We Do Contamination Testing On The Parts Washed With High Purity Di Water – Factors Affecting The Quality Of Ultra Pure Di Water

Can we measure the resistivity using bench top Resistivity meter or Pocket resistivity meter. We need pretty simple electrode or a flow cell is required, right? And now here is a question. What is that which is causing the variation? When we monitor my online resistivity meter the changes are much it varies from 78″ Mohms to 2 Mohms. Of course, if it’s ions why is it not detected in the contamination test. We do contamination testing on the parts washed with High purity DI water. Ions in very low concentration can cause the variation?

The result is always below detectable limit.

Please give your expertise on this, therefore this will also provide a base for knowing more about Ultra pure DI water behavior.

Please contribute as much as possible to this question.


Your application requires higherthannormal precision. Deionized water is an extremely aggressive solvent. It will dissolve anything it possibly can, when water is purified to the level you describe. You should take it into account. Ultra pure’ DI water will dissolve carbon dioxide and similar substances from contact with air, and it will begin to attack the container material -even steel or plastic. DI water. I’m almost sure I want to know more about DI water and its performance when trace contaminants are present. We do have online measurement for measuring the resistivity of DI water and have instruments to estimate the trace ionics in the DI water. That is the reason I was looking for quantitative data. Thank you very much for your valuable reply. You should take this seriously. Tim’s statement about plastics being attacked.

ABS, yes, even that ‘lowly’ material is said to be OK @ room temperature.


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