TRANSLOCATION AND ACCUMULATION OF METALS THROUGH LASER ABLATION IMAGING APPLIED TO SUNFLOWER SEEDS: QUANTITATIVE APPROACH FOR Cd, Cu, Fe, AND Mn

The uptake and accumulation of Cd in sunflower seeds represents an important pathway for imputing potentially toxic metals into human and animal food [1-3]. Thus, bioimaging of Cd and micronutrients (Cu, Fe, Mn and Zn) in the sunflower seeds grown in soil contaminated with Cd are performed, using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). For attaining our proposals, ICP-MS and LA parameters were optimized, and the analytical signal improved to 217, 283, 197, and 232% for 112Cd, 63Cu, 57Fe and 55Mn, respectively. The accuracy of proposed method is evaluated through CRM results (Tomato leaves, NIST SRM 1573a), and no difference is found at 95 % confidence level. A recently developed software (LA-iMageS) is used for elemental bioimaging, which processes all data generated by LA-ICP-MS, ensuring a fast processing workflow as well as the generation of the images [4]. Regarding Cd accumulation in sunflower seeds, the results indicated that Cd is translocated to seeds, and the cotyledons showed the highest concentration, ranging from 10 to 20 µg g-1. Considering both total concentration and the distribution in the seeds, Cd uptake is responsible to the homeostasis misbalance of micronutrients, which play an essential role in the sunflower metabolism. Such results highlight the importance of bioimaging evaluation in the translocation and accumulation of metals, contributing to expand the information available of this culture.