Determination of aminopolycarboxylate complexes of transition metal (Mn²⁺, Cu²⁺ and Fe³⁺) in pulp by capillary zone electrophoresis (CZE-DAD)

Goje Tesfai, Tedros (2004-12)

Thesis (MSc)--Stellenbosch University, 2004.

Thesis

ENGLISH ABSTRACT: The determination of the concentrations of the transition metals Mn2 +, Cu2 + and Fe3 + in various types of pulps was carried out using a combination of chelation with Ethylenediaminetetraacetic acid (EDTA) and ethylenediaminedisuccinic acid (S,SEDDS) and capillary zone electrophoresis (CZE) coupled with diode array uvdetection. The metals were found to be inhomogeneously distributed in the pulps, and therefore a relatively large (20 gms) pulp samples were taken for analysis. Heating the pulp samples at 45°C with stirring for three hours was used to leach the metals into an aqueous phase for complexation with the ligands. Leaching with EDTA enabled the quantitative determination of 0.0091,0.0048 and 0.0014 mM Cu2 + and 0.0088, 0.0012 and 0.0016 mM Mn2 + in the three types of pulps analyzed respectively while detection of Fe3 + was not possible using EDTA. The use of [S,S-EDDS] as the leaching agent on the other hand enabled the quantitative determination of 0.0041, 0.0036 and 0.0031 mM Cu2+ and 0.0024, 0.0018 and 0.0047 mM Fe3+ in the three types of pulps analyzed respectively while determination of Mn2 + was not possible using [S,S-EDDS] as the leaching agent. [S,S-EDDS] was generally better in complexing iron and copper than EDTA. The leaching procedure employed and the detectors response to specific analytes formed were found to be the most important factors in the analysis of the metals in pulp.

AFRIKAANSE OPSOMMING: Die konsentrasies van die oorgangsmetale Mn2 +, Cu2 + and Fe3 + in verskeie tipes pulp is bepaal met behulp van 'n kombinasie van kelasie met etileendiamientetra-asynsuur (EDTA) en etileendiamiendisuksiensuur (S,S-EDDS) en kapillêre elektroforese (CE) gekoppel met UV-deteksie. Daar is bevind dat die metale oneweredig versprei is in die pulp monsters, en gevolglik is relatiewe groot (20 g) monsters gebruik vir die analiese. Die metale is ge-ekstraeer deur kompleksasie met die kelasie-agente in die water-fase, deur die pulp monsters vir drie uur te roer by 45°C. Ekstraksie met EDT A is gebruik om 0.0091,0.0048 en 0.0014 mM Cu2 + en 0.0088,0.0012 and 0.0016 mM Mn2 + in drie tipes pulp te bepaal, terwyl Fe3 + nie waargeneem is met behulp van EDTA nie. Deur [S,S-EDDS] te gebruik as ekstraksie-agent, is 0.0041, 0.0036 en 0.0031 mM Cu2+ en 0.0024, 0.0018 en 0.0047 mM Fe3+ in die drie tipes pulp waargeneem. Die analise van Mn2 + was nie moontlik met die metode nie. Daar is gevind dat die keuse van ekstraksie metode en die detektor-sensitiwiteit vir spesifieke metale die mees bepalende faktore in die analise van metale in pulp monsters is. EDDS was 'n beter keiaat vir Fe3 + en Cu2 + as EDTA.

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