Laser-Induced Breakdown Spectroscopy Applied on Liquid Films: Effects of the Sample Thickness and the Laser Energy on the Signal Intensity and Stability

Table 1

Physical properties and the estimated droplet/film thicknesses for diesel and peanut oil.

	Diesel	Peanut oil
Surface tension at 20°C (mN/m)	25.8 [33]	10.0 [34]
Kinematic viscosity (mm^2/s) at 40°C	2–4	37 [35]
Average thickness of 20 μL droplet (μm)	141 ± 10	320 ± 20
Av. thickness of droplet 5 μL at 18 rpm (μm)	19 ± 4	102 ± 10
Av. thickness of liquid film at 100 rpm (μm)	≤3.0	≤20

means specified by the supplier. means measured for droplet volumes of 0.2 μL and 5 μL for diesel and oil, respectively.