Facile one-pot cleavage with in-situ generated aluminum iodide for reliable quantification of alkylphenol ethoxylates in waterborne coatings

Alkylphenol ethoxylates (APEOs) in waterborne coatings (WBCs) pose substantial health and environmental risks due to their estrogenic degradation metabolites, necessitating robust analytical methods to meet stringent regulations. Conventional liquid chromatography-mass spectrometry (LC-MS) methods often suffer from congener separation difficulties and severe matrix interference. To overcome these limitations, we developed an analytical procedure based on facile one-pot cleavage technique using aluminum iodine (AlI 3 ) generated in-situ for the reliable quantification of APEOs in WBCs. The method integrates three core innovations: (1) rapid dehydration with MgCl 2 (1.5 × the mass of sample water) to prevent moisture-induced AlI 3 decomposition; (2) efficient, one-pot AlI 3 -mediated cleavage under ultrasonic irradiation (85 °C, 20 min) for quantitative APEOs-to-alkylphenol (AP) conversion; and (3) simple, quantitative AP isolation via tert -butyl methyl ether (BME) extraction. Validated using gas chromatography-mass spectrometry (GC-MS), the method exhibited excellent linearity (R 2  > 0.999), low limits of quantification (3.0 mg/kg for OPEO 10 , 9.0 mg/kg for NPEO 10 ), satisfactory recoveries (92.9–107.4%) and relative standard deviations (RSDs) ≤ 11.8%. Compared to routine LC-MS methods, this approach effectively mitigates matrix effects, reduces analytical cost, and offers a greener alternative suitable for batch analysis. Application to 20 real WBC samples confirmed its reliability in quantifying APEOs across concentration ranges, from low-level contaminants to high-load formulations. Overall, this integrated strategy enables sensitive, rapid and accurate APEO analysis, presenting a promising new avenue for screening these contaminants in complex sample matrices such as WBCs.