Microwave-assisted extraction of zearalenone from wheat and corn.
A microwave-assisted extraction (MAE) method has been developed for determination of zearalenone in wheat and corn by LC-MS with an atmospheric pressure chemical ionization interface (APCI). Matrix effects were minimized by use of matrix-matched standard curves for quantification of the analyte. The limit of quantification (LOQ) of the method was 30 ng g(-1) in wheat and 20 ng g(-1) in corn. The rapid LC-MS method enabled analysis of the extracts without clean-up, thereby reducing analyte losses, the time required for the analytical procedure, and costs. A factorial design approach was used to examine the effect on extraction efficiency of the main extraction conditions - time, temperature, and solvent. On the basis of results from statistical assessment extraction was performed with 1:1 (v/v) methanol-acetonitrile at 80 degrees C for 5 min. When these extraction conditions were applied to a wheat sample from a recently conducted international proficiency test, 92% (103 ng g(-1)) of the assigned zearalenone concentration (112 ng g(-1)) in the test material was obtained. This result was within the uncertainty (u) range of the assigned value of the test material (u=+/-15.8 ng g(-1), alpha=0.05) thereby demonstrating the accuracy of the method was sufficient. The precision of the whole method was also confirmed to be adequate, because the observed relative standard deviation (RSD) of 12% (n=10) also fulfils the quality criteria recommended by European guidelines for in-house method validation.
European Commission, Joint Research Center, Institute for Health and Consumer Protection, Food Products Unit, 21020 Ispra (VA), Italy.
Lea
L
Pallaroni
Christoph
C
von Holst
Sparr
S
Eskilsson
Erland
E
Björklund
D002851:Chromatography, High Pressure Liquid; D013058:Mass Spectrometry; D008872:Microwaves; D012997:Solvents; D013696:Temperature; D013997:Time Factors; D014908:Triticum / Q000737:chemistry*; D003313:Zea mays / Q000737:chemistry*; D015025:Zearalenone / Q000302:isolation & purification*
D012997:Solvents; D015025:Zearalenone