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
The spec was turned on and allowed 10min to warm up

Cuvettes were cleaned thoroughly with ethanol before being carefully rinsed with
MilliQ

The spec ran through its utilities check list and the following settings were adjusted:
o Lamp change: 380nm
o Measuring mode: ABS
o Wavelength range (nm): Start: 800, End: 250
o Scan speed: very slow
o Slit width (nm): 5
o Sampling interval (nm): 1

A baseline scan was run to ensure the background noise was between -0.005 and
0.005

The scale was set between 0 and 0.2 when analyzing samples

Four blanks were used for each session, using room temperature MilliQ in the
cuvettes:
o Baseline blank (no cuvettes)
o Blank (reference cuvette only)
o Sample blank (sample cuvette only)
o Blank + sample blank (both reference and sample cuvettes)

Cuvettes were rinsed between samples, twice with MilliQ and once with the imminent
sample

Files and data channels were saved and ASCII files exported before the cuvettes were
cleaned thoroughly and stored safely.

(I noticed that there is a difference in absorbance between samples read immediately
and those read after 24h; SXU174GB was read immediately and showed a lower
absorbance than SXU174TG, which was the same sample read 24h later. Not sure if
the difference is significant. The profile shape remained the same.)
4.12 Trace metal Iron (Fe) in seawaters: south of Atlantic Ocean (Transect
and Langangian process study)
Written by Thato Mtshali,
Key participants: Thato Mtshali, Natasha van Horsten, Bjorn von den Hyden, Raimund
Rentell