Ugh…I think we can all agree that the worst thing that can happen when testing high profile samples is losing an extract due to phthalate contamination. Whether you are extracting 525.2 or 625.1 samples, phthalates can ruin your day and wreak great havoc, causing false positives! We wonder where they all come from and how they got in the extract in the first place because we try our best to make sure our lab supplies and instruments are clean. As we all know though…phthalates are literally everywhere floating around in the air and settling on surfaces. However, I am here to talk about one place in particular: solvent squeeze bottles. We take extra precautions when refilling our squeeze bottles, but there is always the potential of introducing phthalates into them if they are not refilled or used properly.
First things first… we all know that the correct solvent squeeze bottle can be very expensive! If you are specifically looking for phthalates, you want to make sure that you have a solvent squeeze bottle that will not release phthalates when filled with solvent. Whether you are cleaning your disk holder, collection vessels, instruments, or sodium sulfate, it is imperative that your solvent squeeze bottle is made of the proper material. Not all plastics are made equal, so make sure that if you are doing extractions that quantitate phthalates, that you purchase solvent squeeze bottles made of FEP. Solvents do not leach phthalates from this material. One thing to keep in mind is FEP is not a material that we want to use for all EPA Methods. For instance, for EPA Methods 537 and 533, FEP is not the answer for you.
Another aspect to keep in mind with the solvent squeeze bottles is to make sure that when you are filling them, that the straw does not come into contact with the bench-top where it could be a contamination breeding site inhabited by a haven of dust. Something as innocent as putting the squeeze bottle cover on the bench could ruin your day, so do not do it! The phthalates on the bench-top can easily stick to the straw and when it is put back into the full solvent bottle, the solvent could then be contaminated.
Lastly, if you are using the same squeeze bottle for a wide range of concentrated extracts, there is a potential that some highly concentrated compounds could stick to the nozzle of the bottle when rinsing the collection vessel improperly. It is important that the nozzle doesn’t come into contact with the inside of the collection vessel because this will prevent compounds from a highly concentrated sample to be transferred to the less concentrated sample.
With all this new information, now it is time to make sure that you are not doing any of these!