Analysis of neonicotinoids from plant material by desorption atmospheric pressure photoionization-mass spectrometry.
BACKGROUND
Neonicotinoids are widely used insecticides which have been shown to affect the memory and learning abilities of honey bees, and are suspected to play a part in the unexplainable, large-scale loss of honey bee colonies. Fast methods, such as ambient mass spectrometry (MS), for their analysis from a variety of matrices are necessary to control the use of forbidden products and study the spreading of insecticides in nature.


METHODS
The feasibilities of two ambient MS methods, desorption electrospray ionization (DESI) and desorption atmospheric pressure photoionization (DAPPI), for the analysis of five most used neonicotinoid compounds, thiacloprid, acetamiprid, clothianidin, imidacloprid and thiamethoxam, were tested. In addition, DAPPI was used to analyze fresh rose leaves treated with commercially available thiacloprid insecticide and dried and powdered turnip rape flowers, which had been collected from a field treated with thiacloprid-containing insecticide.


RESULTS
DAPPI was found to be more sensitive than DESI, with 2-11 times better signal-to-noise ratios, and limits of detection at 0.4-5.0 fmol for the standard compounds. DAPPI was able to detect thiacloprid from the rose leaves even 2.5 months after the treatment and from the turnip rape flower samples collected from a field. The analysis of plant material by DAPPI did not require extraction or other sample preparation.


CONCLUSIONS
DAPPI was found to be suitable for the fast and direct qualitative analysis of thiacloprid neonicotinoid from plant samples. It shows promise as a fast tool for screening of forbidden insecticides, or studying the distribution of insecticides in nature.
Faculty of Pharmacy, University of Helsinki, P.O. Box 56, 00014, Finland.
Anu
A
Vaikkinen
Department of Food Chemistry, Westfälische Wilhelms-Universität Münster, Münster, Germany.
Henning S
HS
Schmidt
Faculty of Pharmacy, University of Helsinki, P.O. Box 56, 00014, Finland.
Iiro
I
Kiiski
Plant Production Research, MTT Agrifood Research Finland, 31600, Jokioinen, Finland.
Sari
S
Rämö
Chemistry and Toxicology Research Unit, Finnish Food Safety Authority Evira, 00790, Helsinki, Finland.
Kati
K
Hakala
Faculty of Pharmacy, University of Helsinki, P.O. Box 56, 00014, Finland.
Markus
M
Haapala
Faculty of Pharmacy, University of Helsinki, P.O. Box 56, 00014, Finland.
Risto
R
Kostiainen
Faculty of Pharmacy, University of Helsinki, P.O. Box 56, 00014, Finland.
Tiina J
TJ
Kauppila
D029688:Brassica napus / Q000737:chemistry; D035264:Flowers / Q000737:chemistry*; D007306:Insecticides / Q000032:analysis*; D057230:Limit of Detection; D018515:Plant Leaves / Q000737:chemistry*; D011725:Pyridines / Q000032:analysis*; D027826:Rosa / Q000737:chemistry; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D013457:Sulfur Compounds / Q000032:analysis*
D007306:Insecticides; D011725:Pyridines; D013457:Sulfur Compounds