No abstract

An improved procedure is outlined for the polarographic study of organic peroxides in a nonaqueous electrolyte solution. Polarograms were observed for 23 commercial organic peroxide compounds having the following functional peroxide groups: hydroperoxides, peroxy acids, peroxyesters, six-membered bicydic peroxides, diacyl peroxides, other diacyl peroxides, and ketone peroxides. Twenty-one of the compounds showed one or more characteristic reduction waves; they were placed in five groups based on different half-wave potentials.A linear relationship existed between diffusion current and concentration for all of the peroxides investigated

Conjugated fat-soluble vitamins, methylenic interrupted and conjugated fatty acids were polarographically investigated in both basic and neutral solvents. The half-wave potentials of all-trans-retinol, 13-cis-retinol, all-trans-retinyl acetate, all-trans-retinal, and Vitamin D(2) and D(3) were related to the number of double bonds in conjugation and their geometrical configuration. A minimum of three double bonds in conjugation and their geometrical configuration. A minimum of three double bonds in conjugation was required before reduction took place at the cathode, and as the number of conjugated bonds increased in the lipid compounds, the initial reduction wave took place at a lower half-wave potential.Investigation of conjugated double bonds in triglycerides and in alkali-isomerized linolenic and arachidonic acids gave reduction waves the half-wave potentials of which were related to the number of double bonds in conjugation. In both basic and neutral solvents there was a minimum of three double bonds in conjugation necessary to obtain a reduction wave at the dropping mercury electrode. Ultraviolet absorption curves of the prolonged reduction of polyunsaturated conjugated fatty acids indicate a step-wise reduction of each end of the polyunsaturated conjugated double bonds.In neutral solvent the log of the conjugated double bonds versus the half-wave potential (versus mercury pool anode) gave a linear equation, E(1)=2.98-1.6 log C. A proposed mechanism for the step-wise reduction of conjugated lipids is presented and discussed.

ure 1 is a polarogram of a solution containing 3.76 X 10~4M arsenic as arsenite ions, whereas curve B is a polarogram of the same solution but without arsenic. The increase in current of the solution containing the arsenite ions occurred earlier along the voltage axis than the solution containing no arsenite. This difference may indicate that the arsenite ions wrere reduced in this medium but that the polarographic wave was not formed because of the early reduction of the sodium ions present in the supporting electrolyte. This theory agrees with the work of Bayerle (2), who reported polarographic activity for arsenite ions in a sodium hydroxide solution.In the case of the lithium chloridelithium hydroxide electrolyte the lithium ions were not reduced until a potential of -2.1 volts had been reached as shown by curve C. This additional range permits full development of the arsenite wave.Logarithmic analysis of the polarographic curve indicated that it was irreversible. The same analysis indi-VOLTS (-]

The half-wave potentials of all-trans beta-carotene, all-trans retinol, 13-cis retinol, all-trans retinyl acetate, all-trans retinal, and vitamins D(2) and D(3) were related to the number of double bonds in conjugation. A minimum of three double bonds in conjugation was required before reduction took place at the dropping-mercury electrode. As the number of conjugated bonds increased in the fat-soluble vitamins, the initial reduction took place at a lower half-wave potential. All of the waves were linearly proportional to the concentration of the vitamins in the concentration range studied.