Center for Analytical Chemistry

Yuseong gu, South Korea

Center for Analytical Chemistry

Yuseong gu, South Korea

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Malachova A.,Christian Doppler Laboratory | Beltran E.,Center for Analytical Chemistry | Berthiller F.,University of Natural Resources and Life Sciences, Vienna | Krska R.,University of Natural Resources and Life Sciences, Vienna
LC-GC Europe | Year: 2015

A liquid chromatography tandem mass spectrometry (LC–MS–MS) “dilute and shoot” method for the determination of 331 (toxic) secondary metabolites of fungi and bacteria has recently been optimized and validated for different food matrices (1) according to the guidelines established in the Directorate General for Health and Consumer Affairs of the European Commission (SANCO) document No. 12495/2011. This article will provide useful tips for smooth validation of multi-analyte LC–MS–MS methods and summarizes important validation outcomes for 295 analytes, including over 200 mycotoxins. The second part of this article focuses on the performance of the method in proficiency testing with an emphasis on difficult matrices. Z-scores obtained with this method were between -2 and 2 in 368 out of 408 cases for maize, wheat, triticale, bran, nuts, baby food, raisins, figs, coffee, liquorice, and hot pepper. From these results it can be concluded that quantitative determination of mycotoxins by LC–MS–MS based on a “dilute and shoot” approach is also feasible in the case of complex matrices such as such as pepper, coffee, or liquorice. © 2015 Advanstar Communications Inc. All rights reserved.


Jang J.S.,Korea Research Institute of Standards and Science | Jang J.S.,Chungbuk National University | Hwang H.H.,Korea Research Institute of Standards and Science | Kang H.J.,Chungbuk National University | And 11 more authors.
Metrologia | Year: 2012

The relative atomic fraction of Cu(In,Ga)Se 2 (CIGS) films is one of the most important measurements for the fabrication of CIGS thin film solar cells. However, the quantitative analysis of multi-element alloy films is difficult by surface analysis methods due to the severe matrix effect. In this study, the quantitative analysis of CIGS films was investigated by secondary ion mass spectrometry (SIMS). The atomic fractions of Cu, In, Ga and Se in the CIGS films were measured by alloy reference relative sensitivity factors derived from the certified atomic fractions of a reference CIGS film. The total ion intensities of the constituent elements were obtained by a total number counting method. The atomic fractions measured by SIMS were linearly proportional to those certified by inductively coupled plasma mass spectrometry using an isotope dilution method. The uncertainties were determined from the standard uncertainties in the measurements and those of a CIGS thin film certified reference material. © 2012 BIPM & IOP Publishing Ltd.


Rudolf J.,University of Natural Resources and Life Sciences, Vienna | Rudolf J.,Center for Analytical Chemistry | Ansari P.,University of Natural Resources and Life Sciences, Vienna | Ansari P.,Center for Analytical Chemistry | And 6 more authors.
Food Additives and Contaminants - Part A Chemistry, Analysis, Control, Exposure and Risk Assessment | Year: 2012

The accidental uptake of peanuts can cause severe health reactions in allergic individuals. Reliable determination of traces of peanuts in food products is required to support correct labelling and therefore minimise consumers' risk. The immunoanalytical detectability of potentially allergenic peanut proteins is dependent on previous heat treatment, the extraction capacity of the applied buffer and the specificity of the antibody. In this study a lateral flow device (LFD) for the detection of peanut protein was developed and the capacity of 30 different buffers to extract proteins from mildly and strongly roasted peanut samples as well as their influence on the test strip performance were investigated. Most of the tested buffers showed good extraction capacity for putative Ara h 1 from mildly roasted peanuts. Protein extraction from dark-roasted samples required denaturing additives, which were proven to be incompatible with LFD performance. High-pH buffers increased the protein yield but inhibited signal generation on the test strip. Overall, the best results were achieved using neutral phosphate buffers but equal detectability of differently altered proteins due to food processing cannot be assured yet for immunoanalytical methods. © 2012 Taylor & Francis.


Vishwanath V.,Center for Analytical Chemistry | Sulyok M.,Center for Analytical Chemistry | Weingart G.,Center for Analytical Chemistry | Kluger B.,Center for Analytical Chemistry | And 4 more authors.
Talanta | Year: 2011

This study reports on detection of a large number of biological and anthropogenic pollutants using LC-MS/MS and GC-MS technologies in settled floor dust (SFD). The latter technique was applied to obtain a general picture on the presence of microbial as well as non-microbial volatile organic compounds, whereas the targeted LC-MS/MS analysis focused on identification of species specific secondary metabolites. In the absence of moisture monitoring data the relevance of finding of stachybotrylactam and other metabolites of tertiary colonizers are confined only to accidental direct exposure to SFD. To the best of our knowledge 30 of the 71 identified volatile organic compounds (VOCs) are newly reported in SFD matrix. Coordinated application of "AMDIS and Spectconnect" was found beneficial for the evaluation and identification of prime volatile pollutants in complex environmental samples. Principal component analysis (PCA) of peak areas of 18 microbial volatile organic compounds (MVOCs) resulted in identification of nonanal as potential MVOC marker. Two more volatiles toluene and 1-tetradecanol though had discriminative influence, are not regarded as MVOC markers, considering their probable alternate origin from paints and cosmetics, respectively. © 2011 Elsevier B.V. All rights reserved.


This study reports on detection of a large number of biological and anthropogenic pollutants using LC-MS/MS and GC-MS technologies in settled floor dust (SFD). The latter technique was applied to obtain a general picture on the presence of microbial as well as non-microbial volatile organic compounds, whereas the targeted LC-MS/MS analysis focused on identification of species specific secondary metabolites. In the absence of moisture monitoring data the relevance of finding of stachybotrylactam and other metabolites of tertiary colonizers are confined only to accidental direct exposure to SFD. To the best of our knowledge 30 of the 71 identified volatile organic compounds (VOCs) are newly reported in SFD matrix. Coordinated application of AMDIS and Spectconnect was found beneficial for the evaluation and identification of prime volatile pollutants in complex environmental samples. Principal component analysis (PCA) of peak areas of 18 microbial volatile organic compounds (MVOCs) resulted in identification of nonanal as potential MVOC marker. Two more volatiles toluene and 1-tetradecanol though had discriminative influence, are not regarded as MVOC markers, considering their probable alternate origin from paints and cosmetics, respectively.


PubMed | Center for Analytical Chemistry
Type: | Journal: Mycotoxin research | Year: 2013

The employed analytical methods and results of a current large-scale study in the field of the analysis of zearalenone have been compared to several previous interlaboratory comparison studies. Generally, a change in the clean-up techniques could be observed. The more frequent use of immunoaffinity clean-up techniques and the employment of a common reference calibrant resulted in a considerable improvement of the agreement of results between the participating laboratories and an enhanced performance of the employed methods.


PubMed | Center for Analytical Chemistry
Type: | Journal: Mycotoxin research | Year: 2013

Detoxification of ochratoxin A can be achieved by chemical or enzymatic hydrolyzation, the products of such reactions are ochratoxin and phenylalanine. Ochratoxin like ochratoxin A, is a fluorescing molecule, therefore sensitive analysis is possible at very low concentration levels. Methods have been established that make it possible to look for residues of ochratoxin A and its main metabolite ochratoxin in blood and tissues at very low concentration levels. Plasma is extracted by the use of small amounts of chloroform; the extract is cleaned with water and afterwards evaporated to dryness]. The residue is re-dissolved and analysed by HPLC-FLD. Using this method a limit of detection of 0.5g/l for both ochratoxin A and ochratoxin can be reached.


PubMed | Center for Analytical Chemistry
Type: Journal Article | Journal: Biological trace element research | Year: 2013

The validity and intercomparability of data in research related to medical, environmental, and geochemical health problems is of utmost concern and requires specific consideration in the development of an analytical approach. The Environmental Protection Agency/National Bureau of Standards Pilot Environmental Specimen Bank Program provides a vehicle for developing the precise and accurate determination of trace constituents in human livers. This approach, when implemented, gives specific consideration to a valid relationship between the analytical result and the true value in the sample. This is accomplished by minimizing contamination of the sample and/or loss of constituents, and by assuring representative analytical test portions. The analysis of the liver specimens is performed under strict quality control. The applied analytical techniques (atomic absorption spectrometry, isotope dilution mass spectrometry, neutron activation analysis, and voltammetry) have been verified for accuracy through the analysis of Standard Reference Materials. In addition, several elements are determined using two or three of these independent techniques. The first year of the program provided results on 31 elements including Se and Pb in 36 human livers.


PubMed | Center for Analytical Chemistry
Type: Journal Article | Journal: Mycotoxin research | Year: 2013

This work describes a method for the determination of theFusarium mycotoxin moniliformin (MON) in cereals. In addition to the optimization of the clean-up and the HPLC determination the most efficient extraction mode was investigated on natural contaminated samples. The method was validated for maize and wheat using a calibration range from 57 to 2300 g/kg. Due to the ionic nature of the toxin the clean-up of the extracts was carried out with strong-anion-exchange columns. Moniliformin was separated by reversed phase ion-pair-chromatography (RP-Ion pair-HPLC) and detected by DAD. The validated method yielded recoveries of 76%9% (maize) and 87%5% (wheat) and detection limits of 39 g/kg and 30 g/kg, respectively. The suitability of the developed method was demonstrated on natural contaminated samples.


PubMed | Center for Analytical Chemistry
Type: | Journal: Bioresource technology | Year: 2012

An efficient enrichment method using immobilized metal affinity chromatography (IMAC) was developed for selective extraction of bioactive sphingoid base-1-phosphates (SB1Ps) from adventitious roots of Hypericum perforatum cultured in bioreactor. The phosphate-selective IMAC enrichment coupled with LC-MS/MS enabled sensitive analysis of low-abundance SB1Ps present in the root biomass, which would not be feasible otherwise due to severe interferences from complex biological matrices. The time-dependent growth rate and production of SB1Ps from adventitious roots were investigated. The level of phytosphingosine-1-phosphate, which was found to be the major SB1Ps, reached a maximum amount of 635.6pmolpergram of dry weight after 3weeks of culture and decreased between 3 and 5weeks of culture subsequently. On the other hand, sphingosine-1-phosphate and sphinganine-1-phosphate were present at levels of 18.91 and 73.15pmolpergram of dry weight, respectively, after a week of culture and their level decreased thereafter.

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