It took years to figure out proper methods and many subfields have their own adjusted procedures and sometimes even statistical models. At least with DNA you could denature it very effectively, I’m not sure how they’re going to figure out the contamination issue with microplastics.
I can't imagine wafting your hands over the tubes would change the plastic amounts substantially compared to whatever negative controls the papers used. But again, I am not an expert on this kind of analytical chemistry. I always worry more about batch effects. But it does seem like microplastics are becoming the new microbiome.
But as mentioned elsewhere in the thread, everyone knows that it's possible and take measure to mitigate it.
A paper that said those mitigations were insufficient or empirically found not to work would be interesting. A paper saying "you should mitigate this" is... not very interesting.
From the article:
> They found that on average, the gloves imparted about 2,000 false positives per millimeter squared area.
I dunno, that seems like a lot of false positives. Doesn’t that strongly imply that overestimation would be a pretty likely outcome here? Sounds like a completely sterile 1mm^2 area would raise a ton of false positives because of just the gloves.
Then the tested result is Actual Sample Result - Negative Sample Result.
So you'd expect a microplastic sample to have 2,000 plus N per mm^2, and N is the result of your test.
Maybe so, but plastics are also everywhere in our daily lives, including on the food we eat and in the clothes we wear. As we speak I just took some eggs out of a plastic carton, unwrapped some cheese from plastic wrap, and got oatmeal out of a plastic bag. The socks and pants I'm wearing are made of polyester.
If plastics cause contamination in a lab, would you not also expect similar contamination outside of the lab?
When I was an automation engineer at a lab, each liquid handler alone could go through several pounds of plastic pipette tips in a single day. All of that is made out of plastic and coated in a different thin layer of plastic to change the wettability of the tip. Even the glassware often comes coated in plastic and all these coatings are the thin layers most likely to create microplastics from abrasion (like the force of the pipette picking up the tip!). Throw all the packaging on top of that and there is just an insane amount of plastic.
The only place I've seen more plastic consumed is industrial and food manufacturing where everything is sprayed and resprayed with plastic coatings to reduce fouling.