Handling of waste from Radio-HPLC.

[chayyl]

Hi

I am trying to set up a HPLC to perform analysis of radiolabeled compounds using a scintillation-based detector, typically with 13C 32P labels. My only concern is how the waste can be handled. I know with typical HPLC setup, you will have a bottle collecting a waste from the output of the detector such as UV. Security of the waste bottle is not an issue in conventional HPLC, but when the waste is radioactive (i.e. hot in radioactive terms), care needs to be taken against accidental spillage, and similar incidents.

Are there any of you out there that has experienced with performing radio-HPLC analysis, who could render advice on handling and containment of radioactive HPLC waste? Many thanks in advance.

[Mattias]

The scintillation detector I use have a switch valve after the detector cell, in order to divert the waste to either a "hot" or "cold" waste line. This switch can be controlled by the signal of the detector (e.g. send the waste to the "hot" container" when there is radioactivity is passing throught the cell). This reduces the volume of active waste to a minimum, and I have been using the same 2.5 liter "hot" waste bottle for 4 years.

The cold waste does not have to be marked radioactive, and can be treated as normal waste (beware though of the scintillation fluid itself). The hot waste is on the other hand quite radioactive, and will need to be sent to special treatment.

The whole setup is placed in a plastic "cradle" to prevent any spillage to leak on the bench or floor. Since you are working with Beta-emitters, you should not need any lead to shield the radiation.

[chayyl]

Hi Mattias,

Thanks for your suggestions. Initially, the work will involve beta emitters. But as the work and also depending on different types of projects we get, there is always the possibility of handling "hotter" radionuclides than beta-emitters. I just want to make sure we are ready for that when the time comes.

So in the case of "hot waste", do you suggest that we custom-make a lead-lined container to house the waste bottle to prevent against spillage?

[HW Mueller]

One should not work extensively with radioactivity without prior instructions by radio safety people. One should also be very familiar with the laws regarding the handling of radioactivity, especially the amounts of radioactivity involved. In Europe this is stringently controled. For instance, if you work with a certain amount of radioactivity for which the lab has not been certified you can expect severe actions. So, if you don´t know what to do with the waste or how to shield things you should not be in the business. Furthermore, you should learn more about the nature of radiation and its interaction with living things before starting. Thus I wonder what you mean when you say that you may work with radionuclides "hotter" than beta-emitters.

We also place the waste bottles in trays, but made out of stainless steel as it is easier to clean (some radioactive substances strongly adhere to plastic).

[lmh]

You are right to seek help. In fact, can I emphasise what HW Mueller has written? Most countries have extremely strict rules about radioactive work, and you absolutely must consult with someone who knows the local law. Depending on where you are, and how much radioactive material is invoved, failure to comply could mean you and/or someone in your management chain would be looking at time behind bars; the fine for your company will be truly eye-watering.

Further, it's worth having someone technically-aware on board for safety's sake. Several misconceptions have already been aired: (1) 32P is indeed only a beta emitter, but it is a very energetic one. Shielding with 32P is frequently strongly advisable; (2) Lead isn't always the shield to use. If high-energy beta particles such as are emitted by 32P run into lead, they create gamma (or X-, I can't remember) rays as they decelerate, so-called Bremmsstrahlung. Hence thinnish lead shielding can actually make the problem worse instead of better.