Pyrrolizidine alkaloids (PAs) are secondary plant metabolites witch can contaminate food, especially herbs. Due to the fact that alkaloids have a strong adverse effect on human health, it is necessary to use sensitive and selective detection methods. In present study a modified method based on LC-MS/MS was developed and validated for the simultaneous determination of thirty pyrrolizidine alkaloids and their corresponding N-oxides (PANOs) in herbs samples. Sample extraction was based on ultrasound-assisted dispersive solid phase extraction and clean-up using graphene. Method validation showed that the proposed method hold good recoveries (61-128 %) for PAs/PANOs with RSD <15 %. Limits of quantification has been set at 1 mug kg(-1) level for all targeted alkaloids. The optimized method yielded a small matrix effect (-20-20 %) for most PAs/PANOs. The uncertainty associated with the analytical method was not higher than 38 %. The method is operationally simple, time-saving, and can be applied to the analysis of real herb samples. CI - Copyright (c) 2020 Elsevier B.V. All rights reserved.