Porous Polymers Containing Metallocalix[4]arene for the Extraction of Tobacco-Specific Nitrosamines

We designed porous polymers with a tungsten-calix[4]arene
imido
complex as the nitrosamine receptor for the efficient extraction of
tobacco-specific nitrosamines (TSNAs) from water. The interaction
between the metallocalix[4]arene and the TSNA, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone
(nicotine-derived nitrosamine ketone, NNK) was investigated. We found
that the incorporation of the nitrosamine receptor into porous polymers
increased their selectivity toward NNK over nicotine. The polymer
with an optimal ratio of calixarene-containing and porosity-inducing
building blocks showed a high maximum adsorption capacity of up to
203 mg/g toward NNK under sonication, which was among the highest
values reported. The adsorbed NNK could be removed from the polymer
by soaking it in acetonitrile, enabling the adsorbent to be reused.
A similar extraction efficiency to that under sonication could be
achieved using the polymer-coated magnetic particles under stirring.
We also proved that the material could efficiently extract TSNAs from
real tobacco extract. This work not only provides an efficient material
for the extraction of TSNAs but also offers a design strategy for
efficient adsorbents.