Continuous vs. segmented second-dimension system gradients for comprehensive two-dimensional liquid chromatography of sugarcane (Saccharum spp.)

Abstract

A comprehensive two-dimensional liquid chromatography system in combination with photodiode array and mass spectrometry detection was developed for analysis of polyphenols in sugarcane (Saccharum spp.) leaf extracts. To achieve this, a micro cyano column and a partially porous octodecylsilica column were used in the first and the second dimension, respectively. The choice of the cyano column over other reversed-phase columns tested for the first-dimension separation was due to its lower correlation selectivity with respect to the octodecylsilica column, which was used for the second-dimension separation. Even when reversed-phase mode was used in both dimensions, a satisfactory degree of orthogonality was achieved by use of different gradient elution modes in the second dimension. By means of the setup investigated, 38 polyphenolic compounds were detected, and among them 24 were positively identified by means of complementary data from photodiode array and mass spectrometry detection and an in-house database. This is the first time such a powerful analytical technique has been used for polyphenolic characterization of sugarcane extracts.

Theory and Practice of UHPLC and UHPLC–MS

“…The unique performance of these particle columns, offering the advantages of higher efficiencies and rugged design, capable of high-pressure operation, was demonstrated in some studies Marchetti et al, 2007;Cavazzini et al, 2007;Cunliffe and Maloney, 2007;Donato et al, 2009). Because of these attributes, these columns were chosen as 2 D of LC Â LC systems, and several research groups (Mondello, Dugo, Jandera and Cifuentes) used them in natural products applications (Hajek et al, 2008;Dugo et al, 2008cDugo et al, , 2009aRusso et al, 2011;Mondello et al, 2011;Cacciola et al, 2012;Leme et al, 2014;Jandera, 2012;Cesla et al, 2009;Hájek and Jandera, 2012;Montero et al 2013aMontero et al ,b, 2014Montero et al , 2016aDonato et al, 2016). In two of the abovementioned references (Dugo et al, 2008c;Hajek et al, 2008) the performance of a partially porous short column was compared with that of a monolithic column.…”

“…Another type of gradient profile (called segmented in fraction (SIF)) was more recently investigated and applied to antioxidant analysis, and it will be described in Section 5.3 (Leme et al 2014). Nevertheless, such optimization strategies will likely be a very fruitful area of research as soon as they are implemented for the analysis of more sample types.…”

“…On the one hand, for NP  RP separation of carotenoids, either silica or cyanopropyl (CN) stationary phases have been investigated (Dugo et al , 2008d(Dugo et al ,e, 2009cCacciola et al, 2012Cacciola et al, , 2016a, whereas for triacylglycerol (TAG) separation, an Ag  RP combination turned out to be useful for this task Dugo et al, 2006b,c;Van der Klift et al, 2008;Hu et al, 2013;Wei et al, , 2015Costa et al, 2015;. On the other hand, for RP  RP separation of phenolic antioxidants, the effect of several stationary phase chemistries (C8, C18, CN, Diol, F 5 , NH 2 , PEG, Phenyl, RPAmide, and other laboratory-made stationary phases) on the separation selectivity and resolution has been investigated (Blahovà et al, 2006;Cacciola et al, 2006Cacciola et al, , 2007aCacciola et al, ,b,c, 2011Hyilompolo, 2007, 2008;Pol et al, 2007, Pol andDugo et al, 2008cDugo et al, , 2009aJandera et al, 2008aJandera et al, ,b, 2012Hájek et al, 2008Cesla et al, 2009;Kalili and de Villiers, 2009, 2013aZhou et al, 2009;Russo et al, 2011;Fu et al, 2012;Hájek and Jandera, 2012;Kalili et al 2013Kalili et al , 2014Montero et al, 2013aMontero et al, ,b, 2014Montero et al, , 2016aKrol-Kogus et al, 2014;Krauze-Baranowska et al, 2014;Leme et al, 2014;Tanaka et al, 2014;…”

“…The orthogonality of RP-LC Â RP-LC systems can be improved through a critical selection of the mobilephase composition (typically the organic modifier used because pH in the range used for flavonoid analysis has little effect on the selectivity), and especially the stationary phase chemistries used in both dimensions. In the case where gradient separation is performed in both dimensions, the 2 D gradient can be varied throughout the 1 D separation to maximize the utilization of the RP-LC Â RP-LC space Jandera et al, 2010a,b;Hájek and Jandera, 2012;Leme et al, 2014;Donato et al, 2016): "continuously shifting" where only a single gradient spanning the whole 2 D separation time is adopted simultaneously to the 1 D gradient, and "SIF" where different gradient ranges in various segments of the 1 D separation are employed. Fig.…”

Comprehensive two-dimensional liquid chromatography–tandem mass spectrometry for the simultaneous determination of wine polyphenols and target contaminants

“…The coupling of similar columns (e.g., RP-LC×RP-LC) may offer superior resolution [13,14] when different mobile phase pH values [15][16][17] are utilized. This may also be implemented by varying the gradient composition between subsequent 2 D runs [18], according to the properties of the analytes being separated.…”