Dionex IonPac TCC Series, Руководство по эксплуатации продукта

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IonPac TCC-LP1, TCC-ULP1, and TCC-XLP1
Product Manual Page 11 of 17
Doc. No. 034973-06 ©2005 DIONEX September 2005
3.3.1.2. Determination of the Concentrator Column Breakthrough Volume
The breakthrough volume of an analyte ion is that volume of sample which causes an ion of interest to be eluted from, rather
than retained or concentrated on, the concentrator column.
The breakthrough volume for a concentrator column is usually defined as the volume of sample necessary to elute the most
weakly retained ions of interest in the sample. The more strongly retained ions in the sample, such as NH
4
+
, can elute the
more weakly retained ions in the sample, such as Li
+
.
It is also possible for a high concentration of a weakly retained ion such as Li
+
to elute a more strongly retained ion present at
low concentration. This can occur if one is attempting to concentrate trace ions in a concentrated matrix.
The breakthrough is dependent upon several factors.
A. The volume of sample loaded.
B. The rate at which the sample is loaded.
C. The pH of the sample.
D. The ionic strength of the sample.
E. The amount and capacity of resin in the column.
The breakthrough volume is determined as follows.
A. Prepare 1 L of a solution that closely simulates the type of sample to be analyzed. For example, if the sample
contains high levels of NH
4
+
, the simulated sample should also contain NH
4
+
. The ammonium ion will act as an
eluent (E2).
B. Prepare a 1 mg/L standard of the first eluting ion of interest (e.g., Li
+
).
C. Set up the Ion Chromatograph, as shown in Figure 6, “Linearity Determinations for Concentrator Injection.”
D. Equilibrate the TCC-LP1, TCC-ULP1, or TCC-XLP1 with the eluent (E1) to be used in the analysis. Set the flow
rate necessary to achieve a stable baseline and wash the column in this manner for at least 10 minutes.
E. Switch to the simulated sample as an eluent (E2). Without delay, manually inject 50 µL of the 1 mg/L standard.
F. Record the resulting chromatogram and calculate the breakthrough volume, as shown in Figure 7, “Typical Data
Obtained in the Determination of the Breakthrough Volume.”
G. For practical purposes, the volume concentrated should be below 75% of the breakthrough volume.