The characteristic properties of the chelating resin-3926(II) and the advantage of using it in the preconcentration procedure was described. The chemical recoveries determined by the trace technique were presented. The preconcentration procedure put forward in this paper may be used satisfactorily in neutron activation analysis.
Authors:J. Yao, F. Wang, L. Tian, Y. Zhou, H. Chen, K. Chen, N. Gai, R. Zhuang, T. Maskow, B. Ceccanti, and G. Zaray
Using TAM III multi-channel calorimetry combined with direct microorganism counting (bacteria, actinomycetes and fungi) under
laboratory conditions, we determined the microbial population count, resistance and activity toward cadmium (Cd(II)) and hexavalent
chromium (Cr(VI)) toxicity in soil. The thermokinetic parameters, which can represent soil microbial activity, were calculated
from power-time curves of soil microbial activity obtained by microcalorimetric measurement. Simultaneous application of the
two methods showed that growth rate constant (k), peak-heat output power (Pmax) and the number of living microorganisms decreased with increasing concentration of Cd and Cr. The accumulation of Cr on
E. coli was conducted by HPLC-ICP-MS. Cr6+ accumulation by Escherichia coli was increased steadily with increasing Cr6+ concentration. The results revealed that the change in some thermo-kinetic parameters could have good corresponding relationship
with metal accumulation. Our work also suggests that microcalorimetry is a fast, simple, more sensitive, on-line and in vitro
method that can be easily performed to study the toxicity of different species of heavy metals on microorganism compared to
other biological methods, and can combine with other analytic methods to study the interaction mechanism between environmental
toxicants and microbes.