Browsing by Author "Msagati, Titus A. M."

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    Evaluation of the influence of lipophilic extractive residues on dissolving pulp quality parameters by partial least squares method of chemometrics
    (2014-12) Kilulya, Kessy; Mamba, Bhekie B.; Ngila, Jane C.; Bush, Tamara; Msagati, Titus A. M.
    Dissolving pulp samples collected from the various pulping stages of the acid-bisulphite process were analysed for the lipophilic extractive residues as well as their effects and influence on the quality parameters of dissolving pulp were evaluated. The results obtained using the partial least squares (PLS) regression model showed that sterols, fatty alcohol, saturated and unsaturated fatty acids significantly influenced/affected the viscosity, Kappa number and carbohydrates in the pulp. The PLS model clearly separated the analysed pulp in terms of the species of the raw materials and pulping stages. Furthermore, it was observed that lipophilic extractives are negatively correlated to the yield of α-cellulose. Sterols, fatty acids and alcohols negatively influenced glucose in pulp, while xylose was found to be positively correlated to these components. Generally, the components of lipophilic extractives that have a major influence on the quality parameters were found to be sterols and saturated fatty acids.
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    Imidazolium-Based Ionic Liquids as Solvents for Analysis of Lipophilic Extractives from Biomass
    (2015-05) Kilulya, Kessy; Mamba, Bhekie B.; Msagati, Titus A. M.
    Ionic liquids are organic salts made of cations and anions of which most of them are liquids at room temperature [1-3]. This is generally a newly emerging class of compounds which so far has been discovered to have numerous applications in chemistry [2] due to their attractive features such as negligible vapour pressure, high thermal stability, biodegradability, ability to solvate compounds of different polarity and miscibility with aqueous and organic solvents [4], [5]. Different classes of ionic liquids have been synthesised so far, such as, imidazolium, ammonium, pyridinium, isoquinolinium, sulfonium, phosphonium, pyrrolidium and others [6]. Since their discovery ionic liquids have raised a considerable excitement among researchers due to their ability to combine with different reagents in number of applications. The other aspect of ionic liquids is their ability to be recycled which minimizes the cost of usage as well as making them environmentally friendly. Ionic liquids so far have been used as solvents in different areas including for catalysis, synthesis and purification [6]. They have high ability of dissolving biopolymers such as cellulose and other biomass due to their ability to interact with biopolymer matrix forming hydrogen bonding [7] (Scheme 1).
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    Ionic Liquid-Based Extraction of Fatty Acids from Blue-Green Algal Cells Enhanced by Direct Transesterification and Determination Using GC x GC-TOFMS
    (2014-02) Kilulya, Kessy; Msagati, Titus A. M.; Mamba, Bhekie B.
    Blue-green algae commonly referred to as cyanobacteria are known to grow in freshwater bodies when they are provided with suitable growth conditions such as nutrients, temperature and light. Algae biomass is known to contain a large amount of lipids, such as saturated and unsaturated fatty acids. In this study, fatty acids from algal cells were extracted using a newly developed extraction protocol using ionic liquid enhanced by direct transesterification at an elevated temperature. The identification and quantification of fatty acids was performed using gas chromatography coupled to a time-of-flight mass spectrometer (GC × GC-TOFMS). The extracted fatty acids were dominated by those with carbon chain of C16 and C18; [i.e. 7-hexadecenoic acid (C16:1) and hexadecanoic acid (C16:0) for C16, whereas C18 includes γ-linolenic acid (γ-C18:3); linoleic acid (C18:2); linolenic acid (C18:3); 6,9,12,15-octadecatetraenoic acid (C18:4); oleic acid (C18:1) and octadecanoic acid (C18:0)]. The obtained fatty acid composition was then compared with that obtained by organic solvent extraction using a mixture of chloroform and methanol. Statistical evaluation was performed using one-way ANOVA and found that there was no statistically significant difference (P = 0.908) between the two extraction methods, a finding which indicates the usefulness of ionic liquid as a solvent to replace volatile organic solvent to minimize environmental pollution.