Sensor film based on electrical resistance of graphene nanoplatelets and polystyrene (XGNP/PS): fabrication, characterization, and application

The objective of this work was to develop a sensor based on variation of the electrical resistance of graphene-polystyrene sensor film (10.0% XGNP/PS (m/m)) for the determination of ammonia gas in broiler manure samples. The proposed sensor was designed using a data acquisition system, a detection system, a sample compartment, and a detection cell. The characterization of the sensor film by RAMAN, TGA and MEV indicated the formation of a new material with improved thermal and electrical characteristics. From a full factorial design, the influence of four analysis factors on the variation of the electrical resistance of the XGNP/PS composite was studied to determine the best conditions for ammonia gas detection. The variables established were electrical voltage 0 V, time interval of the measurement step 200 s, time interval of the cleaning step 400 s, and sample volume 10 mL. Linear responses were obtained for concentrations of 5-30 mg L-1 (S = (10.643 +/- 0.201) + (0.219 +/- 0.013)*C, where S signal and C concentration in mg L-1, R = 0.996) with detection and quantification limits of 0.046 mg L-1 and 0.154 mg L-1, respectively, and relative standard deviation (RSD) of 0.05% (n = 3, 15 mg L-1 ammonia). The use of this proposed sensor is a simple, viable and versatile option, as it provides a sensitive and fast response at room temperature with low sample consumption.

Automated summary

The objective of this study was to develop a sensor based on variation of the electrical resistance of graphene-polystyrene sensor film for the determination of ammonia gas. The sensor showed linear response to ammonia concentrations from 5-30 mg L-1, with low detection and quantification limits.