Efficient and highly reproducible capillary electrophoresis–mass spectrometry of peptides using Polybrene‐poly(vinyl sulfonate)‐coated capillaries

Abstract

The potential of capillaries noncovalently coated with a bilayer of oppositely charged polymers for the analysis of peptides by CE-MS was investigated. Bilayer coatings were produced by subsequently rinsing fused-silica capillaries with a solution of Polybrene (PB) and poly(vinyl sulfonate) (PVS). The PB-PVS coating showed to be fully compatible with MS detection causing no ionization suppression or background signals. The bilayer coating provided a considerable EOF at low pH, thereby facilitating the fast separation of peptides using a BGE of formic acid (pH 2.5). Under optimized CE-MS conditions, for enkephalin peptides high separation efficiencies were obtained with plate numbers in the range of 300,000-500,000. It is demonstrated that both the cancellation of the hydrodynamic capillary flow induced by the nebulizer gas and a sufficiently high-data acquisition rate are crucial for achieving these efficiencies. The overall performance of the CE-MS system using PB-PVS-coated capillaries was evaluated by the analysis of a tryptic digest of cytochrome c. The system provided an efficient separation of the peptide mixture, which could be effectively monitored by MS/MS detection allowing identification of at least 13 peptides within a time interval of 1.5 min. In addition, the PB-PVS coating proved to be very consistent yielding stable CE-MS patterns with highly favorable migration time reproducibilities (RSDs < 1% over a 3-day period).

Trends in CE‐MS 2005–2006

“…3A). The authors did not observe any background signals, resulting from the coatings and showed stable and reproducible separations of a tryptic digest of cytochrome c [22].…”

Capillary electrophoresis‐time of flight‐mass spectrometry using noncovalently bilayer‐coated capillaries for the analysis of amino acids in human urine

“…Recently, capillaries noncovalently coated with a bilayer of oppositely charged polymers have been used for the fast and highly reproducible analysis of peptides [17]. The coated capillaries were produced by first rinsing the capillary with a solution of the positively charged polymer Polybrene (PB) and subsequently with a solution of the negatively charged polymer poly(vinyl sulfonate) (PVS).…”

Recent developments in CE and CEC of peptides

“…A high and reproducible anodic or cathodic EOF for CE-MS separation of glycopeptides was achieved by noncovalent coating of the FS capillary with polycationic Polybrene or polycationic Polybrene/polyanionic dextrane sulfate single or multiple layers [92]. The latter type of bilayer coating, produced by subsequently rinsing the FS capillary with a solution of Polybrene and poly(vinyl sulfonate), was shown to be suitable for CE separation of enkephalins and tryptic peptides of cytochrome c in acidic 500 mM formic acidbased BGE, pH 2.5, and compatible with ESI-MS detection, causing no ionization suppression or background signals [93]. Dynamic coatings and precoatings with the commercially available agents EOTrol TM and UltraTrol TM have been reported to provide pH and BGE composition independent cathodic or anodic EOF at different flow rates [94].…”