Silicate

ion in olyb ith s good cond g mol −1. T newautonomous silicate sensors easy to handle andwithout reagents. In this paperwepresent the analyt-ical and chemical aspects necessary for a complete documentation of the method before the development of a new reagentless sensor. 1. Introdu The com ural waters addition to the silicate ical reducti which is in [1]. Thisme uous flow s to measure ity between because of t atic salt eff seawater [8 is possible b Silicate chromatogr and in fresh cence detec for determi ∗ Correspon E-mail addction mon analytical technique to measure silicate in nat-is the spectrophotochemical method. It involves the the sample of an acidic molybdate solution to convert to a Keggin anion, SiMo12O404 − and subsequent chem-on to a mixed oxidation state, a molybdenum complex tensely blue with a maximum of absorption at 810nm thod is now frequently carried out in automated contin-ystems [2], and in situ analyzers have been developed nutrients autonomously in the ocean [3–6]. Selectiv-silicate and phosphate remains a significant problem heir very similar chemical behaviour [7], and a system-ect is present in automated nutrient determination in]. Simultaneousdeterminationofphosphate and silicate y first-derivative spectrophotometry [9]. determination was also performed by ion exclusion aphy with UV detection in leaching process waters [10] water usingflow injectionwith luminol chemilumines-tion [11]. Recently a sorption-chromatographic method ning phosphate and silicate ions in waters as molybdi