A 3D-printed platform with repurposed vial inserts for dilution-free smartphone-based colorimetric determination of iron by deep eutectic solvent-based liquid phase microextraction
Microchemical Journal, cilt.230, 2026 (SCI-Expanded, Scopus)
- Yayın Türü: Makale / Tam Makale
- Cilt numarası: 230
- Basım Tarihi: 2026
- Doi Numarası: 10.1016/j.microc.2026.119891
- Dergi Adı: Microchemical Journal
- Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, BIOSIS, Chemical Abstracts Core, Chimica, Index Islamicus, Academic Search Ultimate (EBSCO), Engineering Source (EBSCO)
- Anahtar Kelimeler: 3D printing, Digital image colorimetry, Iron determination, Portable devices, Sample preparation, Water quality monitoring
- Karadeniz Teknik Üniversitesi Adresli: Evet
Özet
A cost-effective, 3D-printed analytical platform was developed for smartphone digital image colorimetry (SDIC) of micro-volume extracts without prior dilution. For this aim, standard high-performance liquid chromatography (HPLC) vial inserts were repurposed as micro-cuvettes within a custom platform that standardizes the optical path and eliminates ambient light interference. By enabling direct measurement of the 100 μL extract, the platform preserves the enrichment achieved during sample preparation. Iron was selected as the model analyte based on its colorimetric reaction with 1,10-phenanthroline. Since the dicationic Fe(II)-phenanthroline complex is hydrophilic, a fatty acid-based deep eutectic solvent (DES) composed of thymol and decanoic acid was used for vortex-assisted liquid-phase microextraction (VA-LPME). The DES functioned as both a green extraction solvent and a multifunctional agent, enabling π-π and ion-pair interactions and allowing the extraction of the complex without additional reagents. The camera acquisition parameters, complexation conditions, and extraction variables were systematically optimized, with the latter evaluated via a Box-Behnken design (BBD). Under optimum conditions, using an 8 mL sample and a total analysis time of approximately 8.5 min, the method exhibited a linear range of 0.01–0.5 mg L−1 with a limit of detection (LOD) of 0.003 mg L−1 and an enrichment factor of 48.7. The relative standard deviation (RSD) was ≤4.9%, and accuracy ranged from 88.4% to 108.9%. The method was successfully applied to determine iron levels in lake and river water samples. The results showed no significant differences from a reference UV–Vis spectrophotometric method, confirming that the platform combines preconcentration sensitivity with portable and low-cost smartphone detection.