摘要
Inorganic pyrophosphate (PPi) is an important biological functional anion and plays crucial roles in life science, environmental science, medicine, and chemical process. Quantification of PPi in water has far-reaching significance for life exploration, disease diagnosis, and water pollution control. The label-free quantitative detection of PPi anions with a nanofluidic sensing device based on a conical single nanochannel is demonstrated. The channel surface is functionalized with a synthetic PPi receptor, triazol-methanaminium-functionalized pillar-[5]arene (TAMAP5), using carbodiimide coupling chemistry. Due to the specific binding between TAMAP5 and PPi, the functionalized nano-channel can discriminate PPi from other inorganic anions with high selectivity through ionic current recording, even in the presence of various interfering anions. The current response exhibits a linear correlation with PPi concentration in the range from 1 x 10-7 to 1 x 10-4 M with a limit of detection of 6.8 x 10-7 M. A spike-and-recovery analysis of PPi in East Lake water samples indicates that the proposed nanofluidic sensor has the ability to quantitate micromolar concentrations of PPi in environmental water samples.