本论文报道了在典型配体乙二胺四乙酸(EDTA)和半胱氨酸(Cys)的存在下三角褐指藻(Phaeodactylum tricornutum)对镉(Cd)的富集机制和转化途径.毒性试验表明,两种配体均可有效降低Cd对三角褐指藻的毒性.ICP-MS分析结果表明,EDTA存在下细胞表面吸附和内部吸收Cd的量随着培养液中EDTA浓度的升高(自由Cd2+浓度的降低)而降低,基本符合自由离子活度模型(Free ion activity model,FIAM)的预测;而Cys存在时,细胞表面吸附Cd的量随着Cys浓度的增大呈现先增加后降低的趋势.在Cys浓度由空白浓度增加至4.45μmol/L时,细胞内部吸收Cd的量呈现增加趋势;而大于4.45μmol/L时,又趋于同一水平的现象,结果偏离FIAM.FTIR和XPS研究确证了细胞壁上的-OH和-NH2基团对Cd的吸附起主要作用.Cd胁迫后P.tricornutum细胞内诱导合成的植物螯合肽(PCs)的HPLC和ESI-IT-MS分析结果证实造成这两种配体对P.tricornutum积累和转化Cd行为产生不同影响的主要原因是Cys作为Cd2+的配体的同时,又是P.tricornutum细胞内PCs合成的前驱体之一.P.tricornutum细胞内PCs、氧化型PCs以及Cd-PC2的发现证明了Cd诱导P.tricornutum合成的PCs反过来钝化细胞内吸收的Cd,降低了其对P.tricornutum细胞的氧化毒性.
A novel reserved\|phase ion\|pair liquid chromatographic method using hexadecyltrimethylammonium bromide（HTMAB） as an ion\|pair reagent for separating the complexes of metal and 8\|hydroxyquinoline\|5\|sulphonic acid（HQS） coupled with on\|line fluorescence detection has been developed. The chromatographic behavior of metal\|HQS complexes in the proposed system was systematically investigated.When the C\-\{18\} column modified by HTMAB and the suitable mobile phase coupled with fluorescence detection（\%λ\%\-\{ex\}=388 nm; \%λ\%\-\{em\}=518 nm） were employed, the detection limit of cadmium is 7.72 ng/mL with an injection volume of 20 μL, and the linear range of calibration curve for cadmium is 50\800 ng/mL. It was successfully applied to determination of bio\|available cadmium in polluted soils of China. Moreover, the possible species of Cd\|HQS on the column has been investigated by log\|log plot analysis.
