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1.
Analysis of T-2 and HT-2 toxins in cereal grains by immunoaffinity clean-up and liquid chromatography with fluorescence detection 总被引:8,自引:0,他引:8
Visconti A Lattanzio VM Pascale M Haidukowski M 《Journal of chromatography. A》2005,1075(1-2):151-158
A sensitive, precise and accurate method has been developed for the simultaneous determination of T-2 and HT-2 toxins in cereal grains at ppb levels using high-performance liquid chromatography (HPLC) with fluorescence detection and 1-antroylnitrile (1-AN) as labeling reagent after immunoaffinity clean-up. Cereal samples were extracted with methanol/water (90:10, v/v), and the extracts were cleaned-up through commercially available immunoaffinity columns containing monoclonal anti-T-2 antibodies (T-2 test HPLC, Vicam). T-2 and HT-2 toxins were quantified by reversed-phase HPLC with fluorometric detection (excitation wavelength 381 nm, emission wavelength 470 nm) after derivatization with 1-AN. The monoclonal antibody showed 100% cross-reactivity with both T-2 and HT-2 toxin, and the immunoaffinity column clean-up was effective up to 1.4 microg of both toxins. The method was successfully applied to the analysis of T-2 and HT-2 toxins in wheat, maize and barley. Recoveries from spiked samples with toxin levels from 25 to 500 microg/kg ranged from 70% to 100%, with relative standard deviation generally lower than 8%. The limit of detection of the method was 5 microg/kg for T-2 toxin and 3 microg/kg for HT-2 toxin, based on a signal-to-noise ratio 3:1. HT-2 toxin was detected in ten naturally contaminated wheat samples out of 14 samples analyzed, with toxin levels ranging from 10 to 71 microg/kg; three of them contained also T-2 toxin up to 12 microg/kg. 相似文献
2.
Multiplex dipstick immunoassay for semi-quantitative determination of Fusarium mycotoxins in cereals
Veronica M.T. Lattanzio Noan Nivarlet Vincenzo Lippolis Stefania Della Gatta Anne-Catherine Huet Philippe Delahaut Benoit Granier Angelo Visconti 《Analytica chimica acta》2012
A multiplex dipstick immunoassay based method for the simultaneous determination of major Fusarium toxins, namely zearalenone, T-2 and HT-2 toxins, deoxynivalenol and fumonisins in wheat, oats and maize has been developed. The dipstick format was based on an indirect competitive approach. Four test lines (mycotoxin–BSA conjugates) and one control line were located on the strip membrane. Labelled antibodies were freeze-dried within the microwell. Two matrix-related sample preparation protocols have been developed for wheat/oats (not containing fumonisins) and maize (containing fumonisins) respectively. The use of a methanol/water mixture for sample preparation allowed recoveries in the range 73–109% for all mycotoxins in all tested cereals, with relative standard deviation less than 10%. The optimized immunoassay was able to detect target mycotoxins at cut off levels equal to 80% of EU maximum permitted levels, i.e. 280, 400, 1400 and 3200 μg kg−1, respectively, for zearalenone, T-2/HT-2 toxins, deoxynivalenol and fumonisins in maize, and 80, 400 and 1400 μg kg−1, respectively, for zearalenone, T-2/HT-2 toxins and deoxynivalenol in wheat and oats. Analysis of naturally contaminated samples resulted in a good agreement between multiplex dipstick and validated confirmatory LC–MS/MS. The percentage of false positive results was less than or equal to 13%, whereas no false negative results were obtained. Data on the presence/absence of 6 mycotoxins at levels close to EU regulatory levels were obtained within 30 min. The proposed immunoassay protocol is rapid, inexpensive, easy-to-use and fit for purpose of rapid screening of mycotoxins in cereals. 相似文献
3.
Liu X Xu J Li Y Dong F Li J Song W Zheng Y 《Analytical and bioanalytical chemistry》2011,399(7):2539-2547
A sensitive and effective method for simultaneous determination of triazolopyrimidine sulfonamide herbicide residues in soil,
water, and wheat was developed using ultra-performance liquid chromatography coupled with tandem mass spectrometry. The four
herbicides (pyroxsulam, flumetsulam, metosulam, and diclosulam) were cleaned up with an off-line C18 SPE cartridge and detected
by tandem mass spectrometry using an electrospray ionization source in positive mode (ESI+). The determination of the target
compounds was achieved in <2.0 min. The limits of detection were below 1 μg kg−1, while the limits of quantification did not exceed 3 μg kg−1 in different matrices. Quantitation was determined from calibration curves of standards containing 0.05–100 μg L−1 with r
2 > 0.997. Recovery studies were conducted at three spiked levels (0.2, 1, and 5 μg kg−1 for water; 5, 10, and 100 μg kg−1 for soil and wheat). The overall average recoveries for this method in water, soil, wheat plants, and seeds at three levels
ranged from 75.4% to 106.0%, with relative standard deviations in the range of 2.1–12.5% (n = 5) for all analytes. 相似文献
4.
Veronica M. T. Lattanzio Michele Solfrizzo Angelo Visconti 《Analytical and bioanalytical chemistry》2009,395(5):1325-1334
The selective enzymatic deacetylation of T-2 toxin to give HT-2 toxin has been investigated in aqueous crude extracts of different
cereals and exploited to develop an analytical method for the determination of the sum of T-2 and HT-2 toxins. The method
has been validated for the analysis of total T-2 and HT-2 toxins in maize, wheat, and oats, showing recoveries from 72 to
97% for maize, from 67 to 84% for wheat, and from 61% to 87% for oats, at spiking levels of 20–400 μg/kg, with relative standard
deviation lower than 10%. Liquid chromatography-tandem mass spectrometry was used for quantitative toxin determination. The
potential biological role of this enzymatic conversion and its perspectives for application in the development of antibody-based
analytical techniques are discussed.
相似文献
5.
Isa Ruppen Canás Keith O’Callaghan Cian Moroney Brett Hamilton Kevin J. James Ambrose Furey 《Analytical and bioanalytical chemistry》2010,398(3):1477-1491
The azaspiracids are a family of lipophilic polyether marine biotoxins that have caused a number of human intoxication incidents
in Europe since 1995 after consumption of contaminated shellfish (Mytilus edulis). Levels of azaspiracids in shellfish for human consumption are monitored in accordance with EU guidelines: only shellfish
with less than 160 μg kg−1 are deemed safe. The limited availability of commercially available standards for azaspiracids is a serious problem, because
validated LC–MS methods are required for routine analysis of these toxins in shellfish tissues. The procedure described herein
has been used for the separation and the isolation of four azaspiracid (AZA) toxins from shellfish, for use as LC–MS–MS reference
materials. Five separation steps have been used to isolate azaspiracids 1, 2, 3, and 6. The purity of the toxins obtained
has been confirmed by multiple mass spectrometric methods using authentic azaspiracid standards. The same techniques have
been used for quantification of the toxins extracted. The isolation procedure involves several chromatographic purification
techniques: solid-phase extraction (diol sorbent, 90% mass reduction, and 95 ± 1% toxin recovery); Sephadex size-exclusion
chromatography (87% mass reduction and up to 95 ± 2% toxin recovery), Toyopearl HW size-exclusion chromatography (90% mass
reduction and up to 92.5 ± 2.5% toxin recovery), and semi-preparative LC (78 ± 3% toxin recovery). The procedure effectively
separates the toxins from the sample matrix and furnishes azaspiracid toxins (AZA1, AZA2, AZA3 and AZA6) of sufficient purity
with an average yield of 65% (n = 5). Triple-quadrupole mass spectrometry was used for qualitative and quantitative monitoring of the isolation efficiency
after each stage of the process. High-resolution mass spectrometric evaluation of the toxic isolated material in both positive
and negative modes suggests high purity. 相似文献
6.
Fluorescence polarization immunoassay for rapid screening of ochratoxin A in red wine 总被引:1,自引:0,他引:1
Francesco Zezza Francesco Longobardi Michelangelo Pascale Sergei A. Eremin Angelo Visconti 《Analytical and bioanalytical chemistry》2009,395(5):1317-1323
A fluorescence polarization (FP) immunoassay, based on a monoclonal antibody and an ochratoxin A (OTA)-fluorescein tracer,
has been developed for rapid screening of OTA in red wine. Wine samples were diluted with methanol and passed through aminopropyl
solid-phase extraction columns prior to the FP assay. Average recoveries from samples spiked with OTA at levels of 2.0 and
5.0 ng/mL were 79% with RDS of 11% (n = 6). The limit of detection of the FP immunoassay was 0.7 ng/mL OTA, and the whole analysis was performed in less than 10 min.
The assay was tested on 154 red wine samples (naturally contaminated or spiked at level ranging from 0.1 to 5.0 ng/mL) and
compared with an high-performance liquid chromatography/immunoaffinity column clean-up method, showing a good correlation
(r = 0.9222). Their compliance with the European regulation (2.0 ng/mL OTA maximum permitted level) was correctly assessed for
70% of the analyzed samples of red wine, whereas confirmatory analyses were required for the remaining ones with OTA levels
close to the regulatory limit. No false-negative or positive results were observed using the FP immunoassay. The proposed
FP assay is a useful screening method for OTA in red wines, when high throughput is required, that could also be used for
white and rosé wines, which are known to contain less interfering compounds such as polyphenols. 相似文献
7.
A confirmatory and quantitative method based on liquid chromatography–electrospray ionization tandem mass spectrometry (LC-ESI/MS/MS)
has been developed for simultaneous determination of seven photoinitiator residues: benzophenone, (1-hydroxycyclohexyl)phenylketone
(Irgacure 184), isopropylthioxanthone (ITX), 2-ethylhexyl-(4-dimethylamino)benzoate (EHA or EHDAB), 2-methyl-1-[4-(methylthio)phenyl]-2-(4-morpholinyl)-1-propanone
(Irgacure 907), (2,4,6-trimethylbenzoyl)diphenylphosphine oxide (TPO) and 2-benzyl-2-(dimethylamino)-1-(4-morpholinophenyl)-1-butanone
(Irgacure 369) in packaged milk and related packaging materials. Residues of photoinitiators were extracted from milk using
acetonitrile, and further enriched and purified on HLB solid-phase extraction cartridges prior to being analyzed by LC-ESI/MS/MS
with selected reaction monitoring mode, while photoinitiators in packaging materials were extracted using the same solvent.
Satisfactory recovery (from 80 to 111%), intra- and inter-day precision (below 12%), and low limits of quantification (from
0.1 to 5.0 μg kg−1) were evaluated from spiked samples at three concentration levels (5.0, 10.0 and 25.0 μg kg−1 for Irgacure 184 and 2.5, 5.0 and 25.0 μg kg−1 for others). These excellent validation data suggested the possibility of using the LC-ESI/MS/MS method for simultaneous
determination of low-level photoinitiator residues migrating from printed food-packaging materials into milk. The method has
been successfully applied to the analysis of real samples of different fat contents ranging from 8 to 30 g L−1. The photoinitiator residues were revealed to be higher in milk with higher fat content and the most important contaminations
were benzophenone and ITX in concentration ranges of 2.84–18.35 and 0.83–8.87 μg kg−1, respectively. 相似文献
8.
Li Y Dong F Liu X Xu J Li J Lu C Wang Y Zheng Y 《Analytical and bioanalytical chemistry》2011,400(9):3097-3107
A rapid and simple miniaturized liquid–liquid extraction method has been developed for the determination of topramezone in
soil, corn, wheat, and water samples using ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-electrospray
ionization (ESI)/MS/MS). The established method for the extraction and purification procedure was based on liquid–liquid partitioning
into an aqueous solution at a low pH (pH ≈ 2.5), followed by back-partitioning into water at pH > 9. Two precursor, product
ion transitions for topramezone were measured and evaluated to provide the maximum degree of confidence in the results. Under
negative ESI conditions, quantitation was achieved by monitoring the fragment at m/z = 334 and the qualitative fragment at m/z = 318, whereas also collecting the corresponding parent ion at m/z = 362. Chromatographic separation was achieved using gradient elution with a mobile phase consisting of methanol and a 0.01%
aqueous ammonium hydroxide solution. Recovery studies for soil, corn, wheat, and water were conducted at four different topramezone
concentrations (5 or 10, 50, 100, and 1,000 μg kg−1); the overall average recoveries ranged from 79.9% to 98.4% with intra-day relative standard deviations (RSD) of 3.1~8.7%
and inter-day RSD of 4.3~7.5%. Quantitative results were determined from calibration curves of topramezone standards containing
1–500 μg L−1 with an R
2 ≥ 0.9994. Method sensitivities expressed as limits of quantitation were typically 6, 8, 9, and 1 μg kg−1 in soil, corn, wheat, and water, respectively. The results of the method validation confirmed that this proposed method was
convenient and reliable for the determination of topramezone residues in soil, corn, wheat, and water. 相似文献
9.
Lina Kantiani Marinella Farré Josep Manuel Grases i Freixiedas Damià Barceló 《Analytical and bioanalytical chemistry》2010,398(3):1195-1205
A fully automated method has been developed for analysis of eighteen antibacterial compounds, including penicillins, cephalosporins
and sulfonamides, in animal feed with limits of quantification in the range 0.25–5.79 μg kg−1. The method is based on pressurized liquid extraction of 3 g homogenized feed with water and online clean-up of 500 μL of
the extract with C18HD cartridges. The purified sample was directly analysed by liquid chromatography–electrospray tandem mass spectrometry (SPE–LC–ESI-MS–MS).
Chromatographic separation was achieved within 10 min by use of a C12 Phenomenex Hydro-RP reversed-phase analytical column and a mobile phase gradient (water + 0.1% formic acid–methanol + 0.1%
formic acid). The method was validated, revealing capability for detection of concentrations as low as 0.09 μg kg−1, decision limits (CCα) and detection capabilities (CCβ) in the range 10–174 μg kg−1 and 22–182 μg kg−1, respectively, and inter-day precision ranging from 0.7 to 8.3%. Recovery, with internal standard correction, was in the
range 93–134% for all analytes. The method was then applied to analysis of fifteen feed samples, nine of which contained at
least one antimicrobial at concentrations between 0.006 and 1.526 mg kg−1. The performance data and results from the method were compared with those from a previous method developed by our group,
using offline SPE, by analyzing the same set of samples by both methods. The online SPE approach resulted in slightly improved
sensitivity, with LODs of 0.09–2.12 μg kg−1 compared with 0.12–3.94 μg kg−1 by the offline approach. In general, better recovery was achieved by use of online purification (for 72% of the analytes)
and the correlation between the two methods was good. The main advantages of the new online method are rapid and automated
sample pre-treatment, and reduction of sample manipulation, enabling high-throughput analysis and highly accurate results.
Because of all these characteristics, the proposed method is applicable and could be deemed necessary within the field of
food control and safety. 相似文献
10.
A. Pena L. J. G. Silva A. Pereira L. Meisel C. M. Lino 《Analytical and bioanalytical chemistry》2010,397(6):2615-2621
A total of 98 poultry samples, including chicken and turkey muscle, were analysed, using a sensitive and reliable analytical
method based on liquid chromatography (LC) with spectrofluorimetric detection, for simultaneous determination of four fluoroquinolone
(FQ) antibiotics, namely enrofloxacin (ENRO), ciprofloxacin (CIPRO), norfloxacin (NOR), and sarafloxacin (SARA). The method
involved extraction with 0.15 mol L−1 HCl and clean-up by solid-phase extraction using Oasis HLB cartridges. Chromatographic separation was carried out on a C18 TSK gel column, in isocratic mode, with 0.025 mol L−1 H3PO4 solution, adjusted to pH 3.0 with tetrabutylammonium hydroxide-methanol (78:22) as mobile phase. Good linearity over the
investigated concentration range was observed, with mean values of correlation coefficients higher than 0.9989 for all the
analytes studied. The limits of quantification (LOQ), expressed as the lowest fortification level with acceptable precision
were 15 μg kg−1 for ENRO, CIPRO, and NOR, and 30 μg kg−1 for SARA; these values are in compliance with requirements for monitoring of maximum residues levels (MRLs). Overall recoveries
from spiked samples ranged from 80% to 92% with relative standard deviations (RSD) lower than 6.1%. Of the chicken and turkey
samples analysed, 44.2% and 37.8%, respectively, were contaminated. The levels found in the analysed poultry samples, collected
from markets of Oporto and Coimbra, located in the north and central zones of Portugal, respectively, were lower than 114.2
and 87.6 μg kg−1 in chicken and turkey muscle samples, respectively. One positive chicken sample was contaminated with ENRO at levels higher
than the MRL. 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.
José Luis Martínez Vidal Antonia Garrido Frenich María de las Nieves Barco Bonilla Roberto Romero-González Juan Antonio Padilla Sánchez 《Analytical and bioanalytical chemistry》2009,395(5):1551-1562
A simple and rapid method based on pressurized liquid extraction has been validated for the simultaneous extraction of polychlorinated
biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs) from agricultural soil samples. Effective extraction was carried
out in less than 17 min for all the studied compounds, and good recoveries were obtained for PAHs and PCBs, ranging from 70%
to 112%, when blank samples were spiked at 2.5 μg kg−1, except for naphthalene with recoveries close to 40%. The separation and determination were performed by gas chromatography
coupled to tandem mass spectrometry using a triple quadrupole mass analyzer. The target compounds were detected by electron
impact with selected reaction monitoring, and mass spectrometric conditions were optimized in order to increase selectivity
and sensitivity. The developed method was validated, and matrix-matched calibration was used for quantification purposes.
Repeatability and interday precision ranged from 0.9% to 16.8% and from 1.6% to 22.3%, respectively. Limits of quantification
ranged from 0.07 to 2.50 μg kg−1. The proposed method was applied to the analysis of agricultural soil samples collected from Almeria (Spain), and PAHs and
PCBs were detected in some samples at concentrations ranging from 0.1 to 210 μg kg−1. 相似文献
13.
Leveriza F. Arenas Benilda S. Ebarvia Fortunato B. Sevilla III 《Analytical and bioanalytical chemistry》2010,397(7):3155-3158
A piezoelectric quartz crystal (PQC) sensor based on a molecularly imprinted polymer (MIP) has been developed for enantioselective
and quantitative analysis of d-(+)-methamphetamine (d(+)-MA). The sensor was produced by bulk polymerization and the resulting MIP was then coated on the
gold electrode of an AT-cut quartz crystal. Conditions such as volume of polymer coating, curing time, type of PQC, baseline
solvent, pH, and buffer type were found to affect the sensor response and were therefore optimized. The PQC-MIP gave a stable
response to different concentrations of d(+)-MA standard solutions (response time = 10 to 100 s) with good repeatability (RSD = 0.03
to 3.09%; n = 3), good reproducibility (RSD = 3.55%; n = 5), and good reversibility (RSD = 0.36%; n = 3). The linear range of the sensor covered five orders of magnitude of analyte concentration, ranging from 10−5 to 10−1 μg mL−1, and the limit of detection was calculated as 11.9 pg d(+)-MA mL−1
. The sensor had a highly enantioselective response to d(+)-MA compared with its response to l(−)-MA, racemic MA, and phentermine.
The developed sensor was validated by applying it to human urine samples from drug-free individuals spiked with standard d(+)-MA
and from a confirmed MA user. Use of the standard addition method (SAM) and samples spiked with d(+)-MA at levels ranging
from 1 × 10−3 to 1 × 10−2 μg mL−1 showed recovery was good (95.3 to 110.9%). 相似文献
14.
Determination of trichothecenes in cereals by gas chromatography with ion trap detection 总被引:1,自引:0,他引:1
Summary A method for determination of the trichothecene toxins, deoxynivalenol, 3α-acetyl-deoxynivalenol, nivalenol, T-2 toxin, HT-2
toxin and diacetoxyscirpenol in cereals (wheat, barley, oats, corn) is described. Extraction was performed according to Tanaka
et al. (J. Chromatogr.328, 271 (1985)) [33], derivatization by trifluoroacylation with trifluoroacetic acid anhydride. For quantitation and confirmation
a capillary gas chromatograph combined with a selective mass detector (ion trap) working in CI-mode with methanol as reagent
gas was used. The quantitation limit for the complete method is 1–5 μg/kg, depending on the chemical characteristics of each
toxin and cleanness of the extracts. Recoverics from spiked cereals were 78–89%. 相似文献
15.
The new analytical method using Quick, Easy, Cheap, Effective, Rugged, and Safe (QuEChERS) procedure for simultaneous determination
of diacylhydrazine insecticide residues in fruits and vegetables was developed using ultra-performance liquid chromatography
coupled with tandem mass spectrometry (UPLC-MS/MS). The four insecticides (tebufenozide, methoxfenozide, chromafenozide, and
halofenozide) were extracted from six fruit and vegetable matrices using acetonitrile and subsequently cleaned up using primary
secondary amine (PSA) or octadecylsilane (C18) as sorbent prior to UPLC-MS/MS analysis. The determination of the target compounds
was achieved in less than 3.0 min using an electrospray ionization source in positive mode (ESI+) for tebufenozide, methoxfenozide,
and halofenozide and in negative mode (ESI−) for chromafenozide. The limits of detection were below 0.6 μg kg−1, while the limit of quantification did not exceed 2 μg kg−1 in different matrices. The QuEChERS procedure by using two sorbents (PSA and C18) and the matrix-matched standards gave satisfactory
recoveries and relative standard deviation (RSD) values in different matrices at four spiked levels (0.01, 0.05, 0.1, and
1 mg kg−1). The overall average recoveries for this method in apple, grape, cucumber, tomato, cabbage, and spinach at four levels ranged
from 74.2% to 112.5% with RSDs in the range of 1.4–13.8% (n = 5) for all analytes. This study provides a theoretical basis for China to draw up maximum residue limits and analytical
method for diacylhydrazine insecticide in vegetables and fruits. 相似文献
16.
L. Giannetti F. Longo F. Buiarelli M. V. Russo B. Neri 《Analytical and bioanalytical chemistry》2010,398(2):1017-1023
A specific, sensitive and robust liquid chromatography tandem mass spectrometry method for determining oxytetracycline, tetracycline,
chlortetracycline and doxycycline in royal jelly and honey samples is presented. Extraction of drug residues was performed
by ammonium acetate buffer as extractant followed by a clean-up with metal chelate affinity chromatography and solid-phase
extraction. Tetracycline analysis was performed using liquid chromatography–electrospray ionisation–tandem mass spectrometry.
The presented method is the first validated for royal jelly and in accordance with the requirements set by Commission Decision
2002/657/EC. Recoveries of the methods, calculated spiking the samples at 5.0, 10.0, 20.0 and 30.0 μg kg−1, were 79% to 90% for honey and 77% to 90% for royal jelly. The intra-day precision (RSD) ranged between 8.1% and 15.0% for
honey and from 9.1% to 16.3% for royal jelly, while inter-day precision values were from 10.2% to 17.6% and from 10.6% to
18.4% respectively for honey and royal jelly. Linearity for the four analytes was calculated from 5.0 to 50.0 μg kg−1. The decision limits (CCα) ranged from 6.2 to 6.4 μg kg−1 and from 6.1 to 6.5 μg kg−1 for honey and royal jelly, respectively. Detection capabilities values (CCβ) ranged between 7.2 and 7.7 μg kg−1 and from 7.3 to 7.9 μg kg−1 respectively for honey and royal jelly. The developed method is currently in use for confirmation of the official control
analysis of honey and royal jelly samples. 相似文献
17.
Reiter EV Cichna-Markl M Chung DH Shim WB Zentek J Razzazi-Fazeli E 《Analytical and bioanalytical chemistry》2011,400(8):2615-2622
The paper presents a new sample clean-up method based on immuno-ultrafiltration for the analysis of ochratoxin A in cereals.
In contrast to immunoaffinity chromatography, in immuno-ultrafiltration, the antibodies are used in non-immobilised form.
Ochratoxin A was extracted with ACN/water (60/40, v/v), and the extract was loaded onto the ultrafiltration device. After a washing step with phosphate-buffered saline, containing
0.05% Tween 20, ochratoxin A was eluted with MeOH/acetic acid (99/1, v/v). The detection of ochratoxin A was carried out with high-performance liquid chromatography and a fluorescence detector coupled
to an electrochemical cell (Coring cell). The electrochemical cell was used to eliminate matrix interferences by oxidising
matrix compounds. The method was validated by repeatedly analysing spiked barley and rye samples as well as a certified wheat
reference material. Recoveries and standard deviations (1 SD) were found to be 71 ± 9%, 77 ± 12% and 77 ± 8% in wheat, barley
and rye, respectively. The limit of detection (S/N = 3) and limit of quantitation (S/N = 10) were determined to be 0.4 μg kg-1 and 1 μg kg-1. The analysis of the certified reference material resulted in ochratoxin A concentrations which were in the range assigned
by the producer. Additionally, the effect of the electrochemical cell on other widely used clean-up techniques, namely the
immunoaffinity clean-up and multifunctional columns (Mycosep #229), was evaluated. In all clean-up methods, an improvement
of the chromatogram quality was registered. 相似文献
18.
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
19.
Bezerra RA Rodrigues JA Ratusznei SM Canto CS Zaiat M 《Applied biochemistry and biotechnology》2011,165(1):347-368
Currently, there is an increasing demand for the production of biodiesel and, consequently, there will be an increasing need
to treat wastewaters resulting from the production process of this biofuel. The main objective of this work was, therefore,
to investigate the effect of applied volumetric organic load (AVOL) on the efficiency, stability, and methane production of
an anaerobic sequencing batch biofilm reactor applied to the treatment of effluent from biodiesel production. As inert support,
polyurethane foam cubes were used in the reactor and mixing was accomplished by recirculating the liquid phase. Increase in
AVOL resulted in a drop in organic matter removal efficiency and increase in total volatile acids in the effluent. AVOLs of
1.5, 3.0, 4.5 and 6.0 g COD L−1 day−1 resulted in removal efficiencies of 92%, 81%, 67%, and 50%, for effluent filtered samples, and 91%, 80%, 63%, and 47%, for
non-filtered samples, respectively, whereas total volatile acids concentrations in the effluent amounted to 42, 145, 386 and
729 mg HAc L−1, respectively. Moreover, on increasing AVOL from 1.5 to 4.5 g COD L−1 day−1 methane production increased from 29.5 to 55.5 N mL CH4 g COD−1. However, this production dropped to 36.0 N mL CH4 g COD−1 when AVOL was increased to 6.0 g COD L−1 day−1, likely due to the higher concentration of volatile acids in the reactor. Despite the higher concentration of volatile acids
at the highest AVOL, alkalinity supplementation to the influent, in the form of sodium bicarbonate, at a ratio of 0.5–1.3 g NaHCO3 g CODfed−1, was sufficient to maintain the pH near neutral and guarantee process stability during reactor operation. 相似文献
20.
Llamas NM Stewart L Fodey T Higgins HC Velasco ML Botana LM Elliott CT 《Analytical and bioanalytical chemistry》2007,389(2):581-587
The mouse bioassay is the methodology that is most widely used to detect okadaic acid (OA) in shellfish samples. This is one
of the best-known toxins, and it belongs to the family of marine biotoxins referred to as the diarrhetic shellfish poisons
(DSP). Due to animal welfare concerns, alternative methods of toxin detection are being sought. A rapid and specific biosensor
immunoassay method was developed and validated for the detection of OA. An optical sensor instrument based on the surface
plasmon resonance (SPR) phenomenon was utilised. A polyclonal antibody to OA was raised against OA–bovine thyroglobulin conjugate
and OA–N-hydroxy succinimide ester was immobilised onto an amine sensor chip surface. The assay parameters selected for the analysis
of the samples were: antibody dilution, 1/750; ratio of antibody to standard, 1:1; volume of sample injected, 25 μl min−1; flow rate, 25 μl min−1. An assay action limit of 126 ng g−1 was established by analysing of 20 shellfish samples spiked with OA at the critical concentration of 160 ng g−1, which is the action limit established by the European Union (EU). At this concentration of OA, the assay delivered coefficient
of variations (CVs) of <10%. The chip surface developed was shown to be highly stable, allowing more than 50 analyses per
channel. When the concentrations of OA determined with the biosensor method were compared with the values obtained by LC–MS
in contaminated shellfish samples, the correlation between the two analytical methods was found to be highly satisfactory
(r
2 = 0.991).
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