Formaldehyde, a hazardous and toxic substance, can be found in most resin treated durable press fabrics. The current formaldehyde regulations are limited to worker exposure in an industrial setting and the possibility of government regulation of formaldehyde release from textiles is of concern to the textile industry. The most common test of formaldehyde release used by the U.S. textile industry is the AATCC Test Method 112, a colorimetric determination based on the Hantzsh reaction between ammonia, formaldehyde, and acetylacetone. The chromophore formed is 3,5-diacetyl-1,4-dihydrolutidine (DDL). In the AATCC test the ammonia and acetylacetone are in the Nash reagent and the formaldehyde is extracted from the fabric by trapped steam. The formaldehyde in solution and the Nash reagent are mixed and the color developed. The purpose of this study was to determine if a more effective formulation of the Nash reagent than currently used by industry can be produced. The reaction between the Nash reagent and formaldehyde is first order in formaldehyde, therefore pseudo-first order kinetics was used as the basis of the study. Reagent effectiveness was determined by comparisons and calculations based on the molar extinction coefficient, maximum absorbance, and rate constant. The study was set up in phases to investigate the effect of different ammonia sources, the effects of varying concentrations of the reactant components, the effect of ageing, and the effect of different temperatures on the formation of DDL. In the final phase the best reformulated reagent was compared to the Nash reagent under the conditions of the AATCC Test Method 112. Several reformulations were found to be comparable to Nash, but none was found to be more effective in formaldehyde detection. This study has shown some of the complexities of the reaction and that the Nash reagent is not able to obtain 100% conversion of formaldehyde to DDL. Therefore, any test that uses the Nash reagent is underestimating the releasable formaldehyde concentration in the fabric. / Ph. D.