We demonstrate a selective and sensitive method for determination of creatinine using citrate-stabilized gold nanoparticles (AuNPs) as a colorimetric probe. It is based on a direct cross-linking reaction that occurs between creatinine and AuNPs that causes aggregation of AuNPs and results in a color change from wine red to blue. The absorption peak is shifted from 520 to 670 nm. Under the optimized conditions, the shift in the absorption peak is related the logarithm of the creatinine concentration in the 0.1 to 20 mM range, and the instrumental detection limit (LOD) is 80 μM. This LOD is about one order of magnitude better than that that of the Jaffé method (720 μM). The assay displays good selectivity over interfering substances including various inorganic ions, organic small compounds, proteins, and biothiols. It was successfully employed to the determination of creatinine in spiked human urine.
The colorimetric assay for creatinine uses citrate-stabilized gold nanoparticles (AuNPs) and a direct cross-linking reaction that occurs between creatinine and AuNPs that causes aggregation of AuNPs and results in a color change from wine red to blue.
This work demonstrates a wireless electroenzymatic platform using carbon microsphere electrodes co-immobilized with a rhodium catalyst and lactate dehydrogenase (LDH) for integrated NADH regeneration and pyruvate-to-L-lactate conversion in a bipolar electrochemical system. The 3D "aggregate reactor" architecture, functionalized via diazonium grafting, Rh coordination, and covalent enzyme coupling, enables spatial coupling of cofactor recycling and biocatalysis, while HPLC revealed a L-lactate production rate of 0.04 mM cm-2 h⁻¹ under 12.5 V cm⁻¹ with a plenty of carbon beads attributed to enhanced mass transport. This wireless, scalable design eliminates wiring constraints and offers modular adaptability for sustainable synthesis of chiral chemicals.
危险品化学品经营许可证（带存储）