MSPD Combined With Fast GC for Ultratrace Analysis of Pesticide Residues in Non-Fatty Food
Milena Dömötörová,a
Eva Matisová,a*
Michal Kirchner,a and Jaap de Zeeuwb
a Faculty
of Chemical and Food Technology, Slovak University of Technology, Radlinského 9,
812 37 Bratislava, Slovakia,
E-mail: eva.matisova@stuba.sk
b Varian
International B.V., Herculesweg 8, P.O. Box 8033, 4330 EA, Middelburg, The
Netherlands
Abstract
Matrix solid phase dispersion (MSPD) sample
preparation method was combined with fast gas chromatography (GC) to determine
pesticide residues of different volatility and polarity at ultratrace
concentration level. Apples as representatives of a non-fatty food were chosen
as a matrix; they are also a common raw material for baby food production. At
fast GC conditions with electron capture detection (ECD) several parameters of
MSPD procedure were optimised. Sample is homogenized with sorbent Florisil,
pesticides are eluted with the optimised volume of etylacetate. After
evaporation of solvent to dryness, reconstitution of the rest to toluene follows
and the final extract is injected utilising splitless injection. These optimised
procedure leads to recoveries
³ 90% (at
concentration level of 60 mg
kg–1) and limits of quantification (LOQs) < 47
mg kg–1
(except of diazinon) utilizing ECD. Except of dimethoate all LOQs are
lower than related maximum residual limits (MRLs) set for commodity
apple. Also the possibilities of mass spectrometric (MS) detection were studied.
Even at the half pre-concentration factor LOQs for all pesticides were
lower than 10 mg
kg–1, the MRL for baby food. Acceptable recoveries were
obtained even at concentration level of 5
mg kg–1
(³
79%).
Key words: MSPD, fast GC, pesticide residues, apples, matrix-effects