IonPac NS1 Manual
Document No. 034024-06
Page 4 of 35
Table 1
IonPac NS1/NG1 Packing Specifications
Column
Particle
Substrate
Diameter
X-linking
µm
%
IonPac NS1 analytical column
10
55
4 x 250 mm
IonPac NG1 guard column
10
55
4 x 35 mm
IonPac NS1-5 µm analytical column
5
55
4 x 150 mm
Always remember that assistance is available for any problem that may be encountered during the shipment or
operation of Dionex instrumentation and columns through the Dionex North America Technical Call Center at
1-800-DIONEX-0 (1-800-346-6390) or through any of the Dionex Offices.
SECTION 1 - INTRODUCTION
The IonPac
®
NS1 (10-micron packing) and the IonPac
®
NS1-5µm (5-micron packing) analytical columns are polymer-based
reversed-phase columns for the analysis of ionic and nonpolar organic compounds. The packing material is a highly cross-linked,
macroporous copolymer with a very high hydrophobic surface area. The 5-micron version provides higher efficiencies than the
10-micron version. A great advantage of polymer-based packings is their chemical inertness not only to commonly used HPLC
solvents but also to the full pH range from 0 to 14. Often organic analytes of interest to the chromatographer are ionized at neutral
pH. Ion suppression chromatography can often be used to great advantage to control the adsorption of ionizable molecules to the
column packing through eluent pH adjustments and therefore control their resulting retention times. This translates to more
resolving power and greater sensitivity. The Anion ICE II MicroMembrane Suppressor (AMMS
®
-ICE II) is a high-capacity, low
void volume dynamic eluent suppressor designed for use with ion exclusion and ion suppression separation modes of ion
chromatography.
Many analytes of interest are neither ionizable nor UV detectable. Organic and inorganic anions and cations which are not UV
detectable can be analyzed using Mobile Phase Ion Chromatography (MPIC
®
) coupled with suppressed conductivity detection.
In these analyses, ionic analytes are complexed in the mobile phase with an ion pair reagent. Separations are achieved through a
two fold mechanism. The first consideration is the degree of adsorption that takes place between the hydrophobic portion of the
ion pair reagent and the column packing. This varies with the length of the hydrophobic portion of the ion pair reagent. The second
consideration is the stability of the ion pair complex between the ion pair reagent and the analyte ion. This can be varied by the
addition of salts to the eluent.
The suppressor for Anion-MPIC is the Anion Self-Regenerating Suppressor
®
ULTRA II (ASRS ULTRA II), which is designed
to suppress tetraalkylammonium pairing reagents. Note: the Anion MicroMembrane Suppressor (AMMS III) cannot be used with
MPIC. The suppressor for Cation-MPIC is the Cation Self-Regenerating Suppressor
®
ULTRA II (CSRS ULTRA II), which can
also be used to suppress conventional cation-exchange eluents. Both the ASRS ULTRA II and CSRS ULTRA II are compatible
with typical organic solvents up to 40% by volume used in reversed-phase ion-pair chromatography. The external water mode must
be used for eluents containing organic solvent.
This manual assumes that you are familiar with the installation and operation of the Dionex Ion Chromatograph (IC). If you do
not understand the operation of the system, take the time to familiarize yourself with the various system components before
beginning an analysis.
