Thanks Lee.

From what I hear she was wearing a lab coat. The syringe did not have a needle affixed to the body.

Using a dropping funnel is an excellent suggestion, as is the Luer-Lok valve.

Sincerely,

-Russ

 

Russell Vernon, Ph.D.

Research Safety

Environmental Health & Safety

University of California, Riverside

900 University Ave

Riverside, CA 92521

www.ehs.ucr.edu

russell.vernon**At_Symbol_Here**ucr.edu

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Russ,

You didn’t mention a lab coat.  Did she have one on?  The amount she had in the syringe (ironic typo of “needless”?) points to poor technique in general as on that scale a dropping funnel should have been in use for addition to a reaction.  Other than having lab coats with gathered cuffs or tucking the sleeves into the gloves, there is no obvious reason for extra precautions above normal PPE.  Sleeve protectors above 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 organic 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 course, the thiols alone should mandate that handling).  The presence of the two anisoles and the dithiol may have helped to carry the TFA lower into the dermis leading to the more serious burn

This type of protecting group cleavage is common in both protein and organic chemistry.  The cocktail she was using is more common for the robot protein synthesizers, though on this scale she was either not using one or was refilling one.  The manufacturers generally 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 valve 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

Lee H. Latimer, PhD
Sr. Director, Chemical Sciences
Elan Pharmaceuticals
800 Gateway Blvd.
South San Francisco, CA 94080
650-877-7664

Hi Don,

I have seen TFA 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 gauntlets and perhaps sleeve protectors would be warranted.

Thanks,

-Russ

Russell Vernon, Ph.D.

Research Safety

Environmental Health & Safety

University of California, Riverside

900 University Ave

Riverside, CA 92521

www.ehs.ucr.edu

russell.vernon**At_Symbol_Here**ucr.edu

Direct (951) 827-5119

Admin (951) 827-5528

Fax (951) 827-5122

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