Atmospheric pressure photoionization mass spectrometry as a valuable method for the identification of polyisoprenoid alcohols.
BACKGROUND
The aim of this study was to determine whether Atmospheric Pressure Photoionization (APPI) was better suited for the mass spectrometric (MS) analysis of polyisoprenoid alcohols than the commonly used Electrospray Ionization (ESI) method. The APPI method should make possible the use of non-polar solvents without any of the additives required by ESI, together with improved detection limits.


METHODS
The liquid chromatography (LC)/APPI-MS and LC/ESI-MS spectra of polyisoprenoid alcohol standards were acquired in both positive and negative ion mode, in methanol and hexane, using a triple quadrupole/linear ion trap tandem mass spectrometer equipped with both an ESI and an APPI ion source.


RESULTS
In the positive ion mode peaks corresponding to [M + H - H(2)O](+) and [M + H](+) ions were observed in the APPI-MS spectra of polyprenols and dolichols, respectively. In the negative ion mode peaks corresponding to [M + O(2)](-•) and [M + Cl](-) ions were observed for both classes of polyisoprenoid alcohols. The detection limit of polyisoprenoid alcohols was established at the level of 10 pg.


CONCLUSIONS
APPI turned out to be a method of choice for the identification and quantitation of polyisoprenoid alcohols by MS using both polar and non-polar solvents. APPI also enabled greater differentiation of polyprenols and dolichols occurring together in natural samples and gave much better TIC chromatograms without the need for the post-column salt addition required by ESI.
Institute of Organic Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland. magdalena.kania@icho.edu.pl
Magdalena
M
Kania
Karolina
K
Skorupinska-Tudek
Ewa
E
Swiezewska
Witold
W
Danikiewicz
D002853:Chromatography, Liquid / Q000379:methods*; D005233:Fatty Alcohols / Q000032:analysis / Q000737:chemistry*; D006586:Hexanes / Q000737:chemistry; D013058:Mass Spectrometry / Q000379:methods*; D000432:Methanol / Q000737:chemistry
D005233:Fatty Alcohols; D006586:Hexanes; D000432:Methanol