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Do I Need to Submit a Field Blank Sample to a Lab?

by Stepan Reut

Air Sampling for Industrial Hygiene is one of a few analytical methodologies where blank use is not only recommended but often prescribed. Many consultants do not see why they need to pay for analysis of the blank samples if the results often come “non-detected”.

There are three reasons why.

Legal: To comply with the law, you need to follow the standard method. If the method says to use 2 blanks, you must use 2 blanks. If you followed the method, then nobody can question your sampling procedure.

Quality of the Results. Sometimes the sample gets contaminated after sampling is complete, often during shipping or storage. Let’s say you collected a sample of formaldehyde and shipped them to my lab in London, Ontario, Canada. We tested them and reported you results of 0.2 ug/sample. Then we tested a field blank sample (that you send us) and found that it also has 0.2 ug of formaldehyde per sample. So the true amount of formaldehyde collected at the client’s location is 0.2-0.2=0 (not detectable), and all formaldehyde that we detected is background contamination absorbed on the sampling media during shipping or storage.

Analytical Requirements. Some tests cannot be performed without the blanks, because the lab result will be biased. Those are the tests where the client expects extreme sensitivity comparable with the method sensitivity.

If you need help or training to build your successful air sampling business, please contact me by email. I offer online and in-person training and will be happy to share my expertise and 25+ years of experience

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It is my personal technical blog about laboratory business. 

All content is based on my first-hand experience of being a business entrepreneur, laboratory owner, laboratory manager, QC manager, laboratory auditor, site assessor for AIHA-LAP, and a bench chemist. 
If you like what you read here, and need my help with establishing your laboratory business in Canada or your home country, please send me a message.

Truly yours,
Stepan Reut, Ph.D.
London, Ontario, Canada
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