Fig. 2

Temporal variation of infrared ATR spectra of plasma with drying. Each absorption spectrum is different in the time elapsed to start the ATR spectrum measurement after the plasma sample is applied to the top surface of the prism (blue: 0 min, orange: 6 min, gray: 12 min, green: 20 min, light blue: 30 min, yellow: 40 min). The overall absorbance increases as the sample dries (in the direction of the gray arrow); the sample dries completed in approximately 20 min and the absorbance stabilizes thereafte