Semi‐online nanoflow liquid chromatography/matrix‐assisted laser desorption ionization mass spectrometry of synthetic polymers using an octadecylsilyl‐modified monolithic silica capillary column

Abstract

We have designed a semi-online liquid chromatography/matrix-assisted laser desorption/ionization mass spectrometry (LC/MALDI-MS) system to introduce eluent from a octadecylsilyl (ODS) group modified monolithic silica capillary chromatographic column directly onto a sample plate for MALDI-MS analysis. Our novel semi-online system is useful for rapidly and sensitively examining the performance of a monolithic capillary column. An additional advantage is the small elution volume of a monolithic capillary column, which allows delicate eluents, such as 1,1,1,3,3,3,-hexafluoroisopropyl alcohol (HFIP), to be used to achieve cost-effective analysis. Using the semi-online LC/MALDI-MS system, chromatographic separation of polymers by the monolithic column with different eluents was studied. Separation of poly(methyl methacrylate) and Nylon 6/6 showed that the column functioned via size-exclusion separation when tetrahydrofuran or HFIP eluent was used. On the other hand, the separation behavior of Nylon 11 indicated a reversed-phase mode owing to the interaction of the polymer with the modified ODS group in the column. Using tetrahydrofuran/methanol (1:1, v/v) as the eluent, the LC/MALDI-MS spectra of poly(lactic acid), which contains both linear and cyclic polymer structures, showed that the column could separate the hydrophobic cyclic polymer and elute it out relatively slowly. The monolithic column functions basically via size-exclusion separation; the reversed-phase separation by interaction with the ODS functions may have less influence on column separation. The semi-online monolithic capillary LC/MALDI-MS method we have developed should provide a means of effectively analyzing synthetic polymers.

Interfacing Multistage Mass Spectrometry with Liquid Chromatography or Ion Mobility Separation for Synthetic Polymer Analysis

“…66,69,71 The vast majority of online or offline LC-MS studies with synthetic polymers has involved gel permeation chromatography or liquid chromatography under critical conditions. [31][32][33]40,72 Applications of adsorption-mode LC (interactive LC) have only begun recently. 33,39,41,42,73,74 Similarly, IM-MS is an emerging method in the characterization of polymers.…”

Monoliths in capillary electrochromatography and capillary liquid chromatography in conjunction with mass spectrometry

“…Commercial monolithic silica‐based capillaries were also used in cLC‐ES‐APLI‐MS (Chromolith® CapROD RP 18, (100 μm × 150 mm)) for the analysis of pyridylaminated oligosaccharides (Ex‐Nano Mono Cap column (0.2 mm id × 250 mm; GL Sciences, Japan)) and for the analysis of PAHs like phenanthrene, fluoranthene, fluorene, and benzo[a]pyrene . By employing a column from Kyoto Monotech, Kyoto, Japan, (200 μm × 1270 mm) and a THF mobile phase in a semi‐on‐line LC‐MALDI‐MS system, the separation of poly(methyl methacrylate), Nylon 6/6, and Nylon 11 was achieved .…”