Determination of 10 triazine herbicides residues in oolong tea and soil by gas chromatography-tandem mass spectrometry with multi-walled carbon nanotubes based on solid-phase extraction

A gas chromatography-tandem mass spectrometry (GC-MS/MS) method has been developed for detecting 10 triazine herbicides (simazine, atrazine, propazine, terbuthylazine, desmetryn, cyprazine, simetryn, ametryn, prometryn, terbutryn) residues in oolong tea and soil. After extracted by acetonitrile, the samples were purified with multi-walled carbon nanotubes, PSA, C18, MgSO4 and analyzed by GC-MS/MS in multiple reaction monitoring mode. Pesticides were quantified by using the blank matrix matching solution of external standard method. Effects of the type of extraction solvents, and the type and the dosage of adsorbents were then investigated. The results showed that linearity of the curves for 10 triazine herbicides all had correlation coefficients greater than 0.99 (10-500 μg/kg for simetryn and prometryn,5-500 μg/kg for others). The limits of quantifications were 5.0-10 μg/kg. The average recoveries were 75%-111%, and the RSD (n=6) were 3.1%-8.7%. This work provided a method with good applicability, better purifying effect and high sensitivity, which could meet the requirements of triazine herbicides residue analysis in oolong tea and soil.