An improved method based on aluminum iodide mediated cleavage technique for determining alkylphenol ethoxylates in leather degreasers using high-performance liquid chromatography equipped with diode array detector.

Alkylphenol ethoxylates (APEOs) in leather chemicals pose substantial pollution risks but are challenging to quantify due to matrix interference and hydrophilic polymerized ethoxylate chains. Here, we developed an improved aluminum iodide (AlI₃)-mediated cleavage technique for selective APEOs analysis, converting hydrophilic APEOs to hydrophobic alkylphenols (AP) to eliminate analytical limitations. The method features rapid AlI₃ generation via sonication at room temperature, a sealed-vial reaction at 85 °C for complete cleavage within 30 min, and efficient water removal using acetone azeotrope evaporation. Critical parameters as temperature, water content, and sample matrices were systematically optimized to ensure robust performance. The developed procedure was applied for analyzing leather degreasers using High-Performance Liquid Chromatography equipped with Diode Array Detector, and achieved limits of detection (LD) of 6.0 and 8.0 mg/kg for OPEOs and NPEOs by normalizing to OPEO10 and NPEO10, respectively. The recoveries were ranged from 90.6% to 103.5% with relative standard deviation (RSD) between 3.8% and 12.9%. Crucially, this approach resolved matrix interference that causes failure using conventional Liquid Chromatography-Mass Spectrometry (LC-MS), enabling reliable quantification in complex industrial matrices. By converting APEOs to hydrophobic AP, the advanced AlI₃ cleavage strategy offers an easy and cost-effective platform for APEOs monitoring.