Tracking and imaging nano-plastics in fresh plant using cryogenic laser ablation inductively coupled plasma mass spectrometry

Tracking and imaging of nano-plastics are extremely challenging, especially in fresh biological samples. Here, we propose a new strategy in which polystyrene (PS) was doped with the europium chelate Eu (DBM)3bpy to quantify, track, and in situ image nano-plastics in fresh cucumber based on inherent metals using cryogenic laser ablation inductively coupled plasma mass spectrometry (cryo-LA-ICP-MS). The cryogenic conditions provide a stable condition for imaging fresh cucumber, suppressing the evaporation of water in fresh plants, and maintaining the original structure of plants with respect to room temperature imaging in LA-ICP-MS. The plants were cultivated in two types of nano-plastics solutions with low (50 mg/L) and high (200 mg/L) concentrations for 9 days. The results showed that nano-plastics mainly enrich the roots and have negative effects, which decrease the trace elements of Zn, Mn, and Cu in cucumber. Smaller PS particles are able to penetrate the plant more easily and inflict serious damage. Novel imaging method provides a novel insight into the tracking and imaging of nano-plastics in fresh plant samples. The results illustrated that nano-plastics deposition on plants has the potential to have direct ecological effects as well as consequences for potential health. It is urgent to accurately track and image nano-plastics accumulation in fresh plants. We propose a new strategy to quantify, track, and in situ image nano-plastics in fresh cucumber based on inherent metals using cryo-LA-ICP-MS. The cryogenic conditions maintain the original structure of plants in LA-ICP-MS. The approach successfully performed precise imaging of the roots, stems, and leaves of fresh cucumbers incubated with nano-plastics, identified that nano-plastics were mainly enriched in cucumber roots, and analyzed the negative effect of nano-plastics on elemental uptake in cucumber growth. This method is important for the environmental risk assessment of nano-plastics on fresh plants.