Study Voltammetry Research Articles

Employment of Voltammetry in Studies of Transport Processes across Artificial Phospholipid Membranes

AbstractThis paper reports on voltammetric methods applied in studies of transport processes connected with the occurrence of toxic cadmium in plants. As a means of transport across model of phospholipid membrane (PLM), calcium ionophore (calcimycin), cell‐penetrating peptides (transportan 10 and mastoparan), and finally protoplasts isolated from barley roots and leaves were used. Using calcimycin, different influences of Cd complexation by citric acid or by malic acid as examples of root exudates were documented. For transport of simplest phytochelatin PC2, voltammetric methods using formation of Hg complex on hanging mercury drop electrode (HMDE) or of Ag complex on mercury meniscus covered silver solid amalgam electrode (m‐AgSAE) were assessed.

Applications of voltammetry in studies of the speciation of heavy metals by organic chelators in sea water

Abstract The general conditions for the speciation of zinc and cadmium in sea water by nonlabile chelate species formed with components of dissolved organic matter (DOM) have been investigated using NTA as a model ligand with defined coordination chemical properties. The specific side effects of the salinity components on the chelation have been determined. The application of the very sensitive differential pulse anodic stripping voltammetry (DPASV) at the hanging mercury drop electrode (EMUE) enabled measurements at rather realistic overall trace metal levels of 3 × 10−9 M Cd(II) and 3.2 × 10−8 M Zn(II). Their chelation behaviour is compared with that of Pb(II). General conclusions on the chelation by DOM‐components of all three heavy metals in natural waters emerge. The with NTA obtained data establish a basis for prognostic estimates on the ligand concentrations required for the formation of chelates with medium stability, i.e. with common'conditional stability constants in the range of 1g K between 8 and 12. From these findings it can be concluded that with respect to the restricted DOM‐levels in major parts of the sea a number of DOM‐components can be ruled out as candidates for significant effects on the speciation of Cd(II), Zn(II) and Pb(II). In terms of methodology the study features the particular suitability of voltammetry for the investigation of heavy metal speciation in natural waters.

Polarography and voltammetry in studies of toxic metals in man and his environment

A brief introduction on sources, occurrence and fate of some toxic trace metals found in the natural environment is followed by a discussion of general methodological aspects from the trace chemical viewpoint. The versatile, significant and specific potentialities of advanced polarographic and voltammetric methods are compared with relevant non-electrochemical alternatives. They are subsequently demonstrated by a survey on representative applications, results and findings on problems from all types of environmental compartments and food chains to man, with emphasis on the toxic trace metals Cu, Cd, Hg, Pb, and also in certain matrices for Zn, As, Se, Tl and Bi. A final section is devoted to the particular potentialities of the electrochemical approach for speciation studies in natural waters at realistic trace levels of the dissolved toxic metals, e.g. Zn, Cd and Pb.