Hydroxyapatite nanorods: a nanobiomaterial for chemical detection of aniline vapor

Selective chemical detection of aniline vapor from benzene, toluene, ethylbenzene, and xylene (BTEX) is still a challenge. Here, we deliberately design a hydroxyapatite (HAP) nanorods nanobiomaterial modifying on the quartz crystal microbalance transducer for highly efficient detection of aniline from aniline/BTEX mixture. Besides, at room temperature, HAP nanorods perform excellent sensitivity of aniline, and the corresponding detection limit can reach down to 5 part per billion (ppb). The stability of HAP nanorods in the sensing process is also satisfactory. The sensing mechanism, as unveiled by the theoretical basis and the enthalpy extraction experiment, is due to the moderate acid–base absorptive interaction between aniline molecule and the HAP structure. The molecular formula of hydrate C6H7N·βH2O existing in wet air (with 50–90% relative humidity) can be obtained as C6H7N·1.36∼1.93H2O based on quantitatively measurement data.