A new method for nanomolar determination of silicic acid in seawater.
A novel method is proposed to determine concentrations of silicic acid in seawater in the nanomolar range of 3-500 nM. It preconcentrates silicic acid through a "Magnesium Induced Co-precipitation" (MAGIC) step before a classical spectrophotometric measurement. The detection limit (3+/-2 nM) is improved by a factor 10 in comparison to the conventional colorimetric methods. The best precision obtained to date is +/-2 nM for a natural sample of 69 nM Si. No interference of phosphate was observed by contrast to previous methods. This simple method offers a simple, sensitive and accurate tool for silicic acid determination in depleted seawater, where its availability remains unknown.
Rimmelin-Maury
Peggy
P
Laboratoire d'Océanographie et de Biogéochimie, Université de la Méditerranée, Centre d'Océanographie de Marseille (OSU), Unité Mixte de Recherche 6535-CNRS, Campus de Luminy-Case 901, Marseille Cedex 09, France. rimmelin@com.univmed.fr
Moutin
Thierry
T
Quéguiner
Bernard
B
D002138:Calibration; D002623:Chemistry Techniques, Analytical / Q000379:methods*; D003124:Colorimetry / Q000379:methods; D004784:Environmental Monitoring / Q000379:methods; D007477:Ions; D008274:Magnesium / Q000737:chemistry; D036103:Nanotechnology / Q000379:methods*; D012623:Seawater; D012680:Sensitivity and Specificity; D012824:Silicic Acid / Q000032:analysis* / Q000302:isolation & purification; D012825:Silicon / Q000032:analysis; D013053:Spectrophotometry / Q000379:methods; D014873:Water Pollutants / Q000032:analysis; D014881:Water Supply
D007477:Ions; D014873:Water Pollutants; D012824:Silicic Acid; D008274:Magnesium; D012825:Silicon