Re: Stability of tritiated thymidine

[D J Hornsey <bssdjh@BATH.AC.UK>]

  Dear Arvic,

          The stability of any labelled compound depends on the solution

it is in and the temperature it is kept.

          Thymidine in water at -20 C in a storage time of 5 weeks had

decomposed by 4% in that time. In 10% ethanol, after 23 weeks it had only

decomposed by 3%. Generaly, any tritiated compound over a year old should

not be used in serious biological investigations unles you are prepared to

purify it. It will decompose into glycol and hydrates. You are correct in

that you will get HTO being formed. It's a message I try to get over to

our biological researchers who hang on to labelled organics for years in

the hope they may eventually use it in a critical experiment. They

mistakenely think that the physical half-life is the controlling

parameter. In the UK, Amersham published a review on the Self

Decomposition of radiochemicals by Evans. It may be still available from

them. It was very useful.



  Best wishes,



     David H.

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On Fri, 28 Jun 2002, Arvic Harms wrote:



> Dear all,

> 

> Does anybody has information on the stability of tritiated thymidine? I

> am aware that tritium bound to carbon is not very labile, but there may

> be a possibility that HTO will form after prolonged storage (i.e., a few

> years).

> 

> Regards,

> 

> Arvic Harms

> 

> 

> Dr Arvic Harms

> Centre for Ionising Radiation Metrology

> National Physical Laboratory

> Queens Road

> Teddington, Middlesex

> TW11 0LW

> United Kingdom

> 

> E-mail: arvic.harms@npl.co.uk

> Tel ++44 20 8943 8512

> Fax ++44 20 8614 0488

> 

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