Rapid photosynthesis of cellulose nanofibril-based imprinted membrane for selective colorimetric determination of isoniazid.

Molecularly imprinted membranes (MIMs) have attracted considerable interest in sensing applications. This study presents a novel rapid UV-assisted photopolymerization technique for synthesizing MIM using cellulose nanofibers (CNF) as the membrane matrix and isoniazid (INH) as the target analyte. The MIM was synthesized rapidly in 5 min, outpacing traditional methods in speed and efficiency. The integration of CNF endowed the membrane with outstanding stability in organic solvents, along with excellent mechanical flexibility and rigidity. These properties, combined with the superior tensile strength and structural integrity, make MIM an excellent candidate for high-performance sensing applications. The MIM was characterized using X-ray diffraction, thermogravimetric analysis, Fourier-transform infrared spectroscopy, mechanical testing, and scanning electron microscopy to evaluate its semicrystalline, thermal, structural, and mechanical properties. A rapid, simple, and highly sensitive colorimetric method for INH determination  was developed utilizing 4-nitrobenzaldehyde and an alkaline phosphate buffer. The MIM exhibited a notable limit of detection (LOD) of 0.03 µg/mL and a limit of quantification (LOQ) of 0.1 µg/mL, with the capability to detect trace levels of INH (0.16 ng/mL) through preconcentration using a solid-phase extraction column. The method was successfully tested in spiked river water and saliva samples, yielding excellent recovery ranging from 94.21 to 100%. This MIM-based sensor provides a practical, high-performance solution for real-time, on-site INH monitoring. Its innovative design and cost-effectiveness offer substantial potential for enhancing environmental safety and public health surveillance, setting a new benchmark for field-deployable analysis technologies.