/MS method was based on the determination of four different peptide biomarkers selective for the Ara h2 and Ara h3/4 peanut proteins. The performance of this method was compared with that of a non-competitive sandwich enzyme-linked immunosorbent assay (ELISA) method with ICP-MS detection of the metal used to tag the antibody for the quantitative peanut protein analysis in food. The limit of detection (LOD) and quantitation of the ICP-MS immunoassay were 2.2 and 5 microg peanuts g(-1) matrix, respectively, the recovery ranged from 86 +/- 18% to 110 +/- 4% and linearity was proved in the 5-50 microg g(-1) range. The LC/MS/MS method allowed us to obtain LODs of 1 and 5 microg protein g(-1) matrix for Ara h3/4 and Ara h2, respectively, thus obtaining significantly higher values with respect to the ELISA ICP-MS method, taking into account the different expression for concentrations. Linearity was established in the 10-200 microg g(-1) range of peanut proteins in the food matrix investigated and good precision (RSD <10%) was demonstrated. Both the two approaches, used for screening or confirmative purposes, showed the power of mass spectrometry when used as a very selective detector in difficult matrices even if some limitations still exist, i.e. matrix suppression in the LC/ESI-MS/MS procedure and the change of the Ag/Ab binding with matrix in the ICP-MS method. 相似文献
8.
9.
A polyclonal antibody against ochratoxin A (OTA) was produced from rabbits immunized with the OTA–BSA conjugate. A competitive
direct enzyme-linked immunosorbent assay (cdELISA) and a membrane-base colloidal gold immunoassay in flow-through format were
developed for the rapid detection of OTA in various food matrices. In the cdELISA, the concentration causing 50% inhibition
was 0.07 ng mL−1, and the effects of different chemical conditions (ionic strength, pH value, and organic solvent) were studied. The sensitivity
of the assay was higher than those previously reported. A simple, rapid, and efficient extraction method was developed and
74–110% recoveries of spiked samples were obtained. Fifty percent methanol extracts of some food samples such as barley, wheat,
oat, corn, rice, and raisins could be analyzed directly by immunoassay after dilution in PBS; grape juice and beer samples
could be analyzed directly after dilution with PBS; for coffee samples, a more complex method was used to remove the matrix
effect effectively. Membrane-based colloidal gold immunoassays had a visual detection limit of 1.0 ng mL−1 for OTA with a detection time of less than 10 min. For the validation of the cdELISA and membrane-based colloidal gold immunoassay,
samples were analyzed by high-performance liquid chromatography. The correlation between data obtained using the microwell
assay and HPLC was good (R
2 = 0.984). The developed immunoassay methods are suitable for the rapid quantitative or qualitative determination of OTA in
food samples. 相似文献
10.
Herranz S Ramón-Azcón J Benito-Peña E Marazuela MD Marco MP Moreno-Bondi MC 《Analytical and bioanalytical chemistry》2008,391(5):1801-1812
Specific polyclonal antibodies against s-triazine herbicides were obtained by preparing immunogens coupling home-synthesized haptens derivatives of simazine (6-chloro-N-ethyl-N′-ethyl-1,3,5-triazine-2,4-diamine) to lysine groups of hemocyanin from keyhole limpets and bovine serum albumin carrier proteins.
Three highly sensitive rabbit antisera were obtained and evaluated with a battery of six enzyme tracers derived from triazine
structures in an optimized ELISA format. The antiserum As8 and the HRP-2f tracer, which yield the best assay sensitivity for
simazine (detection limit 0.11 ± 0.02 μg L−1, IC50 0.88 ± 0.04 μg L−1), were applied to the development of a sensitive flow-through immunoassay for the analysis of this herbicide. The automated
assay was based on a direct competitive immunosorbent assay and fluorescence detection. The optimized method presents an IC50 value of 0.35 ± 0.04 μg L−1 with a detection limit of 1.3 ± 0.9 ng L−1 and a dynamic range from 0.010 to 7.5 μg L−1 simazine. The generic nature of the antiserum was shown by good relative cross-reactivities with other triazines such as
atrazine (420%) or propazine (130%) and a lower response to terbutylazine (6.4%) and desethyl-atrazine (2.2%). No cross-reactivity
was obtained for nonrelated pesticides such as 2,4-dichlorophenoxyacetic acid or linuron and the assay could be applied as
a screening method for triazine herbicides. The total analysis time was 30 min per determination and the immunosensor could
be reused for more than 150 cycles without significant loss of activity. The immunosensor has been successfully applied to
the direct analysis of simazine in surface water samples at the nanogram per liter level. The results obtained by comparative
analysis of the immunosensor with a chromatographic procedure for triazines showed a close correspondence. 相似文献
11.
Giovannoli C Anfossi L Baggiani C Giraudi G 《Analytical and bioanalytical chemistry》2008,392(3):385-393
Experimental work performed was aimed at the assessment of a competitive capillary electrophoresis immunoassay with laser-induced
fluorescence (CEIA-LIF) detection for the determination of the Cry1Ab endotoxin from Bacillus thuringensis. The binding constant of a monoclonal antibody, raised against the insecticide protein Cry1Ab, was determined on a microplate
by indirect enzyme-linked immunosorbent assay (ELISA) and compared with that obtained in-capillary under nonequilibrium separation
conditions. The two binding constants appear comparable—(5.0 ± 1.2) × 106 M−1 and (9.06 ± 5.7) × 106 M−1—reflecting good preservation of the antibody binding behavior in the capillary electrophoresis format. These results allow
use of a calibration curve possible between 0.2 and 150 nM of endotoxin protein, with a limit of detection of 0.5 nM (33 μg L−1). Preliminary recovery experiments on maize extracts spiked with known amounts of Cry1Ab endotoxin also showed promising
results in detecting the toxin in complex real matrices. 相似文献
12.
Silvia Zamponi Anna M. Kijak André J. Sommer Roberto Marassi Pawel J. Kulesza James A. Cox 《Journal of Solid State Electrochemistry》2002,6(8):528-533
The inclusion of a generation-4 polyamidoamine (G4-PAMAM) dendrimer in a silica sol-gel yielded a solid electrolyte that
was used to encapsulate Prussian Blue (PB), iron(III) hexacyanoferrate(II), and cobalt hexacyanoferrate. The PB was synthesized
in the doped silica by sequential immersion of a monolith in 0.1 M K4Fe(CN)6, water, and 0.1 M FeCl3. Inclusion of G4-PAMAM resulted in a nanoporous anion-exchange material with a capacity of 10.1 mmol g–1, which is about four times greater than the capacity of silica alone. Relative to its G0 counterpart, the G4-PAMAM doped
silica increased the rate of formation of PB by a factor of ca. 20. The solid state voltammetry of PB in the doped silica
had the usual features for this compound. At 0.1 V vs. a Ag quasi-reference electrode, a reversible reduction was seen; the
relationship between current and scan rate was that for a surface-confined redox couple. The quasi-reversible oxidation of
PB was observed at 0.85 V. Inclusion of G4-PAMAM increased the lifetime of silica as a solid electrolyte from a few days to
at least three months. Raman microprobe mapping analysis demonstrated that PB was homogeneously distributed across the entire
width (ca. 1 mm) of the G4-doped monolith with 20-h immersions.
Electronic Publication 相似文献
13.
The development of a direct competitive enzyme-linked immunosorbent assay (ELISA) based on polyclonal antibodies specific for semicarbazide (SEM) is described. Molecular modelling of the hapten mimics and other key components of the assay system was conducted to explain antibody properties in relation to hapten design. The small aliphatic molecule SEM was coupled to 3-carboxybenzaldehyde to produce carboxyphenyl-SEM (CPSEM), for the generation of specific antibodies. Five rabbits produced antibodies against NPSEM (used in direct and indirect ELISA formats) exhibiting a 50% binding inhibition level (IC50 values) of 0.06-2.28 μg L−1 in assay buffer for SEM. The most sensitive indirect assay based on the antibody MVK39 showed a high dynamic range providing a linear readout in the range of 0.01-0.2 μg L−1. Antibody MVK31 (IgG) allowed specific SEM detection at an IC50 = 0.14 μg L−1 in direct ELISA and was evaluated using solvent extracted SEM-spiked porcine and baby food samples. Recovery levels determined from fortified samples (0.5, 1.0, 1.5, 5, 10 and 20 μg kg−1) of porcine and baby food ranged from 82.9 to 105.3%, respectively, with a coefficient of variation less than 15.5%. Respective detection capability and threshold of the assay for porcine muscle, set on the basis of acceptance of no false negative results, was 0.3 and 0.11 μg kg−1. 相似文献
14.
Neopterin is a valuable biomarker of cellular immunity associated with various pathological situations such as viral and bacterial
infections, autoimmune, cardiovascular, neurodegenerative and malignant disorders. To produce specific antibodies against
neopterin for a rapid multi-biomarker-based diagnosis, a novel hapten derivative was synthesized and attached to carrier proteins.
The thoroughly characterized conjugates were used for immunization of BALB/c mice and rabbits. The produced monoclonal antibody
reached in both direct and indirect enzyme-linked immunosorbent assay (ELISA) format LoD of 0.18 and 0.45 μg L−1, respectively, and was a superior immunoreagent for further biosensor developments with regard to assay sensitivity and material
availability. The best polyclonal antibody was somewhat more sensitive in direct ELISA with LoD of 0.05 μg L−1. The optimized ELISA method was evaluated with blood samples collected from patients with renal insufficiency, patients with
sepsis, patients without confirmed clinical diagnosis, and healthy volunteers. In plasma samples, neopterin concentrations
ranging from 3.2 to 103 μg L−1 could be determined with the monoclonal ELISA whereas twofold lower results were obtained with the polyclonal ELISA. A satisfactory
correlation of results was found between the polyclonal ELISA and IBL Neopterin ELISA kit within the concentration range 0.5–16 μg L−1 (R = 0.874; n = 40), and slightly lower correlation was found for monoclonal-based ELISA (R = 0.819; n = 40). These data show that the generated antibodies may be used as functional analytical reagents for the integration into
multianalyte biochip detection systems. 相似文献
15.
Gliadin from wheat is a common food allergen that can induce baker’s asthma, wheat-dependent exercise-induced anaphylaxis, atopic dermatitis, and celiac disease. This gliadin assay focuses on rapidly screen and check for gluten contamination in raw materials and in the gluten-free food production process, not only for wheat-sensitive patients but also for the industries producing gluten-free foodstuffs. The developed assay incorporates the use of anti-gliadin antibody-conjugated immunomagnetic beads (IMBs) to capture the gliadin in samples and fluorescent dyes-loaded immunoliposomal nanovesicles (IMLNs) to produce and enhance the detection signal. Hence, a sandwich complex is formed as “IMBs–gliadin–IMLNs”. Experimental results indicate that this detection platform exhibits good sensitivity for gliadin with a detection limit as low as 0.6 μg mL−1 of gliadin; as the polyclonal antibody showed slight cross-reactions with barley and rye. Excellent recovery rates were found ranging from 83.5 to 102.6% as testing the spiked samples. Moreover, the CV (%) of intra- and inter-assay of this developed assay are 4.8–10.6% and 3.5–9.9%, respectively. Based on a parallel analysis of twenty food samples, the results of this developed assay provide a good consistency with those of an AOAC-approved ELISA kit without any false-negative results. The proposed assay method is thus a highly promising alternative method for detecting the contamination of gliadin in the food industry. 相似文献
16.
Yanagisawa N Mecham JO Corcoran RC Dutta D 《Analytical and bioanalytical chemistry》2011,401(4):1173-1181
In this article, we demonstrate a novel approach to implementing multiplex enzyme-linked immunosorbent assay (ELISA) in a
single microfluidic channel by exploiting the slow diffusion of the soluble enzyme reaction product across the different assay
segments. The functionality of the reported device is realized by creating an array of ELISA regions within a straight conduit
that are selectively patterned with chosen antibodies/antigens via a flow-based method. The different analytes are then captured
in their respective assay segments by incubating a 5-μL aliquot of sample in the analysis channel for an hour under flow conditions.
Once the ELISA surfaces have been prepared and the enzyme substrate introduced into the analysis channel, it is observed that
the concentration of the soluble enzyme reaction product (resorufin) at the center of each assay region grows linearly with
time. Further, the rate of resorufin generation at these locations is found to be proportional to the concentration of the
analyte being assayed in that segment provided that the ELISA reaction time in the system (τ
R
) is kept much shorter than that required by the resorufin molecules to diffuse across an assay segment (τ
D
). Under the operating condition τ
R
<< τ
D
, the reported device has been shown to have a 35% lower limit of detection for the target analyte concentration compared
with that on a commercial microtiter plate using only a twentieth of the sample volume. 相似文献
17.
Samuel Melaku Ilse Gelaude Frank Vanhaecke Luc Moens Richard Dams 《Mikrochimica acta》2003,142(1-2):7-12
Microwave digestion reduction-aeration and pyrolysis combined with cold vapour atomic absorption and cold vapour atomic fluorescence
are compared for the determination of total mercury in several biological and environmental matrices. The biological samples
were digested in a mixture of HNO3/H2O2, the environmental samples in a mixture of HNO3/HClO4. After reduction with SnCl2, the mercury was collected by two-stage gold amalgamation. After microwave digestion reduction-aeration, detection limits
of 1.4 ng g−1 and 0.6 ng g−1 were obtained for cold vapour atomic absorption spectrometry (CVAAS) and cold vapour atomic fluorescence spectrometry (CVAFS),
respectively, for 250 mg of environmental samples. For biological samples (500 mg) the detection limits were 0.7 ng g−1 (CVAAS) and 0.4 ng g−1 (CVAFS). After pyrolysis, detection limits of 3.5 ng g−1 and 1.6 ng g−1 for CVAAS and CVAFS, respectively, were obtained for a 10 mg sample. Pyrolysis can only be applied when the organic content
of the sample is not too high. Accurate results were obtained for 8 certified reference materials of both environmental and
biological origin. In addition, a real sludge sample was analysed.
Author for correspondence. E-mail: richard.dams@rug.ac.be
Received September 18, 2002; accepted December 3, 2002
Published online May 5, 2003 相似文献
18.
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
19.
Comparative study of three immunoassays based on monoclonal antibodies for detection of the pesticide parathion-methyl in real samples 总被引:2,自引:0,他引:2
Anna Yu Kolosova Jung-Hyun Park Seon-Ja Park Won-Bo Shim Yong-Tae Lee 《Analytica chimica acta》2004,511(2):323-331
Three immunoassay systems: indirect, direct competitive enzyme-linked immunosorbent assay (IC-ELISA and DC-ELISA), fluorescence polarization immunoassay (FPIA) based on monoclonal antibodies for the detection of parathion-methyl (PM) were developed and optimized. Several PM derivatives (haptens) were conjugated to proteins and fluoresceinthiocarbamyl ethylenediamine (EDF) to obtain immunogens and competitors. The influence of immunogen and competitor structures on the assay performance was investigated. IC-ELISA was the most sensitive of all techniques developed, with a detection limit of 0.08 ng ml−1, but assay time was the longest (3.5 h per 96-well microtitre plate). DC-ELISA was easier to perform and quicker (1.5 h per 96-well microtitre plate) but less sensitive than IC-ELISA (detection limit was 0.5 ng ml−1). FPIA was the fastest and simplest (7 min per 10 samples) but the least sensitive (detection limit was 15 ng ml−1) technique. The methods were characterized by high specificity and reproducibility. The cross-reactivity for parathion-ethyl was around 30-40% for IC-ELISA and FPIA, but significantly higher (125%) for DC-ELISA. The immunoassays were applied to the analysis of PM residues in different food and environmental matrices. Methanol extracts of vegetable, fruit and soil samples were used for the analysis. Recoveries for most spiked samples averaged between 85 and 110%. The methods developed can be used for screening of food and environmental samples for PM residues without complicated clean-up. 相似文献
20.
Martin Röder Stefan Vieths Thomas Holzhauser 《Analytical and bioanalytical chemistry》2009,395(1):103-109
Lateral flow devices (LFDs) are qualitative immunochromatographic tests for the rapid and specific detection of target analytes.
We investigated commercially available LFDs for their ability to detect potentially allergenic peanut and hazelnut in raw
cookie dough and chocolate, two important food matrices in the industrial production of cookies. Each three commercial LFDs
for the detection of hazelnut and peanut were performed according to the manufacturers’ instructions. All LFDs had comparably
satisfactory specificity that was investigated with a variety of characteristic foods and food ingredients used in the production
of cookies. In concordance with hazelnut-specific enzyme-linked immunosorbent assays (ELISAs), walnut was the most cross-reactive
food for hazelnut-specific LFD. The sensitivity was verified in raw cookie doughs and chocolates that were either spiked with
peanut or hazelnut between 1 and 25 mg/kg, respectively. Two hazelnut-specific LFDs detected hazelnut at a level of 3.5 mg/kg
in both matrices, whereas the third LFD detected hazelnut at a level of 3.9 mg/kg in dough and 12.5 mg/kg in chocolate. Two
peanut-specific LFDs detected peanut at a level of 1 mg/kg in both matrices. The third LFD detected peanut at a level of 14.2 mg/kg
in chocolate and 4 mg/kg in dough. In conclusion, specific and sensitive LFD were identified for each hazelnut and peanut,
having a level of sensitivity that is comparable to commercial ELISA for the investigated matrices. Such sensitive, specific,
and rapid tests are useful analytical tools for allergen screening and sanitation in the industrial manufacture of foods. 相似文献