**4.2.3 Preparation technology for liquid samples with different boiling points**

1. Liquid with low boiling points

174 Macro to Nano Spectroscopy

Fig. 2. PMMA Infrared Spectrum from Different Sample Preparation Methods

Fig. 3. PMMA Chloroform Solution and Difference Spectrum of Chloroform

As the sample has low boiling point, a sealed tank should be used to prevent evaporation of sample. The thickness of the liquid membrane is decided by the nature of the sample. The stronger the polarity, the thinner the tanker is.

2. Liquid with high boiling point and low viscosity

Liquid sample with high boiling point, good flow property and low viscosity may be dropped between the two window slices of the removable liquid tank, then compress the automatically formed even liquid film for measurement.

3. Sample with high boiling point and high viscosity

For qualitative analysis of plasticizer and pyrolysates used in the samples with high boilling point and high viscosity, such as grease, polymers, apply a small amount of sample on KBr window slice by stainless spatula, and scrape evenly, then put it on the sample rack for measurement.
