The single adsorbent nano-TiO2 modified QuEChERS for simultaneous determination of 18 pyrrolizidine alkaloids in ginseng samples via LC-MS/MS

Abstract

Pyrrolizidine alkaloids (PAs) are a group of naturally occurring toxins, which have been widely found in herbs. However, the complexity of the herbs made the accurate and simple determination of PAs challenging. Herein, the present work described the development of a simple and effective QuEChERS method for simultaneous determination of 18 PAs in various ginseng samples. The extraction and purification processes were systematically optimized and validated coupled to LC-MS/MS analysis. After intensive screening, a single adsorbent nano-TiO2 was employed as a cleanup adsorbent during the dispersive solid phase extraction process to remove the matrix interferences and retain the target PAs in the sample solution, achieving the simultaneous determination of 18 PAs. The validation results displayed that the PAs had good linearity, sensitivity and satisfactory accuracy by the developed method. The method LODs and LOQs of PAs ranged from 0.05-1.49 μg/kg and 0.17–4.95 µg/kg, respectively. The average recoveries were 70.1 %-111 % with RSD less than 13 % under different spiked concentrations. Compared to the conventional QuEChERS method, this method gave rise to better purification effect and recoveries under the condition of only using one adsorbent nano-TiO2, which obvious improved its simplicity and versatility. Furthermore, this method was used to analyze the real ginseng samples and PAs were detected with concentrations ranging from 1.02 to 139 μg/kg, which further verified the feasibility of the developed method in the PAs analysis from the traditional herbal medicines.