Fate studies of the non-ionic surfactant alkyl glucamide by liquid chromatography/electrospray mass spectrometry

✍ Scribed by Eichhorn, Peter; Knepper, Thomas P.

• Publisher: John Wiley and Sons
• Year: 2000
• Tongue: English
• Weight: 116 KB
• Volume: 35
• Category: Article
• ISSN: 1076-5174
• DOI: 10.1002/(sici)1096-9888(200003)35:3<468::aid-jms962>3.0.co;2-r

✦ Synopsis

Alkyl glucamides (AGs) were analyzed by reversed-phase liquid chromatography (LC) coupled to mass spectrometry with electrospray ionization (ESMS). Analytes were separated according to the chain length of two homologs, C 12 -and C 14 -glucamide. Mass spectrometric detection in the positive ion mode exhibited higher overall sensitivity where, apart from fragments, different molecular and quasi-molecular ions were obtained. However, application of the negative ion mode offered advantages in terms of reproducibility and extent of information when analyzing environmental samples. Therefore, a simple and sensitive analytical methodology was developed for the determination of AGs in municipal sewage treatment plant influent and effluent based on solid-phase enrichment, LC separation and negative ion ESMS quantification. After preconcentration of 100 ml of aqueous sample, the recoveries using polymeric LiChrolut EN cartridges exceeded 89%. A quantification limit of 0.1 µg l -1 was achieved. Studies on the biodegradability and metabolic pathway of C 10 -glucamide were carried out on a laboratory-scale microbial test unit under aerobic conditions. A postulated metabolism including ω-oxidation of the alkyl chain followed by subsequent b-oxidations was checked by LC/ESMS. Identification and formation of 'C 4 -glucamide acid' as a degradation intermediate was confirmed by mass spectrometric studies. Higher homolog acids such as C 10 -, C 8 -and C 6 -glucamide acids, which should be predicted precursors of C 4 -glucamide acid, and any other metabolites, were not detectable, presumably owing to rapid breakdown.