Analysis of Dimethicone Based on USP-Specified Method

Introduction

Quantitative analysis of liquid solutions by spectroscopy is often conducted by the "solution method," in which a fixed pathlength cell is utilized. However, when the solutions are viscous in nature, not only is cleaning of the cell a time-consuming and tedious task, injection can be difficult depending on the sample, and measurement can also be problematic due to the formation of bubbles. In such cases, the ATR method is effective because the close contact required between the sample and prism is easily achieved by merely applying a droplet of sample onto the prism, thereby permitting simple measurement. Here, using a viscous solution of silicone oil, dimethicone (dimethyl polysiloxane) as the sample, we introduce an example of ATR measurement in which excellent repeatability was obtained. This analysis of dimethicone is based on the method specified in the United States Pharmacopeia (referred to below as USP).

June 26, 2012 GMT