Measurement of Nail Polish using IR Microscopy with Clear-View™ ATR
September 8, 2023
Introduction
Q. How can microscopic foreign objects be measured by Attenuated Total Reflectance (ATR)?
A. In FTIR microscopy, sample observation is important to positively identify that the correct area of interest is being measured and analyzed; however, historically it has been impossible to view samples through the crystal of an ATR objective. JASCO has developed the Clear-View™ ATR objectives to allow observation of the sample and perform ATR spectral measurement using a single Cassegrain objective. The IQ Mapping function can be used in combination with a Clear-View™ ATR objective to measure areas around the center of the crystal by moving the aperture in the entire the field of view of the objective.
There are three different prism materials for Clear-View™ ATR objectives: ATR-5000-SS (Zinc Sulfide), ATR-5000-SD (Diamond), and ATR-5000-SG (Germanium). In addition to being able to observe samples before contact with the crystal, the ATR-5000-SS and ATR-5000-SD can also provide observation of the sample through the crystal while in contact with the sample (Fig. 1).
By combining the IQ Mapping function with a ClearView™ ATR objective, an optical image of the sample in contact with the crystal and spectra from not only the center of the crystal, but the entire field of view, can be obtained without any contamination or cumbersome repeated contact to the sample with the crystal. As a result, the ATR crystal only contacts the sample once per mapping, and areas of interest can be measured and analyzed, even when the actual target position moves from the center of the crystal.
Application of ClearView™ ATR (ATR-5000-SS) – Colored Particles in Nail Polish
This application describes the measurement of the base and the colored particles in a nail polish sample using an IRT-5200 with a Clear-View™ ATR objective (ATR-5000-SS) and IQ Mapping. The optical image before sample contact is shown in Figure 2, and the image during sample contact is shown in the Figure 3. When the ClearView™ ATR prism was placed in contact with the sample, the colored particles in the nail polish were positioned outside the center of the crystal. IQ Mapping was used to measure several areas of interest around the contact point by moving the aperture in the field of view of the objective. The base spectrum was identified as a dye, and the colored particle spectrum was identified as silica gel (Fig. 4.).
