Improved method to detect nitric oxide in biological systems

In this work an improved method is described for using organic solvent extr acting to detect nitric oxide. The partition coefficients of the diethylthi ocarbamate (DETC)-Fe2+ complex between different organic solvents and water , the signal intensity of the: same NO trapping complex concentration in di fferent organic solvents, and the extracting abilities of the organic solve nts were determined. It was found that ethyl acetate was the optimal organi c solvent. With ethyl acetate as extracting solvent, the (DETC)(2)-Fe2+-NO complex was extracted from water phase to organic phase, and low concentrat ion of nitric oxide in large volume could be detected by electron spin reso nance (ESR) at room temperature. The ESR signal intensity had a good linear relationship with the concentration of nitric oxide, at a signal-to-noise ratio of 2. The detection threshold of this method was improved to lower th an 50 nM, which was more sensitive than the usually used method. The (DETC) (2)-Fe2+-NO complex was stable in the dark at 0-4 degreesC, and there was l ittle change after days. Nitric oxide produced by cardiomyocytes cultured i n media and other biological systems was firstly detected with this method.