HPLC‐MSⁿ to Investigate the Oxidative Destruction Pathway of Aromatic Sulfonate Wastes

Abstract

The article concerns the problem of destruction and remediation of industrial wastes containing aromatic sulfonates. The effects of an oxidation process induced by thermally activated persulfate in the degradation of 1,5-naphthalenedisulfonate (NDS) are investigated by the use of UV-Vis spectrophotometry, high performance liquid chromatography-mass spectrometry (HPLC-MS) and HPLC-MS(n) techniques. The results obtained indicated that thermal activation (80 degrees C) of a solution containing NDS and sodium persulfate in a molar ratio equal to 1 leads to the cleavage of the naphthalene structure. Estimated chemical oxygen demand (COD) indicates that when the excess of persulfate is equal to 100, NDS undergoes a mineralization of the order of 90%. A degradation pathway undergone by NDS when thermally activated in the presence of persulfate is proposed.

Effects of functional groups on the fragmentation of dyes in electrospray and atmospheric pressure chemical ionization mass spectra

“…In connection with soft ionization techniques, tandem mass spectrometry (MS/MS) or multiple-stage tandem mass spectrometry (MS n ) is essential, because of the lack of fragment ions in the first-order mass spectra [16,21,25]. The HPLC methods for the analysis of medium and low polar dyes employ the common reversed-phase C18 column packing and mobile phases consisted of aqueous methanol or acetonitrile.…”

Investigating the fragmentation pathways of β‐naphthol pigments using liquid chromatography/electrospray ionization quadrupole time‐of‐flight mass spectrometry

“…Different MS ionization sources have been used, such as thermospray, 22 laser desorption ionization, 23 matrix‐assisted laser desorption ionization, 24 atmospheric pressure chemical ionization, 25 and electrospray ionization (ESI) 26 . Most studies are based on the use of HPLC‐DAD 25–37 and LC/MS (using triple quadrupole or ion trap instruments as detectors), 22,25,26,30–32,36,38–41 whereas only a few used high‐resolution mass spectrometers 42–49 . ESI is the method of choice for the analysis of polar dyes and pigments, and negative‐ion mode is the best for determining the molecular weights of anionic dyes containing proton‐donor groups, such as hydroxyls and sulfonyls, as already demonstrated in a study on the fragmentation of (poly‐)sulfonated dyes 41 .…”