Optimization and correlation of HPLC-ELSD and HPLC–MS/MS methods for identification and characterization of sophorolipids

• Published in: Journal of chromatography. B, Analytical technologies in the biomedical and life sciences Analytical technologies in the biomedical and life sciences, 2012-06, Vol.899, p.72-80
• Main Authors: Ribeiro, Isabel A., Bronze, M. Rosário, Castro, Matilde F., Ribeiro, Maria H.L.
• Format: Article
• Language: English
• Subjects: Ascomycota - chemistry; Ascomycota - metabolism; bioactive properties; biosurfactants; Chromatography, High Pressure Liquid - methods; Correlation; electrospray ionization mass spectrometry; Evaporative; Fragmentation; high performance liquid chromatography; HPLC-ELSD; HPLC–ESI-MS/MS; hydroxy fatty acids; Ionization; Light scattering; Lipid Metabolism; Lipids - chemistry; Liquid chromatography; Rhodotorula; Rhodotorula - chemistry; Rhodotorula - metabolism; Rhodotorula bogoriensis; Sophorolipid; sophorolipids; Spectrometry, Mass, Electrospray Ionization - methods; Starmerella bombicola; surface active properties; Tandem Mass Spectrometry - methods; TLC; Yeast; yeasts
• ISSN: 1570-0232; 1873-376X
• DOI: 10.1016/j.jchromb.2012.04.037

► TLC, HPLC-ELSD and HPLC–ESI-MS/MS were optimized and correlated for SLs analysis. ► HPLC–ESI-MS/MS analysis allowed identification of SLs from different sources. ► A [M+Na]+ fragmentation pattern of acidic and lactonic SLs was established. ► For the first time C24:0 monoacetylated and diacetylated SLs were identified. High-performance liquid chromatography (HPLC) with evaporative light scattering detection (ELSD) and HPLC with electrospray ionization tandem mass spectrometry (HPLC–ESI-MS/MS) methods were implemented and optimized to separate and identify sophorolipids (SLs) produced by Rhodotorula bogoriensis and Starmerella bombicola. SLs are carbohydrate-based amphiphilic biosurfactants with increased interest in pharmaceutical and environmental areas. Rhodotorula bogoriensis and Starmerella bombicola are mainly producers of respectively C22, and C16 and C18 SLs. Mass fragmentation patterns of SLs produced by both yeasts were investigated by HPLC–ESI-MS/MS in the positive mode for [M+Na]+. Based on the established fragmentation pattern, SLs produced by both yeasts were identified and characterized. A correlation between HPLC-ELSD and HPLC- ESI-MS/MS methods was established and made possible the identification of SLs by the HPLC-ELSD technique. TLC is a common tool for the analysis of SLs mixtures. In this work, TLC scrapped bands were analysed by HPLC-ELSD and HPLC–MS allowing the correlation between RF values and the identification of sophorolipids by this technique. Identification of monoacetylated and diacetylated C24:0 hydroxy fatty acids sophorolipids produced by Rhodotorula bogoriensis was for the first time accomplished with this study. Although present in lower quantity these longer chain SLs can assume special importance regarding their biological activity and surface active properties.