Preparation of Sulfoxide Residue Bonded Silica Stationary Phase for Separation of Polychlorinated Biphenyls from Mineral Oils

Abstract

In this study, a sulfoxide residue bonded silica stationary phase was prepared for the separation of polychlorinated biphenyls (PCBs) from mineral oils, and its properties were investigated. Organic sulfide was attached to a silica surface by an amide bond, and the bonded sulfide residues were oxidized to sulfoxide with hydrogen peroxide to afford sulfoxide and sulfone residues bonded to the stationary phases (0.84 and 0.63 mmol of sulfur bonded per gram, respectively). The oxidation states of sulfur atoms bonded on the stationary phases could be determined using high-resolution X-ray fluorescence spectra. The modified stationary phases, especially sulfoxide-bonded one, separated PCBs from mineral oils (paraffin-based transformer oils) more efficiently than aminopropyl silica or other polar stationary phases that have been used for the cleanup of PCBs. The chromatographic parameters for an aliphatic hydrocarbon (eicosane) and some PCB congeners indicated strong retention of highly chlorinated biphenyls by the sulfoxide-bonded silica compared with the aminopropyl silica. A cleanup procedure was established for simple determination of PCBs in mineral oil samples using the sulfoxide-bonded silica packed column fractionation. The analytical method was validated using a certified reference material and a PCB-fortified transformer oil sample.

Polar-Embedded and Polar-Endcapped Stationary Phases for LC

“…Sulfoxide-linked hydroxyl and diol phases displayed U-shaped retention curves for adenosine and guanosine, giving the opportunity to operate in both RP and HILIC (HydrophILic Interaction Chromatography) modes . A 58 mm silica stationary phase with embedded amide and terminal sulfoxide groups displayed improved normal-phase retention of polychlorinated biphenyls (PCBs) in mineral oils (Numata et al 2007)-performance further improved when an embedded amine was also incorporated into the structure (Numata et al 2008). The well-known RP=WAX (reversed-phase=weak anion exchange) phases also include a thioether linkage, which may contribute to the retention profile (Lammerhofer et al 2008).…”

Mineral oil certified reference materials for the determination of polychlorinated biphenyls from the National Metrology Institute of Japan (NMIJ)

“…In addition to the official method (dimethylsulfoxide (DMSO) extraction [ 7 , 9 ]), chromatographic techniques (normal-phase liquid chromatography [ 10 , 11 ], gel permeation chromatography [ 12 ], reversed-phase liquid chromatography [ 13 ]) have been evaluated, and were used for the characterizations. A new stationary phase for liquid chromatography, sulfoxide-bonded silica [ 14 ], was also used for the analysis. Separation efficiencies of PCBs from the mineral oils by the chromatographic techniques were mainly estimated from their elution profiles.…”

Photokatalyse mit sichtbarem Licht: Welche Bedeutung hat sie für die organische Synthese?

“…In einem zweiten Bericht erweiterten sie den Anwendungsbereich der Reaktion auf primäre und sekundäre alkylsubstituierte und heteroarylsubstituierte Sulfone mit guten Ergebnissen (Schema 35 b). [130] Daher wurden bereits mehrere Synthesewege beschrieben, darunter die Oxidation von Sulfiden zu Sulfoxiden [131] oder die nucleophile Substitution von Sulfinylderivaten mit Organomagnesiumreagenzien (Schema 36). [126] Aromatische Sulfoxideinheiten sind ein Strukturelement in Naturstoffen, [127] Herbiziden, [128] Arzneistoffen [129] und Hochleistungsmaterialien.…”

“…[126] Aromatische Sulfoxideinheiten sind ein Strukturelement in Naturstoffen, [127] Herbiziden, [128] Arzneistoffen [129] und Hochleistungsmaterialien. [130] Daher wurden bereits mehrere Synthesewege beschrieben, darunter die Oxidation von Sulfiden zu Sulfoxiden [131] oder die nucleophile Substitution von Sulfinylderivaten mit Organomagnesiumreagenzien (Schema 36). [132] Darüber hinaus wurden elektrophile aromatische Substitutionssreaktionenzur Synthese genutzt, zum Beispiel die Aluminiumchlorid-katalysierte Arensulfinylierung von Benzol oder Toluol mit Sulfinylchloriden [133] oder die Friedel-Crafts-Reaktion von Methylsulfinaten mit elektronenreichen Aromaten unter Verwendung von stçchiometrischen Mengen Aluminiumchlorid.…”