[labnetwork] H2SO4 and HF Delivery and Acceptance

[Prashant Srinivasan]

Kathy,


Could you elaborate a bit on the nature of the contamination? 
Appearance? Chemical composition? We purchase from Fisher Scientific and 
VWR.


If you are referring to crystals, especially in BHF, this is normal. The 
concentration of Ammonium Fluoride is very high, often near saturation 
and crystallization typically occurs when the temperature drops. If you 
see crystals around the cap, local evaporation is the likely cause. In 
either case, diluting slightly with DI water or bringing up the bottle 
to 23- 25 C should solve the issue. If you have a large amount of 
crystals, the chemical composition might have changed. It is hard to say 
without pictures.  Note that HF (not BHF) should not have crystals.


Prashant


On 7/2/2026 11:20 AM, Kathy Anderson wrote:
> Hello Lab Network,
>
> What is your lab's strategy to minimize the occurrence rate of 
> receiving incoming boxes of H2SO4 or HF bottles with chemical 
> contaminating the inside of the box and/or the outside of the bottles?
>
> Do you have a preferred vendor or vendors you avoid for this reason?  
> We are experiencing this phenomenon sporadically from multiple 
> vendors.  Some respond by wrapping their bottles or the rims of 
> bottles before shipping for a time, but not indefinitely, and some are 
> only willing to replace.
>
> Kathy
>
> Block U Logo 	
> *Kathy Anderson*
> */Chemical Engineer III/*
> Utah Nanofab
> The University of Utah
> O: 801-213-6555 | C: 801-440-1465
> https://www.nanofab.utah.edu
> 36 S Wasatch Drive Suite 2500
> Salt Lake City, UT 84112
> /kathy.anderson at utah.edu/
>
>
>
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-- 
Prashant Srinivasan
Teaching Cleanroom Engineer
Electrical & Computer Engineering
Univ. of California Santa Barbara
https://www.ece.ucsb.edu/department-resources/electronics-shop/tcr
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