Ultrasensitive graphene sensor for nitrate detection using triethylamine as a probe molecule

Nitrate anions are the main form of nitrogen in the environment and threaten the ecosystem and human health when their concentration is beyond 0.3 mg L −1 . Here, we designed and fabricated a novel nitrate sensor based on graphene field-effect transistors using triethylamine (TEA) as the probe molecule. The sensor uses graphene grown by chemical vapor deposition as the channel material. Triethylamine is modified on the graphene surface to detect nitrate anions. The sensitivity of the proposed TEA/graphene sensor reaches 1.3 nM (0.111 μg L −1 ), which is higher than that of mainstream sensors. This easy-to-fabricate and low-cost sensor also shows high specificity for other anions, such as Cl − , CO 3 2– , and SO 4 2− . Our study provides an excellent technical means for the rapid, accurate, and real-time monitoring of water pollution caused by nitrate anions.