Determination of phenolic antioxidants additives in industrial wastewater from polypropylene production using solid phase extraction with high-performance liquid chromatography.

This paper describes a new method for the effective extraction of the residues of five synthetic phenolic antioxidants (AOs): Ditertbutylphenol (DTF), Irganox 1010, Irganox 1076, Ethanox 330 and Cyanox 1790, from industrial water produced during the polypropylene (PP) deodorization process. In the deordorization process, PP is stored in a column for an average time of four hours and exposed to nitrogen and water vapor to remove inflammable compounds which may generate atypical odors in the PP. The samples of interest were taken in the desorber, followed by cleansing and pre-concentration using modified styrene divinylbenzene polymer cartridges. Liquid chromatography was performed with a reversed phase column and diode array. The method was validated for linearity, recovery, precision, specificity, limits of detection (LOD) and limits of quantification (LOQ). The chromatographic method showed LOQ from 5.4 to 16 mg L-1 and LOD between 1.6 and 4.8 mg L-1. The worldwide challenge to develop an analytical methodology which incorporates SPE with HPLC to identify and quantify AOs in industrial wastewater is addressed in this study. The recovery percentages were above 90% for most AOs, except for Irganox 1076 which showed a value of 83.2%. The ability to separate these five AOs of most frequent use worldwide, permits precision of measurement of the degree of contamination, making it useful for environmental regulation and the protection of public health.