| High performance liquid chromatography (HPLC) method is widely used in pharmaceutical and environmental analysis for its high resolution and fast analyzing. But when it comes to those samples with complicate base or contain trace component, a pretreatment step will usually be imperative for purifying and enrichment. Traditional offline pretreatment method such as SPE or LLE consumes lots of solvent and takes long time. In addition either method will lead to partial loss of the compounds. So on-line pretreatment technique coupled with HPLC methods are created. On-ling SPE-HPLC method combines the advantages of both SPE and HPLC and gains extensive application in the analysis of organism sample and environmental pollutant.One convenient on-line SPE-HPLC method was established in this paper that enriching compounds by the analytical column. Thus this method was called on-column enrichment-HPLC. The new method was used for the analysis of several trace pollutant in water after its performance was assessed. The main content of this paper is summarized as follows:In chapter 2, On-column Enrichment-HPLC was established based on the summarizing of characters of On-ling SPE-HPLC methods and changing operation mode of HPLC. When enriching time and sample concentration was changed, good linear correlation was found between peak area and influence factors through investigation. And the correlation coefficient was 0.9996 and 0.9840 which indicate the method was able to enrich trace compounds quantificationally. In chapter 3, PAEs in water were analyzed by On-column Enrichment-HPLCmethod. The optimum analyzing condition for DMP was obtained after the investigation of each influence factor: water sample added with 5% methanol, enriched for 30 min under the flow rate of 0.6 mL/min, eluted with 60% methanol and detected under 240 nm. The LOD of DMP is 20ng/L under optimum analyzing condition. The concentration of DMP in lake water on the campus was detected as 0.3μg/L. On the other side, multi-component analysis has been attempt on the base of single component analysis.In chapter 4 and 5, four aromatic compounds and five phenols in tap water were analyzed by On-column Enrichment-HPLC method. The optimum analyzing condition for four aromatic compounds was: water sample added with 5% methanol, enriched for 20 min under the flow rate of 0.6 mL/min, eluted with 75% methanol and detected under 260 nm. And the optimum analyzing condition for five phenols was: water sample added with 5% methanol, enriched for 20 min under the flow rate of 0.6 mL/min, eluted with 65% methanol (added with 0.5% HAc) and detected under 280nm. LODs for nitrobenzene, benzene, chlorlbenzene and bromobenzene were 0.024, 3.346, 1.268 and 1.189μg/L. And LODs for p-nitrophenol, p-hydroxytoluene, o-nitrophenol, p-chlorophenol and 2,4-dichlorophenol were 20.8, 34.17, 18.96, 54.74 and 74.63 ng/L. Calibration curves were established and spiked tap water was detected. By the way, the anti-jamming capability towards surfactant and salt possibly contained in the sample of the new method was tested in chapter 5. At last, the investigation of three influence factors (enriching time, enriching flow rate and sample concentration) gave some directions for the enriching experiment.In short, the On-column Enrichment-HPLC method is convenient to operate, possesses good enriching effect and high resolution and is capable for the determination of trace pollutant in water.
|
PDF Full Text Request