Measurement of total selenium and selenium(IV) in seawater by stripping chronopotentiometry.
We developed a stripping chronopotentiometric method (constant current stripping analysis, CCSA) with a mercury film electrode for selenium quantification in seawater. A sensitivity and detection limit of 222 ms ng(-1) l and 4 ng l(-1) (50 pM), respectively, were accomplished for a 3-min electrolysis time. Compared to the other chronopotentiometric methods available for a single selenium measurement only in natural waters, our procedure exhibits a ten times better sensitivity. It, therefore, allows one to reach the current concentration thresholds found in coastal and oceanic waters (30-200 ng l(-1)). Moreover, a simple change in operating conditions enables one to also quantify Se(IV), a toxic dissolved species. With respect to the other electrochemical methods of current use, our procedure is beneficial because of its ease-of-use: it needs neither degassing step, nor catalyser.
Riso
Ricardo D
RD
Laboratoire de Chimie Marine, Université de Bretagne Occidentale (IUEM), UMR CNRS 7127 Roscoff, Place Nicolas Copernic, Technopôle Brest-Iroise, 29280 Plouzané, France. riso@univ-brest.fr
Waeles
Matthieu
M
Garbarino
Sébastien
S
Le Corre
Pierre
P
D002712:Chlorides / Q000737:chemistry; D004572:Electrolysis; D006863:Hydrogen-Ion Concentration; D011199:Potentiometry / Q000379:methods*; D012623:Seawater / Q000737:chemistry*; D012643:Selenium / Q000032:analysis*; D012680:Sensitivity and Specificity; D013997:Time Factors
D002712:Chlorides; D012643:Selenium