Selective screening of trace trazine herbicides in tomato samples employing dummy molecularly imprinted solid-phase extraction coupled with liquid chromatography

A highly selective dummy molecularly imprinted solid-phase extraction (DMISPE) method combined with liquid chromatography-ultraviolet detection was developed for the clean-up and screening of two triazine herbicides (cyanazine and atrazine) in tomato samples. The dummy molecularly imprinted polymers (DMIPs) were synthesized under thermal irradiation by bulk polymerization using cyromazine as a template molecule to avoid the effect of template leakage on quantitative analysis. Tomato juice samples could be directly loaded onto the DMIP cartridges and revealed the outstanding purifying effect. Under the optimum conditions of DMISPE-HPLC, good linearity for the two triazines were achieved in a range of 0.004-0.400 mu g g(-1) (r(2) >= 0.9996) and their average recoveries at three spiked levels ranged from 97.8 to 108.5% with a relative standard deviation <= 4.9% (n = 3). The developed DMISPE-HPLC method eliminated the effect of template leakage while exhibiting the advantages of simplicity, selectivity and sensitivity, and could be potentially applied for the determination of triazine herbicides in complicated samples.