Determination of zearalenone and its metabolites alpha- and beta-zearalenol in beer samples by high-performance liquid chromatography-tandem mass spectrometry.

A fast, robust and sensitive LC-MS-MS method for the determination of zearalenone (ZON) and its metabolites alpha-zearalenol (alpha-ZOL) and beta-zearalenol (beta-ZOL) in beer samples is described. Sample preparation was performed by direct RP-18 solid-phase extraction of undiluted beer samples followed by selective determination of analytes by LC-MS-MS applying an atmospheric pressure chemical ionization (APCI) interface. Using the negative ion mode limits of determination of 0.03-0.06 microg l(-1) beer and limits of quantification of 0.07-0.15 microg l(-1) beer were achieved, which was distinctly more sensitive than in the positive ion mode. Twenty-three beer samples from different countries, produced from different grains and under different brewing conditions, were investigated by this method, but only in one sample could beta-ZOL and ZON be detected. Independently of the type of beer, relative standard deviations between 2.1% and 3.3%, a linear working range of 0.15 microg l(-1) to 500 microg l(-1) beer and recovery rates around 100% could be achieved when zearalanone (ZAN) was used as internal standard.

Determination of zearalenone and its metabolites in urine and tissue samples of cow and pig by LC-MS/MS.

For the sensitive and selective determination of zeranol, taleranol, α-zearalenol, ß-zearalenol and zearalenone in animal urine and tissue a LC-MS/MS method has been developed. Sample preparation included extraction of meat samples and enzymatic digest of urine samples followed by solid-phase extraction with RP-18 columns for sample clean-up. Mass spectrometric determination was carried out with an atmospheric pressure chemical ionisation interface (APCI) in the multi-reaction monitoring mode (MRM). Using the negative ion mode detection limits between 0.1 and 0.5 ppb and determination limits between 0.5 and 1 ppb could be achieved. With zearalanone as internal standard, a linear range between 0.5 (1.0) and 100 ppb in urine samples (cow; pig) and between 1 and 100 ppb in meat samples (cow, calf, pig) could be established. Depending on the biological matrix and analyte standard deviations were below 8.2 %, with recovery rates between 86 and 102 % in spiked samples. The applicability of the method was demonstrated via several contaminated cow and pig urine samples.

Determination of zearalenone in grains by high-performance liquid chromatography-tandem mass spectrometry after solid-phase extraction with RP-18 columns or immunoaffinity columns.

In this paper a robust, sensitive and selective LC-MS-MS method for the determination of zearalenone (ZON) in several cereals is described. Sample preparation was performed by extraction of the commodities with a mixture of acetonitrile and water followed by solid-phase extraction with RP-18 columns or immunoaffinity columns. The selective determination of ZON was achieved with an atmospheric pressure chemical ionization interface. Using the negative ion mode a detection limit of 0.5 microg/kg and a determination limit of 1 microg/kg grain was achieved, which is by a factor of 100 more sensitive than the positive ion mode. Zearalanone (ZAN), which does not occur in nature, was used as internal standard for quantification. A linear working range from 1.0 microg/kg to 1000 microg/kg could be achieved in grains with a standard deviation of 4% and recovery rates around 100%. All these results were independent from the grain matrices (maize, barley, oats, wheat) when ZAN was used as internal standard. Sample preparation with RP-18 and immunoaffinity materials gave comparable results. In addition, the method was successfully used for the investigation of naturally contaminated maize samples in the course of an interlaboratory comparison test.