核糖核酸与中性红作用机理及含量测定的研究

研究了在弱酸性介质中小分子中性红与生物大分子核糖核酸强烈相互作用，导致分子构象的变化，引起分子光谱最大吸收波长和吸光度的变化。应用光谱法研究了反应体系酸度、缓冲溶液用量、中性红用量、反应时间对反应速度的影响，确定了实验最佳条件，提出并建立了测定核糖核酸的新方法。线性范围为0～9.0 μg·mL-1,检出限为0.10 μg·mL-1,相关系数r为0.999 8。实际样品测定，结果满意。初步探讨了反应机理，认为静电缔合作用使中性红分子与凝聚在RNA分子链上的反离子交换，然后，以协同方式与RNA分子发生键合，使中性红平面共轭芳香结构受到破坏，π-电子叠合程度降低，吸光度降低，最大吸收波长紫移。

Studies on the Interaction between RNA with Neutral Red and Determination of RNA by Spectrophotometry

An analytical method for the determination of ribonucleic acid by spectrophotometry was established. At the maximum absorption wavelength for neutral red in B-R buffer solution, and under the best conditions, the decrease in the absorbance was linear with the amount of ribonucleic acid. The linearity range was 0.0-9.0 microg x mL(-1), the detection limit was 0.52 microg x mL(-1), and the correlation coeffient was 0.999 8. This method was simple, rapid, and selective. So its application to the determination of ribonucleic acid was satisfactory. The reaction mechanism was that the electrostatic interaction leads to molecular association of RNA with neutral red, resulting in anti-ion permutation and bonding reaction.