Operation; General Notes - Endress+Hauser analytikjena multi N/C UVHS Operating Manual

Operation

5 Operation
5.1

General notes

58
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.
¡ Observe all instructions and specifications in the safety data sheets.
CAUTION
Risk of poisoning from sodium persulfate
The strong oxidizing agent sodium peroxide is toxic when ingested. The salt irritates
skin, eyes and respiratory pathways. Contact can cause allergic reactions, respiratory
problems or asthma-like symptoms.
¡ Wear safety goggles and protective clothing when handling sodium persulfate. Work
under an extractor.
¡ Observe all instructions and specifications in the safety data sheet.
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.
¡ 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.
¡ To acidify samples, use analytically pure acid (H
concentrated acid and TOC water.
¡ For TIC detection, only use orthophosphoric acid (H
trated acid (p.a.) and TOC water.
For wet chemical UV digestion, prepare the following oxidant: Dissolve 80 g of
¡
sodium persulfate solution Na
one liter of TOC water. Acid concentration in the finished solution: H
¡ Solutions made from the following are suitable as standard solutions: Potassium hy-
drogen phthalate, sodium carbonate/sodium hydrogen carbonate, sucrose.
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
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.
multi N/C UVHS, multi N/C pharma UV
SO (2 mol/l)) and make it out of
2 4
PO
3
S O and 10 ml of concentrated sulfuric acid H
2 2 8
, organic vapors) can change the solu-
2
, 10 %) made from concen-
4
SO
2
SO (2 mol/l).
2 4
in
4