Due to its strong ultraviolet absorption, high salt tolerance, and little interference in the low molecular weight region, N-(1-naphthyl) ethylenediamine dihydrochloride (NEDC) has been applied as a matrix to measure the level of glucose in rat brain microdialysates by matrix-assisted laser desorption/ionization mass spectrometry (MALDI MS) in combination with in vivo microdialysis. By monitoring the ion signals of (glucose + Cl)(-) in the mass spectra, we achieved a low detection limit of ~10 μM for glucose in 126 mM NaCl, which is a typical component in artificial cerebrospinal fluid, without prior sample purification. It is concluded that NEDC-assisted laser desorption/ionization (LDI) MS is a fast and general method for sensitive detection of small molecules (such as glucose and amino acids) in high ionic strength solutions.
© 2011 American Chemical Society