科研之友
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摘要
The determination of nitric oxide (NO) concentration in seawater medium by fluorometric method has been investigated based on the reaction that 2,3-diaminonaphthalene (DAN) can trapp NO to form the highly fluorescent, 2,3-naphthotriazole (NAT). The optimum conditions such as fluorometric determination conditions (lambda(ex) = 383 nm, lambda(em) = 410 nm), the influence of temperature and equilibrium time on the DAN trapping NO, and the influence of DAN solution on the trapping have been examined. The fluorometric intensity is linear with the NO concentration in the range of 1.4 - 1400 nmol/L with an r of 0.9985 (P <0.0001). The detection limit is 1 nmol/L (S/N = 3); the relative standard deviation is 1.6% (14 nmol/L NO); and there is no interference from the medium. Compared with fluorometric determination of NO concentration in NaOH medium, the method enhances one magnitude order of the detection limit. Combining the purging-trapping operation, the NO concentration of seawater in Shilaoren of Qingdao (36 degrees 05'46 '' N; 12 degrees 29'40 '' E) was detected to be (0.12 +/- 0.01) nmol/L. The method can also be applied to supervise the self-releasing NO change of sodium nitroprusside in seawater. The lower detection limit, high accuracy and good repeatability are the advantages of this method.
