Photoacoustic gas sensing with a commercial external cavity-quantum cascade laser at 10.5 μm

•We report the implementation of a commercial EC-QCL in a photoacoustic spectrometer.•This spectrometer enables measurements at 10.5μm on spectral range up to 60cm−1.•The Mode-Hop Free tuning enables to detect small molecules such as carbon dioxide.•The wide tuning range permits the detection of complex molecules such as butane.