In May 2016, the U.S. Food and Drug Administration (FDA) issued a final rule to deem cigars to be subject to the Federal Food, Drug, and Cosmetic Act, as amended by the Family Smoking Prevention and Tobacco Control Act. As part of this regulation, the FDA will require manufacturers to report the quantities of harmful and potentially harmful constituents (HPHCs) in cigar filler and smoke. Standardized methods do exist for the analysis of carbonyls in cigarette smoke; however, these methods have not been shown to be fit for purpose for the analysis of cigars. CORESTA Recommended Method (CRM) No. 74, “Determination of Selected Carbonyls in Mainstream Cigarette Smoke by High Performance Liquid Chromatography” was based on Health Canada method T-104 and is the basis of ISO/CD 21160:2017, “Determination of selected carbonyls in the mainstream smoke of cigarettes -- Method using High Performance Liquid Chromatography”. Due to the fact that it may take an hour or more to collect cigar smoke, we hypothesized that the carbonyl–DNPH derivative would degrade over time, resulting in decreased carbonyl yields. Cigar smoke was collected and time studies were conducted to determine carbonyl stability in the acidic DNPH trapping solution. The result of this work indicates that the DNPH derivatives may not be stable during smoke collection. Results will be presented for different cigar blend types. Furthermore, these results indicate that specialized methods need to be developed for the robust analysis of carbonyls in cigar smoke.