Capillary Diffusional Microtitration And It's Application

A novel micro-titration method was developed by using fused silica capillary column as volumetric micro-burette, acid-base titration and oxidation-reduction as the main types; both indicator and infrared detector were used to detect the end point. Combined with pre-distillation system, this technique had been applied to determine animonium ion in water and particles.The effects of many factors on diffusion rate were also studied. The results showed that the diffusion rates were only related with the inner diameter and length of capillary at the same level of reagent reservoir and magnetic stirring speed. In practical operation, diffusion rate may be simply changed by adjusting the length or inner diameter of capillary column to suit an appropriate determination.A micro-distillation device was also assembled, and the favorable distillation temperature and time were 600C and 45 mm, respectively. Comparison with the traditional pre-distillation device, it is simple in operation, lower operating temperature, only 1.0 ml sample needed and may be treated several samples simultaneously. Using this micro-device, ammonia distillation ratios were all over 92.0% and the mean recovery was 97.0%.By means of statistical calculation, the results obtained by diffusional mico-titration were correspondent to those by traditional titration.