Research on Octyl-functionalized Ionic Liquid Bonding Silica Gel for Solid Phase Extraction of Shellfish Toxins in Seawater

Shellfish toxins are a kind of important marine pollutant. In this study, a novel ionic liquid bonded silica gel material (silica- [SOIM] [PF6]) was prepared by grafting octyl-functionalized ionic liquid onto silica gel, which was characterized and analyzed by infrared spectroscopy (IR), nuclear magnetic resonance (NMR), and elemental analysis. Solid phase extraction cartridge of silica-[SOIM] [PF6], coupled with LC-MS/MS technique was used to extract and determine the concentration of shellfish toxins [Okadaic acid (OA), Dinophysistoxin-1 (DTX-1) and Dinophysistoxin-2 ( DTX-2)] in seawater for the first time. It was found that the solid phase extraction material silica- [SOIM] [PF6] had multiple interactions with the 3 kinds of shellfish toxins, such as hydrophobic and ion-exchange. The method was optimized in aspects of volume and pH of the loaded sample solution, as well as the usage of rinsing and eluting reagents. Results indicated that the silica-[SOIM] [PF6] had good extraction effect on target shellfish toxins in seawater, which was better than or equivalent to the performance of commercial extraction materials. The method had a good linearity (R-2 >0. 995 ) in the concentration range of shellfish toxins from 0.02 mu g/L to 2. 50 mu g/L, with limit of detection (LOD) of 0. 01 mu g/L and limit of quantification ( LOQ) of 0. 05 mu g/L. The average recoveries for 3 kinds of shellfish toxins were 93. 0% -116. 0% at different spiking levels in blank seawater. Simultaneously, the material had good reproducibility, with the relative standard deviation (RSD) of less than 15% intra- and inter-batch. This method was accurate, sensitive, simple and reliable, and could be used for the extraction and detection of shellfish toxins in actual samples.