Ultrasound-assisted liquid-phase microextraction and high-performance liquid chromatographic determination of nitric oxide produced in PC12 cells using 1,3,5,7-tetramethyl-2,6-dicarbethoxy-8-(3′, 4′-diaminophenyl)-difluoroboradiaza-s-indacene

To reveal the function of nitric oxide (NO) that has been reported as an intracellular second messenger and a diffusible intercellular messenger, a novel ultrasound-assisted liquid-phase microextraction (ULPME) and high-performance liquid chromatographic method for the determination of NO produced in PC12 cells has been developed. 1,3,5,7-Tetramethyl-2,6-dicarbethoxy-8-(3',4'-diaminophenyl)-difluoroboradiaza-s-indacene (DAMBO-CO2Et) has been used for NO trapping to form corresponding triazole (DAMBO-CO2Et-T). The enrichment factor of DAMBO-CO2Et-T reached 150 in 2.5 min with the proposed ULPME method. NO produced in (200 +/- 5) PC 12 cells has been determined directly with the detection limit (S/N = 3) of 2.5 x 10(-13) mol/L (5 amol), which was the lowest in HPLC determination of NO reported yet. The proposed method was sensitive, selective, convenient and rapid, which has great prospect in the qualitative and quantitative determination of NO in minimal biological samples. (c) 2005 Elsevier B.V. All rights reserved.