Determination of perchlorate in river by electrospray ionization tandem mass spectrometry following ion-pair hollow-fiber liquid-phase microextraction

• Main Authors: Wen-tsen Chen, 陳玟岑
• Other Authors: Wang-Hsien Ding
• Format: Others
• Language: zh-TW
• Published: 2008
• Online Access: http://ndltd.ncl.edu.tw/handle/86862117820904784924

碩士 === 國立中央大學 === 化學研究所 === 96 === Perchlorate, ClO4?, is regarded as the most concerning inorganic contaminant in the USA and worldwide due to its high stability and interfering with iodide for uptake by the human thyroid because of their similar size. Currently, more and more reports have been published on the occurrence of perchlorate in different countries and various environmental matrices. Perchlorate can be considered as a widespread environmental contaminant. However, there is no data available in Taiwan, as there are many legal and illegal fireworks produced and set off in Taiwan, there could be perchlorate pollution in Taiwan. Recently, hollow-fiber liquid-phase microextraction (HF-LPME) technique has been developed to extract various organic pollutants from water samples. HF-LPME offers as a fast, simple and inexpensive sample preparation technique, which combines extraction, concentration and sample introduction into one step. However, HF-LPME has not been employed to extract inorganic contaminants from water samples. In this study, the effects of various operating parameters (i.e., extraction solvents, type and concentration of ion pair reagents, stirring speed, extraction temperatures and times) for the quantitative extraction of perchlorate by ion-pair HF-LPME were systematically investigated and optimized. Ion-paired perchlorate was then quantitated by tandem mass spectrometry coupled with direct electrospray (ESI-MS/MS) in negative ionization mode. The ion-paired perchlorate can be extracted by 60 ?L of octanol at 30 ?C with 40 min using di-n-hexylammonium acetate (5 mM) as the ion-pair reagent, stirring speed 300 rpm. The limit of detection (LOD) was 1 ?g/L and the limit of quantification (LOQ) was 3 ?g/L. Preliminary results show that no perchlorate residue was detected in the drinking water and bottle water samples collected in Taiwan. However, perchlorate residue was detected in some river water samples which collected near the explosion area of illegal fireworks via standard addition method. The concentrations of perchlorate in these samples were 6.3 and 130 ?g/L, and the correlation coefficient (r2) were 0.994 and 0.999, respectively. The analytical procedure developed herein demonstrated that the ion-pair HF-LPME and direct ESI-MS/MS methods are reliable, sensitive and offer a convenient analytical technique for trace determination of perchlorate in various water samples.