Study On Instrument Miniaturization And Analytical Methods For Elements Of As, Se, Sb, Sn

Element analysis is an important research area in analytical chemistry. Recently, trace analysis is gradually becoming one of the crucial aspects of element analysis in order to meet the increasing demands. Because it is hard to take large-scale instruments in the practical field investigation and research, miniaturization is one of the central areas and development directions of element analysis instrument.The aim of this research is to study the miniaturization of element analysis instrument and develop the analytical methods of trace elements (As, Se, Sb, Sn) which have received increasing attention. This dissertation describes a simple and fast detection technique based on gas-phase chemiluminescence for arsenic speciation, and a new hydride atomizer for atomic absorption spectrometry based on atmospheric pressure dielectric barrier discharge microplasma, which is applied to the determination of Se, Sb and Sn. The main contents of the present dissertation are as follows:1. This dissertation reports an on-line system based on high efficiency photooxidation and O3 gas-phase chemiluminescence detection technique, that can be employed for As(III), As(V), MMA and DMA determination. Using high efficiency photooxidation reactor, organic arsenic species (MMA and DMA) could be oxidized to As(V) in several seconds. Compared with other detectors, the present gas-phase chemiluminescence detector is small-sized and inexpensive. Detection limits were 3.7, 10.3, 10.2, 10.0μg/L for As(III), As(V), MMA and DMA, respectively. This determination system can be used to develop the miniature and portable analyzer for arsenic speciation.2. Trace elements Se, Sb, Sn have received increasing attention, and researchers need a small-sized determination instrument. The atomizer in atomic absorption spectrometry instrument has been improved in this dissertation. The electrothermal quartz atomizer was replaced with an atomizer based on atmospheric pressure dielectric barrier discharge microplasma. This atomizer offers the advantages of small-sized, low operation temperature and low power consumption in comparison with the electrothermal quartz atomizer. Results indicated DBD could be used for atomization of hydrides of Se, Sb, Sn. Detection limits were 0.6, 13.0, 10.6μg/L for Se, Sb, Sn, respectively. This study provides a possibility to design a fast, inexpensive, portable, miniature and mobile detector for field analysis for Se, Sb, Sn.