posted on 2022-07-27, 15:08authored byTomoka Yoshii, Mai Mochida, Kogi Kaizu, Yasuki Soda, Kazuyoshi Kanamori, Kazuki Nakanishi, Takaaki Sato, Hiroaki Imai, Daniel Citterio, Yuki Hiruta
A way to utilize eggshells is desired because most of
the eggshell
waste is disposed of in landfills. Despite eggshells having attractive
features such as a thermodynamically stable porous crystalline structure,
their effective utilization as a functional material has yet to be
demonstrated. Herein, we developed an alkali-stable column packing
material for reversed-phase preparative high-performance liquid chromatography
(HPLC) based on eggshells. Nanocrystals and biopolymers present on
eggshell powder were removed by surface treatment with buffered ethylenediaminetetraacetic
acid (EDTA) and sodium hypochlorite solutions, resulting in bare calcium
carbonate with a uniform porous surface. The obtained particles were
modified with poly(maleic acid-alt-1-octadecene)
(PMAcO) having hydrophobic alkyl chains and anionic carboxylate groups.
The prepared PMAcO-modified eggshell-based material was applied to
an HPLC column, and its performance is evaluated. The column succeeded
in the separation of alkylbenzenes, steroids, and diastereomers. It
was also used for the separation of basic tricyclic antidepressants
in an alkaline mobile phase, showing excellent retention capacity
and alkali stability. This study demonstrates the potential of eggshell
utilization, providing not only a practical stationary phase for HPLC
but also a solution for recycling calcium carbonate-based biomineral
waste.