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General Cleaner Info: Pharmaceutical Cleaning Validation CAP Residue Detection Methods
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Thursday, September 10, 2009
Surface UV Fluorescence Detection

Question: Can UV Fluorescence be used for soil detection?

Answer:

Surface Ultraviolet (UV) Fluorescence—Many organic and some inorganic contaminants will fluoresce under UV light. Shining a UV light on the surface makes residues more visible, particularly in a slightly darkened or dark room. The higher the intensity of the light used, the lower the level of contaminants easily detected. Note, however, that the typical black light found in novelty or specialty gift stores may not be strong enough to cause much residue to fluoresce. More powerful UV lights, available from scientific supply houses or industrial suppliers, will provide far better results. The test is performed by shining the light on the surface and observing an easily seen, fluorescent—typically a yellow, orange or green, sometimes red—color which glows under the light.

Contact Alconox technical support for selecting the right aqueous critical cleaner!

Alconox, Inc manufactures a range of aqueous critical cleaners from powder to liquid, acid to alkaline, highly emulsifying to low foaming. GMP compliant brands are available globally. Downloadable certificates of analysis (COA), MSDS, technical bulletins and trace analysis from the Alconox website at www.alconox.com

(Surface UV Fluorescence Detection)

Tuesday, September 08, 2009
Nonvolatile Residue Inspection

Question: What is a nonvolatile residue inspection?

Answer:

Nonvolatile Residue Inspection (NVR)—involves extraction of soil from a dirty surface into a solvent. The solvent is then evaporated onto a coupon of known weight after the solvent is evaporated off the coupon, any residue will be deposited on the coupon. The coupon is then re-weighed and any weight increase detected is attributed to the nonvolatile residue. Many solvents can be used for this purpose. It is important to use a solvent that can dissolve the soil being detected. (Isopropyl alcohol, methylene chloride, acetone and other solvents have been used for this purpose.)

To get more information on how to measure cleanliness, contact Alconox Critical Cleaning Experts at cleaning@alconox.com

(Nonvolatile Residue Inspection)

Thursday, September 03, 2009
Water Break Test

Question:
Is a water break test similar to an atomizer test?

Answer:
Water-break test- uses running water, allowing it to form a sheet, across the surface. Breaks in the water indicate the presence of hydrophobic (water-fearing) residues. (See "The Hydrophobic Surface Film by the Water Break Test," ASTM Method F 22-65-found at astm.org) The water break test is a fairly crude test which is suitable for detecting films of process oils and heavy fingerprints. It does not readily detect non-hydrophobic residues. This test is often used for parts washing and may not be suitable for precision cleaning applications.

Atomizer test- a variation of the water-break test, involves a gently sprayed water mist. Any areas, where water repulsion occurs, indicate the presence of a hydrophobic soil. The atomizer test is slightly more sensitive to hydrophobic soils than the water break test in which the kinetic energy of the flowing water may overcome a hydrophobic residue. In contrast, the atomizer test allows you to see a small droplet of water being repelled by a hydrophobic contaminant.

With over 60 years of experience in detergent manufacturing, talk to the critical cleaning experts at Alconox to solve your most difficult cleaning challenges. Contact the Critical Cleaning Experts at cleaning@alconox.com.

(Water Break Test)

Tuesday, August 25, 2009
Tape Test

Question:
Need a simple method that will aid visual inspection?

Answer:
The Tape Test is a simple method that aids visual inspection and is well suited for testing the cleanliness of smooth metal and plastic parts. It involves attaching transparent adhesive tape to the surface being measured, firmly pressing it down, carefully removing it and then placing it on a sheet of clean white paper. Visually comparing the sample with an adjacent piece of white paper is a fast, easy way to monitor particulates and sometimes even film residues.

Need to get your hard surfaces cleaner? Alconox, Inc manufactures a range of aqueous critical cleaners from acid to alkaline, powder to liquid, highly emulsifying to low foaming. Brands are available globally with consistent formulations and are GMP compliant. Certificates of analysis, technical bulletins, MSDS, trace analysis, and inhibitory residue testing are downloadable from the Alconox website.

(Tape Test)

Friday, August 21, 2009
Measuring Cleanliness - Low Tech Detection Methods

Question:
What low tech and easy to perform detection methods can be used to measure cleanliness at 0.01 grams per square centimeter?

Answer:
Visual inspection is best used to detect residues of contrasting color or texture. Good lighting can enhance visual inspection. Magnification and fiber optic lighting, which throws light across a surface, improve detection.

Low-power microscope inspection is a quick and efficient way to verify cleanliness of residual oils and greases, flux residues, particles and surfaces.

Wiping with a white wipe provides a contrasting surface with which to detect dark residues (the white glove test).

For more information on how to measure cleanliness, request a free copy of The Aqueous Cleaning Handbook. Entire chapter dedicated to Measuring Cleanliness! To get your FREE copy, simply email request to cleaning@alconox.com.

(Measuring Cleanliness - Low Tech Detection Methods)

Thursday, August 20, 2009
Methods for Measuring Cleanliness

Question:
What methods can be used to detect cleanliness at 0.01, 0.01 to 0.001, and below 0.001 grams of soil per square centimeter?

Answer:
Depending upon method selected, cleanliness can be detected to varying degrees or levels.

Cleanliness can be detected to 0.01 grams per square centimeter levels by using visual inspection, low power microscope inspection, wiping and visual inspecting, water break tests, atomizer tests, nonvolatile residue inspection, surface UV Fluorescence detection, tape test.

The level of cleanliness typically suitable for automotive, aerospace, electrical and many surface preparations is between 0.01 to 0.001 grams per square centimeter. This level of detection can be achieved through Millipore filter measurement techniques such as optical microscopy, extraction, oil evaporation, oil soluble Fluorescence, gravimetric analysis, surface energy tests, contact angle measurement, particle counting.

The highest level of cleanliness measurement, below 1 microgram per square centimeter, is suitable for use in semiconductor, disk drive, and medical device applications. Techniques that are used for this level of precise cleanliness measurement include carbon coulometry, electron spectroscopy for chemical analysis (ESCA), Fourier transform infrared (FTIR), Gas chromatography/mass spectrophotometry (GC/MS), Ion chromatography (IC), Optically stimulated electronic emissions (OSEE), Particle counting, scanning electron microscopy (SEM) and Secondary ion mass spectroscopy (SIMS).

Need to get your surface cleaner? Need help selecting an aqueous critical cleaner to best meet you critical cleaning needs? The Critical Cleaning Experts at Alconox, Inc. can help, click here to “Ask Alconox”.

(Methods for Measuring Cleanliness)

Thursday, August 13, 2009
Cleaning parts with complex geometries

Question:
What is the best way to clean parts with complex geometries such blind holes so that optimal cleaning is achieved?

Answer:
When cleaning parts with complex geometries, you should pay particular attention to any blind hole that can trap air, particles or cleaning solution during the cleaning and rinsing process. Air trapped in a blind hole interferes with cleaning and rinsing. Blind holes that face up and trap solution can potentially trap particles and cleaning solution that would otherwise rinse away if the hole was able to drain. To clean a blind hole, you need to make sure that cleaning and rinsing fluid gets in to the hole and back out. If blind holes are all on one axis of a part, and you are cleaning under immersion such as with ultrasonics, then one way to assure this is to put the parts in with the blind holes horizontal so that they fill up with solution and release any trapped air, then under immersion, rotate the part so that the blind holes face down, which allows gravity assisted release of any particles or residues that are removed during the process. Reverse the process to remove the part from the tank to allow the cleaning solution to pour out from the blind holes in a horizontal position. Repeat for immersion rinsing, or better yet, rinse with running water being sure to flush the blind holes. If a part has blind holes on multiple axis, then for immersion cleaning, you would want to rotate the part under immersion in order to release all trapped air and fill the holes with cleaning solution. If practical, it is desirable to further rotate the part during cleaning to pause for a period of time so that each axis of blind hole faces downwards for part of the cleaning cycle. In some cases it can even be worth creating a basket or bracket system that continually rotates the parts during cleaning and rinsing if rinsing is done under immersion. For spray cleaning of parts with blind holes, you want to pay attention to the orientation of the spray to make sure it penetrates and flushes the blind hole during cleaning and rinsing.

Alconox, Inc manufacture’s a range of aqueous critical cleaners from acid to alkaline, powder to liquid, highly emulsifying to low foaming. Brands are available globally with consistent formulations and are GMP compliant. Downloadable certificates of analysis, technical bulletins, MSDS, trace analysis, and inhibitory residue testing are available from the Alconox website at Alconox.com.

(Cleaning parts with complex geometries)