| Anions in concentrated and highly viscous bases?
Inline sample neutralization is the key to
eliminate this difficult sample matrix.
Metrohm offers the tried and proven "MSM"
technology for this application; but now with
a by a factor of four increased capacity: The 833
IC Liquid Handling Sample Preparation Unit or the
Prep
3 module of the Professional IC are the tools used
for this type of anion analysis. The cartridge built
into the Sample Preparation Module is packed with a
special cation exchanger.
For Metrohm, "inline" means that the system
with its integrated sample preparation steps is completely
automated. The matrix is eliminated "inline";
regeneration and rinsing are carried out in parallel
"offline". This means that the capacity of
the Sample Preparation Unit is unlimited, as after each
measurement the module is completely regenerated and
rinsed.
The automated procedure is as follows:
- A loop volume of sample is injected into a stream
of transfer solution (ultrapure water).
- When the sample passes the Sample Preparation Unit
all cations are replaced by H+. In this step all the
hydroxide ions are converted to H2O.
- The sample anions in pure water are subsequently
collected on the preconcentration column and finally
analyzed.
Sample viscosity is no problem as a peristaltic pump
is used. This is an important feature because viscous
samples of e.g. 30 % sodium hydroxide cause problems
in sample changers using the active displacement principle.
 |
A: With Metrohm Inline
Neutralization,
B: direct injection (not recommended) |
See example: Application Notes (list
for download, Info Center)
| S-126 |
Determination of anions in NaOH after
inline neutralization |
Inline neutralization of very acidic samples
The same setup as above is used. But instead of water,
a salt solution (e.g. LiCl) is used for rinsing. This
converts the cation exchanger into the Li form. After
pre-rinsing of the neutralization chamber, the acidic
sample solution will be neutralized to the corresponding
lithium salt solution.
 |
Setup |
Instruments: Metrohm Professional IC Systems with
Inline Neutralization
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MISP Overview |
