
FIGURE 4. Raman spectra of ambient atmospheric air sample

FIGURE 5 N2 and O2 peak height stability over 4-h duration

FIGURE 6 CO2 v1 and v2 peaks and N2 peak tracking over filling/purging 100-min duration

FIGURE 7 Raman spectrum of CO2/N2 sample captured at 26 min as shown in Figure 6

FIGURE 8 Raman spectrum of gas mix containing 0.32% propane (C3H8), 3.68% methane (CH4) and 96% carbon dioxide (CO2)

FIGURE 9 Methane Raman peak intensity versus methane concentration: A linearity response assessment. Linear trend lines for each plot are shown.

FIGURE 10 Raman spectra of ethane and methane at concentrations as labelled.

FIGURE 11 Raman peak intensity versus gas concentration plots: (a) methane 2880-cm1 peak and (b) ethane peak. Linear trendlines for each plot are shown.





