The Importance of High Purity Water for Ion Chromatography

Ion chromatography is a powerful analytical technique used to separate and quantify ions in a sample. It has become an essential tool in various industries, including environmental monitoring, Chem/Petrochem, Food and Beverage, and many others. To ensure accurate and reliable results, the use of high purity water is of utmost importance, especially in ion chromatography.

Why is High Purity Water Necessary?

In ion chromatography, the quality of water used directly affects the accuracy and sensitivity of the analysis. Impurities present in the water can interfere with the separation and detection of ions, leading to erroneous results. Equally, impure water shortens the life of guard columns, analytical columns, suppressors, and is more likely to cause baseline noise. Therefore, using high purity water is crucial to minimize any potential sources of contamination.

When it comes to high purity water, there are different levels of purity. However, for ion chromatography, the highest level of purity is required. This level of purity can only be achieved by using an EDI or RO water purification system with a polishing system on the backend then filtering the water through a 0.22 micron filter. This will produce 18.2 MegOhm water filtered prior to use. I call this UHP DI Water for the remainder of this article.

The Role of the 0.22 micron Filter

A 0.22 micron filter is commonly used in laboratories to remove particles and microorganisms from water. It is an effective filter that can eliminate most bacteria, fungi, and other contaminants, ensuring that the water is free from any potential interferences.

By passing the UHP water through a 0.22 micron filter, it not only removes particulate matter but also reduces the concentration of dissolved impurities. This filtration process helps to eliminate any potential sources of interference that could affect the accuracy and reproducibility of ion chromatography results.

The Importance of UHP Filtered Water for Standards, Check Samples, Blanks, and Reagents

In ion chromatography, standards, check samples, blanks, and reagents are essential components of the analysis. These substances serve as reference points, quality control measures, and in the reagents, the UHP insures the purest reagents possible, assuming for this article the chemicals and acids are of equal purity. It is crucial to create these components using the highest purity filtered water for the following reasons:

1. Standards:

Standards are used to calibrate the instrument and determine the concentration of ions in a sample. The accuracy of the standards directly affects the accuracy of the analysis. By creating standards with high purity filtered water, any potential contamination or interference from impurities in the water is minimized, ensuring accurate calibration and reliable results.

2. Check Samples:

Check samples are used to verify the performance of the ion chromatography system and ensure its accuracy over time. Using high purity filtered water to prepare check samples helps to eliminate any potential sources of contamination that could compromise the validity of the system's performance evaluation.

3. Blanks:

Blanks are used to measure and subtract any background signal or impurities present in the system. By creating blanks with high purity filtered water, any interference from impurities in the water is minimized, allowing for a more accurate determination of the analyte concentrations in the samples.

4. Reagents: Eluents, Regenerants, Post Column

Reagents are used in various steps of the ion chromatography analysis, such as sample preparation, eluent preparation, suppressor regeneration (in some systems), and post-column reactions. Using high purity filtered water to prepare reagents ensures that the reagents themselves do not introduce any impurities that could affect the analysis. It helps to maintain the integrity of the reagents and the accuracy of the results. As the eluent is by far the most used reagent flowing through the column, a lower quality water or non-filtered water, can contain micro-particles which can over time shorten the life of the column, increase backpressure, and increase costs.

I hope this introductory article has raised your awareness of the necessity to use only high purity water filtered through a 0.22 micron filter as essential for ion chromatography. It helps to minimize potential sources of contamination, ensuring accurate and reliable results. Creating standards, check samples, blanks, and reagents with high purity filtered water further enhances the quality and validity of the analysis. By prioritizing the use of high purity water in ion chromatography, analysts can have confidence in their results, make informed decisions based on accurate data, increase the life of their columns and suppressors, as well as reduce maintenance due to poor water quality.