Formaldehyde determination in seawater. Preliminary application to coastal samples at Terra Nova Bay (Antarctica).
A sensitive spectrofluorimetric-FIA (flow injection analysis) method for formaldehyde (HCHO) determination was improved with the aim of analysing seawater samples. The fluorescence emission versus HCHO concentration shows a linear pattern from sub microg L(-1) to about 1000 microg L(-1). The reproducibility at 15 ppb level is about 2%. Interferences from other aldehydes were checked; only glyoxal shows a significative interference, but only when its concentration is about 6000 times higher than that of formaldehyde. Superficial (microlayer, just sub-pack or sea-ice free sea surface) and deep (along the water column, sub-pack or in sea-ice free areas) seawater samples were collected near the coast at Terra Nova Bay (Ross Sea, Antarctica) during the 1998/1999 and 2001/2002 Italian Antarctic Expedition. We report here the preliminary results of the spectrofluorimetric-FIA determination of the HCHO content. The mean seawater superficial formaldehyde concentration was 15 microg L(-1); the concentration along the water column ranged between 4.5 to over 40 microg L(-1)(20 microg L(-1) mean concentration), usually with a maximum value for the 30 m depth, corresponding to a fluorescence maximum. The sampling was repeated 7 times in the austral summer in order to evaluate seasonal changes in the formaldehyde concentration/seawater depth profiles. The results show changes in the formaldehyde concentration at different depths.
Largiuni
O
O
Centre for Geotechnologies, University of Siena, V. Vetri Vecchi 34, I-52027, San Giovanni Valdarno (AR), Arezzo, Italy. ombretta.largiuni@unisi.it
Becagli
S
S
Innocenti
M
M
Stortini
A M
AM
Traversi
R
R
Udisti
R
R
D000864:Antarctic Regions; D004784:Environmental Monitoring / Q000379:methods; D017022:Flow Injection Analysis; D005557:Formaldehyde / Q000032:analysis*; D007053:Ice; D009792:Oceans and Seas; D010839:Phytoplankton; D012621:Seasons; D012623:Seawater / Q000032:analysis; D013050:Spectrometry, Fluorescence / Q000379:methods*; D014874:Water Pollutants, Chemical / Q000032:analysis*
D007053:Ice; D014874:Water Pollutants, Chemical; D005557:Formaldehyde