Simple and selective method for determination of iodide in pharmaceutical products by flow injection analysis using the iodine-starch reaction

• Main Authors: Nacapricha D., Uraisin K., Ratanawimarnwong N., Grudpan K.
• Format: Article
• Language: English
• Published: 2014
• Online Access: http://www.scopus.com/inward/record.url?eid=2-s2.0-3042853217&partnerID=40&md5=4b5ac979a0489ce2600142117d2f83b7; http://cmuir.cmu.ac.th/handle/6653943832/4774
• Institution: Chiang Mai University

This work exploited the well-known iodine-starch reaction for development of a simple flow-injection (FI) method for determination of iodide in pharmaceutical samples. Iodide in an injected zone was oxidized to iodine. A gas diffusion unit enables selective permeation of iodine through a hydrophobic membrane. Detection was made very selective for elemental iodine by employing formation of the I3--starch complex. The detection limit (3S/N) of the system was 1mgIL-1. For a liquid patent medicine used for asthma treatment we suggested modification of the system. Direct injection of this sample, which contains a particularly high concentration level of iodide (ca. 9000 mgIL-1), can be achieved by coupling a dialysis unit to the FI system. This has increased the working range to 6000-10,000 mgIL -1 without employing complicated nanoliter injection. © Springer-Verlag 2003.