环境水样中三氟乙酸的分析

建立了环境水样中三氟乙酸(TFA)的分析方法. 环境水样加入内标物五氟丙酸后经旋转蒸发浓缩至约50 mL, 以2, 4-二氟苯胺作衍生化剂, N, N′-二环己基二酰亚胺作催化剂, 乙酸乙酯为溶剂, 进行衍生化反应. 三氟乙酸的苯胺产物经过一系列萃取、洗涤净化、浓缩定容等步骤后, 采用气相色谱-质谱进行分析. 该方法在0.61～24.4 μg/L范围内呈线性关系(R2＞0.997), 检出限1.8 ng/L, 加标回收率在79.3%～94.8%之间. 方法适用于环境水中的痕量TFA的分析.     

The Purification and Rapid Identification of Heavy Metal-binding Peptides of Water Hyacinth

This paper studies the rapid identification of heavy metal-binding peptides (phytochelatin) by taking Water Hyacinth as a model plant. Plants were cultured in water containing 2 μg/ml Cd2+ for 13 days. The Sephadex G-50 chromatography of root extract under low salt concentration (0. 01 mol/L PBS) gave a Cd-binding peak with MW of 10 ,000 determined by SEC HPLC. After oxidation with performic acid, its SEC HPLC molecular weight decreased to below 1300 and the reverse phase HPLC showed one peptide peak, whose amino acid composition is the same as that of the sample never undertaking oxidation, and (Glu/Gln):Cys:Gly=2:2:1. According to the general structure of phytochelatin (γ-Glu-Cys)n-Gly, n is 2 in this case. The protocol including the sequential steps of Sephadex G-50 chromatography→performic acid oxidation→reverse phase HPLC→amino acid analysis is a rapid and effective method to identify the existence of phytochelatin and determine its values of n.     

吹扫捕集/色谱-质谱法测定植物叶片中的单萜烯类化合物

植物叶片样品经甲醇浸提后, 用吹扫捕集/色谱-质谱法对其单萜烯含量进行了测定。对9种单萜烯甲醇浸提效率大于90%, 吹扫捕集效率大于99%, 甲醇中9种单萜烯含量在0.5~100.0μg/mL范围内质量浓度与响应值有很好的线性关系(r>0.99)。5 g鲜叶共用100 mL甲醇浸提并取20μL进样情况下, 9种单萜烯的方法检出限在1.1~2.7μg/g。方法简便, 可用于常温下叶片中单萜烯含量的快速准确分析。     

凤眼莲重金属螯合肽的分离纯化及快速鉴定

本文以凤眼莲为模式植物,研究植物重金属螯合肽的分离纯化及其快速鉴定。凤眼莲放养在含2μg/ml Cd~(2+)的水中诱导13天。组织抽提液在低盐浓度下(0.01mol/L PBS)经Sephadex G-50柱层析,得到一个含Cd的巯基峰,凝胶过滤HPLC表观分子量为10000。将此巯基峰用过甲酸氧化,凝胶过滤HPLC表观分子量降至1300以下,经反相HPLC分析只有一个肽峰。G-50 Cd-巯基峰与反相HPLC肽峰的氨基酸组成相同,均为(Glu/Gln):Cys:Gly=2:2:1。依据重金属螯合肽的通式(γ-Glu-Cys)_n-Gly,可知n=2。过甲酸氧化后,反相HPLC和氨基酸组成偶联分析是鉴定是否为重金属结合肽以及其n值的快速有效的方法。