In‐line SPE‐CE using a fritless bead string design—Application for the analysis of organic sulfonates including inline SPE‐CE‐MS for APTS‐labeled glycans

Abstract

Despite many advantages like high separation efficiency CE comprises the main limitation of low concentration sensitivity, when compared to HPLC. In-line SPE is an efficient way to increase concentration sensitivity. Here, a fritless in-line-SPE-CE-MS method was developed in order to analyze anions of strong acids. Mixed-mode (weak anion exchange and RP) particles were used for enrichment and an acidic BGE was applied for separation. Different particle and capillary sizes were tested. A novel bead string design with a 100 μm id column filled with particles of 90 μm followed by a separation capillary with 50 μm id was easy to prepare and showed the best performance with respect to separation efficiency and reproducibility. Three aromatic sulfonic acids were employed in an in-line SPE-CE-UV approach for method development. Method validation was performed with respect to reproducibility, robustness, and linearity. Thereafter the method was transferred to SPE-CE-MS and applied to the analysis of glycans labeled with 8-aminopyrene-1,3,6-trisulfonic acid. Lower limits of detection in the low nM range were achieved injecting about 10 μL of sample. This corresponds to an enrichment factor of more than 800 compared to the corresponding CE-MS method without preconcentration.

Enantioselective determination of cathinones in urine by high pressure in‐line SPE–CE

“…To overcome this, different preconcentration strategies have been developed, and in recent years, there has been much interest in the in‐line coupling of SPE with CE (in‐line SPE–CE). In in‐line SPE–CE a microcartridge (or preconcetrator) is inserted near the inlet end of the separation capillary, so it is an integral part of the separation capillary . There are various designs used for the preconcentrator in in‐line SPE–CE, the most popular being the fritless packed bed .…”

Capillary Electrophoresis Separations of Glycans

“… 70 The in-line fritless cartridge was used to enrich anionic samples prior to the CE separation and was successfully applied to APTS-labeled glycans. 70 Finally, slab gel electrophoresis was reported for glycan purification by excising gels and extracting the labeled glycans. 51 …”

Recent advances in enhancing the sensitivity of electrophoresis and electrochromatography in capillaries and microchips (2012–2014)

“…Jooß et al prepared a “bead string design” SPE column in which a 4‐mm section of 100 μm id capillary is filled with a string of 90 μm mixed‐mode beads . This design prevents clogging or formation of hollow spaces inside SPE column, which usually happens in conventional packed bed design.…”