硝酸银沉淀L-精氨酸的研究

Investigation on L-Arginine Precipitated by Silver Nitrate

以硝酸银为沉淀剂,用稀硝酸和热氢氧化钡调节pH值,沉淀溶液中的L-精氨酸。考察沉淀温度、pH值、硝酸银与L-精氨酸的摩尔比、L-精氨酸的初始质量浓度、和L-赖氨酸对硝酸银沉淀L-精氨酸的影响。结果表明,随着温度升高沉淀率略有下降;pH值在10.0以上时沉淀率明显增大,pH值至11.0时沉淀率达到最大,继续增大pH值沉淀率基本不再变化;硝酸银与L-精氨酸的摩尔比达到2.0时,沉淀率可达90.0%以上;L-精氨酸的初始浓度应大于10.0 g/L,沉淀率才可达90.0%以上;钠离子浓度对沉淀率基本无影响,但是当铵离子浓度或L-赖氨酸与L-精氨酸的质量比增大时,沉淀率迅速下降。最后,用2.0 mol/L盐酸溶解沉淀,过滤,滤液用高效毛细管电泳检测,并与L-精氨酸标准峰比较,结果表明沉淀中的L-精氨酸可初步分离出来。

L-arginine is precipitated when hot barium hydroxide is added to a solution containing arginine together with silver nitrate. Effects of temperature, pH, mole ratio of silver nitrate to L-arginine, initial L- arginine concentration, NH4^＋ and Na^＋ concentration and mass ratio of L-lysine to L-arginine on the yield of L-arginine precipitation were investigated. Results show that, temperature has little effect on the precipitation yield, the maximum precipitation yield is reached at pH higher than 11.0. The mole ratio of silver nitrate to L-arginine should be higher than 2.0 and the initial L-arginine concentration should be more than 10.0 g/L to keep over 90.0% precipitation yield. The precipitation yield hardly changes with the increase of Na^＋ concentration but decreases sharply with the increase of NH4 concentration and the increase of mass ratio of L- lysine to L-arginine. At last, we purified L-Arg from the precipitation using of 2.0 mol/L HCl, L-Arg of the solution was detected by HPCE.