Quantification of carboxyl-functionalized multiwall carbon nanotubes in plant tissues with programmed thermal analysis.

In this study, carboxyl functionalized multiwall carbon nanotubes (c-MWCNTs) in plant (lettuce [Lactuca sativa Bionda Ricciolina]) tissues were quantitatively analyzed with programmed thermal analysis coupled with a sequential digestion. Programmed thermal analysis evidenced a linear relationship between c-MWCNT-bound C and elemental C detected. A detection limit of 114-708 μg C g-1 plant tissues (dry mass) was achieved for analysis of c-MWCNTs. The method was demonstrated using the tissues of lettuce cultured hydroponically for 3 wk with c-MWCNTs at an exposure of 10 and 20 μg ml-1 . This quantitative analysis can be used to provide insights into carbon nanotube exposure through agricultural products and promote its sustainable application.