Thesis (Ph.D.)--Chulalongkorn University, 2013

The automated on-line analysis systems coupled with membrane separation unit have been developed. The membrane separation units were designed for incorporation with automated on-line analysis systems. Two systems were proposed; (1) on-line hollow fiber membrane dialysis for determination of Fe(II) ion in fruit juices (2) on-line hollow fiber membrane liquid phase microextraction (HF-LPME) for determination of chromium ion in environmental samples. In the first system, the membrane separation unit was used as an on-line dialysis for screening off interferences in the juice samples before colorimetric determination of iron ion. The working range was at 3 to 30 mg/L. The system provided high sample throughput of 24 samples per hour without any sample pretreatment processes. The second system was proposed for determination of chromium ion by on-line HF-LPME. The system was developed for fully automation, where the hollow fiber membrane was conditioned for extraction, cleaned and regenerated for the next extraction, automatically. The working range was at 30 to 500 µ/L. It could be used for more than 100 times of analyses. Both membrane separation units were easy assembly, durable and cost effective.