Chemistry Reference
In-Depth Information
2 Experimental
2.1 Instrument
The measuring system is the oscillating bubble tensiometer, described in
detail elsewhere (Loglio et al. 1996, 1998b, 2001, Kovalchuk et al. 2001,
Miller et al. 2000). Figure 1 shows a schematic drawing of the measure-
ment assembly, which is composed of three parts: 1) the sample (20 mm x
20 mm x 40 mm) pyrex vessel, 2) the capillary (2.00 mm internal diameter
stainless-steel tube with flat tip ), 3) an air chamber with deformable walls
(made with piezoelectric discs). Possible fluidodynamic instability of the
bubble has been taken into account in the design of the bubble pneumatic
circuit.
The instrument was located inside a small onshore laboratory, at the
Municipal Aquarium of Leghorn (Italy). Measurement procedure, calibra-
tion and bubble profile processing were performed as previously described
(Loglio et al. 1996, 1998b, 2001, Kovalchuck et al. 2001, Miller et al.
2000).
Fig. 1.
Schematic diagram of the measurement assembly
2.2 Materials
Sea water samples were collected in the Tyrrhenian Sea, in front of the on-
shore laboratory.
n
-Dodecyl-dimethylphosphine oxide (DC
12
PO) was pur-
chased from Gamma-Service, Berlin. Water was doubly distilled from al-
kaline permanganate.
