OBJECTIVETo establish a method to determine underivatized endogenous amino acids in brain tissues after cerebral ischemia based on RRLC-QQQ.

METHODDiamonsil chromatographic column C18 (4.6 mm x 250 mm, 5 microm) was adopted to determine 12 amino acids in 15 min, with acetonitrile-0.1% formic acid for gradient elution. The flow rate was set at 0.5 mL x min(-1). With ESI as the ion source, positive ion scanning mode was adopted for multi-reaction monitoring.

RESULTEach amino acid standard curve (AAs) showed good linear relationship within the detection range (r > 0.996), with the limit of detection of less than 11%, the limit of quantitation of less than 3.09 microg x L(-1). The RSD of intra- and inter-day precisions at high, middle and low concentrations were less than 11%.

CONCLUSIONThe determination results of actual samples showed that compared with the levels of AAs of the sham operation group, all of the remaining amino acids apart from N-acetyl-aspartate increased in brain tissues. Some amino acids showed significant changes in a time-dependent manner after the operation. The method is so simple, rapid and sensitive that it can be used for finding biological metabolite markers of cerebral ischemia, and exploring cerebral ischemia molecular mechanisms and synergistic mechanism of combined administration of multi-component traditional Chinese medicines.