This application note examines the impact of sample preparation and sampling techniques on FT-IR spectral library search results. Using examples like calcium carbonate and corn starch, it demonstrates how KnowItAll software and spectral databases can be used to improve match quality and identification reliability, correctly confirming materials when samples are properly prepared while flagging the mismatches that result from poor preparation or environmental factors like moisture exposure. It proves that careful sample preparation is a key factor in achieving trustworthy identification results.