Advanced quantification of tris(hydroxymethyl)aminomethane (THAM) in solid adsorbents: comparing UV-Vis, HPLC-UV, and...

Tromethamine (THAM), an amino alcohol, exhibits a strong capacity for capturing formaldehyde. As a result, incorporating THAM into adsorbent materials can significantly enhance their adsorption capabilities toward volatile organic compounds (VOCs), particularly aldehydes. Quantifying the THAM content in these materials is crucial for assessing their performance. However, no prior studies have focused on measuring THAM content in solid adsorbents. In this study, we present the development of three analytical methods for quantifying this molecule in different matrices such as water, polyacrylonitrile (PAN) and activated carbon (AC). The three techniques involve derivatization of THAM, with either benzoyl chloride (BC) or 1-naphthoyl chloride (1-NC) by Schotten-Baumann reaction, followed by analysis by UV-Vis spectroscopy, HPLC-UV or HPLC-fluorescence (FL). Our findings reveal that the activated carbon matrix can affect the quantitative measurement of THAM, whereas PAN does not. The analytical methods developed in this study demonstrate excellent linearity (R² > 0.99), high accuracy (mean recovery of 96.6-102.9%), and high repeatability (RSD of 2.7-5.2%). Among the three developed methods, UV-Vis is the simplest method whereas HPLC-FL is the most sensitive, with a limit of detection (LOD) of 0.017 wt% for THAM content analyses in AC (compared to UV-Vis with a LOD = 0.59 wt% and HPLC-UV with a LOD = 0.023 wt%). Our assay will serve as a reliable basis for THAM quantification in other solid adsorbents, such as zeolites and porous silica. Additionally, the methods may be adapted for studying solid adsorbents doped with other amino alcohols.