Separation hydrophilic-interaction liquid

One weakness of the dominant reverse phase separations mechanism has been the poor retention of highly polar analytes, and hydrophilic interaction liquid chromatography (HILIC) has emerged as an alternative. In HILIC, a polar stationary phase such as silica gel is used to retain highly polar analytes. Mobile phases components similar to those described above for reverse phase separations are used, but the proportions of aqueous vs. organic are changed. Analytes are retained under conditions of relatively low water content, and eluted using increased water content. 

A selective, sensitive, and rapid hydrophilic interaction liquid chromatography with electrospray ionization tandem mass spectrometry was developed for the determination of donepezil in human plasma [32], Donepezil was twice extracted from human plasma using methyl-ferf-butyl ether at basic pH. The analytes were separated on an Atlantis HILIC Silica column with the mobile phase of acetonitrile ammonium formate (50 mM, pH 4.0) (85 15, v/v) and detected by tandem mass spectrometry in the selective reaction monitoring mode. The calibration curve was linear (r = 0.9994) over the concentration range of 0.10-50.0 ng/ ml and the lower limit of quantification was 0.1 ng/ml using 200 /d plasma sample. The CV and relative error for intra- and inter-assay at four quality control levels were 2.7% to 10.5% and —10.0% to 0.0%, respectively. There was no matrix effect for donepezil and cisapride. The present method was successfully applied to the pharmacokinetic study of donepezil after oral dose of donepezil hydrochloride (10 mg tablet) to male healthy volunteers. 

Antidepressant separation was usually performed by reversed-phase chromatography with typical C8 or C18 alkyl chain columns, although phenyl [30, 59] or cyano [48,64, 84] stationary phases were also employed. As an exception, hydrophilic interaction liquid chromatography (HILIC), a variation of normal phase chromatography, was employed in two analytical methods for duloxetine [38] and... 

Application of LC-MS to the analysis of aminoglycosides has also been problematic, due to the low retention of the parent compounds on the reversed phase columns commonly used. To fry to resolve this problem, ionpairing reagents, such as fluorinated acids, have been used. The introduction of hydrophilic interaction liquid chromatography (HILIC) has provided an alternative means for the retention and separation of aminoglycosides prior to mass specfromefric determination (see Chapter... 

Today, the most rational way to address the separation of very hydrophilic and uncharged compounds in HPLC is by utilizing hydrophilic interaction liquid chromatography (HILIC) [4-7], which is considered to be a variant of... 

Separation Mechanism in Hydrophilic Interaction Liquid Chromatography 685... 

Separation Mechanism in Hydrophilic interaction Liquid Chromatography... 

Karson, G. (2011) Development and application of methods for separation of carbohydrates by hydrophilic interaction liquid chromatography, in Hydrophilic Interaction Liquid Chromatography (HILIC) and Advanced Applications (eds P.G. Wang and W. He), CRC Press, Boca Raton, p. 491. 

Hydrophilic interaction liquid chromatography in gradient mode with charged aerosol detection can also be used for separating oligosaccharides. As an example, Figure 8.83 shows the separation of maltose oligomers up to DP7 on... 

More recently, hydrophilic-interaction liquid chromatography (HILIC) has been exploited for the separation of lipids, as well. In this type of chromatography, individual lipid classes are separated on silica or diol columns according to their polarity [58,59]. 

Partition chromatography is also an alternative for the separation of carbohydrates. Hydrophilic interaction liquid chromatography (HILIC) provides improved separations compared with more-conventional reversed-phase LC methods. These HILIC-based separations are normally carried out using functionalized silica-particle columns, in which an amino group, such as a trifimctional aminopropylsilane, is bonded. 

Since TTX is a very polar compoimd, retention on conventional reversed-phase columns is poor. Even though reversed-phase liquid chromatography is overall the most commonly used separation technique for TTX, certain TTXs are not retained. Use of an ion-pair reagent or hydrophilic interaction liquid chromatography (HILIC) can help solve this problem. Previous studies conducted with different columns and MS methods showed that 5,6,11-trideoxyTTX was not retained on a C18... 

Liquid chromatography is a powerful separation tool because multiple separation mechanisms can be employed partitioning (RP), adsorption (NP), hydrophilic interaction liquid chromatography (HILIC), ion... 

Lakso HA, Appelblad P, Schneede J. Quantification of methylmalonic acid in human plasma with hydrophilic interaction liquid chromatography separation and mass spectrometric detection. Clin Chem 2008 54 2028—35. 

Hydrophilic interaction liquid chromatography (HILIC) was proposed for the separation of diketopiperazines such as cyclo(Ala-Ser), cyclo(Gly-Leu), and cyclo(Ala-Gly), for carbohydrates, and nucleotides by Alpert [13]. Yoshida [14] analyzed peptides on a carbamide derivatized stationary phase. Later Strege [15] used HILIC-ESI-MS for the discovery of polar natural drugs such as vancomycin, terreic add, and cephalosporin C. 

Figure 6 Hydrophilic interaction liquid chromatography (HILIC) separation of the taste-active subfraction FI of an acid-deamidated wheat gluten hydrolysate that was not retained by reversed-phase high-performance liquid chromatography (RP-HPLC). Fru-Val, A -(l-deoxy-D-fructos-l-yl)-valine Fru-Glu, A -(l-deoxy-D-fructos-l-yl)-glutamic acid (cf. Fig. 7).

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