Please use this identifier to cite or link to this item: http://scholarbank.nus.edu.sg/handle/10635/14784
Title: On-line pre-concentration techniques in capillary electrophoresis for environmental analysis
Authors: TU CHUAN HONG
Keywords: Capillary Electrophoresis, On-line Pre-concentration, Environmental Analysis, Nitrate, Haloacetic Acids, Phenoxy Acids, Phenols
Issue Date: 23-Sep-2005
Source: TU CHUAN HONG (2005-09-23). On-line pre-concentration techniques in capillary electrophoresis for environmental analysis. ScholarBank@NUS Repository.
Abstract: This work focused on the development of on-line sample pre-concentration techniques to improve detection sensitivity in capillary electrophoresis (CE) for environmental analysis. Several on-line enrichment methods were established for acidic compounds with various pKa values, including a strong acid (nitrate), weak acids (haloacetic acids, phenoxy acids, pKa 0.6-4.8) and very weak acids (phenols, pKa 7.5-10.6) in different sample matrices.In CE, the sample matrix plays an important role in developing on-line pre-concentration techniques. For enrichment of nitrate in seawater sample, a leading-type transient isotachophoresis was employed, in which natural chloride in the sample functioned as a leading ion. The co-ions in the background electrolyte (BGE) functioned as a terminating ion. Weakly acidic compounds (haloacetic acids, phenoxy acids and phenols) were usually dissolved in NaOH solution during off-line sample pretreatment. These compounds in NaOH solution were pre-concentrated with either a low-pH BGE or BGEs with weak bases as counter-ions.
URI: http://scholarbank.nus.edu.sg/handle/10635/14784
Appears in Collections:Ph.D Theses (Open)

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