Hello Sabine,

we use 96 MTP's from Thermo Scientific for LC/MS measurements. They have a volume of 800 µL (order number: AB-0859). The plates are sealed with a heatsealer from 4titude. The foils for the heatsealer are thin aluminium foils which can be pierced by the needle of the autosampler. The foil then adheres firmly to the MTP, but can also be removed again if, for example, the plate needs to be refilled and sealed. There are also adhesive foils, but I can only advise against them. They can either not be pierced or the adhesive hangs on the needle of the injector (with all the unpleasant side effects). Solvents can also dissolve the glue and then you have all the rubbish in your system.We have been working with the above combination (MTP+Heatsealer) for years and have no problems.

Regards

Markus

Dear Sabine

I would just add to the answer from Marcus that LC-MS instruments from different manufactures often have a list of preferred plate producers. For example, Agilent and Waters give you a list of 96-well plates that will be directly accepted by the instrument, and I did not have any problems with this function. Alternatively, you can use non-listed producers, but this likely will require to customize LC-MS by precise measurement of the "unidentified plate", which is totally doable with digital caliper.

Markus Christ

Thank you very much. That is a brilliant solution to our problem. No adhesive seals for sure. They are nothing but a pain in the neck.

Albert Batushansky

Thank you. That is very true and usually applies. During the installation and introduction, I asked teh manufacturer if we can either buy it from them or if they have any recommendations. However, they don't have any and were only able to give recommendations from personal experience back from when they were PhD students. It seems you can buy barcodes for an arm and a leg which are then recognised automatically but are one-time use only...or you just tell the autosampler that it has a 96-well plate.

I would suggest testing a sample plate before committing - reference Albert Batushansky comments on fit, but also regarding chemical compatibility. It is less of an issue today, but still exists, that chemicals from the plate (less likely) or the manufacturing process (more likely) can affect your sample. Manufacturers often use mould release agents to help take the plate out of the mould, and also anti-static agents to prevent adherance of particles to the finished article. These can affect samples. In addition, complex plastics are not one thing. Polypropylene is a complex mix that the producers of the resin typically "tweak" to maintain flow properties when moulding, by adding more or less plasticiser or shorter chain polymers ... so do check before you buy!