Operation
multi N/C 2100S (duo, pharma)
52
5
Operation
5.1
General notes
WARNING
Risk of chemical burns from concentrated acids
Concentrated acids are highly corrosive and sometimes have an oxidizing effect.
¡
Wear safety goggles and protective clothing when handling concentrated acids.
Work under an extractor.
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Observe all instructions and specifications in the safety data sheets.
¡
When analyzing samples with high acidic or saline content, aerosols can form in the
TIC condensation vessel. The capacity of the halogen trap is then depleted relatively
quickly. The water trap also clogs up quickly. Both components have to be replaced
frequently if this is the case. If possible, dilute such samples before measurement,
for example 1:10.
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When significant aerosol formation occurs, the analyzer is immediately protected by
the integrated aerosol trap (water trap) and the carrier gas supply is automatically
interrupted. Additionally, to protect the analyzer, remove the hose of the water trap
on the front side.
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To acidify samples, use analytically pure acid (HCl (2 mol/l)) and make it out of con-
centrated acid and TOC water.
¡
For TIC detection, only use orthophosphoric acid (H
3
PO
4
, 10 %) made from concen-
trated acid (p.a.) and TOC water.
¡
Solutions made from the following are suitable as standard solutions: Potassium hy-
drogen phthalate, sodium carbonate/sodium hydrogen carbonate, sucrose.
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Only apply the maximum indicated sample volume (50 to 500 µl) per injection. Add
samples manually only when prompted to do so by the software.
¡
Only clean, particle-free glass containers (volumetric flasks, sample vessels) may be
used for the preparation and storage of the solutions.
¡
When preparing and storing solutions with very low concentrations (<1 mg/l), ob-
serve that the laboratory air components (CO
2
, organic vapors) can change the solu-
tion concentrations. The following measures can remedy this:
– Keep the free space above liquids, the so-called headspace, as small as possible.
– During autosampler operation, cover the vessels on the sample tray with foil.
This is important in particular with differential mode, as the samples remain on
the sample tray for a longer time.
– Eliminate the source of organic vapors.
– Optionally: Fill the headspace above the samples with inert gas.
