Ion chromatography
Ion chromatography (IC) or ion-exchange chromatography is a chromatographic method for the verification of ions in liquids.
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How does ion chromatography work?
Ion chromatography is based on the principle that the ions in the sample displace their counterions in the eluent. However, these ions do not remain stationary, instead they are in turn displaced by their counterions due to the continued addition of eluent. The eluent then flushes them to the detector, by means of which the eluent's specific peaks can be identified. The sample's peaks are compared to peaks for known standards.
Ion chromatography
this is what Quality Analysis can do for you
- Qualitative and quantitative evaluation of ionic contamination: printed circuit boards, assemblies & IPC (IPC-TM-650 2.3.28/IPC-B-28)
- Verification of inorganic ions
- Routine checks on process water, cleaning baths, electroplating baths, water-mixed cooling lubricants
- Analytics in battery research/recycling
- Trace analytics
The evaluation is undertaken in accordance with established standards such as IPC TM-650 or in accordance with you own, customer-specific standards.
In a dialogue with you, our experts find the most reliable, quickest and most economical method to answer your question reliably and unambiguously. We compile all our results in a detailed test report that provides you with practical answers.
We would also be pleased to analyse your sample at short notice.
Still have questions? Then simply call us and we will provide advice without any obligation.
Ion-exchange chromatography in detail
Ion-exchange chromatography is based, like all chromatographic separation methods, on a stationary and mobile phase, the so-called eluent. For IC, the former is mostly a polymer resin these days. The selection of the mobile phase depends, above all, on whether anions or cations are to be separated. While for the separation of anions predominantly ammonium salt compounds are used, as a rule sulphonic acids are used as the eluent for the separation of cations. Independent of the selection of the eluent, it is particularly important that the separation column is filled with this eluent before injection.
After injection, the ions from the sample displace their counterions in the eluent. If the addition of eluent is continued, in turn the ions from the sample are displaced and transported by the mobile phase to the detector.
High-Performance Liquid Chromatography (HPLC)
In high-performance liquid chromatography (HPLC) the substances to be analysed are not only separated, they are also identified and quantified with the aid of standards. For the identification of an unknown substance, its retention time is compared to that of the standard. Quantification is undertaken by comparing the peak areas in the sample with those of a standard of known concentration.
Practical application of ion-exchange chromatography
Ion chromatography is used in numerous areas for the verification of contamination. In particular, ionic contamination can be separated particularly well into its individual substances using this method which is why it is a commonly used method for ensuring technical cleanliness. However, the method is also valuable in water analytics such as during the detection of undesirable leachates, for example nitrite.
The broad range of applications has ensured that ion chromatography is today indispensable in many industrial sectors (e.g. in the paper industry, petrochemicals or metal processing), and also in agriculture (e.g. for the analysis of soil samples) and in mining.
Semiconductor industry
The semiconductor industry often has to fight with ionic contamination. The cause of the contamination can be the poor quality of the water used. Other possible causes are incomplete rinsing processes, contamination of the chemicals used or the quality of the polymers. Contamination can also occur in the passivation layers. By means of ion chromatography, it is not only possible to verify, but also to analyse in detail the contamination present.
Ion chromatography is also used for continuous quality monitoring and surface qualification (for instance before the application of a coating). Potential defects (e.g. possible corrosion) can also be assessed using IC.
Electroplating industry
Routine quality control of the coating baths in the electroplating industry is also often undertaken using ion chromatography. The reaction products in the baths (for instance inorganic anions or organic acids) can also be analysed using IC.
In summary: Ion chromatography
Ion chromatography is based on the exchange of ions with a positive or negative charge. A polymer resin is used as a stationary phase, while as a rule the mobile phase is an ammonium salt compound (for the separation of anions) or a sulphonic acid (for the separation of cations).
