Liquid chromatography hydrophilic interaction

4 Ultra-High-Performance or Ultra-High-Pressure Liquid Chromatography 

Conventional LC with CIS-modified silica stationary-phase or HILIC columns has been widely used in antibiotic residue analysis as discussed above. Since the 1980s, the need for faster and more powerful separations for the analyses of constituents, such as protein digests, in complex matrices led to the development of highly mechanically stable (to high back-pressures) columns and 

5- and 5.0-ttm particles, respectively, at equal column lengths. Furthermore, column efficiency at the optimum 

The fact that the van Deemter plots of small particles are generally flat beyond the optimum linear velocity means that higher linear velocity would not compromise column efficiency significantly. Therefore, in practice, rapid gradients and high flow rates are usually applied in small particle columns to shorten the runtime and increase sample throughput. The column temperature also affects separation speed and column efficiency, and is used to control the selectivity of the separation as well. An increase in temperature leads to a decrease in retention in reversed phase UHPLC. It is generally considered that the A term 

Ultra-high-performance liquid chromatography has been increasingly used for the determination of multi-residue or multi-class antibiotics in food (Table 6.1). For example, an UHPLC/ESI-MS/MS method was reported to simultaneously analyze 17 different veterinary drug residues belonging to several classes of antibiotics such as macrolides, tetracyclines, quinolones, and sulfonamides 

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Van Nuijs ALN, Tarcomnicu I, Bervoets L, Blust R, Jorens PG, Neels H, Covaci A (2009) Analysis of dmgs of abuse in wastewater by hydrophilic interaction liquid chromatography-tandem mass spectrometry. Anal Bioanal Chem 395 819-828... 

Direct injection of plasma or supernatant after protein precipitation on a short column with a high liquid flow rate is a common method for reducing analysis time in the pharmaceutical industry. The direct injection of a sample matrix is also known as the dilute-and-shoot (DAS) approach.62 DAS can be applied to all types of matrices and approaches and is the simplest sample preparation method with matrix dependency. Direct injection can also be approached through the extraction of eluent from PPT, SPE, and LLE onto a normal phase analytical column. The procedure is called hydrophilic interaction liquid chromatography (HILIC)70110111 and it avoids the evaporation and reconstitution steps that may cause loss of samples from heat degradation and absorption. 

Hydrophilic interaction liquid chromatography (HILIC) can handle the matrix effects nonvolatiles, which may reduce the evaporation of volatile ions during the electrospray process. Ion-exchange methods that require the use of salts could otherwise interfere with MS. 

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... 

Naidong W, Eerkes A (2004) Development and validation of a hydrophilic interaction liquid chromatography-tandem mass spectrometric method for the analysis of paroxetine in human plasma. Biomed Chromatogr 18 28-36... 

Qin F, Zhao Y, Sawyer MB, Li X (2008) Hydrophilic interaction liquid chromatography-tandem mass spectrometry determination of estrogens conjugates in human urine. Anal Chem... 

Quintela O, Lendoiro E, Cruz A, de Castro A, Quevedo A, Jurado C, Lopez-Rivadulla M (2010) Hydrophilic interaction liquid chromatography-tandem mass spectrometry (HILIC-MS/MS) determination of cocaine and its metabolites benzoylecgonine, ecgonine methyl ester, and cocaethylene in hair samples. Anal Bioanal Chem 396(5) 1703-1712. doi 10.1007/s00216-009-3393-5... 

Nygren, Y., Hemstrdm, P., Astot, C., Naredi, P., Bjorn, E. Hydrophilic interaction liquid chromatography (HILIC) coupled to inductively coupled plasma mass spectrometry (ICPMS) utilizing a mobile phase with a low-volatile organic modifier for the determination of cisplatin, and its monohydrolyzed metabolite. J. Anal. At. Spectrom. 23, 948-954 (2008)... 

DelTAversano, C., Eaglesham, G., Quilliam, M.A. (2004). Analysis of cyanobacterial toxins by hydrophilic interaction liquid chromatography-mass spectrometry. J. Chromatogr. A 1028 155-64. 

Strege, M.A. Stevenson, S. Lawrence, S.M. Mixed-Mode Anion-Cation Exchange/Hydrophilic Interaction Liquid Chromatography-Electrospray Mass Spectrometry as an Alternative to Reversed Phase for Small Molecule Drug Discovery, Anal. Chem. 72,4629-4633 (2000). 

Xue, Y.J., Liu, J., and Unger, S., A 96-well single-pot liquid-liquid extraction, hydrophilic interaction liquid chromatography-mass spectrometry method for the determination of muraglitazar in human plasma, J. Pharm. Biomed. Anal., 41(3), 979, 2006. 

Troyer JK, Stephenson KK, Fahey JW. Analysis of glucosinolates from broccoli and other cruciferous vegetables by hydrophilic interaction liquid chromatography. J Chromatogr A 2001 991 299-304. 

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... 

Wang, P.G. He, W. Hydrophilic Interaction Liquid Chromatography (HILIC) and Advanced Applications. Taylor Francis Boca Raton, FL, 2011. 

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