Quantitative analysis of adenosine using liquid chromatography/atmospheric pressure chemical ionization-tandem mass spectrometry (LC/APCI-MS/MS)

Adenosine-secreting cellular brain implants constitute a promising therapeutic approach for the treatment of epilepsy To engineer neural stem cells for therapeutic adenosine delivery, a reliable and fast analytical method is necessary to quantify cell-based adenosine release Het e we describe the development, optimization and validation of adenosine measurement using liquid chromatography-atmospheric pressure chemical ionization-tandem mass spectrometry (LC-APCI-MS/MS) LC-MS/MS in positive ion mode used selected reaction monitoring at m/z of 268 2/136.1 and 302 2/1700 for adenosine and the internal standard. respectively The bias was within 15% of the nominal value and evaluation of precision showed a relative standard deviation lower than 15% for all measured concentrations The towel limit of quantification of adenosine was 156 ng/ml Freeze and thaw stability and processed sample stability also fulfilled the acceptance criteria Evaluation of the matrix effect showed that the method is not affected by relative matrix effects The major advantages of this method are the absence of an extraction phase and the combination of the high selectivity and sensitivity characteristic for the LC-MS/MS technique. with a short run time of 4 5 min These results demonstrate that this method is a useful tool to measure adenosine concentrations in culture medium released from stem cells in vitro. (C) 2010 Elsevier BV All lights reserved