Trace element determination in seawater by ICP-SFMS coupled with a microflow nebulization/desolvation system

Direct and simultaneous determination of Al,Ag, As, Cd, Co, Cr, Cu, Fe, Mn, Mo, Pb, Sb, U, Vand Zn in diluted (1:10 v:v) seawater from the AntarcticOcean and the Venice Lagoon at the ng mL-1and pg mL-1 level has been performed by using aninductively coupled plasma sector field mass spectrometer(ICP-SFMS). Samples were analysed by usinga PFA microflow nebulizer coupled with a desolvationsystem or a PFA microflow nebulizer coupled with aTeflon spray chamber, respectively. Measurementswere carried out at low (LR, m/Dm=300), medium(MR, m/Dm=3,000) and high (HR, m/Dm=7,500)resolutions depending on the studied isotope. To avoidcontamination, sample pre-treatment was carried outin a clean laboratory equipped with a Class 100 verticallaminar flow hood. Concentration ranges (minimum maximum in ng mL-1) found in the Antarcticseawater samples (in depth profiles) were: Ag 0.0004 0.0018, As 0.69 1.32, Cd 0.031 0.096, Co 0.018 0.065,Cr 0.18 0.46, Cu 0.04 1.58, Fe 0.13 1.63, Mn 0.02 0.12, Mo 5.97 12.46, Pb 0.007 0.074, Sb 0.033 0.088,U 0.5 1.9, V 0.6 2.5 and Zn 0.16 0.80. Concentrationranges (min max in ng mL-1) found in the VeniceLagoon water samples (temporal profile from a benthicchamber experiment) were: Al 0.24 0.61, Ag 0.007 0.031, As 1.42 2.27, Cd 0.050 0.182, Co 0.440 1.461,Cr 0.15 0.34, Cu 0.81 2.46, Fe 0.25 1.66, Mn 11.6 31.7, Mo 6.50 10.6, Pb 0.047 0.225, Sb 0.240 0.492,U 1.7 3.3, V 1.3 2.8 and Zn 5.20 21.5. The detection limits range between 0.06 pg mL-1 for Ag and U to15 pg mL-1 for Fe. In order to check the accuracy ofthe analytical procedure, measurements of the traceelements in a certified reference material (coastalAtlantic seawater, CASS-4-NRCC) were comparedwith the certified values. In addition, the results fromthe Antarctic and Venice Lagoon samples were comparedwith those obtained by using different analyticaltechniques.