How to Remove Water Spots & Oil On Laboratory Glassware

Q. We see white water spots on cleaned and depyrogenated vials. Looks to be scale from the washer. Do you have a recommended cleaning agent for vial washing? I am told that use of detergents is not an industry norm. We also have baked on process fluids (oils) and would like to know if it is an industry norm to use detergents to remove such substances from glass vials used for injectable drugs. Can you provide me any literature on the subject?

A. Use of free-rinsing, interfering residue free aqueous detergents, such as those manufacturing by Alconox, Inc. are very much industry norms.  This will cover lab and process equipment across biotech, medical device, pharma, cosmetics and scores of other industries as well.

White spots on automated washer cleaned vials is likely some variation of water spots. If any glassware or equipment is loaded in to a washer that has a geometry that tends to hold water, that will be a candidate source.  For example, an upturned cup shape such as the bottom of a graduated cylinder will hold a dose of dirty wash water which then gets spread on the other glassware by the rinse cycle.

It is very important to pay attention to how glassware and equipment is loaded in to a washer so as to minimize trapping any water from cycle to cycle – often by appropriately tilting vials, glassware and equipment, it can be oriented to drain completely and not trap dirty wash solution. 

The above is with the assumption that deionized water for rinsing is being used in your automated washer.  If you are using tap water for rinsing (or washing in some cases), then the white residues can be simply evaporated tap water that deposits calcium, magnesium and iron residues (water hardness).     

The scale/water spots from washing are typically the result of calcium, magnesium and iron hydroxide/oxide deposits that form from the alkalinity in the detergent in the wash cycle.  If deionized water is used in the wash cycle there is less likelihood of scale formation.  

If there is scale formation, water spots, white spots, etc. the use of an acid rinse cycle using Citrajet® Low-Foam Liquid Acid Cleaner/Rinse detergent will eliminate the scale buildup.  Many automated lab washers have the capability of an acid rinse cycle.  If the automated washer does not have an acid rinse system, then a periodic maintenance cycle done in an empty washer by adding Citrajet detergent to the bottom of the washer will help control scale formation in a washer.