Establishment And Application Of Valve Switching Technology In Ion Chromatograph

This paper aimed to study the valve switching technology in ion chromatograph. The corresponding valve switching process was designed according to the characteristics of the targeted samples, and the effectiveness was evaluated.'Pre'online sample neutralization ion chromatography technology was designed and developed to determine of trace chloride and bromide in TBAH. A good neutralization result was obtained by the application of'pre'pretreatment concept and accurate calculation of valve switching time window.A valve switching ion chromatography which could improve the detection limit by 20 times with the application of online sample neutralization, column concentration and online standard addition was further designed on the basis of'pre'online sample neutralization technology. The loop size, neutralization column and valve switching time were optimized, and online standard addition method was chose for quantitative calculation. The trace anions in alkaline air absorbing solution was separated to demonstrate the utility of this approach and the result showed that carbonate interference had been eliminated effectively. The separation was automatic, the result was accurate and the detected limit was extremely low.A two dimensional ion chromatograph approach which aimed to determine inorganic ion and organic gluconic acid with pulsed amperometric detection and conductive detection was designed and demonstrated. The analytes were switched from the first dimension to the second dimension with a switching-valve and a guard column without affecting the one-dimensional analysis of four inorganic anions. A good separation effect and linear was obtained. This approach provided a reference for the future design of two-dimensional ion chromatography.All the approaches studied in this paper was practical and original, and can be further promoted in the determination of the ions which were difficult to separate.