On-line analysis of sample atmospheres using membrane inlet mass spectrometry as a method of monitoring vegetable respiration rate Original Research Article

Current techniques for vegetable respiration rate measurement, based on headspace gas analysis, have a number of perceived limitations. These include intrusive sampling protocols, limited experimental resolution and restricted detection capability. An alternative technique is proposed using membrane inlet mass spectrometry for characterisation of respiration rate. Use of a membrane inlet system provides a passive on-line sampling interface that overcomes the limitations of conventional methods. The flexibility of the developed system is demonstrated by its capability of measuring vegetable samples with widely varying respiration rates. Results for carbon dioxide respiration rates of minimally processed potato and broccoli samples stored at 289 K were obtained as 22.4 and 44.7 mg h−1 kg−1, respectively. Equivalent oxygen respiration rates for the samples were 29.0 and 80.8 mg h−1 kg−1, respectively. The effects of storage temperature variation in the range 281–289 K on the respiration rate of potato samples are also presented.