In this thesis mass spectral and chromatographic techniques were developed and applied to identify and characterise numerous novel platinum(II) and (IV) compounds designed as anticancer agents. In a novel method for the synthesis of cis-oxalato(trans- -1,2- cyclohexanediamine)platinum(II) or oxaliplatin these techniques could be applied to differentiate between the molecular complex and the autoionised analogue (viz. Ptdach2 2+Ptox2 2-). In another novel synthetic method for the same compound the ligand exchange reactions at various temperatures could be investigated and kinetic curves obtained served to illuminate the chemistry involved, indicating the role of small amounts of water in the essentially non-aqueous solvent systems dmf and isoamyl alcohol respectively. These allowed ligand exchange without resulting in hydrolyses even up to 85°C. The ionisation rate of divalent platinum halide complexes was determined for various amine ligands as well as N-S chelate ligands. A comparison of these could suggest why N-S complexes have poor anticancer action. Ionisation was not only studied for neutral molecular species but also for monocationic ones. Relationships could be found with stereochemical aspects of the chelates used. By investigating results of EV-CAD studies thermodynamic data could be obtained which indicated that bond strength decreases from chloro to iodo analogues although extent of ionisation in aqueous solution, i.e kinetic stability, is the reverse. Products formed by the reaction of NO2 gas with Platinum(II) compounds could be identified and separated which greatly contributed to the understanding of the chemistry involved in the formation of mononitro platinum(IV) complexes. Some of these proved to have exceptional anticancer properties. Studies of the interaction of thiol containing biomolecules were performed as a function of time. The results contributed to the understanding of the action of the anticancer agents.

The effects of transition metal ions as components of the mobile phase on the retentions in HPLC of 2-aminophenol and selected α-diketones were studied on both ODS-silica and porous polymer columns. The compounds were used as model compounds in an investigation which set out to derive a detailed understanding of the mechanisms Involved when metal ions are used to selectively modify the retention of compounds capable of interaction. This technique, which has parallels with ion-pair chromatography, provides another method by which the conditions of a separation may be altered and the selectivity adjusted to give better resolution.

Two samples of gum supposedly obtained from Sapotaceae achras and named "sapote gum" were studied using the methods of partition chromatography. The two samples were proven to be entirely different in composition and to constitute in fact two separate and distinct gums. The previously unreported gum was characterized and shown to contain D-xylose, L-arabinose, D-galactose, and one or more glucuronic acids, including some methoxy-glucuronic acid. A new spray reagent was developed for paper chromatography of the sugars, and a novel technique used for making permanent photographic prints of the papergrams. Crystalline sugars were obtained from hydrolysates in pure form by separation on partition columns of powdered cellulose. / Science, Faculty of / Chemistry, Department of / Graduate

Studies in the general field of gas chromatographic analysis have been made and some of the methods developed have been applied to a kinetic investigation of the reactions of methyl radicals with butene-1. In Part I the developments in the field of gas chromatography are described. An all-metal thermal conductivity cell with platinum sensing elements has been designed and constructed. Excellent compensation for the resulting changes of flow rate of the carrier gas was attained in analyses with rising column temperature. The use of thermistors as sensing elements in such cells was also studied. The influence of polarity of the stationary phase on relative retention volumes in gas partition chromatography was investigated in conjunction with the analysis of a complex mixture of organic sulfur compounds. Satisfactory separations of hydrogen sulfide, methyl mercaptan, ethyl mercaptan, methyl sulfide, propyl mercaptan, ethyl sulfide, thiophene and dimethyl disulfide were obtained. Isopentane and n-pentane were included for purposes of comparison. Irregularities were observed in relating retention volumes to boiling points for some of these compounds. Reversal of normal elution order within groups of compounds with different columns was related to the polarity of the column and the polarisability of the eluents. A high-sensitivity ionization gauge detector for gas chromatography was developed. By keeping the grid potential below the ionization potential of helium the device is sensitive only to the eluted compounds in the gas stream. Sensitivities from 100 to 500 times greater than those of thermal conductivity cells were observed. Only a small fraction of the gas stream emerging from the column is sufficient for detection purposes, and the device is insensitive to temperature and flow rate changes. Significant advantages may be obtained from the application of the newly developed ionization gauge detector to displacement chromatography because of the possibility of distinguishing between isomeric organic compounds. Results obtained with gas chromatographic methods without the use of a carrier gas are reported. A partial separation of a mixture of volatile organic compounds was obtained. The ionization gauge detector may be useful in the development of this method. In Part II the results obtained from the reaction of methyl radical with butene-1 are described. Alumina, squalane-pelletex, and tricresyl phosphate columns were used for the gas chromatographic analysis. Mass spectrometric identification of products was done where necessary. In the temperature range 160 to 220°C with di-t-butyl peroxide as the methyl source the following reaction products were identified: methane, ethane, 3-methyl-butene-1, pentene-2, n-pentane, isopentane, 3-methyl-pentane, and acetone. A mechanism accounting for the formation of these products and supported by kinetic evidence is presented. The butenyl and pentyl radicals formed in the reaction are stable near 200°C. Butenyl radical does not abstract hydrogen from butene-1 near 200°C, but combines with methyl to yield pentene-2 and 3-methyl-butene-1. The energy of activation for the formation of 3-methyl-butene-1 is from 2 to 4 kcal/mole higher than for the formation of pentene-2. Hydrogen abstraction by pentyl radicals from butene-1 gives n-pentane, and isopentane. The reactivity of the branched radical •CH₂CH[CH₃]CH₂CH₃ in hydrogen abstraction is twice as great as that of the straight chain radical CH₃CH₂CHCH₂CH₃. From material balances obtained it was found that 60 to 80% of butenyl, and from 7 to 30% of pentyl radicals are removed from the system by reactions other than combination with methyl and hydrogen abstraction in the case of pentyl. The disproportionation of pentyl radicals to pentane and pentene was unimportant in the present system. At 450 and 492°C methyl radicals do not sensitize the formation of the cyclic reaction products which were observed by other workers in the unsensitized pyrolysis of butene-1 at temperature near 500°C. The main reaction product of methyl with butene-1 at 450 and 492°C was found to be butene-2. The isomerization to butene-2 in the unsensitized reaction is a chain process with chain length increasing with temperature reduction. The mechanism of the chain reaction of isomerization is postulated to be: CH₂=CHCH₂CH₃ → CH₃ • + CH₂ = CHCH₂ • / CH₃ • + CH₂=CHCH₂CH₃ → CH₂=CHCHCH₃ + CH₄ / CH₂=CHCHCH₃ ↔ •CH₂CH=CHCH₃ / •CH₂CH=CHCH₃ + CH₂=CHCH₂CH₃ → CH₃CH=CHCH₃+ CH₂=CHCHCH₃. The chain length at 450°C was found to be 12.6, and at 492°C as 2.3. / Science, Faculty of / Chemistry, Department of / Graduate

A study was made on the back mixing or circulation in the continuous phase of a spray type liquid-liquid extraction tower. Concentration profiles of both continuous and dispersed phases were obtained by internal sampling. Mass transfer data are presented for the transfer of acetic acid between water and methyl isobutyl ketone in the 1.5-in. I.D. columns of three different heights. Considerable circulation in the continuous water phase was observed which resulted in the reduction of the driving force for mass transfer. A driving force correction factor, F(m), was obtained from the H.T.U. data using a simplified picture of behaviour at the interface. The height of the tower did not seem to have any effect on F(m). The overall H.T.U. values, obtained from the experimental profiles, were correlated with the flow rates. The end effect due to the agitation and coalescence of the drops at the interface was measured. This end effect was correlated with the overall capacity coefficients and the dispersed phase flow rates. / Applied Science, Faculty of / Chemical and Biological Engineering, Department of / Graduate

Patterns of flavonoid and melanic pigmentation were studied by visual and qualitative chemical means in 20 varieties of cultivated barley. Two new techniques, one manual and one chemical, were developed which made possible the study of the pigments in the separate tissues of the caryopsis. The observation that anthocyanins are localized in the spermoderm and not in pericarp is an example of the usefulness of the techniques. Environmental modifications of pigmentation patterns in varieties and in individual plants are large and biochemical and genetical analyses of patterns are thereby greatly complicated. For example, pelargonidin derivatives were regularly produced in field grown plants but not in greenhouse grown plants. Genes which control pigment production and disappearance during development add to the complexity of pigment patterns. Colors which are visually very similar may be biochemically dissimilar. Leucoanthocyanins occur in aleurone and endosperm but do not occur at any stage in pericarp, spermoderm, or other maternal tissues. In aleurone, which is alkaline, anthocyanins occur as anhydro bases. In aleurone, also, and in certain other tissues, such as the hood veins of the black variety Gatami, anthocyanins may occur as pseudo bases. In young aleurone tissue, anthocyanins are largely free and minor amounts are tissue bound; later in development most are tissue bound. At any stage of development anthocyanins in aleurone are difficult to extract because the nucellar epidermis, alone or with the aleurone envelope, is highly impermeable to most solvents. Biochemical differentiation of anthocyanins, using accepted techniques of extraction and processing, and using paper chromatography, was undertaken for varieties, lines and tissues. Support and extension of earlier genetical study is given. Biochemical phenotypes could be differentiated from basal leaf sheath extracts when visual phenotypes could not be. In varieties such as Black Hulless, anthocyanins from aleurone were largely delphinidin and petunidin derivatives while those from spermoderm were largely derivatives of cyanidin and peonidin. Anthocyanin patterns from different maternal tissues of a single plant were similar but some seasonal variations were recorded. Anthocyanin patterns in varieties, with very different breeding such as Gopal and Black Hulless, even when grown under a variety of environments, were similar and pointed to parallel genetical control of color. Three new anthocyanins with novel characteristics were found in young, but not in mature, caryopses; an outstanding property was their rapid movement on chromatopaper when BAW was the solvent. Whether or not their frequent disappearance was due to inherent instability or was a normal feature of development was uncertain. In some varieties and tissues at least it was established that cyanidin derivatives form first and pelargonidin and/or peonidin derivatives form later. Qualitative associations in development of polyphenols, anthocyanins and melanins were noted. In future, studies of anthocyanins in development would be greatly aided if the experimental barley was grown in constant environments. Detailed characterization of the anthocyanins of barley was made difficult by the complexities of the color patterns and by their instability when commonly accepted processing procedures were used. Most of the anthocyanins of barley were complex and split readily into simpler components. Ninety-three isolates were obtained from basal leaf sheaths and caryopses; some isolates split into as many as 5 components while others did not split. The anthocyanidins of 63 anthocyanin isolates, run against known anthocyanidins, were identified by Rf values obtained in 7 solvents and by spectra; 39 isolates were hydrolyzed for sugar analyses and 25 were hydrolyzed partially for structural elucidation. Many anthocyanins were crystallized and many were rather fully characterized. Many of the anthocyanins of barley are new and had not been reported for other species. New techniques were devised to achieve anthocyanin stability and to enable work with micro amounts of tissue from single hybrid plants. It was shown that evaporation to dryness of extracts in 1% methanolic HC1, a common procedure, is a very serious, but not the single, cause of anthocyanin degradation; certain anthocyanins show a degradative spectral peak ca. 360 mu attributed provisionally to that of chalcones and most show splittings. Clamping and sewing of chromatobands directly to new paper avoided elution and flash evaporation in methanolic HC1. Modification of existing spectral technique also permitted the examination of even very weak anthocyanin bands on paper. Employment of very weak (0.03%) methanolic HCl in procedures was useful. Although the problems of anthocyanin lability were reduced by modifying older procedures and devising new techniques, they were not eliminated. Evidence was obtained finally which showed that anthocyanins are best extracted in neutral methanol as pseudo bases rather than, as is customary, in acidified methanol, as flavylium salts. Not only were techniques devised for anthocyanin stability, they were also devised for handling micro extracts from single plants. Time and materials were conserved in techniques for hydrolysis, concentration, purification and characterization on paper. Complementary equipment for banding and hydrolysis on paper was developed. New solvents for anthocyanidin chromatography greatly aided characterization. Hydrolyses of eluates both from anthocyanins and blank chromatopaper yielded glucose, galactose, xylose and arabinose; a method to remove paper-derived sugar artefacts from chromatographically purified anthocyanins is presented. Additionally, it was found that glycosidic hydrolysis of anthocyanins occurs even on chromatopaper and that the so-called irreversibly adsorbed anthocyanins of many investigators are anthocyanidins. Moreover 'glycosidic' hydrolysis of certain barley anthocyanins, even in crystalline state, to simpler anthocyanins, is the basis of anthocyanin splitting and explains the appearance of the complex chromatoband patterns. Other investigators have also found in other species complex patterns but have assumed them to be in vivo patterns. If biochemical responses to gene action and biogenesis of anthocyanins are to be studied precisely in barley, procedures must avoid artefact production during extraction and processing and yield anthocyanins in their in vivo state. / Land and Food Systems, Faculty of / Graduate

No description available.

No description available.

A sodium fusion-Ion chromatographic method for determination of fluorine, chlorine, bromine, and iodine in organic compounds is described. Seventeen organic halogen compounds and eleven mixtures were decomposed by Na fumes at 280-290°C for one hour or longer. The absorbing solutions were injected for ion chromatographic analysis using electrochemical and conductometric detectors. The arrangement of the apparatus includes the placement of the electrochemical and conductometric detectors. This method provides a mechanism providing for complete analysis for all four halogens in one ion chromatographic sample injection. Reproducibility is excellent and liquid sample handling is mentioned.

Several chromatographic and spectroscopic techniques were applied to Suwanne River reference fulvic acids (FA) and their permethylated derivatives. Retention mechanisms, structural characteristics, and thermal stabilities of FA and its derivatives and fractions were evaluated.