2.5.2. Arsenic Speciation Analysis Method
Arsenic Content, Speciation, and Distribution in Wild Cordyceps sinensis
Evid Based Complement Alternat Med, Feb 19, 2021; DOI: 10.1155/2021/6651498

The different species of arsenic were separated by HPLC and detected by ICP-MS. An anion-exchange column (Hamilton RPR 100 column, 250 mm × 4.6 mm, 5 μm) was used for separation with a gradient system of eluent A, 10 mmol/L NH4H2PO4 (containing 1% methanol V/V, NH3·H2O adjusted pH 9.7), and eluted with B, 40 mmol/L NH4H2PO4 (containing 1% methanol V/V, NH3·H2O adjusted pH 6.7) solution, at a flow rate of 1.0 mL/min. The HPLC elution condition was achieved using the following procedures. For eluent A, 100.0% initial proportion, 100.0% maintained for 4.0 min; linear decrease to 0.0% at 4.5 min and 0.0% maintained for 13.5 min; linear increase to 100.0% at 14.0 min; equilibrium maintained for for 4.0 min. The total sample injection time was 18.0 min, and the acquisition time was 14 min. The injection volume was 10.0 μL.

The method of arsenic speciation analysis was validated by the standard addition method, and the recoveries of each arsenic speciation were used for evaluating the method feasibility. The total arsenic in the extraction solution and the residue of the extracted sample were ingested by microwave digestion method, and the total arsenic was determined by the method in Section 2.4. Then, total arsenic results of extraction solution and residue of extraction were compared with the results of sum of six arsenic species in C. sinensis.