Speciation Analysis of Cadmium in Indian Mustard (Brassica Juncea) by Size Exclusion Chromatography-High Performance Liquid Chromatography-Inductively Coupled Plasma Mass Spectrometry

The method based on the coupling of size-exclusion high-performance liquid chromatography with inductively coupled plasma-mass spectrometry was used for speciation analysis of cadmium binding nonprotein thiols in extracts of Indian mustard (Brassica Juncea). In the presence of Cd stress, Phytochelatins (PCs) were induced, and Cd ions in extracts were associated with the induced PCs. Four different Cd species of PC3-Cd, PC2-Cd, GSH-Cd, and Cys-Cd were detected in samples, which demonstrated that PCs were enzymatically synthesized from glutathione (GSH, Glu-Cys-Gly) by the constitutive enzyme PC syntheses. The results indicated that GSH-Cd exists as the main specie in leaf samples, whereas PC2-Cd is the main specie in root samples. A nonoxidizing (Nitrogen) preparation environment and a −70°C preservation condition were used to avoid the oxidation of sulfhydryl groups.