Validation of an Electronic VOC Sensor Against Gas Chromatography–Mass Spectrometry

Gas chromatography (GC) is a standard method to quantify volatile organic compounds (VOCs). However, this technique has high capital costs and is not suitable for real-time monitoring. Commercial metal oxide (MOX) sensors, on the other hand, are compact, cost-effective, and capable of providing real-time data to inform process control. This work used α -pinene in dry argon as a model system to compare the VOC detection performance of Bosch Sensortec’s BME680 sensor against the same VOC analyzed by thermal desorption-GC–mass spectrometry (TD-GC-MS) after adsorption onto a polymeric sorbent. Electronic sensor measurements were conducted in temperature- and atmosphere-controlled environments to minimize confounding effects on the resistance response. The BME680 electronic sensors showed limits of detection (LODs) ranging from 20 to 39 parts per billion (ppb), with a linear range above 40 ppb. The GC-MS in multiple reaction monitoring (MRM) mode exhibited an LOD at ( 0.61 ± 0.33 ) ppb and a linear range from 1 to 100 ppb, equivalent to an adsorption volume of 2- μ L VOC gas samples at concentrations of 1–100 ppb of α -pinene in the gas control system. The overlapping calibration region ranges for these two methods spanned from 40 to 100 ppb. There was >30% sensor-to-sensor variability in the response from the MOX sensing components that were reduced to 5%–7% using a two-point calibration method.