Determination of Arsenic Species in Edible Insects by LC-ICP-MS

Background Edible insects may contain arsenic. Analysis of arsenic species is necessary in order to accurately assess arsenic exposure. Objective An analytical method was validated and used to determine and quantitate arsenic species in edible insects. Methods Arsenic species were extracted from edible insects by heating at 100 & DEG;C in 0.3 mol/L nitric acid. The concentration of arsenic species was then determined by LC-inductively coupled plasma-mass spectrometry (LC-ICP-MS) using an octadecylsilane (ODS) column with a mobile phase containing an ion-pair reagent. Results The LOD (0.007-0.012 mg/kg), LOQ (0.021-0.038 mg/kg), repeatability (1.2-3.2%), intermediate precision (2.8-4.5%), and trueness (recoveries 97-102% based on spiked samples) of the proposed method were satisfactory for inorganic arsenic, dimethylarsinic acid (DMA), and arsenobetaine (AB) in edible insects. Total arsenic was detected in all samples obtained in Japan (Asian forest scorpion, diving beetles, giant water bug, grasshoppers, June beetles, mole crickets, male rhino beetle, female rhino beetle, sago worms, and silkworm pupae) and consisted of mostly inorganic arsenic. Beetles in particular showed relatively high levels. Conclusion Arsenic content varies among edible insect species. Feed control is important, as arsenic concentrations in edible insects may be feed dependent.