Biomedical subjects

R Krska

Publications and source records attributed to R Krska.

22 records · Page 2Linked to original sources

PubMed1998

High-performance liquid chromatography-atmospheric-pressure chemical ionization mass spectrometry as a new tool for the determination of the mycotoxin zearalenone in food and feed.

A new method for the determination of the mycotoxin zearalenone (ZON) in food and feed, based on HPLC-MS with an atmospheric-pressure chemical ionization (APCI) interface after extraction from cereals and clean-up by either conventional solid-phase or immunoaffinity cartridge is presented. The APCI interface parameters are optimized to provide detection of ZON with maximum sensitivity after RP separation of ZON on a C18 column with acetonitrile-water (40:60, v/v) at 1 ml/min column flow without split. Using APCI-MS detection, the sensitivity of the method was improved by a factor of ca. 50 in comparison to HPLC with fluorescence detection, allowing determination of ZON down to 0.12 microgram/kg maize which is well below present threshold values. Due to the selectivity of MS detection, it also was possible to quantitatively determine ZON both in raw extracts without clean-up using a normal-size (100 mm) chromatographic column or using only a short (20 mm) chromatographic column, when a clean-up was done to minimize possible interferences.

Animal Feed↗

PubMed1998

Performance of modern sample preparation techniques in the analysis of Fusarium mycotoxins in cereals.

The efficiency of modern sample preparation techniques are discussed and compared to well-established techniques with respect to the determination of zearalenone in corn and B-trichothecenes in wheat in the microgram/kg range. This includes the use of immuno-affinity columns and of multifunctional Mycosep columns as well as the employment of supercritical fluid extraction for the trace analysis of these major Fusarium mycotoxins. In addition, the performance of new analytical methods was investigated in an interlaboratory comparison study only recently organized by our laboratory. From both the validation data, and from the results of the intercomparison study, the suitability and competitiveness of the described methods could be clearly demonstrated.

Chromatography, Affinity↗

PubMed1998

Determination of trichothecene mycotoxins in wheat by use of supercritical fluid extraction and high-performance liquid chromatography with diode array detection or gas chromatography with electron capture detection.

The extraction behaviour of the Fusarium mycotoxin deoxynivalenol (DON) and some related type B trichothecenes from spiked seasand, spiked wheat flour and naturally contaminated wheat flour with modified supercritical CO2 has been investigated and optimized under several conditions. The extraction fluid was decompressed over a solid-phase trap and the amount of deposited analytes was determined by HPLC-diode array detection (DAD) or GC-electron capture detection (ECD) without any further clean-up. Recovery rates as high as 90.1 +/- 10.7% were achieved for spiked wheat samples and 53.0 +/- 3.2% for naturally contaminated samples. The performance of the optimized supercritical fluid extraction (SFE) method was compared with an already well established analytical method employing extraction on a rotary shaker in combination with Mycosep clean-up. Moreover, the SFE procedure developed for naturally DON contaminated wheat was employed for the simultaneous extraction of 5 type B trichothecenes by GC-ECD. This work represents the first successful approach in obtaining an SFE-method for the extraction of Fusarium mycotoxins from wheat with reasonable recoveries and good precision.

Chromatography, Gas↗

PubMed1996

Determination of the Fusarium mycotoxin beauvericin at micrograms/kg levels in corn by high-performance liquid chromatography with diode-array detection.

A method is described for the detection of the Fusarium mycotoxin beauvericin (BEA) in corn and corn meal. Spectral data obtained with a diode-array detector showed that the most sensitive wavelength for the detection of BEA is 192 nm. The detection limit for BEA was 50 micrograms/kg, which is an increase in sensitivity by a factor of at least twenty compared to previously published analytical methods for this mycotoxin.

Anti-Bacterial Agents↗