Submitted to: Journal of Chromatography
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/1/2007
Publication Date: 12/8/2008
Citation: Cajka, T., Hajslova, J., Lacina, O., Mastovska, K., Lehotay, S.J. 2008. Rapid analysis of multiple pesticide residues in fruit-based baby food using programmed temperature vaporiser injection–low pressure gas chromatography–high-resolution time-of-flight mass spectrometry. Journal of Chromatography A. 1186:281-294.
Interpretive Summary: Analysis of multiple pesticide residues in food commodities is a challenging task due to the large number and diversity of pesticides and food matrices, especially when very low concentration levels have to be determined. Regulatory agencies and food producers are faced with an increasing demand for more sensitive, rapid, and reliable methods. The developed method combines several highly advanced approaches, including fast and inexpensive QuEChERS (quick, easy, cheap, effective, rugged, and safe) sample preparation method, large volume injection using a temperature-programmable inlet for sensitive and rugged sample introduction, rapid separation of 100 pesticides within 7 min using low-pressure fast gas chromatography, and high-resolution mass spectrometry for highly selective and sensitive analyte determination. The lowest calibration levels for the pesticides tested were generally '0.01 mg/kg, which is a regulatory limit for pesticides in baby foods in many countries as well as a desirable reporting level for unregistered pesticides in any commodity. This method will benefit regulatory and other laboratories involved in pesticide residue analysis, providing them with tools for sensitive and rapid multiclass, multiresidue analysis of pesticides in foods.
Technical Abstract: A rapid method using programmed temperature vaporizer injection–low-pressure gas chromatography–high-resolution time-of-flight mass spectrometry (PTV–LP-GC–HRTOFMS) for the analysis of multiple pesticide residues in fruit-based baby food was developed. The fast and inexpensive buffered QuEChERS extraction method and “conventional” approach that employs ethyl acetate extraction followed by gel permeation chromatography (GPC) cleanup were employed for sample preparation. A PTV injector in solvent venting mode was used to reduce volume of acetonitrile and acetic acid (from the buffered QuEChERS extracts) that caused higher column bleed without their elimination. Otherwise, the time-to-digital converter would become saturated in HRTOFMS. For fast GC separation allowing analysis of 100 analytes within a 7 min runtime, both a high temperature programming rate and vacuum conditions in a megabore GC column were employed. The use of HRTOFMS allowed the unbiased identification and reliable quantification of target analytes through the application of a narrow mass window (0.02 Da) for extracting analyte ions and the availability of full spectral information even at very low levels. With only a few exceptions, the lowest calibration levels for the pesticides tested were '0.01 mg/kg for both sample preparation methods, which meets the EU maximum residue limit set for pesticide residues in cereal-based foods and baby foods (2003/13/EC).