Analysis of N-acylhomoserine lactones after alkaline hydrolysis and anion-exchange solid-phase extraction by capillary zone electrophoresis-mass spectrometry.
A quantitative, specific, and sensitive method for the determination of N-acylhomoserine lactones (HSLs - a group of bacterial semiochemicals) in the form of their hydrolysis products (N-acylhomoserines, HSs) is presented. Real samples were analyzed by capillary zone electrophoresis-mass spectrometry (CZE-MS) after alkaline lactonolysis and extraction by mixed-mode anion-exchange solid-phase extraction. The presented cleanup significantly speeds up the HSL extraction procedure, strongly reduces sample consumption, and is more selective compared to the commonly used liquid/liquid extraction. Completeness of the hydrolysis reaction was examined by nuclear magnetic resonance spectroscopy. This CZE-MS method complements recently published capillary separation techniques (nano liquid chromatography-MS, partial-filling micellar electrokinetic chromatography-MS, gas chromatography-MS) and provides a possibility to differentiate quantitatively between the homoserines (as naturally occurring degradation products) besides the intact homoserine lactones. The method was found to be quantitative down to a concentration of 0.05 microg/mL (limit of quantification), while the limit of detection was determined with 0.01 microg/mL - sufficient for the analysis of culture supernatants.
Frommberger
Moritz
M
Institute of Ecological Chemistry, Rhizosphere Biology Group, GSF-Research Center for Environment and Health Neuherberg, Germany.
Hertkorn
Norbert
N
Englmann
Matthias
M
Jakoby
Sarah
S
Hartmann
Anton
A
Kettrup
Antonius
A
Schmitt-Kopplin
Philippe
P
D015107:4-Butyrolactone / Q000031:analogs & derivatives* / Q000032:analysis; D000468:Alkalies / Q000737:chemistry*; D000837:Anion Exchange Resins; D002852:Chromatography, Ion Exchange / Q000295:instrumentation / Q000379:methods*; D019075:Electrophoresis, Capillary / Q000379:methods*; D006868:Hydrolysis; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry / Q000379:methods*
D000468:Alkalies; D000837:Anion Exchange Resins; C088386:homoserine lactone; D015107:4-Butyrolactone