热研88-13胶乳中乙烯释放量GC测定方法及其变化

摘要

探讨采用毛细管柱气相色谱法测定橡胶树胶乳中乙烯释放量的方法.并初步测定了首次割胶的胶乳中乙烯释放量和乙烯刺激割胶不同割次的乙烯释放量.试验用岛津GC2010型气相色谱仪,采用外标法,以保留时间定性,以峰面积定量,胶乳中乙烯释放量测定结果相对标准偏差(RSD)为1.08%,检出限为0.03μL·L~(-1).用气相色谱法测定橡胶树中胶乳的乙烯含量和生成速率有简便、快速、高效、准确、灵敏度高等优点.橡胶树采用乙烯利刺激(S/2d/2+3.0%ET),在涂药后第1～5割次的胶乳乙烯释放量分别为:18.62、9.86、3.40、4.90、3.65μL·L~(-1),而橡胶树首次割胶(对照)的胶乳中乙烯释放量为2.36μL·L~(-1);第1～5割次的胶乳乙烯生成速率分别为:2.83、1.53、0.50、0.67、0.54 nL·g~(-1)·h~(-1),而对照的为0.36 nL·g~(-1)·h~(-1).结果表明:经乙烯利刺激后,橡胶树胶乳中乙烯释放量和生产速率均呈双峰型变化趋势,其中涂药后第1割次的胶乳中乙烯释放量最高;橡胶树胶乳中乙烯释放量与乙烯生成速率呈极显著正相关.r=0.9997~(**).%Latex collected from rubber trees of Clone Reyan 88-13 at the first tapping prior to ethrel stimulation and at different tappings after ethrel stimulation were determined in terms of ethylene rate by using capillary gas chromatography (GC). The results showed that the relative standard deviation (RSD) of ethylene determination in latex was 1.08%,with the detectable level of gas chromatography being 0.03 μL/L by using Shimadzu GC2010 GC. The capillary gas chromatography was found easier,faster,more accurate and more highly sensitive in determining the ethylene content and ethylene producing rate in the latex of rubber tree than other methods. In the rubber trees tapped under ethrel stimulated system (S/2 d/2 +3.0% ET) ,the ethylene release rates in the latex from the 1st to the 5th tappings were 18.62,9.86,3.40,4.90 and 3.65 μL/L respectively,and that the ethylene producing rate in latex from the 1st to the 5th tappings were 2.83,1.53,0.50,0.67 and 0.54 nL/(g·h),respectively,whereas the ethylene release rate and the ethylene producing rate of the control without stimulation were 2.36 μL/L and 0.36 nL/(g·h),respectively. The experiment indicated that,after the rubber trees were stimulated by ethrel,the latex gave a bimodal change in both ethylene release rate and ethylene producing rate and had the highest ethylene release rate at the first tapping,and that the ethylene release rate in the latex had a highly significant positive correlation with the ethylene producing rate,(r=0.999 7~(**)) .