Hydrophilic interaction chromatography HILIC matrix

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. 

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. 

Acronyms d SPE dispersive solid-phase extraction HILIC hydrophilic interaction liquid chromatography IT ion trap LLE liquid—liquid extraction MSPD matrix solid-phase dispersion PGC porous graphitized carbon PLE pressurized-liquid extraction PHWE pressurized hot-water extraction QqQ triple quadrupole QLIT quadrupole linear ion trap QuEChERS quick, easy, cheap, effective, rugged, and safe TCA trichloroacetic acid UHPLC ultraperformance liquid chromatography ZIC ttILIC zwitterionic hydrophilic-interaction liquid chromatography. 

Acronyms BHT = butylated hydroxytoluene FL = fluorescence detection HILIC = hydrophilic-interaction LC IDMS = isotope-dilution mass spectrometry IS = internal standard MSPD = matrix solid-phase dispersion QqQ = triple quadrupole SRM = standard reference material TCA = trichloroacetic acid TEA = trifluoroacetic acid UPLC = ultraperformance liquid chromatography. 

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