Tandem HILIC‐RP liquid chromatography for increased polarity coverage in food analysis

Abstract

Comprehensive non-targeted analysis of food products normally requires two complementary chromatographic runs to achieve maximum compound coverage. In this study, we present a sensitive tandem-LC method, which combines RP and HILIC separation in a single run. The setup consists of a C18 trap column and two subsequently coupled analytical columns (HILIC and C18) which are operated in parallel. First, hydrophobic compounds are retained on the RP trap column while rather hydrophilic compounds are directly transferred onto a HILIC phase. Next, the pre-fractionated sample composition is analyzed by HILIC or RP chromatography, respectively. The presented setup allows individual and independent gradient elution as well as interfacing with mass spectrometry. The performance of the method has been proven by means of food relevant standards and analysis of complex food samples (e.g. red wine, meat extract). The simple and robust setup provides high flexibility in the selection of column combinations and does not require sophisticated instrumental setups or software. The method significantly increases the covered polarity range compared to classical one-dimensional chromatography. Our results indicate that tandem LC is a valuable and universal tool in the non-targeted screening of various types of complex food samples.

Simulated Sunlight Selectively Modifies Maillard Reaction Products in a Wide Array of Chemical Reactions

“…Control samples, which were protected from light exposure, were also placed in the suntester system for four and eight hours. Subsequently, we analyzed the samples by direct‐infusion Fourier transform ion cyclotron resonance mass spectrometry (FT‐ICR‐MS) and tandem‐column LC‐MS/MS, which combines hydrophilic interaction chromatography (HILIC) and reversed‐phase (RP) liquid chromatography (LC) in a single chromatographic run . Direct‐infusion FT‐ICR‐MS allows a highly sensitive and holistic nontargeted screening of complex samples on the level of accurate molecular formulae .…”

“…Aliquots (16 mL) of the irradiated samples were lyophilized until dryness and immediately reconstituted in 200 μL of an aqueous solution containing 2 % acetonitrile prior to LC‐MS/MS analysis. Instrumental setup and chromatographic conditions were the same as recently described . Each sample was injected and analyzed in triplicate.…”

“…Subsequently,w e analyzed the samples by direct-infusion Fouriert ransform ion cyclotron resonancem ass spectrometry (FT-ICR-MS) and tandem-column LC-MS/MS, which combines hydrophilic interaction chromatography (HILIC) and reversed-phase (RP) liquid chromatography (LC) in as ingle chromatographic run. [26] Direct-infusion FT-ICR-MSa llows ah ighly sensitive and holistic nontargeted screening of complex samples on the level of accurate molecular formulae. [27] Principalc omponent analysis (PCA) of the obtainedF T-ICR-MS raw data could clearly separate irradiated model systemsfrom controls on PC1 (exemplarily shown for the ribose-histidine model in Figure S1, Supporting Information).…”

“…Instrumental setup and chromatographic conditions were the same as recently described. [26] Each sample was injected and analyzed in triplicate. The MS data were recorded with ahigh-resolution Bruker maXis qTOF-MSe quipped with an APOLLO II electrospray ion source (Bruker Daltonics, Bremen, Germany), which was operated in electrospray positive mode to achieve maximum compound coverage.…”

“…The MS data were recorded with ahigh-resolution Bruker maXis qTOF-MSe quipped with an APOLLO II electrospray ion source (Bruker Daltonics, Bremen, Germany), which was operated in electrospray positive mode to achieve maximum compound coverage. [26] Precursor and product ion scans were recorded in a mass range from m/z = 50-1500 with as canning rate of 5Hz. For data-dependent fragmentation, after each precursor scan, the two most abundant precursors were isolated and subjected to collision-induced fragmentation.…”