Date: Fri, 24 Sep 2010 08:59:06 -0700
Reply-To: DCHAS-L Discussion List <DCHAS-L**At_Symbol_Here**LIST.UVM.EDU>
Sender: DCHAS-L Discussion List <DCHAS-L**At_Symbol_Here**LIST.UVM.EDU>
From: "Latimer, Lee" <Lee.Latimer**At_Symbol_Here**ELAN.COM>
Subject: Re: BOC clevage safety protocols
In-Reply-To: <006a01cb5bfa$b541a180$1fc4e480$**At_Symbol_Here**vernon**At_Symbol_Here**>


You didn’t mention a lab coat.  Did she have one on?  The amount she had in the syringe (ironic typo o f “needless”?) points to poor technique in general as on that scale a dropping funnel shou ld have been in use for addition to a reaction.  Other than having lab co ats with gathered cuffs or tucking the sleeves into the gloves, there is no obv ious reason for extra precautions above normal PPE.  Sleeve protectors abov e the elbow as are used with HF chemistry is certainly acceptable, but of a higher level than I see the need for.

TFA is indeed a vigorous liquid organi c acid in the same range as methanesulfonic acid, both of which should be handled as HCl and in ventilated situations such as a hood for all transfers (of cours e, the thiols alone should mandate that handling).  The presence of the t wo anisoles and the dithiol may have helped to carry the TFA lower into the dermis lead ing to the more serious burn

This type of protecting group cleavage is common in both protein and organic chemistry.  The cocktail she was us ing is more common for the robot protein synthesizers, though on this scale she was either not using one or was refilling one.  The manufacturers generall y sell premade cocktails, and should be providing handling instructions.  ; I’ll see if I can find a reference in Organic Synthesis for your files.

A final piece that could help prevent such occurrences that many of us use with alkyl lithium reagents is a syringe va lve between the body of the syringe and the needle (using Luer-Lok connections).  These are sold by at least Aldrich.  They prevent leaks due to accidental pressure on the barrel or general drips during transfers.


Lee H. Latimer, PhD
Sr. Director, Chemical Sciences
Elan Pharmaceuticals
800 Gateway Blvd.
South San Francisco , CA 94080

From: DCHAS-L Discussion List [mailto:DCHAS-L**At_Symbol_Here**] On Behalf Of Russell Vernon
Sent: Friday, September 24, 2010 8:11 AM
To: DCHAS-L**At_Symbol_Here**LIST.UVM.EDU
Subject: Re: [DCHAS-L] BOC c levage safety protocols

Hi Don,

I have seen TF A exposures and they never were as significant as this one is reported to be.

I believe they made the mixture themselves from the pure reagents.

I’m sure you are right that good protocols for handling corrosives should be protective. From the description of this incident, it seems the addition of long gauntl ets and perhaps sleeve protectors would be warranted.< /p>





Russell Vernon, P h.D.

Research Safety< /font>

Environmental Health & Safety

Un iversity of California, Riverside

900 University Ave

Riverside , CA 92521


Direct (951) 827-5119

Admin (951) 827-5528

Fax (951) 827-5122



From: DCHAS-L Discussion List [mailto:DCHAS-L**At_Symbol_Here**] On Behalf Of Don Abramowitz
Sent: Friday, September 24, 2010 7:23 AM
To: DCHAS-L**At_Symbol_Here**LIST.UVM.EDU
Subject: Re: [DCHAS-L] BOC c levage safety protocols

Seems to me the injury was primarily a function of the TFA (trifluoroacetic acid), whic h is a pretty aggressive corrosive material.    I would think gen eric protocols for handling corrosives would be applicable. 

My questions are:   To what extent do users understand what's in the cocktail?  If the mixture has a name of its own, does awareness of its hazardous properties get lost along the way?


Donald Abramowitz
Environmental Health & Safety Officer
Bryn Mawr College
Bryn Mawr, PA

My first question is: where was the PPE?

As for a written protocol, I would include working within a VBE  
(vent. balance enclosure), gloves and safety glasses...

I am certain others here have more feedback...


George D. McCallion
Chemist III
Chemical Process Research & Development
Johnson Matthey Pharmaceutical Materials
2003 Nolte Drive
West Deptford, NJ 08066-1742
Voice: 856.384.7255
Fax: 856.384.7186
E-Mail: medchem**At_Symbol_Here**
************************************************************************ *********

On Sep 23, 2010, at 9:38 PM, Russell Vernon wrote:

> Dear Fellow Chemists,
> A researcher at one of our sister campuses was using a needless  
> syringe filled with a solution of 36 mL TFA, 2 mL thioanisole, 1.2  
> mL ethane dithiol, and 0.8 mL anisole, She inadvertently expelled a  
> portion which impacted her elbow. She very quickly washed the   > exposure with copious water. The skin became seriously discolored  
> and it is likely the treatment will include skin grafts.
> This isn’t my area of expertise but from what I read it is a com mon  
> protecting group cleavage cocktail for protein synthesis.
> If any of you have any written procedures that would improve the   ;
> process we would appreciate getting a copy.
> Sincerely,
> -Russ
> Russell Vernon, Ph.D.
> Research Safety
> Environmental Health & Safety
> University of California, Riverside
> 900 University Ave
> Riverside, CA 92521
> russell.vernon**At_Symbol_Here**
> Direct (951) 827-5119
> Admin (951) 827-5528
> Fax (951) 827-5122

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