Determination of N,N′-ethylenebisstearamide additive in polymer by normal phase liquid chromatography with evaporative light scattering detection

A new method for N,N′-ethylenebisstearamide (EBS) analysis was developed and validated in normal phase-HP liquid chromatography (NP-HPLC) with diol column at 50 °C with 100% CHCl3 at 1 mL min−1 and evaporative light scattering detection with elution time at 3.0 min. EBS solubility was the best at 0.80 g L−1 in CHCl3/methanol 90:10. The molecular structure of commercial samples of EBS was determined by GC–MS which ascertained that the main structure is C18/C18 at approximately 45%. The remaining part was constituted by molecules with different alkyl chain length. The HPLC quantification method was proved linear (r = 0.9983), accurate (99.6%) and precise (1.95%). Limit of quantification (LOQ) and limit of detection (LOD) were equal to 2.0 and 0.8 μg mL−1, respectively. The suitability of this method was assessed with a dissolution/precipitation extraction procedure of EBS from ethylene vinyl acetate (EVA) polymer which showed that other additives and polymer do not interfere with EBS analysis. The intra-day and day-to-day precisions of extraction method were equal to 9.1% and 9.9%, respectively.