Liquid chromatography with APCI and SALDI mass spectrometry detection using silver nanoparticles in cholesteryl esters analysis
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| Year of publication | 2017 |
| Type | Conference abstract |
| MU Faculty or unit | |
| Citation | |
| Description | Nonpolar lipid separation can be accomplished by several chromatographic modes according to the length of the fatty acyl chains and the number of double bonds position. Reversed-phase high performance liquid chromatography (RP-HPLC) in combination with UV detection at low wavelengths is often used for the detection of common lipids, but low sensitivity may cause difficulties. In this case, HPLC coupled to mass spectrometry with atmospheric pressure chemical ionization (APCI) can provide more specific information about studied analytes. Presented work is aimed to the combination of RP-HPLC with on-line UV and off-line mass spectrometry detection for cholesteryl esters determination. A simple HPLC method with on-line UV and APCI MS detection was proposed for analysis of cholesteryl esters with different number of double bonds in fatty acids chain in our case were selected cholesteryl ester stearate (CHS), cholesteryl ester oleate (CHE), cholesteryl ester linoleate (CHL) and cholesteryl ester arachidonate (CHA) [1]. Off-line detection was facilitated by surface-assisted laser desorption/ionization mass spectrometry (SALDI MS) using suspension of silver nanoparticles as matrix. After separation, a splitter combined with a laboratory-built spotter was used for eluent deposition on a target over a layer of silver nanoparticles for SALDI experiments [2]. The selected analytes were characterized based on comparison of identified fragment ions from spectra obtained by those two techniques. In SALDI spectra, cholesteryl esters fragment ions characteristic for fatty acids or molecular adduct ions with silver and sodium were observed. On the other hand, spectra obtained by APCI MS showed only cholesterol (Ch) fragment ion [Ch-H2O+H]+ (m/z 369.35). Combination of MS techniques with different ionization mechanisms allow obtaining complementary information for better characterization of the studied lipids. Developed method was used for determination of presented cholesteryl esters in human plasma samples. |
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