LED-based broadband cavity-enhanced spectrometer for high-sensitive optical detection of diacetyl in gas phase

Diacetyl (C4H6O2) is an important organic diketone that is widely used as flavoring agent and food additive. It is toxic when inhaled or exposed to high concentrations and may lead to chronic respiratory disease and neurodegenerative disorders. But, a viable optical detection method for rapid and quantitative estimation of diacetyl molecules in gas phase does not currently exist. Here, we report the design and development of a simple, compact and cost-effective robust optical technique exploiting incoherent broadband cavity-enhanced absorption spectroscopy (IBBCEAS) technique for high-sensitive selective detection and quantitative estimation of gas-phase diacetyl levels in real-time using a visible light emitting diode (LED) operating at 450 nm. The IBBCEAS method demonstrates an effective optical-path length of 4.5 km within an optical cavity (Finesse similar to 15706) composed of two high-reflective mirrors. A typical detection limit of similar to 190 parts-per-billion (ppb) for diacetyl was achieved with an optimum acquisition time of similar to 4 s at an optimal cavity pressure of 100 Torr. LED-based diacetyl sensor system was optimized, calibrated and demonstrated for trace detection of gaseous diacetyl at the ppb levels in various food products and liquor samples as a few representative applications, thus paving the way for development of future optical monitors. Graphical abstractThis work represents the development of a LED-based optical setup for the detection of diacetyl molecule in gas phase.