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Updated: Apr 22, 2026
Fabrication of a Dipole-assisted Solid Phase Extraction Microchip for Trace Metal Analysis in Water Samples
Published on: August 7, 2016
3D-printed removable-cap device with embedded magnet for magnetic solid phase extraction
Camilla Fonseca Silva1, Matheus Martins Guedes2, Daiane Dulcileia Moraes de Paula2
1Departamento de Ciências Naturais, Universidade Federal de São João del-Rei (UFSJ), Campus Dom Bosco, Praça Dom Helvécio 74, Fábricas, São João del-Rei, Minas Gerais, 36301-160, Brazil; Departamento de Química, Instituto de Ciências Exatas, Universidade Federal de Minas Gerais, Av. Presidente Antônio Carlos, 6627, Belo Horizonte, MG, 31270-901, Brazil.
Background:
Magnetic adsorbents are widely employed in sample preparation, but magnetic solid-phase extraction (MSPE) still faces limitations related to magnet handling and pipetting, which increase time, variability, and operational costs. To overcome these drawbacks, we developed a 3D-printed magnetic removable-cap extraction device aimed at simplifying manipulation, improving reproducibility, and minimizing solvent consumption in the extraction step. As a proof of concept, a restricted-double-access magnetic polypyrrole adsorbent was synthesized, characterized, and applied to the extraction of nifedipine (NDP) and nimodipine (NMDP) from human plasma prior to chromatographic analysis.
Results:
The magnetic adsorbent was evaluated using the 3D-printed magnetic removable-cap device and compared with conventional MSPE approaches. Structural and morphological characterization confirmed its mesoporous and hydrophobic properties, together with strong macromolecule exclusion. After optimization, both extraction formats demonstrated suitable precision and accuracy, while the 3D-printed device provided a faster workflow and simpler operation. Optimal conditions involved 15 mg of adsorbent, 250 μL of plasma at pH 10.0, 1000 μL of methanol for elution, and 60 s of agitation. The HPLC-UV method showed linearity from 100 to 3500 ng mL-1, with adequate selectivity and accuracy. The limits of detection and quantitation were 50 and 100 ng mL-1, respectively, and protein removal reached 93%. The magnetic adsorbent was reusable for up to three extraction cycles without loss of performance.
Significance:
Coupling the 3D-printed device with the magnetic adsorbent enabled efficient, selective, and reproducible determination of NDP and NMDP in human plasma while minimizing sample handling and solvent use. Green analytical metrics confirmed this workflow as an eco-friendly, rapid, and reliable alternative for bioanalytical sample preparation.
