The significant reduction of extraction time using high-pressurized microwave extraction method for arsenic species...

To address the challenges of traditional extraction methods like time-consuming and insufficient extraction efficiency, this work integrated high pressure to microwave-assisted extraction. The proposed extraction way only required 3 min for achieving a great increase of extraction efficiency (1-2.5 times) of nine arsenic species from rice, compared to ultrasonic, heat-assisted, and microwave-assisted methods under the same conditions (solvent, temperature, and time). After the significant promotion of high pressure for extracting arsenic species was proved, other factors including extraction solvent, temperature and time were optimized. For 0.50 g of rice sample, the efficient extraction of nine arsenic species was accomplished in 5 mL of hydrochloric acid (0.023 mol L^-1), under 45 bar, 90 °C and 3 min. Coupled with HPLC-ICP-MS, an analytical method was established in 0.2-500 μg kg^-1, and it exhibited better sensitivity (LODs, 0.04-0.12 μg kg^-1) than other methods. Then some rice samples were analyzed, inorganic arsenic pollutants (sum of As(III) and As(V), 56.0-127.8 μg kg ^-1) and some organic arsenic targets containing DMA, MMA, ASC and ASB were found. The spiked recovery was ranged from 88.6 % to 103.1 % in rice samples, with relative standard deviations less than 4.55 %. These indicated the analytical method was suitable for the rapid determination of trace arsenic species in rice.