Metabolic profiling of mouse cerebrospinal fluid by sheathless CE-MS

Anal Bioanal Chem. 2012 Dec;404(10):2895-900. doi: 10.1007/s00216-012-6431-7. Epub 2012 Oct 7.

Abstract

The need for sensitive analytical technologies applicable to metabolic profiling of volume-restricted biological samples is high. Here, we demonstrate feasibility of capillary electrophoresis (CE) coupled to electrospray ionization mass spectrometry (MS) with sheathless nano-electrospray interface for non-targeted profiling of ionogenic metabolites in body fluids of experimental animals. A representative mixture of the metabolites and body fluids of mice such as cerebrospinal fluid (CSF), urine and plasma were used as examples of low-volume biological samples for method evaluation. An injection volume of only 9 nL resulted in limits of detection between 0.7 and 12 nM for the metabolite mixture. The method allowed the detection of ~350 molecular features in mouse CSF (an injection volume of ca. 45 nL), while ~400 features were observed in mouse plasma and ~3,500 features in mouse urine (an injection volume of ca. 9 nL). The low-volume body fluid samples were analyzed directly after only 1:1 dilution with water, thereby fully retaining sample integrity, which is of crucial importance for non-targeted metabolic profiling. As little is known about the metabolic composition of mouse CSF, we identified a fraction of the molecular features in mouse CSF using accurate mass information, migration times, MS/MS data, and comparison with authentic standards. We conclude that sheathless CE-MS can be used for sensitive metabolic profiling of volume-restricted biological samples.

MeSH terms

  • Animals
  • Cerebrospinal Fluid / chemistry
  • Cerebrospinal Fluid / metabolism*
  • Electrophoresis, Capillary / methods*
  • Male
  • Metabolome*
  • Metabolomics / methods*
  • Mice
  • Mice, Inbred C57BL
  • Spectrometry, Mass, Electrospray Ionization / methods*