Development of an optical-chemical sensor for the detection of ammonium ions

✍ Scribed by W. Sellien; R. Czolk; J. Reichert; H.J. Ache

• Publisher: Elsevier Science
• Year: 1992
• Tongue: English
• Weight: 495 KB
• Volume: 269
• Category: Article
• ISSN: 0003-2670
• DOI: 10.1016/0003-2670(92)85136-t

✦ Synopsis

An optsal-chemical sensor for momtormg ammomum Ions m aqueous solutions was developed The propertles of the sensor, which IS based on an lmmobdized pH mdlcator were investigated For the munoblhzat~on microporous PTFE membranes were used and the changes m the reflectance spectra were measured The detection hmlt IS dependent on the pK, value of the pH indicator used and on the pH and the temperature of the sample With p-Xylenol Blue (pK, = 2 0) the detection limit IS 1 X 10m6 mol I-' NH: (pH = 6 8, T= 22°C) The response time depends on the ammonium ion concentration and ranges from 1 to 60 mm The long-term stability of the sensors IS better than 6 months The sensor was optimized to analyse waste water wlthout pretreatment of the sample The measured ammomum ion concentration correlated well with the results obtamed by conventional analytical methods