提出了一种新型的基于半透膜被动采样技术的微萃取方法(semi-permeable membrane based micro-extraction,SPM-ME),并以菲为模型污染物,测试了SPM-ME用于测定土壤间隙水中自由溶解态憎水性有机污染物的可行性。结果表明,菲在该SPE-ME装...提出了一种新型的基于半透膜被动采样技术的微萃取方法(semi-permeable membrane based micro-extraction,SPM-ME),并以菲为模型污染物,测试了SPM-ME用于测定土壤间隙水中自由溶解态憎水性有机污染物的可行性。结果表明,菲在该SPE-ME装置与水相间的平衡可在6h内达到,并且随着装置中三油酸甘油酯含量的增加,单元SPE-ME对于菲的富集系数也相应增加。该装置对土壤间隙水中菲的富集在10d内能达到平衡,整个过程主要受菲从土壤向间隙水的传质控制。该装置测得间隙水中菲的浓度与实际测得间隙水浓度十分吻合,而由传统的相平衡分配法计算所得间隙水浓度则高出实测值4～5倍。同时,该装置对体系中污染物的耗竭小于体系中污染物总量的1%。因此,SPE-ME是一种准确、有效、非耗竭式的微萃取技术。展开更多
A generally accepted method for predicting the bioavailability and transfer of cadmium(Cd) from soil to plants has not yet been established. In this study, the diffusive gradients in thin films(DGT) and conventional e...A generally accepted method for predicting the bioavailability and transfer of cadmium(Cd) from soil to plants has not yet been established. In this study, the diffusive gradients in thin films(DGT) and conventional extraction methods for metal fractions were used to investigate how effective these methods were at predicting Cd bioavailability to ryegrass(Lolium perenne) and to assess whether these holistic variables were independent of the soil property variables. The influences of soil properties on the predictive capabilities of the different methods were evaluated using multivariate statistics. The Cd concentrations in the shoots and roots of ryegrass correlated more closely with the effective Cd concentration measured by DGT(CE), compared with those with soil total Cd, pore water Cd, and ethylenediaminetetraacetic acid disodium salt(Na2EDTA)- and acetic acid(HOAc)-extractable Cd. When soil properties were included in a stepwise multiple linear regression, Cd transfer to L. perenne was negatively influenced by p H and positively influenced by organic matter(OM). The multivariate statistics showed that the adjusted correlation coefficients for the plots involving soil total Cd, pore water Cd, and Na2EDTA- and HOAc-extractable Cd had been significantly improved after considering the influences of soil properties, which suggested that these methods were p H and OM dependent. For CE, the relationship was p H independent or only dependent in strongly acidic soils. These results suggested that the main soil factors affecting bioavailability had the lowest impact on the DGT technique. Therefore, the DGT technique provided significant advantages over conventional methods when assessing Cd bioavailability.展开更多
文摘提出了一种新型的基于半透膜被动采样技术的微萃取方法(semi-permeable membrane based micro-extraction,SPM-ME),并以菲为模型污染物,测试了SPM-ME用于测定土壤间隙水中自由溶解态憎水性有机污染物的可行性。结果表明,菲在该SPE-ME装置与水相间的平衡可在6h内达到,并且随着装置中三油酸甘油酯含量的增加,单元SPE-ME对于菲的富集系数也相应增加。该装置对土壤间隙水中菲的富集在10d内能达到平衡,整个过程主要受菲从土壤向间隙水的传质控制。该装置测得间隙水中菲的浓度与实际测得间隙水浓度十分吻合,而由传统的相平衡分配法计算所得间隙水浓度则高出实测值4～5倍。同时,该装置对体系中污染物的耗竭小于体系中污染物总量的1%。因此,SPE-ME是一种准确、有效、非耗竭式的微萃取技术。
基金supported by the China Postdoctoral Science Foundation (No. 2013M530783)the Research Foundation for Advanced Talents of Qingdao Agricultural University, China (No. 6631115029)
文摘A generally accepted method for predicting the bioavailability and transfer of cadmium(Cd) from soil to plants has not yet been established. In this study, the diffusive gradients in thin films(DGT) and conventional extraction methods for metal fractions were used to investigate how effective these methods were at predicting Cd bioavailability to ryegrass(Lolium perenne) and to assess whether these holistic variables were independent of the soil property variables. The influences of soil properties on the predictive capabilities of the different methods were evaluated using multivariate statistics. The Cd concentrations in the shoots and roots of ryegrass correlated more closely with the effective Cd concentration measured by DGT(CE), compared with those with soil total Cd, pore water Cd, and ethylenediaminetetraacetic acid disodium salt(Na2EDTA)- and acetic acid(HOAc)-extractable Cd. When soil properties were included in a stepwise multiple linear regression, Cd transfer to L. perenne was negatively influenced by p H and positively influenced by organic matter(OM). The multivariate statistics showed that the adjusted correlation coefficients for the plots involving soil total Cd, pore water Cd, and Na2EDTA- and HOAc-extractable Cd had been significantly improved after considering the influences of soil properties, which suggested that these methods were p H and OM dependent. For CE, the relationship was p H independent or only dependent in strongly acidic soils. These results suggested that the main soil factors affecting bioavailability had the lowest impact on the DGT technique. Therefore, the DGT technique provided significant advantages over conventional methods when assessing Cd bioavailability.
