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Hydrogel-confined Fe-MOF nanozyme sensor chip for matrix-tolerant colourimetric screening of malathion in Chinese medicinal matrices
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DOI:10.1039/D6AN00495D.png)
Abstract
En 中文
Matrix-induced colour drift remains a major barrier to translating nanozyme-based colourimetric assays from buffer systems to Chinese medicinal matrices. Here; we report a sodium alginate (SA)-confined iron-based metal–organic framework (Fe-MOF) nanozyme chip; denoted as the Fe-MOF/SA chip; for smartphone-assisted screening of malathion in pretreated herbal extracts. The hydrogel does not merely carry the Fe-MOF catalyst; rather; it confines the Fe-MOF within a more stable H2O2-TMB chromogenic microenvironment; thereby converting a drift-prone inhibition response in the dispersed nanozyme system into a more reproducible colour readout based on the b* coordinate of the Commission Internationale de l’Éclairage L*a*b* (CIE L*a*b*) colour space; where b* represents the blue–yellow component. Under optimised conditions; the chip provided a linear response from 10 to 500 ng mL−1 with an LOD of 4.4 ng mL−1. Relative to free Fe-MOF; the hydrogel-confined format markedly reduced matrix-dependent response deviations in chrysanthemum; honeysuckle and coptis extracts. Standard-addition recoveries of 93.5–108.3% with RSDs of 2.7–3.7% were obtained; and HPLC analysis of the same spiked extracts gave comparable concentrations. These results support the use of the Fe-MOF/SA chip as a portable front-end screening platform for malathion in chemically heterogeneous herbal matrices.
Journal
A
IF:
3.3
Papers:
1.6W
Citations:
3.3W
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