Determination of multi-walled carbon nanotube bioaccumulation in earthworms measured by a microwave-based detection technique

Reliable quantification techniques for carbon nanotubes (CNTs) are limited. In this study, a new procedure was developed for quantifying multi-walled carbon nanotubes (MWNTs) in earthworms (Eisenia fetida) based on freeze drying and microwave-induced heating. Specifically, earthworms were first processed into a powder by freeze drying. Then, samples were measured by utilizing 10 s exposure to 30 W microwave power. This method showed the potential to quantitatively measure MWNTs in earthworms at low concentrations (~ 0.1 μg in 20 mg of earthworm). Also, a simple MWNT bioaccumulation study in earthworms indicated a low bioaccumulation factor of 0.015 ± 0.004. With an appropriate sample processing method and instrumental parameters (power and exposure time), this technique has the potential to quantify MWNTs in a variety of sample types (plants, earthworms, human blood, etc.).

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► MWNTs in earthworms could be detected and quantified by microwave-induced heating.
► Freeze drying was a reliable sample processing method for MWNT microwave analysis.
► Bioaccumulation study indicated low MWNT bioaccumulation in earthworms.