117 research outputs found
Use of pJANUSâą-02-001 as a calibrator plasmid for Roundup Ready soybean event GTS-40-3-2 detection: an interlaboratory trial assessment
Owing to the labelling requirements of food and feed products containing materials derived from genetically modified organisms, quantitative detection methods have to be developed for this purpose, including the necessary certified reference materials and calibrator standards. To date, for most genetically modified organisms authorized in the European Union, certified reference materials derived from seed powders are being developed. Here, an assessment has been made on the feasibility of using plasmid DNA as an alternative calibrator for the quantitative detection of genetically modified organisms. For this, a dual-target plasmid, designated as pJANUSâą-02-001, comprising part of a junction region of genetically modified soybean event GTS-40-3-2 and the endogenous soybean-specific lectin gene was constructed. The dynamic range, efficiency and limit of detection for the soybean event GTS-40-3-2 real-time quantitative polymerase chain reaction (Q-PCR) system described by Terry et al. (J AOAC Int 85(4):938â944, 2002) were shown to be similar for in house produced homozygous genomic DNA from leaf tissue of soybean event GTS-40-3-2 and for plasmid pJANUSâą-02-001 DNA backgrounds. The performance of this real-time Q-PCR system using both types of DNA templates as calibrator standards in quantitative DNA analysis was further assessed in an interlaboratory trial. Statistical analysis and fuzzy-logic-based interpretation were performed on critical method parameters (as defined by the European Network of GMO Laboratories and the Community Reference Laboratory for GM Food and Feed guidelines) and demonstrated that the plasmid pJANUSâą-02-001 DNA represents a valuable alternative to genomic DNA as a calibrator for the quantification of soybean event GTS-40-3-2 in food and feed products
Robustness testing in the determination of seven drugs in animal muscle by liquid chromatographyâtandem mass spectrometry
In this work, the robustness of the sample preparation procedure for the determination of six tranquilizers (xylazine, azaperone, propionylpromazine, chlorpromazine, haloperidol, and azaperol) and a beta-blocker (carazolol) in animal muscle by LC/MSâMS was assessed through the experimental design methodology. A 2III7 â 4 fractional factorial design was performed to evaluate the influence of seven variables on the final concentration of the seven drugs in the samples, in accordance with what is laid down in Commission Decision No 2002/657/EC. The variation considered for each of those seven factors is likely to happen when preparing the samples, being the values chosen as level â 1, the nominal operating conditions. The results of the experimentation were evaluated from different statistical strategies, such as hypothesis testing using an external variance previously estimated, Lenth's method, and Bayesian analysis. Both Lenth's and Bayes' approaches enabled to determine the effect of every variable even though no degrees of freedom were left to estimate the residual error. The same conclusion about the robustness of the extraction step was reached from the three methodologies, namely, none of the seven factors examined influenced on the method performance significantly, so the sample preparation procedure was considered to be robust.Ministerio de
Ciencia e InnovaciĂłn (CTQ2011-26022) and MINECO (CTQ2014-
53157-R)
Description of a strain from an atypical population of Aspergillus parasiticus that produces aflatoxins B only, and the impact of temperature on fungal growth and mycotoxin production
In this study, an atypical strain of Aspergillus parasiticus is described. This strain, reported from Portuguese almonds, was named Aspergillus parasiticus B strain. The strain is herein characterised at the morphological and physiological levels, and compared with the typical A. parasiticus strain and other similar species in section Flavi. Previously published morphological and molecular data support that the B strain is very closely related to the A. parasiticus type strain. However, while A. parasiticus typically produces aflatoxins B and G, B strain produces aflatoxins B only. Furthermore, this atypical strain showed to differ from the typical strain in the fact that higher growth (colony diameter) and strain. This strain can become a major food safety concern in colder regions where the typical A. parasiticus strains are not well adapted.NORTE-07-0124-FEDER-000028PEst-OE/EQB/LA0023/2013PEst-OE/AGR/UI0690/201
Determination of chlorinated solvents in industrial water and wastewater by DAIâGCâECD
A very simple and quick analytical method, based on direct aqueous injection, for determination of halogenated solvents in refinery water and wastewater, is described. There is a need to determine halogenated solvents in refinery water streams, because they may originate from several processes. There is also a need to develop methods enabling VOX to be determined in samples containing oil fractions. The method described enables simultaneous determination of 26 compounds with low detection limits (sub-ÎŒg Lâ1) and excellent precision, especially for highly halogenated solvents. The matrix effects of four types of sample were evaluatedâthe method seemed to be relatively insensitive to variations in matrix composition. Deuterated 1,2-dichloroethane was used as internal standard and surrogate compound in quantitative analysis; application of isotopically labelled compounds is rarely reported when non-mass spectrometric detectors are used for analysis. Analysis of real samples showed that the most frequently detected compounds were dichloromethane and 1,2-dichloroethane
Simple methodology for the quantitative analysis of fatty acids in human red blood cells
In the last years, there has been an increasing
interest in evaluating possible relations between fatty acid
(FA) patterns and the risk for chronic diseases. Due to the
long life span (120 days) of red blood cells (RBCs), their
FA profile reflects a longer term dietary intake and was
recently suggested to be used as an appropriate biomarker
to investigate correlations between FA metabolism and diseases.
Therefore, the aim of this work was to develop and
validate a simple and fast methodology for the quantification
of a broad range of FAs in RBCs using gas chromatography
with flame ionization detector, as a more common
and affordable equipment suitable for biomedical and
nutritional studies including a large number of samples. For
this purpose, different sample preparation protocols were
tested and compared, including a classic two-step method
(Folch method) with modifications and different one-step methods, in which lipid extraction and derivatization were
performed simultaneously. For the one-step methods, different
methylation periods and the inclusion of a saponification
reaction were evaluated. Differences in absolute FA
concentrations were observed among the tested methods,
in particular for some metabolically relevant FAs such as
trans elaidic acid and eicosapentaenoic acid. The one-step
method with saponification and 60 min of methylation time
was selected since it allowed the identification of a higher
number of FAs, and was further submitted to in-house validation.
The proposed methodology provides a simple, fast
and accurate tool to quantitatively analyse FAs in human
RBCs, useful for clinical and nutritional studies.This work received financial support from the
European Union (FEDER funds through COMPETE) and National
Funds (FCT, Fundação para a CiĂȘncia e Tecnologia) through project
PTDC/SAU-ENB/116929/2010 and EXPL/EMS-SIS/2215/2013.
ROR acknowledges PhD scholarship SFRH/BD/97658/2013 attributed
by FCT (Fundação para a CiĂȘncia e Tecnologia).info:eu-repo/semantics/publishedVersio
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