A Mull Cell Holder is a specialized tool used in infrared (IR) spectroscopy, particularly in Fourier Transform Infrared (FTIR) analysis, to hold a mull sample for analysis. A mull is a type of sample preparation method where a solid sample, typically a powdered material, is mixed with a liquid (often mineral oil or a similar inert liquid) to create a thick, viscous suspension. This mull is then placed between the windows of the mull cell for spectroscopic analysis.