Determination of betaine metabolites and dimethylsulfoniopropionate in coral tissues using liquid chromatography-time-of-flight mass spectrometry and stable isotope-labeled internal standards.
A convenient procedure for determination of seven betaine analogs and dimethylsulfoniopropionate (DMSP) in extracts of coral tissues using LC-MS stable isotope dilution is described. Extraction procedures were optimized for selective extraction of polar metabolites from coral tissues. The LC-MS protocol employed a pentafluorophenylpropyl (PFPP) column for HPLC separation, with chromatographic resolution of isobaric and isomeric zwitterionic metabolites optimized by adjusting the acidity of the mobile phase. A ternary gradient was used to exploit the unusual retention characteristics of cationic metabolites on the PFPP column, with incorporation of ammonium acetate in a later gradient stage promoting elution of more hydrophobic betaines which are retained at high organic content in the absence of ammonium acetate. We demonstrate that the new LC-MS based method provides accurate measurements from nanomolar to high micromolar concentrations, and can be applied for profiling of betaine metabolites and DMSP in corals or other aquatic organisms.
Li
Chao
C
Department of Chemistry, Michigan State University, East Lansing, MI 48824, USA.
Hill
Richard W
RW
Jones
A Daniel
AD
D000596:Amino Acids; D000818:Animals; D037421:Anthozoa / Q000737:chemistry*; D001622:Betaine / Q000032:analysis* / Q000737:chemistry; D002853:Chromatography, Liquid / Q000379:methods*; D007553:Isotope Labeling; D016014:Linear Models; D012015:Reference Standards; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*; D013452:Sulfonium Compounds / Q000032:analysis* / Q000737:chemistry
D000596:Amino Acids; D013452:Sulfonium Compounds; D001622:Betaine; C068078:dimethylpropiothetin