Tunable Diode Laser Absorption Spectroscopy for Non-invasive Detection of Microbial Growth

摘要

This paper reports the use of tunable diode laser absorption spectroscopy (TDLAS) to measure the carbon dioxide (CO_2) in the culture vials. The accumulated CO_2 concentration in the headspace is linked with the growth of the microorganisms cultured in the vials. The 2004.1 nm spectral line of CO_2 is selected as the sensing transition for its strong absorption strength. The proposed TDLAS sensor is calibrated and verified with several CO_2 standard gases, yielding a minimum 1σ detection limit of 0.084% with an integral time of 3 s. The suitability of the sensor to the microorganisms is performed, almost the results agree with the growth laws of microbiology. Since the sensor is fast and nondestructive, it can be promising for in-line detection of microbial growth.