« Previous AbstractImpairment of benthic diatom adhesion and photosynthetic activity by allelopathic compounds from a green alga: involvement of free fatty acids?    Next AbstractEvaluating the responses of a territorial solitary carnivore to potential mates and competitors »

J Chromatogr A

Title:		Isolation of the components of a complex mixture by means of column switching for their enhanced detection by mass spectrometry
Author(s):		Allen JR; Williams JD; Burinsky DJ; Cole SR;
Address:		"Pharmaceutical Development Division, Glaxo Wellcome Inc., Research Triangle Park, NC 27709, USA. ja8673@glaxowellcome.com"
Journal Title:		J Chromatogr A
Year:		2001
Volume:		913
Issue:		1-Feb
Page Number:		209 - 219
DOI:		10.1016/s0021-9673(01)00536-2
ISSN/ISBN:		0021-9673 (Print) 0021-9673 (Linking)
Abstract:		"Mass spectral characterization of low-level impurities in drug substances and formulations may be challenging when using a validated HPLC method developed for optimal chromatographic performance. In many cases, either the mobile phase contains non-volatile additives that are deleterious to the operation of the mass spectrometer, or some of the related substances fail to ionize effectively under electrospray ionization or atmospheric pressure chemical ionization conditions. This paper describes a way to capture these low-level compounds from an analytical HPLC column using a small trapping column. Mixture components are retained on the trapping column by means of reducing the solvent strength of the eluent. Subsequent elution of trapped compounds using mobile phases more amenable to mass spectral analysis yields improved detection and characterization of low-level compounds of interest. Possible applications of peak trapping and elution include: (1) analysis of compounds separated using a mobile phase containing high concentrations of non-volatile additives, (2) analysis of organic acids separated using a low-pH mobile phase (containing trifluoroacetic acid), and (3) improving the detection limit of a low-level compound of interest through multiple collections. The peak trapping apparatus and optimization experiments are described"
Keywords:		"Chromatography, High Pressure Liquid/*methods Indomethacin/analysis Mass Spectrometry/*methods Tolbutamide/analysis;"
Notes:		"MedlineAllen, J R Williams, J D Burinsky, D J Cole, S R eng Netherlands 2001/05/18 J Chromatogr A. 2001 Apr 13; 913(1-2):209-19. doi: 10.1016/s0021-9673(01)00536-2"